[v3,5/6] platform/x86: Add intel_skl_int3472 driver

ACPI devices with _HID INT3472 are currently matched to the tps68470
driver, however this does not cover all situations in which that _HID
occurs. We've encountered three possibilities:

1. On Chrome OS devices, an ACPI device with _HID INT3472 (representing
a physical TPS68470 device) that requires a GPIO and OpRegion driver
2. On devices designed for Windows, an ACPI device with _HID INT3472
(again representing a physical TPS68470 device) which requires GPIO,
Clock and Regulator drivers.
3. On other devices designed for Windows, an ACPI device with _HID
INT3472 which does **not** represent a physical TPS68470, and is instead
used as a dummy device to group some system GPIO lines which are meant
to be consumed by the sensor that is dependent on this entry.

This commit adds a new module, registering a platform driver to deal
with the 3rd scenario plus an i2c driver to deal with #1 and #2, by
querying the CLDB buffer found against INT3472 entries to determine
which is most appropriate.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Daniel Scally <djrscally@gmail.com>
---
Changes in v3:

	- Added clk_recalc_rate() operation to the clk that's registered, plus
	  some associated functions / revisions.
	- Moved source and header files to their own folder within platform/x86
	- Switched the GPIO toggling for the clock from enable/disable to
	  prepare/unprepare to avoid any sleep problems
	- Switched handling of the privacy LED GPIO from map-to-sensor to being
	  toggled along with the clk enable GPIO; register the clock in
	  intel_skl_int3472_parse_crs() instead of during handle_gpio_resources
	- Better commenting in a lot of places
	- Used the sensor_name formed from acpi_dev_name(int3472->sensor) and
	  the i2c name format macro as the dev_id in regulator init data rather
	  than hardcoding an instance name.
	- Fetched the sensor module config a single time rather than once per
	  GPIO
	- Switched int3472-tps68470 driver to use MFD framework properly rather
	  than open coding the same functionality
	- A myriad of other fixes too minor to call out.

Suggested changes (from Andy) that I didn't follow:

	- Using clk-gpio.c as a library: The requirement to add clk_recalc_rate
	so that clk_get_rate() would be supported, along with driving the
	privacy LED on clk_enable() meant this wouldn't work I think
	- Leave the MFD driver in its usual place, and prevent the INT3472 from
	probing as an i2c device from ACPI. I definitely see the argument for
	this, but in the end I think probably having all the code for the HID
	within a single place is probably a bit preferable.

 MAINTAINERS                                   |   5 +
 drivers/platform/x86/Kconfig                  |   2 +
 drivers/platform/x86/Makefile                 |   1 +
 drivers/platform/x86/intel-int3472/Kconfig    |  31 +
 drivers/platform/x86/intel-int3472/Makefile   |   4 +
 .../intel-int3472/intel_skl_int3472_common.c  | 106 ++++
 .../intel-int3472/intel_skl_int3472_common.h  | 110 ++++
 .../intel_skl_int3472_discrete.c              | 592 ++++++++++++++++++
 .../intel_skl_int3472_tps68470.c              | 113 ++++
 9 files changed, 964 insertions(+)
 create mode 100644 drivers/platform/x86/intel-int3472/Kconfig
 create mode 100644 drivers/platform/x86/intel-int3472/Makefile
 create mode 100644 drivers/platform/x86/intel-int3472/intel_skl_int3472_common.c
 create mode 100644 drivers/platform/x86/intel-int3472/intel_skl_int3472_common.h
 create mode 100644 drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c
 create mode 100644 drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c

Hi all

On 22/02/2021 13:07, Daniel Scally wrote:
> diff --git a/drivers/platform/x86/intel-int3472/Kconfig b/drivers/platform/x86/intel-int3472/Kconfig
> new file mode 100644
> index 000000000000..b94622245c21
> --- /dev/null
> +++ b/drivers/platform/x86/intel-int3472/Kconfig
> @@ -0,0 +1,31 @@
> +config INTEL_SKL_INT3472
> +	tristate "Intel SkyLake ACPI INT3472 Driver"
> +	depends on ACPI
> +	depends on REGULATOR
> +	depends on GPIOLIB
> +	depends on COMMON_CLK && CLKDEV_LOOKUP
> +	depends on I2C
> +	select MFD_CORE
> +	select REGMAP_I2C
> +	help
> +	  This driver adds support for the INT3472 ACPI devices found on some
> +	  Intel SkyLake devices.
> +
> +	  The INT3472 is an Intel camera power controller, a logical device
> +	  found on some Skylake-based systems that can map to different
> +	  hardware devices depending on the platform. On machines
> +	  designed for Chrome OS, it maps to a TPS68470 camera PMIC. On
> +	  machines designed for Windows, it maps to either a TP68470
> +	  camera PMIC, a uP6641Q sensor PMIC, or a set of discrete GPIOs
> +	  and power gates.
> +
> +	  If your device was designed for Chrome OS, this driver will provide
> +	  an ACPI OpRegion, which must be available before any of the devices
> +	  using it are probed. For this reason, you should select Y if your
> +	  device was designed for ChromeOS. For the same reason the
> +	  I2C_DESIGNWARE_PLATFORM option must be set to Y too.
> +
> +	  Say Y or M here if you have a SkyLake device designed for use
> +	  with Windows or ChromeOS. Say N here if you are not sure.
> +
> +	  The module will be named "intel-skl-int3472"
The Kconfig option for the existing tps68470 driver is a bool which
depends on I2C_DESIGNWARE_PLATFORM=y, giving the following reason:

This option is a bool as it provides an ACPI operation
region, which must be available before any of the devices
using this are probed. This option also configures the
designware-i2c driver to be built-in, for the same reason.

One problem I've faced is that that scenario only applies to some
devices that this new driver can support, so hard-coding it as built in
didn't make much sense. For that reason I opted to set it tristate, but
of course that issue still exists for ChromeOS devices where the
OpRegion will be registered. I opted for simply documenting that
requirement, as is done in aaac4a2eadaa6: "mfd: axp20x-i2c: Document
that this must be builtin on x86", but that's not entirely satisfactory.
Possible alternatives might be setting "depends on
I2C_DESIGNWARE_PLATFORM=y if CHROME_PLATFORMS" or something similar,
though of course the User would still have to realise they need to
build-in the INTEL_SKL_INT3472 Kconfig option too.

Feedback around this issue would be particularly welcome, as I'm not
sure what the best approach might be.

Hi,

On 2/22/21 2:19 PM, Daniel Scally wrote:
> Hi all
> 
> On 22/02/2021 13:07, Daniel Scally wrote:
>> diff --git a/drivers/platform/x86/intel-int3472/Kconfig b/drivers/platform/x86/intel-int3472/Kconfig
>> new file mode 100644
>> index 000000000000..b94622245c21
>> --- /dev/null
>> +++ b/drivers/platform/x86/intel-int3472/Kconfig
>> @@ -0,0 +1,31 @@
>> +config INTEL_SKL_INT3472
>> +	tristate "Intel SkyLake ACPI INT3472 Driver"
>> +	depends on ACPI
>> +	depends on REGULATOR
>> +	depends on GPIOLIB
>> +	depends on COMMON_CLK && CLKDEV_LOOKUP
>> +	depends on I2C
>> +	select MFD_CORE
>> +	select REGMAP_I2C
>> +	help
>> +	  This driver adds support for the INT3472 ACPI devices found on some
>> +	  Intel SkyLake devices.
>> +
>> +	  The INT3472 is an Intel camera power controller, a logical device
>> +	  found on some Skylake-based systems that can map to different
>> +	  hardware devices depending on the platform. On machines
>> +	  designed for Chrome OS, it maps to a TPS68470 camera PMIC. On
>> +	  machines designed for Windows, it maps to either a TP68470
>> +	  camera PMIC, a uP6641Q sensor PMIC, or a set of discrete GPIOs
>> +	  and power gates.
>> +
>> +	  If your device was designed for Chrome OS, this driver will provide
>> +	  an ACPI OpRegion, which must be available before any of the devices
>> +	  using it are probed. For this reason, you should select Y if your
>> +	  device was designed for ChromeOS. For the same reason the
>> +	  I2C_DESIGNWARE_PLATFORM option must be set to Y too.
>> +
>> +	  Say Y or M here if you have a SkyLake device designed for use
>> +	  with Windows or ChromeOS. Say N here if you are not sure.
>> +
>> +	  The module will be named "intel-skl-int3472"
> The Kconfig option for the existing tps68470 driver is a bool which
> depends on I2C_DESIGNWARE_PLATFORM=y, giving the following reason:
> 
> This option is a bool as it provides an ACPI operation
> region, which must be available before any of the devices
> using this are probed. This option also configures the
> designware-i2c driver to be built-in, for the same reason.
> 
> One problem I've faced is that that scenario only applies to some
> devices that this new driver can support, so hard-coding it as built in
> didn't make much sense. For that reason I opted to set it tristate, but
> of course that issue still exists for ChromeOS devices where the
> OpRegion will be registered. I opted for simply documenting that
> requirement, as is done in aaac4a2eadaa6: "mfd: axp20x-i2c: Document
> that this must be builtin on x86", but that's not entirely satisfactory.
> Possible alternatives might be setting "depends on
> I2C_DESIGNWARE_PLATFORM=y if CHROME_PLATFORMS" or something similar,
> though of course the User would still have to realise they need to
> build-in the INTEL_SKL_INT3472 Kconfig option too.
> 
> Feedback around this issue would be particularly welcome, as I'm not
> sure what the best approach might be.

This is a tricky area, I actually wrote the "mfd: axp20x-i2c: Document
that this must be builtin on x86" patch you refer to. At first I tried
to express the dependency in Kconfig language but things got too complex
and Kconfig sometimes became unhappy about circular deps (or something
like that).

The most important thing here is to make sure that the generic configs
shipped by distros get this right; and we can hope that people creating
those configs at least read the help text...

So all in all I believe that just documenting the requirement is fine.

The alternative would be to just change I2C_DESIGNWARE_PLATFORM (and the
core) to a bool, or at least make it not selectable as module when
X86 and ACPI are set... That would be a bit of a big hammer but might
not be the worst idea actually.

Regards,

Hans

On Mon, Feb 22, 2021 at 3:12 PM Daniel Scally <djrscally@gmail.com> wrote:
>
> ACPI devices with _HID INT3472 are currently matched to the tps68470
> driver, however this does not cover all situations in which that _HID
> occurs. We've encountered three possibilities:
>
> 1. On Chrome OS devices, an ACPI device with _HID INT3472 (representing
> a physical TPS68470 device) that requires a GPIO and OpRegion driver
> 2. On devices designed for Windows, an ACPI device with _HID INT3472
> (again representing a physical TPS68470 device) which requires GPIO,
> Clock and Regulator drivers.
> 3. On other devices designed for Windows, an ACPI device with _HID
> INT3472 which does **not** represent a physical TPS68470, and is instead
> used as a dummy device to group some system GPIO lines which are meant
> to be consumed by the sensor that is dependent on this entry.
>
> This commit adds a new module, registering a platform driver to deal
> with the 3rd scenario plus an i2c driver to deal with #1 and #2, by
> querying the CLDB buffer found against INT3472 entries to determine
> which is most appropriate.

Can you split CLK parts (and maybe regulators as well) to something
like intel_skl_int3472_clk.c?

...

> +#include <linux/acpi.h>
> +#include <linux/i2c.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>

> +               dev_err(&adev->dev, "%s object is not an ACPI buffer\n", id);

Perhaps acpi_handle_err() et al. instead of dev_*(&adev->dev, ...)
where it's applicable?

...

> +       if (obj->buffer.length > sizeof(*cldb)) {
> +               dev_err(&adev->dev, "The CLDB buffer is too large\n");
> +               ret = -EINVAL;

ENOSPC? ENOMEM?

> +               goto out_free_obj;
> +       }

...

> +static int skl_int3472_init(void)
> +{

> +       int ret = 0;

Redundant assignment.

> +       ret = platform_driver_register(&int3472_discrete);
> +       if (ret)
> +               return ret;
> +
> +       ret = i2c_register_driver(THIS_MODULE, &int3472_tps68470);
> +       if (ret)
> +               platform_driver_unregister(&int3472_discrete);

Not a fan of the above, but let's see what others will say...

> +       return ret;
> +}
> +module_init(skl_int3472_init);

...

> +#include <linux/clk-provider.h>

This is definitely not for *.h. (Not all C files needed this)

> +#include <linux/gpio/machine.h>

Ditto.

> +#include <linux/regulator/driver.h>
> +#include <linux/regulator/machine.h>

Ditto.

...

> +/*
> + * 79234640-9e10-4fea-a5c1-b5aa8b19756f
> + * This _DSM GUID returns information about the GPIO lines mapped to a
> + * discrete INT3472 device. Function number 1 returns a count of the GPIO
> + * lines that are mapped. Subsequent functions return 32 bit ints encoding
> + * information about the GPIO line, including its purpose.
> + */
> +static const guid_t int3472_gpio_guid =
> +       GUID_INIT(0x79234640, 0x9e10, 0x4fea,
> +                 0xa5, 0xc1, 0xb5, 0xaa, 0x8b, 0x19, 0x75, 0x6f);

uuid.h ?

...

> +/*
> + * The regulators have to have .ops to be valid, but the only ops we actually
> + * support are .enable and .disable which are handled via .ena_gpiod. Pass an
> + * empty struct to clear the check without lying about capabilities.
> + */
> +static const struct regulator_ops int3472_gpio_regulator_ops = { 0 };

{ 0 } is implied by the static keyword and C standard.

...

> +static int skl_int3472_clk_prepare(struct clk_hw *hw)
> +{
> +       struct int3472_gpio_clock *clk = to_int3472_clk(hw);
> +
> +       gpiod_set_value(clk->ena_gpio, 1);

> +       if (clk->led_gpio)

Make it optional and drop this check. Same for other places of use of this GPIO.

> +               gpiod_set_value(clk->led_gpio, 1);
> +
> +       return 0;
> +}

...

> +static int skl_int3472_clk_enable(struct clk_hw *hw)
> +{
> +       /*
> +        * We're just turning a GPIO on to enable, which operation has the
> +        * potential to sleep. Given enable cannot sleep, but prepare can,
> +        * we toggle the GPIO in prepare instead. Thus, nothing to do here.
> +        */

Missed . and / or  () in some words? (Describing callbacks, personally
I use the form "->callback()" in such cases)

> +       return 0;
> +}

...

> +static unsigned int skl_int3472_get_clk_frequency(struct int3472_discrete_device *int3472)
> +{
> +       union acpi_object *obj;

> +       unsigned int ret = 0;

unsigned for ret is unusual. Looking into the code, first of all it
doesn't need this assignment; second, it probably can gain a better
name: "frequency"?

> +       obj = skl_int3472_get_acpi_buffer(int3472->sensor, "SSDB");
> +       if (IS_ERR(obj))
> +               return 0; /* report rate as 0 on error */
> +
> +       if (obj->buffer.length < CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET + sizeof(u32)) {
> +               dev_err(int3472->dev, "The buffer is too small\n");
> +               goto out_free_buff;
> +       }
> +
> +       ret = *(u32 *)(obj->buffer.pointer + CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET);
> +
> +out_free_buff:
> +       kfree(obj);
> +       return ret;
> +}

...

> +       sensor_config = int3472->sensor_config;

> +       if (!IS_ERR_OR_NULL(sensor_config) && sensor_config->function_maps) {

Hmm...

Would

if (IS_ERR_OR_NULL(sensor_config))
  return 0;

if (!_maps)
  return 0;

with respective comments working here?

> +               const struct int3472_gpio_function_remap *remap =
> +                       sensor_config->function_maps;

Split assignment so we can see what is the initial for-loop iterator value.

> +               for (; remap->documented; ++remap)

remap++

> +                       if (!strcmp(func, remap->documented)) {
> +                               func = remap->actual;
> +                               break;
> +                       }
> +       }
> +
> +       /* Functions mapped to NULL should not be mapped to the sensor */
> +       if (!func)
> +               return 0;

...

> +static int skl_int3472_register_clock(struct int3472_discrete_device *int3472)
> +{
> +       struct clk_init_data init = {
> +               .ops = &skl_int3472_clock_ops,
> +               .flags = CLK_GET_RATE_NOCACHE,
> +       };
> +       int ret = 0;
> +
> +       init.name = kasprintf(GFP_KERNEL, "%s-clk",
> +                             acpi_dev_name(int3472->adev));

devm_*() ? Or is the lifetime different?

> +       if (!init.name)
> +               return -ENOMEM;
> +
> +       int3472->clock.frequency = skl_int3472_get_clk_frequency(int3472);
> +
> +       int3472->clock.clk_hw.init = &init;
> +       int3472->clock.clk = clk_register(&int3472->adev->dev,
> +                                         &int3472->clock.clk_hw);
> +       if (IS_ERR(int3472->clock.clk)) {
> +               ret = PTR_ERR(int3472->clock.clk);
> +               goto out_free_init_name;
> +       }
> +
> +       int3472->clock.cl = clkdev_create(int3472->clock.clk, NULL,
> +                                         int3472->sensor_name);
> +       if (!int3472->clock.cl) {
> +               ret = -ENOMEM;
> +               goto err_unregister_clk;
> +       }
> +
> +       goto out_free_init_name;
> +
> +err_unregister_clk:
> +       clk_unregister(int3472->clock.clk);
> +out_free_init_name:
> +       kfree(init.name);
> +
> +       return ret;
> +}

...

> +       sensor_config = int3472->sensor_config;
> +       if (IS_ERR_OR_NULL(sensor_config)) {
> +               dev_err(int3472->dev, "No sensor module config\n");

> +               return PTR_ERR(sensor_config);

NULL -> 0. Is it okay?

> +       }

...

> +       int ret = 0;

Seems redundant assignment.
...

> +       if (ares->type != ACPI_RESOURCE_TYPE_GPIO ||
> +           ares->data.gpio.connection_type != ACPI_RESOURCE_GPIO_TYPE_IO)
> +               return 1; /* Deliberately positive so parsing continues */

I don't like to lose control over ACPI_RESOURCE_TYPE_GPIO, i.e.
spreading it over kernel code (yes, I know about one existing TS
case).
Consider to provide a helper in analogue to acpi_gpio_get_irq_resource().

...

> +       if (ret < 0 && ret != -EPROBE_DEFER)
> +               dev_err(int3472->dev, err_msg);

dev_err_probe() will make the above conditional go away. And you may even do...

> +       int3472->n_gpios++;
> +       ACPI_FREE(obj);

> +       return ret;

...here

return dev_err_probe(...);

...

> +       struct list_head resource_list;

> +       INIT_LIST_HEAD(&resource_list);

LIST_HEAD(resource_list);

will do two in one.

...

> +       if (int3472->clock.ena_gpio) {

Not sure you need this here.

> +               ret = skl_int3472_register_clock(int3472);
> +               if (ret)
> +                       goto out_free_res_list;

> +       } else {
> +               if (int3472->clock.led_gpio)

Ditto.

> +                       dev_warn(int3472->dev,
> +                                "No clk GPIO. The privacy LED won't work\n");
> +       }

...

> +       /* Max num GPIOs we've seen plus a terminator */
> +       int3472 = kzalloc(struct_size(int3472, gpios.table,
> +                         INT3472_MAX_SENSOR_GPIOS + 1), GFP_KERNEL);

Wonder of you can use devm_*() APIs in this function.

> +       if (!int3472)
> +               return -ENOMEM;

...

> +       int3472->sensor = acpi_dev_get_dependent_dev(adev);
> +       if (IS_ERR_OR_NULL(int3472->sensor)) {
> +               dev_err(&pdev->dev,
> +                       "INT3472 seems to have no dependents.\n");

> +               ret = -ENODEV;

Don't shadow error code when you got IS_ERR() case.

> +               goto err_free_int3472;
> +       }

...

> +int skl_int3472_discrete_remove(struct platform_device *pdev)
> +{
> +       struct int3472_discrete_device *int3472 = platform_get_drvdata(pdev);

> +       if (int3472->gpios.dev_id)
> +               gpiod_remove_lookup_table(&int3472->gpios);

gpiod_remove_lookup_table() is now NULL-aware.
But in any case I guess you don't need the above check.

> +       if (!IS_ERR(int3472->regulator.rdev))

> +               regulator_unregister(int3472->regulator.rdev);

Shouldn't it be the pointer to the regulator itself?

> +       if (!IS_ERR(int3472->clock.clk))

If you get it optional, you won't need this additional check.

> +               clk_unregister(int3472->clock.clk);
> +
> +       if (int3472->clock.cl)
> +               clkdev_drop(int3472->clock.cl);
> +
> +       gpiod_put(int3472->regulator.gpio);
> +       gpiod_put(int3472->clock.ena_gpio);
> +       gpiod_put(int3472->clock.led_gpio);
> +
> +       acpi_dev_put(int3472->sensor);
> +
> +       kfree(int3472->sensor_name);
> +       kfree(int3472);
> +
> +       return 0;
> +}

...

> +       ret = skl_int3472_fill_cldb(adev, &cldb);
> +       if (!ret && cldb.control_logic_type != 2) {
> +               dev_err(&client->dev, "Unsupported control logic type %u\n",
> +                       cldb.control_logic_type);
> +               return -EINVAL;
> +       }
> +
> +       if (ret)
> +               cldb_present = false;

if (ret)
  ...
else if (...)  {
  ...
  return ...;
}

Hi Andy - thanks for comments!

On 22/02/2021 14:58, Andy Shevchenko wrote:
> On Mon, Feb 22, 2021 at 3:12 PM Daniel Scally <djrscally@gmail.com> wrote:
>> ACPI devices with _HID INT3472 are currently matched to the tps68470
>> driver, however this does not cover all situations in which that _HID
>> occurs. We've encountered three possibilities:
>>
>> 1. On Chrome OS devices, an ACPI device with _HID INT3472 (representing
>> a physical TPS68470 device) that requires a GPIO and OpRegion driver
>> 2. On devices designed for Windows, an ACPI device with _HID INT3472
>> (again representing a physical TPS68470 device) which requires GPIO,
>> Clock and Regulator drivers.
>> 3. On other devices designed for Windows, an ACPI device with _HID
>> INT3472 which does **not** represent a physical TPS68470, and is instead
>> used as a dummy device to group some system GPIO lines which are meant
>> to be consumed by the sensor that is dependent on this entry.
>>
>> This commit adds a new module, registering a platform driver to deal
>> with the 3rd scenario plus an i2c driver to deal with #1 and #2, by
>> querying the CLDB buffer found against INT3472 entries to determine
>> which is most appropriate.
> Can you split CLK parts (and maybe regulators as well) to something
> like intel_skl_int3472_clk.c?


Sure, no problem

>
>> +#include <linux/acpi.h>
>> +#include <linux/i2c.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/slab.h>
>> +               dev_err(&adev->dev, "%s object is not an ACPI buffer\n", id);
> Perhaps acpi_handle_err() et al. instead of dev_*(&adev->dev, ...)
> where it's applicable?


Ah - yes, ok, thanks. TIL those exist

>> +       if (obj->buffer.length > sizeof(*cldb)) {
>> +               dev_err(&adev->dev, "The CLDB buffer is too large\n");
>> +               ret = -EINVAL;
> ENOSPC? ENOMEM?


I still think EINVAL actually, as in this case the problem isn't that
space couldn't be allocated but that the buffer in the SSDB is larger
than I expect it to be, which means the definition of it has changed /
this device isn't actually supported.

>> +       ret = platform_driver_register(&int3472_discrete);
>> +       if (ret)
>> +               return ret;
>> +
>> +       ret = i2c_register_driver(THIS_MODULE, &int3472_tps68470);
>> +       if (ret)
>> +               platform_driver_unregister(&int3472_discrete);
> Not a fan of the above, but let's see what others will say...


Yeah; happy to discuss this more if needed.

>> +#include <linux/clk-provider.h>
> This is definitely not for *.h. (Not all C files needed this)
>
>> +#include <linux/gpio/machine.h>
> Ditto.
>
>> +#include <linux/regulator/driver.h>
>> +#include <linux/regulator/machine.h>
> Ditto.


Yep; I'll move them to *_clk.c and *_regulator.c files.

>> +static int skl_int3472_clk_prepare(struct clk_hw *hw)
>> +{
>> +       struct int3472_gpio_clock *clk = to_int3472_clk(hw);
>> +
>> +       gpiod_set_value(clk->ena_gpio, 1);
>> +       if (clk->led_gpio)
> Make it optional and drop this check. Same for other places of use of this GPIO.


Oops, of course, thanks

>> +static int skl_int3472_clk_enable(struct clk_hw *hw)
>> +{
>> +       /*
>> +        * We're just turning a GPIO on to enable, which operation has the
>> +        * potential to sleep. Given enable cannot sleep, but prepare can,
>> +        * we toggle the GPIO in prepare instead. Thus, nothing to do here.
>> +        */
> Missed . and / or  () in some words? (Describing callbacks, personally
> I use the form "->callback()" in such cases)


OK, I'll fix the comment to match that style.


>> +static unsigned int skl_int3472_get_clk_frequency(struct int3472_discrete_device *int3472)
>> +{
>> +       union acpi_object *obj;
>>
>> +       unsigned int ret = 0;
> unsigned for ret is unusual. Looking into the code, first of all it
> doesn't need this assignment; second, it probably can gain a better
> name: "frequency"?


Yep ok, I'll rename to freq/frequency

>> +       if (!IS_ERR_OR_NULL(sensor_config) && sensor_config->function_maps) {
> Hmm...
>
> Would
>
> if (IS_ERR_OR_NULL(sensor_config))
>   return 0;
>
> if (!_maps)
>   return 0;
>
> with respective comments working here?


No, because the absence of either sensor_config or
sensor_config->function_maps is not a failure mode. We only need to
provide sensor_configs for some platforms, and function_maps for even
fewer. So if that check is false, the rest of the function should still
execute.

>> +static int skl_int3472_register_clock(struct int3472_discrete_device *int3472)
>> +{
>> +       struct clk_init_data init = {
>> +               .ops = &skl_int3472_clock_ops,
>> +               .flags = CLK_GET_RATE_NOCACHE,
>> +       };
>> +       int ret = 0;
>> +
>> +       init.name = kasprintf(GFP_KERNEL, "%s-clk",
>> +                             acpi_dev_name(int3472->adev));
> devm_*() ? Or is the lifetime different?


No it's not; I'll use devm_*(), thanks

>> +       sensor_config = int3472->sensor_config;
>> +       if (IS_ERR_OR_NULL(sensor_config)) {
>> +               dev_err(int3472->dev, "No sensor module config\n");
>> +               return PTR_ERR(sensor_config);
> NULL -> 0. Is it okay?


Ah, no it's not - good catch thank you.

>> +       if (ares->type != ACPI_RESOURCE_TYPE_GPIO ||
>> +           ares->data.gpio.connection_type != ACPI_RESOURCE_GPIO_TYPE_IO)
>> +               return 1; /* Deliberately positive so parsing continues */
> I don't like to lose control over ACPI_RESOURCE_TYPE_GPIO, i.e.
> spreading it over kernel code (yes, I know about one existing TS
> case).
> Consider to provide a helper in analogue to acpi_gpio_get_irq_resource().


Sure, but I probably name it acpi_gpio_is_io_resource() - a function
named "get" which returns a bool seems a bit funny to me.

>> +       if (ret < 0 && ret != -EPROBE_DEFER)
>> +               dev_err(int3472->dev, err_msg);
> dev_err_probe() will make the above conditional go away. And you may even do...


Ah-ha - thought that must exist but couldn't find it - thank you.

>> +       if (int3472->clock.ena_gpio) {
> Not sure you need this here.


We haven't seen a device that lacks a clock enable GPIO it's true, but
since all the other kinds seem optional it didn't seem impossible that
that one is optional too. I can remove if you prefer and we can just
deal with it when we encounter one like that though?

>> +       /* Max num GPIOs we've seen plus a terminator */
>> +       int3472 = kzalloc(struct_size(int3472, gpios.table,
>> +                         INT3472_MAX_SENSOR_GPIOS + 1), GFP_KERNEL);
> Wonder of you can use devm_*() APIs in this function.


Yeah I can, I'll switch to that.


>> +int skl_int3472_discrete_remove(struct platform_device *pdev)
>> +{
>> +       struct int3472_discrete_device *int3472 = platform_get_drvdata(pdev);
>> +       if (int3472->gpios.dev_id)
>> +               gpiod_remove_lookup_table(&int3472->gpios);
> gpiod_remove_lookup_table() is now NULL-aware.
> But in any case I guess you don't need the above check.


Sorry; forgot to call out that I didn't follow that suggestion;
int3472->gpios is a _struct_ rather than a pointer, so &int3472->gpios
won't be NULL, even if I haven't filled anything in to there yet because
it failed before it got to that point. So, not sure that it quite works
there.

>
>> +       if (!IS_ERR(int3472->regulator.rdev))
>> +               regulator_unregister(int3472->regulator.rdev);
> Shouldn't it be the pointer to the regulator itself?
int3472->regulator is type struct int3472_gpio_regulator, the .rdev is
the normal regulator_dev


>
>> +       if (!IS_ERR(int3472->clock.clk))
> If you get it optional, you won't need this additional check.


Yes - here it will definitely work; thanks, I'll add that patch

>> +       ret = skl_int3472_fill_cldb(adev, &cldb);
>> +       if (!ret && cldb.control_logic_type != 2) {
>> +               dev_err(&client->dev, "Unsupported control logic type %u\n",
>> +                       cldb.control_logic_type);
>> +               return -EINVAL;
>> +       }
>> +
>> +       if (ret)
>> +               cldb_present = false;
> if (ret)
>   ...
> else if (...)  {
>   ...
>   return ...;
> }


Oh yeah...now you point that out I have no idea what I was thinking there...

Hi Hans, thanks for the input

On 22/02/2021 13:27, Hans de Goede wrote:
> Hi,
>
> On 2/22/21 2:19 PM, Daniel Scally wrote:
>> Hi all
>>
>> On 22/02/2021 13:07, Daniel Scally wrote:
>>> diff --git a/drivers/platform/x86/intel-int3472/Kconfig b/drivers/platform/x86/intel-int3472/Kconfig
>>> new file mode 100644
>>> index 000000000000..b94622245c21
>>> --- /dev/null
>>> +++ b/drivers/platform/x86/intel-int3472/Kconfig
>>> @@ -0,0 +1,31 @@
>>> +config INTEL_SKL_INT3472
>>> +	tristate "Intel SkyLake ACPI INT3472 Driver"
>>> +	depends on ACPI
>>> +	depends on REGULATOR
>>> +	depends on GPIOLIB
>>> +	depends on COMMON_CLK && CLKDEV_LOOKUP
>>> +	depends on I2C
>>> +	select MFD_CORE
>>> +	select REGMAP_I2C
>>> +	help
>>> +	  This driver adds support for the INT3472 ACPI devices found on some
>>> +	  Intel SkyLake devices.
>>> +
>>> +	  The INT3472 is an Intel camera power controller, a logical device
>>> +	  found on some Skylake-based systems that can map to different
>>> +	  hardware devices depending on the platform. On machines
>>> +	  designed for Chrome OS, it maps to a TPS68470 camera PMIC. On
>>> +	  machines designed for Windows, it maps to either a TP68470
>>> +	  camera PMIC, a uP6641Q sensor PMIC, or a set of discrete GPIOs
>>> +	  and power gates.
>>> +
>>> +	  If your device was designed for Chrome OS, this driver will provide
>>> +	  an ACPI OpRegion, which must be available before any of the devices
>>> +	  using it are probed. For this reason, you should select Y if your
>>> +	  device was designed for ChromeOS. For the same reason the
>>> +	  I2C_DESIGNWARE_PLATFORM option must be set to Y too.
>>> +
>>> +	  Say Y or M here if you have a SkyLake device designed for use
>>> +	  with Windows or ChromeOS. Say N here if you are not sure.
>>> +
>>> +	  The module will be named "intel-skl-int3472"
>> The Kconfig option for the existing tps68470 driver is a bool which
>> depends on I2C_DESIGNWARE_PLATFORM=y, giving the following reason:
>>
>> This option is a bool as it provides an ACPI operation
>> region, which must be available before any of the devices
>> using this are probed. This option also configures the
>> designware-i2c driver to be built-in, for the same reason.
>>
>> One problem I've faced is that that scenario only applies to some
>> devices that this new driver can support, so hard-coding it as built in
>> didn't make much sense. For that reason I opted to set it tristate, but
>> of course that issue still exists for ChromeOS devices where the
>> OpRegion will be registered. I opted for simply documenting that
>> requirement, as is done in aaac4a2eadaa6: "mfd: axp20x-i2c: Document
>> that this must be builtin on x86", but that's not entirely satisfactory.
>> Possible alternatives might be setting "depends on
>> I2C_DESIGNWARE_PLATFORM=y if CHROME_PLATFORMS" or something similar,
>> though of course the User would still have to realise they need to
>> build-in the INTEL_SKL_INT3472 Kconfig option too.
>>
>> Feedback around this issue would be particularly welcome, as I'm not
>> sure what the best approach might be.
> This is a tricky area, I actually wrote the "mfd: axp20x-i2c: Document
> that this must be builtin on x86" patch you refer to. At first I tried
> to express the dependency in Kconfig language but things got too complex
> and Kconfig sometimes became unhappy about circular deps (or something
> like that).


Yes, I had a go too; with similar results

> The most important thing here is to make sure that the generic configs
> shipped by distros get this right; and we can hope that people creating
> those configs at least read the help text...
>
> So all in all I believe that just documenting the requirement is fine.


OK - that's what I'm hoping is the consensus, as I don't think it can be
made _entirely_ seamless through dependencies or whatever anyway, in
which case documenting it seems like the cleanest approach to me.

>
> The alternative would be to just change I2C_DESIGNWARE_PLATFORM (and the
> core) to a bool, or at least make it not selectable as module when
> X86 and ACPI are set... That would be a bit of a big hammer but might
> not be the worst idea actually.
>
> Regards,
>
> Hans
>

On Mon, Feb 22, 2021 at 10:35:44PM +0000, Daniel Scally wrote:
> On 22/02/2021 14:58, Andy Shevchenko wrote:
> > On Mon, Feb 22, 2021 at 3:12 PM Daniel Scally <djrscally@gmail.com> wrote:

...

> >> +       if (obj->buffer.length > sizeof(*cldb)) {
> >> +               dev_err(&adev->dev, "The CLDB buffer is too large\n");
> >> +               ret = -EINVAL;
> > ENOSPC? ENOMEM?
> 
> I still think EINVAL actually, as in this case the problem isn't that
> space couldn't be allocated but that the buffer in the SSDB is larger
> than I expect it to be, which means the definition of it has changed /
> this device isn't actually supported.

OK!

...

> >> +       if (!IS_ERR_OR_NULL(sensor_config) && sensor_config->function_maps) {
> > Hmm...
> >
> > Would
> >
> > if (IS_ERR_OR_NULL(sensor_config))
> >   return 0;
> >
> > if (!_maps)
> >   return 0;
> >
> > with respective comments working here?
> 
> No, because the absence of either sensor_config or
> sensor_config->function_maps is not a failure mode. We only need to
> provide sensor_configs for some platforms, and function_maps for even
> fewer. So if that check is false, the rest of the function should still
> execute.

I see, thanks for elaboration.

...

> >> +       if (ares->type != ACPI_RESOURCE_TYPE_GPIO ||
> >> +           ares->data.gpio.connection_type != ACPI_RESOURCE_GPIO_TYPE_IO)
> >> +               return 1; /* Deliberately positive so parsing continues */
> > I don't like to lose control over ACPI_RESOURCE_TYPE_GPIO, i.e.
> > spreading it over kernel code (yes, I know about one existing TS
> > case).
> > Consider to provide a helper in analogue to acpi_gpio_get_irq_resource().
> 
> Sure, but I probably name it acpi_gpio_is_io_resource() - a function
> named "get" which returns a bool seems a bit funny to me.

But don't you need the resource itself?

You may extract and check resource at the same time as
acpi_gpio_get_irq_resource() does.

...

> >> +       struct int3472_discrete_device *int3472 = platform_get_drvdata(pdev);
> >> +       if (int3472->gpios.dev_id)
> >> +               gpiod_remove_lookup_table(&int3472->gpios);
> > gpiod_remove_lookup_table() is now NULL-aware.
> > But in any case I guess you don't need the above check.
> 
> Sorry; forgot to call out that I didn't follow that suggestion;
> int3472->gpios is a _struct_ rather than a pointer, so &int3472->gpios
> won't be NULL, even if I haven't filled anything in to there yet because
> it failed before it got to that point. So, not sure that it quite works
> there.

I think if you initialize the ->list member you can remove without check.

On 23/02/2021 12:01, Andy Shevchenko wrote:
>>>> +       if (ares->type != ACPI_RESOURCE_TYPE_GPIO ||
>>>> +           ares->data.gpio.connection_type != ACPI_RESOURCE_GPIO_TYPE_IO)
>>>> +               return 1; /* Deliberately positive so parsing continues */
>>> I don't like to lose control over ACPI_RESOURCE_TYPE_GPIO, i.e.
>>> spreading it over kernel code (yes, I know about one existing TS
>>> case).
>>> Consider to provide a helper in analogue to acpi_gpio_get_irq_resource().
>> Sure, but I probably name it acpi_gpio_is_io_resource() - a function
>> named "get" which returns a bool seems a bit funny to me.
> But don't you need the resource itself?
>
> You may extract and check resource at the same time as
> acpi_gpio_get_irq_resource() does.


Oh! Reading comprehension fail; I didn't notice it was returning the
pointer through agpio; you're right of course.

>
> ...
>
>>>> +       struct int3472_discrete_device *int3472 = platform_get_drvdata(pdev);
>>>> +       if (int3472->gpios.dev_id)
>>>> +               gpiod_remove_lookup_table(&int3472->gpios);
>>> gpiod_remove_lookup_table() is now NULL-aware.
>>> But in any case I guess you don't need the above check.
>> Sorry; forgot to call out that I didn't follow that suggestion;
>> int3472->gpios is a _struct_ rather than a pointer, so &int3472->gpios
>> won't be NULL, even if I haven't filled anything in to there yet because
>> it failed before it got to that point. So, not sure that it quite works
>> there.
> I think if you initialize the ->list member you can remove without check.


I'll give that a try - thanks

>

Hi Daniel,

Thank you for the patch.

On Mon, Feb 22, 2021 at 01:07:34PM +0000, Daniel Scally wrote:
> ACPI devices with _HID INT3472 are currently matched to the tps68470
> driver, however this does not cover all situations in which that _HID
> occurs. We've encountered three possibilities:
> 
> 1. On Chrome OS devices, an ACPI device with _HID INT3472 (representing
> a physical TPS68470 device) that requires a GPIO and OpRegion driver
> 2. On devices designed for Windows, an ACPI device with _HID INT3472
> (again representing a physical TPS68470 device) which requires GPIO,
> Clock and Regulator drivers.
> 3. On other devices designed for Windows, an ACPI device with _HID
> INT3472 which does **not** represent a physical TPS68470, and is instead
> used as a dummy device to group some system GPIO lines which are meant
> to be consumed by the sensor that is dependent on this entry.
> 
> This commit adds a new module, registering a platform driver to deal
> with the 3rd scenario plus an i2c driver to deal with #1 and #2, by
> querying the CLDB buffer found against INT3472 entries to determine
> which is most appropriate.
> 
> Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Signed-off-by: Daniel Scally <djrscally@gmail.com>
> ---
> Changes in v3:
> 
> 	- Added clk_recalc_rate() operation to the clk that's registered, plus
> 	  some associated functions / revisions.
> 	- Moved source and header files to their own folder within platform/x86
> 	- Switched the GPIO toggling for the clock from enable/disable to
> 	  prepare/unprepare to avoid any sleep problems
> 	- Switched handling of the privacy LED GPIO from map-to-sensor to being
> 	  toggled along with the clk enable GPIO; register the clock in
> 	  intel_skl_int3472_parse_crs() instead of during handle_gpio_resources
> 	- Better commenting in a lot of places
> 	- Used the sensor_name formed from acpi_dev_name(int3472->sensor) and
> 	  the i2c name format macro as the dev_id in regulator init data rather
> 	  than hardcoding an instance name.
> 	- Fetched the sensor module config a single time rather than once per
> 	  GPIO
> 	- Switched int3472-tps68470 driver to use MFD framework properly rather
> 	  than open coding the same functionality
> 	- A myriad of other fixes too minor to call out.
> 
> Suggested changes (from Andy) that I didn't follow:
> 
> 	- Using clk-gpio.c as a library: The requirement to add clk_recalc_rate
> 	so that clk_get_rate() would be supported, along with driving the
> 	privacy LED on clk_enable() meant this wouldn't work I think
> 	- Leave the MFD driver in its usual place, and prevent the INT3472 from
> 	probing as an i2c device from ACPI. I definitely see the argument for
> 	this, but in the end I think probably having all the code for the HID
> 	within a single place is probably a bit preferable.
> 
>  MAINTAINERS                                   |   5 +
>  drivers/platform/x86/Kconfig                  |   2 +
>  drivers/platform/x86/Makefile                 |   1 +
>  drivers/platform/x86/intel-int3472/Kconfig    |  31 +
>  drivers/platform/x86/intel-int3472/Makefile   |   4 +
>  .../intel-int3472/intel_skl_int3472_common.c  | 106 ++++
>  .../intel-int3472/intel_skl_int3472_common.h  | 110 ++++
>  .../intel_skl_int3472_discrete.c              | 592 ++++++++++++++++++
>  .../intel_skl_int3472_tps68470.c              | 113 ++++
>  9 files changed, 964 insertions(+)
>  create mode 100644 drivers/platform/x86/intel-int3472/Kconfig
>  create mode 100644 drivers/platform/x86/intel-int3472/Makefile
>  create mode 100644 drivers/platform/x86/intel-int3472/intel_skl_int3472_common.c
>  create mode 100644 drivers/platform/x86/intel-int3472/intel_skl_int3472_common.h
>  create mode 100644 drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c
>  create mode 100644 drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a091b496fdd8..cf44b3e77b90 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -9147,6 +9147,11 @@ S:	Maintained
>  F:	arch/x86/include/asm/intel_scu_ipc.h
>  F:	drivers/platform/x86/intel_scu_*
>  
> +INTEL SKYLAKE INT3472 ACPI DEVICE DRIVER
> +M:	Daniel Scally <djrscally@gmail.com>
> +S:	Maintained
> +F:	drivers/platform/x86/intel-int3472/intel_skl_int3472_*
> +
>  INTEL SPEED SELECT TECHNOLOGY
>  M:	Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
>  L:	platform-driver-x86@vger.kernel.org
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 91e6176cdfbd..9739d30951b6 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -844,6 +844,8 @@ config INTEL_CHT_INT33FE
>  	  device and CONFIG_TYPEC_FUSB302=m and CONFIG_BATTERY_MAX17042=m
>  	  for Type-C device.
>  
> +source "drivers/platform/x86/intel-int3472/Kconfig"
> +
>  config INTEL_HID_EVENT
>  	tristate "INTEL HID Event"
>  	depends on ACPI
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index 581475f59819..2293b6c3d1c2 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -86,6 +86,7 @@ obj-$(CONFIG_INTEL_HID_EVENT)		+= intel-hid.o
>  obj-$(CONFIG_INTEL_INT0002_VGPIO)	+= intel_int0002_vgpio.o
>  obj-$(CONFIG_INTEL_MENLOW)		+= intel_menlow.o
>  obj-$(CONFIG_INTEL_OAKTRAIL)		+= intel_oaktrail.o
> +obj-$(CONFIG_INTEL_SKL_INT3472)		+= intel-int3472/
>  obj-$(CONFIG_INTEL_VBTN)		+= intel-vbtn.o
>  
>  # MSI
> diff --git a/drivers/platform/x86/intel-int3472/Kconfig b/drivers/platform/x86/intel-int3472/Kconfig
> new file mode 100644
> index 000000000000..b94622245c21
> --- /dev/null
> +++ b/drivers/platform/x86/intel-int3472/Kconfig
> @@ -0,0 +1,31 @@
> +config INTEL_SKL_INT3472
> +	tristate "Intel SkyLake ACPI INT3472 Driver"
> +	depends on ACPI
> +	depends on REGULATOR
> +	depends on GPIOLIB
> +	depends on COMMON_CLK && CLKDEV_LOOKUP
> +	depends on I2C

Maybe these could be sorted alphabetically ?

> +	select MFD_CORE
> +	select REGMAP_I2C
> +	help
> +	  This driver adds support for the INT3472 ACPI devices found on some
> +	  Intel SkyLake devices.
> +
> +	  The INT3472 is an Intel camera power controller, a logical device
> +	  found on some Skylake-based systems that can map to different
> +	  hardware devices depending on the platform. On machines
> +	  designed for Chrome OS, it maps to a TPS68470 camera PMIC. On
> +	  machines designed for Windows, it maps to either a TP68470
> +	  camera PMIC, a uP6641Q sensor PMIC, or a set of discrete GPIOs
> +	  and power gates.
> +
> +	  If your device was designed for Chrome OS, this driver will provide
> +	  an ACPI OpRegion, which must be available before any of the devices
> +	  using it are probed. For this reason, you should select Y if your
> +	  device was designed for ChromeOS. For the same reason the
> +	  I2C_DESIGNWARE_PLATFORM option must be set to Y too.
> +
> +	  Say Y or M here if you have a SkyLake device designed for use
> +	  with Windows or ChromeOS. Say N here if you are not sure.
> +
> +	  The module will be named "intel-skl-int3472"
> diff --git a/drivers/platform/x86/intel-int3472/Makefile b/drivers/platform/x86/intel-int3472/Makefile
> new file mode 100644
> index 000000000000..c887ee7d52ca
> --- /dev/null
> +++ b/drivers/platform/x86/intel-int3472/Makefile
> @@ -0,0 +1,4 @@
> +obj-$(CONFIG_INTEL_SKL_INT3472)		+= intel_skl_int3472.o
> +intel_skl_int3472-objs			:= intel_skl_int3472_common.o \
> +					   intel_skl_int3472_discrete.o \
> +					   intel_skl_int3472_tps68470.o
> diff --git a/drivers/platform/x86/intel-int3472/intel_skl_int3472_common.c b/drivers/platform/x86/intel-int3472/intel_skl_int3472_common.c
> new file mode 100644
> index 000000000000..f61166b6c497
> --- /dev/null
> +++ b/drivers/platform/x86/intel-int3472/intel_skl_int3472_common.c
> @@ -0,0 +1,106 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Author: Dan Scally <djrscally@gmail.com> */
> +
> +#include <linux/acpi.h>
> +#include <linux/i2c.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#include "intel_skl_int3472_common.h"
> +
> +union acpi_object *skl_int3472_get_acpi_buffer(struct acpi_device *adev,
> +					       char *id)
> +{
> +	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> +	acpi_handle handle = adev->handle;
> +	union acpi_object *obj;
> +	acpi_status status;
> +
> +	status = acpi_evaluate_object(handle, id, NULL, &buffer);
> +	if (ACPI_FAILURE(status))
> +		return ERR_PTR(-ENODEV);
> +
> +	obj = buffer.pointer;
> +	if (!obj)
> +		return ERR_PTR(-ENODEV);
> +
> +	if (obj->type != ACPI_TYPE_BUFFER) {
> +		dev_err(&adev->dev, "%s object is not an ACPI buffer\n", id);
> +		kfree(obj);
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	return obj;
> +}
> +
> +int skl_int3472_fill_cldb(struct acpi_device *adev, struct int3472_cldb *cldb)
> +{
> +	union acpi_object *obj;
> +	int ret = 0;
> +
> +	obj = skl_int3472_get_acpi_buffer(adev, "CLDB");
> +	if (IS_ERR(obj))
> +		return PTR_ERR(obj);
> +
> +	if (obj->buffer.length > sizeof(*cldb)) {
> +		dev_err(&adev->dev, "The CLDB buffer is too large\n");
> +		ret = -EINVAL;
> +		goto out_free_obj;
> +	}
> +
> +	memcpy(cldb, obj->buffer.pointer, obj->buffer.length);
> +
> +out_free_obj:
> +	kfree(obj);
> +	return ret;
> +}
> +
> +static const struct acpi_device_id int3472_device_id[] = {
> +	{ "INT3472", 0 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(acpi, int3472_device_id);
> +
> +static struct platform_driver int3472_discrete = {
> +	.driver = {
> +		.name = "int3472-discrete",
> +		.acpi_match_table = int3472_device_id,
> +	},
> +	.probe = skl_int3472_discrete_probe,
> +	.remove = skl_int3472_discrete_remove,
> +};
> +
> +static struct i2c_driver int3472_tps68470 = {
> +	.driver = {
> +		.name = "int3472-tps68470",
> +		.acpi_match_table = int3472_device_id,
> +	},
> +	.probe_new = skl_int3472_tps68470_probe,
> +};
> +
> +static int skl_int3472_init(void)
> +{
> +	int ret = 0;
> +
> +	ret = platform_driver_register(&int3472_discrete);
> +	if (ret)
> +		return ret;
> +
> +	ret = i2c_register_driver(THIS_MODULE, &int3472_tps68470);
> +	if (ret)
> +		platform_driver_unregister(&int3472_discrete);
> +
> +	return ret;
> +}
> +module_init(skl_int3472_init);
> +
> +static void skl_int3472_exit(void)
> +{
> +	platform_driver_unregister(&int3472_discrete);
> +	i2c_del_driver(&int3472_tps68470);
> +}
> +module_exit(skl_int3472_exit);
> +
> +MODULE_DESCRIPTION("Intel SkyLake INT3472 ACPI Device Driver");
> +MODULE_AUTHOR("Daniel Scally <djrscally@gmail.com>");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/platform/x86/intel-int3472/intel_skl_int3472_common.h b/drivers/platform/x86/intel-int3472/intel_skl_int3472_common.h
> new file mode 100644
> index 000000000000..9169356cd522
> --- /dev/null
> +++ b/drivers/platform/x86/intel-int3472/intel_skl_int3472_common.h
> @@ -0,0 +1,110 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Author: Dan Scally <djrscally@gmail.com> */
> +
> +#ifndef _INTEL_SKL_INT3472_H
> +#define _INTEL_SKL_INT3472_H
> +
> +#include <linux/clk-provider.h>
> +#include <linux/gpio/machine.h>
> +#include <linux/regulator/driver.h>
> +#include <linux/regulator/machine.h>
> +#include <linux/types.h>
> +
> +/* PMIC GPIO Types */
> +#define INT3472_GPIO_TYPE_RESET					0x00
> +#define INT3472_GPIO_TYPE_POWERDOWN				0x01
> +#define INT3472_GPIO_TYPE_POWER_ENABLE				0x0b
> +#define INT3472_GPIO_TYPE_CLK_ENABLE				0x0c
> +#define INT3472_GPIO_TYPE_PRIVACY_LED				0x0d
> +
> +#define INT3472_PDEV_MAX_NAME_LEN				23
> +#define INT3472_MAX_SENSOR_GPIOS				3
> +
> +#define GPIO_REGULATOR_NAME_LENGTH				21
> +#define GPIO_REGULATOR_SUPPLY_NAME_LENGTH			9
> +
> +#define CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET			86
> +
> +#define INT3472_REGULATOR(_name, _supply, _ops)			\
> +	(const struct regulator_desc) {				\
> +		.name = _name,					\
> +		.supply_name = _supply,				\
> +		.type = REGULATOR_VOLTAGE,			\
> +		.ops = _ops,					\
> +		.owner = THIS_MODULE,				\
> +	}
> +
> +#define to_int3472_clk(hw)					\
> +	container_of(hw, struct int3472_gpio_clock, clk_hw)
> +
> +#define to_int3472_device(clk)					\
> +	container_of(clk, struct int3472_discrete_device, clock)
> +
> +struct platform_device;
> +struct i2c_client;
> +struct acpi_device;

Alphabetical order ?

> +
> +struct int3472_cldb {
> +	u8 version;
> +	/*
> +	 * control logic type
> +	 * 0: UNKNOWN
> +	 * 1: DISCRETE(CRD-D)
> +	 * 2: PMIC TPS68470
> +	 * 3: PMIC uP6641
> +	 */
> +	u8 control_logic_type;
> +	u8 control_logic_id;
> +	u8 sensor_card_sku;
> +	u8 reserved[28];
> +};
> +
> +struct int3472_gpio_function_remap {
> +	char *documented;
> +	char *actual;

const char for both ?

> +};
> +
> +struct int3472_sensor_config {
> +	const char *sensor_module_name;
> +	struct regulator_consumer_supply supply_map;
> +	const struct int3472_gpio_function_remap *function_maps;
> +};
> +
> +struct int3472_discrete_device {
> +	struct acpi_device *adev;
> +	struct device *dev;
> +	struct acpi_device *sensor;
> +	const char *sensor_name;
> +
> +	struct int3472_sensor_config *sensor_config;

const

> +
> +	struct int3472_gpio_regulator {
> +		char regulator_name[GPIO_REGULATOR_NAME_LENGTH];
> +		char supply_name[GPIO_REGULATOR_SUPPLY_NAME_LENGTH];
> +		struct gpio_desc *gpio;
> +		struct regulator_dev *rdev;
> +		struct regulator_desc rdesc;
> +	} regulator;
> +
> +	struct int3472_gpio_clock {
> +		struct clk *clk;
> +		struct clk_hw clk_hw;
> +		struct clk_lookup *cl;
> +		struct gpio_desc *ena_gpio;
> +		struct gpio_desc *led_gpio;
> +		u32 frequency;
> +	} clock;
> +
> +	unsigned int n_gpios; /* how many GPIOs have we seen */
> +	unsigned int n_sensor_gpios; /* how many have we mapped to sensor */
> +	struct gpiod_lookup_table gpios;
> +};
> +
> +int skl_int3472_discrete_probe(struct platform_device *pdev);
> +int skl_int3472_discrete_remove(struct platform_device *pdev);
> +int skl_int3472_tps68470_probe(struct i2c_client *client);
> +union acpi_object *skl_int3472_get_acpi_buffer(struct acpi_device *adev,
> +					       char *id);
> +int skl_int3472_fill_cldb(struct acpi_device *adev, struct int3472_cldb *cldb);
> +
> +#endif
> diff --git a/drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c b/drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c
> new file mode 100644
> index 000000000000..40652161bbbf
> --- /dev/null
> +++ b/drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c
> @@ -0,0 +1,592 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Author: Dan Scally <djrscally@gmail.com> */
> +
> +#include <linux/acpi.h>
> +#include <linux/clkdev.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/overflow.h>
> +#include <linux/platform_device.h>
> +#include <linux/regulator/driver.h>
> +#include <linux/slab.h>
> +
> +#include "intel_skl_int3472_common.h"
> +
> +/*
> + * 79234640-9e10-4fea-a5c1-b5aa8b19756f
> + * This _DSM GUID returns information about the GPIO lines mapped to a
> + * discrete INT3472 device. Function number 1 returns a count of the GPIO
> + * lines that are mapped. Subsequent functions return 32 bit ints encoding
> + * information about the GPIO line, including its purpose.
> + */
> +static const guid_t int3472_gpio_guid =
> +	GUID_INIT(0x79234640, 0x9e10, 0x4fea,
> +		  0xa5, 0xc1, 0xb5, 0xaa, 0x8b, 0x19, 0x75, 0x6f);
> +
> +/*
> + * 822ace8f-2814-4174-a56b-5f029fe079ee
> + * This _DSM GUID returns a string from the sensor device, which acts as a
> + * module identifier.
> + */
> +static const guid_t cio2_sensor_module_guid =
> +	GUID_INIT(0x822ace8f, 0x2814, 0x4174,
> +		  0xa5, 0x6b, 0x5f, 0x02, 0x9f, 0xe0, 0x79, 0xee);
> +
> +/*
> + * Here follows platform specific mapping information that we can pass to
> + * the functions mapping resources to the sensors. Where the sensors have
> + * a power enable pin defined in DSDT we need to provide a supply name so
> + * the sensor drivers can find the regulator. The device name will be derived
> + * from the sensor's ACPI device within the code. Optionally, we can provide a
> + * NULL terminated array of function name mappings to deal with any platform
> + * specific deviations from the documented behaviour of GPIOs.
> + *
> + * Map a GPIO function name to NULL to prevent the driver from mapping that
> + * GPIO at all.
> + */
> +
> +static const struct int3472_gpio_function_remap ov2680_gpio_function_remaps[] = {
> +	{ "reset", NULL },
> +	{ "powerdown", "reset" },
> +	{ }
> +};
> +
> +static struct int3472_sensor_config int3472_sensor_configs[] = {

This should be static const (and there will be some fallout due to that,
as skl_int3472_register_regulator() modifies the supply_map, so I think
you'll have a copy of supply_map in int3472_discrete_device).

> +	/* Lenovo Miix 510-12ISK - OV2680, Front */
> +	{ "GNDF140809R", { 0 }, ov2680_gpio_function_remaps},

Missing space before } (and below too).

> +	/* Lenovo Miix 510-12ISK - OV5648, Rear */
> +	{ "GEFF150023R", REGULATOR_SUPPLY("avdd", NULL), NULL},
> +	/* Surface Go 1&2 - OV5693, Front */
> +	{ "YHCU", REGULATOR_SUPPLY("avdd", NULL), NULL},
> +};
> +
> +/*
> + * The regulators have to have .ops to be valid, but the only ops we actually
> + * support are .enable and .disable which are handled via .ena_gpiod. Pass an
> + * empty struct to clear the check without lying about capabilities.
> + */
> +static const struct regulator_ops int3472_gpio_regulator_ops = { 0 };
> +
> +static int skl_int3472_clk_prepare(struct clk_hw *hw)
> +{
> +	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
> +
> +	gpiod_set_value(clk->ena_gpio, 1);
> +	if (clk->led_gpio)
> +		gpiod_set_value(clk->led_gpio, 1);
> +
> +	return 0;
> +}
> +
> +static void skl_int3472_clk_unprepare(struct clk_hw *hw)
> +{
> +	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
> +
> +	gpiod_set_value(clk->ena_gpio, 0);
> +	if (clk->led_gpio)
> +		gpiod_set_value(clk->led_gpio, 0);
> +}
> +
> +static int skl_int3472_clk_enable(struct clk_hw *hw)
> +{
> +	/*
> +	 * We're just turning a GPIO on to enable, which operation has the
> +	 * potential to sleep. Given enable cannot sleep, but prepare can,
> +	 * we toggle the GPIO in prepare instead. Thus, nothing to do here.
> +	 */
> +	return 0;
> +}
> +
> +static void skl_int3472_clk_disable(struct clk_hw *hw)
> +{
> +	/* Likewise, nothing to do here... */
> +}
> +
> +static unsigned int skl_int3472_get_clk_frequency(struct int3472_discrete_device *int3472)
> +{
> +	union acpi_object *obj;
> +	unsigned int ret = 0;
> +
> +	obj = skl_int3472_get_acpi_buffer(int3472->sensor, "SSDB");
> +	if (IS_ERR(obj))
> +		return 0; /* report rate as 0 on error */
> +
> +	if (obj->buffer.length < CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET + sizeof(u32)) {

Should we define an ssdb structure instead of peeking into the buffer
with an offset ?

> +		dev_err(int3472->dev, "The buffer is too small\n");
> +		goto out_free_buff;
> +	}
> +
> +	ret = *(u32 *)(obj->buffer.pointer + CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET);
> +
> +out_free_buff:
> +	kfree(obj);
> +	return ret;
> +}
> +
> +static unsigned long skl_int3472_clk_recalc_rate(struct clk_hw *hw,
> +						 unsigned long parent_rate)
> +{
> +	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
> +	struct int3472_discrete_device *int3472 = to_int3472_device(clk);
> +
> +	return int3472->clock.frequency;

Maybe just

	struct int3472_gpio_clock *clk = to_int3472_clk(hw);

	return clk->frequency;

> +}
> +
> +static const struct clk_ops skl_int3472_clock_ops = {
> +	.prepare = skl_int3472_clk_prepare,
> +	.unprepare = skl_int3472_clk_unprepare,
> +	.enable = skl_int3472_clk_enable,
> +	.disable = skl_int3472_clk_disable,
> +	.recalc_rate = skl_int3472_clk_recalc_rate,
> +};
> +
> +static struct int3472_sensor_config *
> +skl_int3472_get_sensor_module_config(struct int3472_discrete_device *int3472)
> +{
> +	struct int3472_sensor_config *ret;
> +	union acpi_object *obj;
> +	unsigned int i;
> +
> +	obj = acpi_evaluate_dsm_typed(int3472->sensor->handle,
> +				      &cio2_sensor_module_guid, 0x00,
> +				      0x01, NULL, ACPI_TYPE_STRING);
> +
> +	if (!obj) {
> +		dev_err(int3472->dev,
> +			"Failed to get sensor module string from _DSM\n");
> +		return ERR_PTR(-ENODEV);
> +	}
> +
> +	if (obj->string.type != ACPI_TYPE_STRING) {
> +		dev_err(int3472->dev,
> +			"Sensor _DSM returned a non-string value\n");
> +		ret = ERR_PTR(-EINVAL);
> +		goto out_free_obj;
> +	}
> +
> +	ret = NULL;
> +	for (i = 0; i < ARRAY_SIZE(int3472_sensor_configs); i++) {
> +		if (!strcmp(int3472_sensor_configs[i].sensor_module_name,
> +			    obj->string.pointer)) {
> +			ret = &int3472_sensor_configs[i];
> +			break;
> +		}
> +	}
> +
> +out_free_obj:
> +	ACPI_FREE(obj);
> +	return ret;
> +}
> +
> +static int skl_int3472_map_gpio_to_sensor(struct int3472_discrete_device *int3472,
> +					  struct acpi_resource *ares,
> +					  char *func, u32 polarity)
> +{
> +	char *path = ares->data.gpio.resource_source.string_ptr;
> +	const struct int3472_sensor_config *sensor_config;
> +	struct gpiod_lookup *table_entry;
> +	struct acpi_device *adev;
> +	acpi_handle handle;
> +	acpi_status status;
> +	int ret;
> +
> +	if (int3472->n_sensor_gpios >= INT3472_MAX_SENSOR_GPIOS) {
> +		dev_warn(int3472->dev, "Too many GPIOs mapped\n");
> +		return -EINVAL;
> +	}
> +
> +	sensor_config = int3472->sensor_config;
> +	if (!IS_ERR_OR_NULL(sensor_config) && sensor_config->function_maps) {
> +		const struct int3472_gpio_function_remap *remap =
> +			sensor_config->function_maps;
> +
> +		for (; remap->documented; ++remap)
> +			if (!strcmp(func, remap->documented)) {
> +				func = remap->actual;
> +				break;
> +			}

No strictly required, but I'd use curly braces for the for loop. Up to
you.

> +	}
> +
> +	/* Functions mapped to NULL should not be mapped to the sensor */
> +	if (!func)
> +		return 0;
> +
> +	status = acpi_get_handle(NULL, path, &handle);
> +	if (ACPI_FAILURE(status))
> +		return -EINVAL;
> +
> +	ret = acpi_bus_get_device(handle, &adev);
> +	if (ret)
> +		return -ENODEV;
> +
> +	table_entry = &int3472->gpios.table[int3472->n_sensor_gpios];
> +	table_entry->key = acpi_dev_name(adev);
> +	table_entry->chip_hwnum = ares->data.gpio.pin_table[0];
> +	table_entry->con_id = func;
> +	table_entry->idx = 0;
> +	table_entry->flags = polarity;
> +
> +	int3472->n_sensor_gpios++;
> +
> +	return 0;
> +}
> +
> +static int skl_int3472_map_gpio_to_clk(struct int3472_discrete_device *int3472,
> +				       struct acpi_resource *ares, u8 type)
> +{
> +	char *path = ares->data.gpio.resource_source.string_ptr;
> +	struct gpio_desc *gpio;
> +
> +	switch (type) {
> +	case INT3472_GPIO_TYPE_CLK_ENABLE:
> +		gpio = acpi_get_gpiod(path, ares->data.gpio.pin_table[0],
> +				      "int3472,clk-enable");
> +		if (IS_ERR(gpio))
> +			return (PTR_ERR(gpio));
> +
> +		int3472->clock.ena_gpio = gpio;
> +		break;
> +	case INT3472_GPIO_TYPE_PRIVACY_LED:
> +		gpio = acpi_get_gpiod(path, ares->data.gpio.pin_table[0],
> +				      "int3472,privacy-led");
> +		if (IS_ERR(gpio))
> +			return (PTR_ERR(gpio));
> +
> +		int3472->clock.led_gpio = gpio;
> +		break;
> +	default:
> +		dev_err(int3472->dev, "Invalid GPIO type 0x%hx for clock\n",
> +			type);

type being a u8, it should be %hhx, but I'd just use 0x%02x.

> +		break;
> +	}
> +
> +	return 0;
> +}
> +
> +static int skl_int3472_register_clock(struct int3472_discrete_device *int3472)
> +{
> +	struct clk_init_data init = {
> +		.ops = &skl_int3472_clock_ops,
> +		.flags = CLK_GET_RATE_NOCACHE,
> +	};
> +	int ret = 0;
> +
> +	init.name = kasprintf(GFP_KERNEL, "%s-clk",
> +			      acpi_dev_name(int3472->adev));
> +	if (!init.name)
> +		return -ENOMEM;
> +
> +	int3472->clock.frequency = skl_int3472_get_clk_frequency(int3472);
> +
> +	int3472->clock.clk_hw.init = &init;
> +	int3472->clock.clk = clk_register(&int3472->adev->dev,
> +					  &int3472->clock.clk_hw);
> +	if (IS_ERR(int3472->clock.clk)) {
> +		ret = PTR_ERR(int3472->clock.clk);
> +		goto out_free_init_name;
> +	}
> +
> +	int3472->clock.cl = clkdev_create(int3472->clock.clk, NULL,
> +					  int3472->sensor_name);
> +	if (!int3472->clock.cl) {
> +		ret = -ENOMEM;
> +		goto err_unregister_clk;
> +	}
> +
> +	goto out_free_init_name;
> +
> +err_unregister_clk:
> +	clk_unregister(int3472->clock.clk);
> +out_free_init_name:
> +	kfree(init.name);
> +
> +	return ret;
> +}
> +
> +static int skl_int3472_register_regulator(struct int3472_discrete_device *int3472,
> +					  struct acpi_resource *ares)
> +{
> +	char *path = ares->data.gpio.resource_source.string_ptr;
> +	struct int3472_sensor_config *sensor_config;
> +	struct regulator_init_data init_data = { };
> +	struct regulator_config cfg = { };
> +	int ret;
> +
> +	sensor_config = int3472->sensor_config;
> +	if (IS_ERR_OR_NULL(sensor_config)) {
> +		dev_err(int3472->dev, "No sensor module config\n");
> +		return PTR_ERR(sensor_config);
> +	}
> +
> +	if (!sensor_config->supply_map.supply) {
> +		dev_err(int3472->dev, "No supply name defined\n");
> +		return -ENODEV;
> +	}
> +
> +	init_data.constraints.valid_ops_mask = REGULATOR_CHANGE_STATUS;
> +	init_data.num_consumer_supplies = 1;
> +	sensor_config->supply_map.dev_name = int3472->sensor_name;
> +	init_data.consumer_supplies = &sensor_config->supply_map;
> +
> +	snprintf(int3472->regulator.regulator_name,
> +		 sizeof(int3472->regulator.regulator_name), "%s-regulator",
> +		 acpi_dev_name(int3472->adev));
> +	snprintf(int3472->regulator.supply_name,
> +		 GPIO_REGULATOR_SUPPLY_NAME_LENGTH, "supply-0");
> +
> +	int3472->regulator.rdesc = INT3472_REGULATOR(
> +						int3472->regulator.regulator_name,
> +						int3472->regulator.supply_name,
> +						&int3472_gpio_regulator_ops);
> +
> +	int3472->regulator.gpio = acpi_get_gpiod(path,
> +						 ares->data.gpio.pin_table[0],
> +						 "int3472,regulator");
> +	if (IS_ERR(int3472->regulator.gpio)) {
> +		dev_err(int3472->dev, "Failed to get regulator GPIO lines\n");

s/lines/line/ (sorry, it was a typo in my review of v2)

> +		return PTR_ERR(int3472->regulator.gpio);
> +	}
> +
> +	cfg.dev = &int3472->adev->dev;
> +	cfg.init_data = &init_data;
> +	cfg.ena_gpiod = int3472->regulator.gpio;
> +
> +	int3472->regulator.rdev = regulator_register(&int3472->regulator.rdesc,
> +						     &cfg);
> +	if (IS_ERR(int3472->regulator.rdev)) {
> +		ret = PTR_ERR(int3472->regulator.rdev);
> +		goto err_free_gpio;
> +	}
> +
> +	return 0;
> +
> +err_free_gpio:
> +	gpiod_put(int3472->regulator.gpio);
> +
> +	return ret;
> +}
> +
> +/**
> + * skl_int3472_handle_gpio_resources: Map PMIC resources to consuming sensor
> + * @ares: A pointer to a &struct acpi_resource
> + * @data: A pointer to a &struct int3472_discrete_device
> + *
> + * This function handles GPIO resources that are against an INT3472
> + * ACPI device, by checking the value of the corresponding _DSM entry.
> + * This will return a 32bit int, where the lowest byte represents the
> + * function of the GPIO pin:
> + *
> + * 0x00 Reset
> + * 0x01 Power down
> + * 0x0b Power enable
> + * 0x0c Clock enable
> + * 0x0d Privacy LED
> + *
> + * There are some known platform specific quirks where that does not quite
> + * hold up; for example where a pin with type 0x01 (Power down) is mapped to
> + * a sensor pin that performs a reset function or entries in _CRS and _DSM that
> + * do not actually correspond to a physical connection. These will be handled
> + * by the mapping sub-functions.
> + *
> + * GPIOs will either be mapped directly to the sensor device or else used
> + * to create clocks and regulators via the usual frameworks.
> + *
> + * Return:
> + * * 0		- When all resources found are handled properly.
> + * * -EINVAL	- If the resource is not a GPIO IO resource
> + * * -ENODEV	- If the resource has no corresponding _DSM entry
> + * * -Other	- Errors propagated from one of the sub-functions.
> + */
> +static int skl_int3472_handle_gpio_resources(struct acpi_resource *ares,
> +					     void *data)
> +{
> +	struct int3472_discrete_device *int3472 = data;
> +	u16 pin = ares->data.gpio.pin_table[0];
> +	union acpi_object *obj;
> +	char *err_msg;
> +	int ret = 0;
> +	u8 type;
> +
> +	if (ares->type != ACPI_RESOURCE_TYPE_GPIO ||
> +	    ares->data.gpio.connection_type != ACPI_RESOURCE_GPIO_TYPE_IO)
> +		return 1; /* Deliberately positive so parsing continues */
> +
> +	/*
> +	 * n_gpios + 2 because the index of this _DSM function is 1-based and
> +	 * the first function is just a count.
> +	 */
> +	obj = acpi_evaluate_dsm_typed(int3472->adev->handle,
> +				      &int3472_gpio_guid, 0x00,
> +				      int3472->n_gpios + 2,
> +				      NULL, ACPI_TYPE_INTEGER);
> +
> +	if (!obj) {
> +		dev_warn(int3472->dev, "No _DSM entry for GPIO pin %u\n", pin);
> +		return 1;
> +	}
> +
> +	type = obj->integer.value & 0xff;
> +
> +	switch (type) {
> +	case INT3472_GPIO_TYPE_RESET:
> +		ret = skl_int3472_map_gpio_to_sensor(int3472, ares, "reset",
> +						     GPIO_ACTIVE_LOW);
> +		if (ret)
> +			err_msg = "Failed to map reset pin to sensor\n";
> +
> +		break;
> +	case INT3472_GPIO_TYPE_POWERDOWN:
> +		ret = skl_int3472_map_gpio_to_sensor(int3472, ares,
> +						     "powerdown",
> +						     GPIO_ACTIVE_LOW);
> +		if (ret)
> +			err_msg = "Failed to map powerdown pin to sensor\n";
> +
> +		break;
> +	case INT3472_GPIO_TYPE_CLK_ENABLE:
> +	case INT3472_GPIO_TYPE_PRIVACY_LED:
> +		ret = skl_int3472_map_gpio_to_clk(int3472, ares, type);
> +		if (ret)
> +			err_msg = "Failed to map GPIO to clock\n";
> +
> +		break;
> +	case INT3472_GPIO_TYPE_POWER_ENABLE:
> +		ret = skl_int3472_register_regulator(int3472, ares);
> +		if (ret)
> +			err_msg = "Failed to map regulator to sensor\n";
> +
> +		break;
> +	default:
> +		dev_warn(int3472->dev,
> +			 "GPIO type 0x%02x unknown; the sensor may not work\n",
> +			 type);
> +		ret = 1;
> +		break;
> +	}
> +
> +	if (ret < 0 && ret != -EPROBE_DEFER)
> +		dev_err(int3472->dev, err_msg);
> +
> +	int3472->n_gpios++;
> +	ACPI_FREE(obj);
> +
> +	return ret;
> +}
> +
> +static int skl_int3472_parse_crs(struct int3472_discrete_device *int3472)
> +{
> +	struct list_head resource_list;
> +	int ret;
> +
> +	INIT_LIST_HEAD(&resource_list);
> +
> +	int3472->sensor_config = skl_int3472_get_sensor_module_config(int3472);

I have forgotten some of the context I'm afraid :-/ Are there valid use
cases for not checking for an error here, or should we do so and drop
the error checks in other functions above ?

> +
> +	ret = acpi_dev_get_resources(int3472->adev, &resource_list,
> +				     skl_int3472_handle_gpio_resources,
> +				     int3472);
> +	if (ret)
> +		goto out_free_res_list;
> +
> +	if (int3472->clock.ena_gpio) {
> +		ret = skl_int3472_register_clock(int3472);
> +		if (ret)
> +			goto out_free_res_list;
> +	} else {
> +		if (int3472->clock.led_gpio)
> +			dev_warn(int3472->dev,
> +				 "No clk GPIO. The privacy LED won't work\n");
> +	}
> +
> +	int3472->gpios.dev_id = int3472->sensor_name;
> +	gpiod_add_lookup_table(&int3472->gpios);
> +
> +out_free_res_list:
> +	acpi_dev_free_resource_list(&resource_list);
> +
> +	return ret;
> +}
> +
> +int skl_int3472_discrete_probe(struct platform_device *pdev)
> +{
> +	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
> +	struct int3472_discrete_device *int3472;
> +	struct int3472_cldb cldb;
> +	int ret;
> +
> +	ret = skl_int3472_fill_cldb(adev, &cldb);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Couldn't fill CLDB structure\n");
> +		return ret;
> +	}
> +
> +	if (cldb.control_logic_type != 1) {
> +		dev_err(&pdev->dev, "Unsupported control logic type %u\n",
> +			cldb.control_logic_type);
> +		return -EINVAL;
> +	}
> +
> +	/* Max num GPIOs we've seen plus a terminator */
> +	int3472 = kzalloc(struct_size(int3472, gpios.table,
> +			  INT3472_MAX_SENSOR_GPIOS + 1), GFP_KERNEL);
> +	if (!int3472)
> +		return -ENOMEM;
> +
> +	int3472->adev = adev;
> +	int3472->dev = &pdev->dev;
> +	platform_set_drvdata(pdev, int3472);
> +
> +	int3472->sensor = acpi_dev_get_dependent_dev(adev);
> +	if (IS_ERR_OR_NULL(int3472->sensor)) {
> +		dev_err(&pdev->dev,
> +			"INT3472 seems to have no dependents.\n");
> +		ret = -ENODEV;
> +		goto err_free_int3472;
> +	}
> +	get_device(&int3472->sensor->dev);

I see no corresponding put_device(), am I missing something ? I'm also
not sure why this is needed.

> +
> +	int3472->sensor_name = kasprintf(GFP_KERNEL, I2C_DEV_NAME_FORMAT,
> +					 acpi_dev_name(int3472->sensor));

This needs a NULL check.

> +
> +	ret = skl_int3472_parse_crs(int3472);
> +	if (ret) {
> +		skl_int3472_discrete_remove(pdev);
> +		return ret;
> +	}
> +
> +	return 0;
> +
> +err_free_int3472:
> +	kfree(int3472);
> +	return ret;
> +}
> +
> +int skl_int3472_discrete_remove(struct platform_device *pdev)
> +{
> +	struct int3472_discrete_device *int3472 = platform_get_drvdata(pdev);
> +
> +	if (int3472->gpios.dev_id)
> +		gpiod_remove_lookup_table(&int3472->gpios);
> +
> +	if (!IS_ERR(int3472->regulator.rdev))
> +		regulator_unregister(int3472->regulator.rdev);
> +
> +	if (!IS_ERR(int3472->clock.clk))
> +		clk_unregister(int3472->clock.clk);
> +
> +	if (int3472->clock.cl)
> +		clkdev_drop(int3472->clock.cl);
> +
> +	gpiod_put(int3472->regulator.gpio);
> +	gpiod_put(int3472->clock.ena_gpio);
> +	gpiod_put(int3472->clock.led_gpio);
> +
> +	acpi_dev_put(int3472->sensor);
> +
> +	kfree(int3472->sensor_name);
> +	kfree(int3472);
> +
> +	return 0;
> +}
> diff --git a/drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c b/drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c
> new file mode 100644
> index 000000000000..d0d2391e263f
> --- /dev/null
> +++ b/drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c
> @@ -0,0 +1,113 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Author: Dan Scally <djrscally@gmail.com> */
> +
> +#include <linux/i2c.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/tps68470.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#include "intel_skl_int3472_common.h"
> +
> +static const struct mfd_cell tps68470_c[] = {
> +	{ .name = "tps68470-gpio" },
> +	{ .name = "tps68470_pmic_opregion" },
> +};
> +
> +static const struct mfd_cell tps68470_w[] = {

Maybe more explicit names than _c and _w could be nice ?

> +	{ .name = "tps68470-gpio" },
> +	{ .name = "tps68470-clk" },
> +	{ .name = "tps68470-regulator"},

Missing space before }.

> +};
> +
> +static const struct regmap_config tps68470_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = TPS68470_REG_MAX,
> +};
> +
> +static int tps68470_chip_init(struct device *dev, struct regmap *regmap)
> +{
> +	unsigned int version;
> +	int ret;
> +
> +	/* Force software reset */
> +	ret = regmap_write(regmap, TPS68470_REG_RESET, TPS68470_REG_RESET_MASK);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_read(regmap, TPS68470_REG_REVID, &version);
> +	if (ret) {
> +		dev_err(dev, "Failed to read revision register: %d\n", ret);
> +		return ret;
> +	}
> +
> +	dev_info(dev, "TPS68470 REVID: 0x%02x\n", version);
> +
> +	return 0;
> +}
> +
> +int skl_int3472_tps68470_probe(struct i2c_client *client)
> +{
> +	struct acpi_device *adev = ACPI_COMPANION(&client->dev);
> +	struct int3472_cldb cldb = { 0 };
> +	bool cldb_present = true;
> +	struct regmap *regmap;
> +	int ret;
> +
> +	regmap = devm_regmap_init_i2c(client, &tps68470_regmap_config);
> +	if (IS_ERR(regmap)) {
> +		dev_err(&client->dev, "Failed to create regmap: %ld\n",
> +			PTR_ERR(regmap));
> +		return PTR_ERR(regmap);
> +	}
> +
> +	i2c_set_clientdata(client, regmap);
> +
> +	ret = tps68470_chip_init(&client->dev, regmap);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "TPS68470 init error %d\n", ret);
> +		return ret;
> +	}
> +
> +	/*
> +	 * Check CLDB buffer against the PMIC's adev. If present, then we check
> +	 * the value of control_logic_type field and follow one of the
> +	 * following scenarios:
> +	 *
> +	 *	1. No CLDB - likely ACPI tables designed for ChromeOS. We
> +	 *	create platform devices for the GPIOs and OpRegion drivers.
> +	 *
> +	 *	2. CLDB, with control_logic_type = 2 - probably ACPI tables
> +	 *	made for Windows 2-in-1 platforms. Register pdevs for GPIO,
> +	 *	Clock and Regulator drivers to bind to.
> +	 *
> +	 *	3. Any other value in control_logic_type, we should never have
> +	 *	gotten to this point; fail probe and return.
> +	 */
> +	ret = skl_int3472_fill_cldb(adev, &cldb);
> +	if (!ret && cldb.control_logic_type != 2) {
> +		dev_err(&client->dev, "Unsupported control logic type %u\n",
> +			cldb.control_logic_type);
> +		return -EINVAL;
> +	}
> +
> +	if (ret)
> +		cldb_present = false;
> +
> +	if (cldb_present)
> +		ret = devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_NONE,
> +					   tps68470_w, ARRAY_SIZE(tps68470_w),
> +					   NULL, 0, NULL);
> +	else
> +		ret = devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_NONE,
> +					   tps68470_c, ARRAY_SIZE(tps68470_c),
> +					   NULL, 0, NULL);
> +
> +	if (ret) {
> +		dev_err(&client->dev, "Failed to add MFD devices\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}

Hi Laurent

On 23/02/2021 20:04, Laurent Pinchart wrote:
> +
> +/*
> + * Here follows platform specific mapping information that we can pass to
> + * the functions mapping resources to the sensors. Where the sensors have
> + * a power enable pin defined in DSDT we need to provide a supply name so
> + * the sensor drivers can find the regulator. The device name will be derived
> + * from the sensor's ACPI device within the code. Optionally, we can provide a
> + * NULL terminated array of function name mappings to deal with any platform
> + * specific deviations from the documented behaviour of GPIOs.
> + *
> + * Map a GPIO function name to NULL to prevent the driver from mapping that
> + * GPIO at all.
> + */
> +
> +static const struct int3472_gpio_function_remap ov2680_gpio_function_remaps[] = {
> +	{ "reset", NULL },
> +	{ "powerdown", "reset" },
> +	{ }
> +};
> +
> +static struct int3472_sensor_config int3472_sensor_configs[] = {
> This should be static const (and there will be some fallout due to that,
> as skl_int3472_register_regulator() modifies the supply_map, so I think
> you'll have a copy of supply_map in int3472_discrete_device).


Ack to all of the constness; you mentioned that last time too - not sure
how I missed doing those! I think I can just having a local struct
regulator_consumer_supply in skl_int3472_register_regulator and fill it
from int3472->sensor_config.supply_map

>> +static unsigned int skl_int3472_get_clk_frequency(struct int3472_discrete_device *int3472)
>> +{
>> +	union acpi_object *obj;
>> +	unsigned int ret = 0;
>> +
>> +	obj = skl_int3472_get_acpi_buffer(int3472->sensor, "SSDB");
>> +	if (IS_ERR(obj))
>> +		return 0; /* report rate as 0 on error */
>> +
>> +	if (obj->buffer.length < CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET + sizeof(u32)) {
> Should we define an ssdb structure instead of peeking into the buffer
> with an offset ?


I thought about that, but in the end decided it didn't seem worth
defining the whole SSDB structure just to use one field. Particularly
since we use it in cio2-bridge already, so if we're going to do that it
really ought to just live in a header that's included in both - and that
seemed even less worthwhile.


I don't have a strong feeling though, so if you think it's better to
define the struct I'm happy to.


>> +static unsigned long skl_int3472_clk_recalc_rate(struct clk_hw *hw,
>> +						 unsigned long parent_rate)
>> +{
>> +	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
>> +	struct int3472_discrete_device *int3472 = to_int3472_device(clk);
>> +
>> +	return int3472->clock.frequency;
> Maybe just
>
> 	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
>
> 	return clk->frequency;


Oops, of course.

>> +static int skl_int3472_register_regulator(struct int3472_discrete_device *int3472,
>> +					  struct acpi_resource *ares)
>> +{
>> +	char *path = ares->data.gpio.resource_source.string_ptr;
>> +	struct int3472_sensor_config *sensor_config;
>> +	struct regulator_init_data init_data = { };
>> +	struct regulator_config cfg = { };
>> +	int ret;
>> +
>> +	sensor_config = int3472->sensor_config;
>> +	if (IS_ERR_OR_NULL(sensor_config)) {
>> +		dev_err(int3472->dev, "No sensor module config\n");
>> +		return PTR_ERR(sensor_config);
>> +	}
>> +
>> +	if (!sensor_config->supply_map.supply) {
>> +		dev_err(int3472->dev, "No supply name defined\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	init_data.constraints.valid_ops_mask = REGULATOR_CHANGE_STATUS;
>> +	init_data.num_consumer_supplies = 1;
>> +	sensor_config->supply_map.dev_name = int3472->sensor_name;
>> +	init_data.consumer_supplies = &sensor_config->supply_map;
>> +
>> +	snprintf(int3472->regulator.regulator_name,
>> +		 sizeof(int3472->regulator.regulator_name), "%s-regulator",
>> +		 acpi_dev_name(int3472->adev));
>> +	snprintf(int3472->regulator.supply_name,
>> +		 GPIO_REGULATOR_SUPPLY_NAME_LENGTH, "supply-0");
>> +
>> +	int3472->regulator.rdesc = INT3472_REGULATOR(
>> +						int3472->regulator.regulator_name,
>> +						int3472->regulator.supply_name,
>> +						&int3472_gpio_regulator_ops);
>> +
>> +	int3472->regulator.gpio = acpi_get_gpiod(path,
>> +						 ares->data.gpio.pin_table[0],
>> +						 "int3472,regulator");
>> +	if (IS_ERR(int3472->regulator.gpio)) {
>> +		dev_err(int3472->dev, "Failed to get regulator GPIO lines\n");
> s/lines/line/ (sorry, it was a typo in my review of v2)


No problem!

>> +static int skl_int3472_parse_crs(struct int3472_discrete_device *int3472)
>> +{
>> +	struct list_head resource_list;
>> +	int ret;
>> +
>> +	INIT_LIST_HEAD(&resource_list);
>> +
>> +	int3472->sensor_config = skl_int3472_get_sensor_module_config(int3472);
> I have forgotten some of the context I'm afraid :-/ Are there valid use
> cases for not checking for an error here, or should we do so and drop
> the error checks in other functions above ?


Not all platforms need a sensor_config; only those which have either a
regulator pin or need a GPIO function to be remapped; the rest will do
without it.

So, we need to not check for an error here because the absence of a
sensor_config isn't necessarily an error, we won't know till later.

> +int skl_int3472_discrete_probe(struct platform_device *pdev)
> +{
> +	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
> +	struct int3472_discrete_device *int3472;
> +	struct int3472_cldb cldb;
> +	int ret;
> +
> +	ret = skl_int3472_fill_cldb(adev, &cldb);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Couldn't fill CLDB structure\n");
> +		return ret;
> +	}
> +
> +	if (cldb.control_logic_type != 1) {
> +		dev_err(&pdev->dev, "Unsupported control logic type %u\n",
> +			cldb.control_logic_type);
> +		return -EINVAL;
> +	}
> +
> +	/* Max num GPIOs we've seen plus a terminator */
> +	int3472 = kzalloc(struct_size(int3472, gpios.table,
> +			  INT3472_MAX_SENSOR_GPIOS + 1), GFP_KERNEL);
> +	if (!int3472)
> +		return -ENOMEM;
> +
> +	int3472->adev = adev;
> +	int3472->dev = &pdev->dev;
> +	platform_set_drvdata(pdev, int3472);
> +
> +	int3472->sensor = acpi_dev_get_dependent_dev(adev);
> +	if (IS_ERR_OR_NULL(int3472->sensor)) {
> +		dev_err(&pdev->dev,
> +			"INT3472 seems to have no dependents.\n");
> +		ret = -ENODEV;
> +		goto err_free_int3472;
> +	}
> +	get_device(&int3472->sensor->dev);
> I see no corresponding put_device(), am I missing something ? I'm also
> not sure why this is needed.
>

The put is acpi_dev_put() in skl_int3472_discrete_remove(); there seems
to be no acpi_dev_get() for some reason. We use the sensor acpi_device
to get the clock frequency, and to fetch the sensor module string, so I
thought it ought to hold a reference on those grounds.


>> diff --git a/drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c b/drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c
>> new file mode 100644
>> index 000000000000..d0d2391e263f
>> --- /dev/null
>> +++ b/drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c
>> @@ -0,0 +1,113 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/* Author: Dan Scally <djrscally@gmail.com> */
>> +
>> +#include <linux/i2c.h>
>> +#include <linux/mfd/core.h>
>> +#include <linux/mfd/tps68470.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regmap.h>
>> +
>> +#include "intel_skl_int3472_common.h"
>> +
>> +static const struct mfd_cell tps68470_c[] = {
>> +	{ .name = "tps68470-gpio" },
>> +	{ .name = "tps68470_pmic_opregion" },
>> +};
>> +
>> +static const struct mfd_cell tps68470_w[] = {
> Maybe more explicit names than _c and _w could be nice ?


_chrome and _windows was in my mind - sound ok?

Hi Daniel,

On Tue, Feb 23, 2021 at 10:36:18PM +0000, Daniel Scally wrote:
> On 23/02/2021 20:04, Laurent Pinchart wrote:
> >> +
> >> +/*
> >> + * Here follows platform specific mapping information that we can pass to
> >> + * the functions mapping resources to the sensors. Where the sensors have
> >> + * a power enable pin defined in DSDT we need to provide a supply name so
> >> + * the sensor drivers can find the regulator. The device name will be derived
> >> + * from the sensor's ACPI device within the code. Optionally, we can provide a
> >> + * NULL terminated array of function name mappings to deal with any platform
> >> + * specific deviations from the documented behaviour of GPIOs.
> >> + *
> >> + * Map a GPIO function name to NULL to prevent the driver from mapping that
> >> + * GPIO at all.
> >> + */
> >> +
> >> +static const struct int3472_gpio_function_remap ov2680_gpio_function_remaps[] = {
> >> +	{ "reset", NULL },
> >> +	{ "powerdown", "reset" },
> >> +	{ }
> >> +};
> >> +
> >> +static struct int3472_sensor_config int3472_sensor_configs[] = {
> >
> > This should be static const (and there will be some fallout due to that,
> > as skl_int3472_register_regulator() modifies the supply_map, so I think
> > you'll have a copy of supply_map in int3472_discrete_device).
> 
> Ack to all of the constness; you mentioned that last time too - not sure
> how I missed doing those! I think I can just having a local struct
> regulator_consumer_supply in skl_int3472_register_regulator and fill it
> from int3472->sensor_config.supply_map
> 
> >> +static unsigned int skl_int3472_get_clk_frequency(struct int3472_discrete_device *int3472)
> >> +{
> >> +	union acpi_object *obj;
> >> +	unsigned int ret = 0;
> >> +
> >> +	obj = skl_int3472_get_acpi_buffer(int3472->sensor, "SSDB");
> >> +	if (IS_ERR(obj))
> >> +		return 0; /* report rate as 0 on error */
> >> +
> >> +	if (obj->buffer.length < CIO2_SENSOR_SSDB_MCLKSPEED_OFFSET + sizeof(u32)) {
> >
> > Should we define an ssdb structure instead of peeking into the buffer
> > with an offset ?
> 
> I thought about that, but in the end decided it didn't seem worth
> defining the whole SSDB structure just to use one field. Particularly
> since we use it in cio2-bridge already, so if we're going to do that it
> really ought to just live in a header that's included in both - and that
> seemed even less worthwhile.
> 
> I don't have a strong feeling though, so if you think it's better to
> define the struct I'm happy to.

If the structure is available already, sharing it in a common header
would be best I think, but that's not a blocker. It can be done on top
of this series.

> >> +static unsigned long skl_int3472_clk_recalc_rate(struct clk_hw *hw,
> >> +						 unsigned long parent_rate)
> >> +{
> >> +	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
> >> +	struct int3472_discrete_device *int3472 = to_int3472_device(clk);
> >> +
> >> +	return int3472->clock.frequency;
> >
> > Maybe just
> >
> > 	struct int3472_gpio_clock *clk = to_int3472_clk(hw);
> >
> > 	return clk->frequency;
> 
> Oops, of course.
> 
> >> +static int skl_int3472_register_regulator(struct int3472_discrete_device *int3472,
> >> +					  struct acpi_resource *ares)
> >> +{
> >> +	char *path = ares->data.gpio.resource_source.string_ptr;
> >> +	struct int3472_sensor_config *sensor_config;
> >> +	struct regulator_init_data init_data = { };
> >> +	struct regulator_config cfg = { };
> >> +	int ret;
> >> +
> >> +	sensor_config = int3472->sensor_config;
> >> +	if (IS_ERR_OR_NULL(sensor_config)) {
> >> +		dev_err(int3472->dev, "No sensor module config\n");
> >> +		return PTR_ERR(sensor_config);
> >> +	}
> >> +
> >> +	if (!sensor_config->supply_map.supply) {
> >> +		dev_err(int3472->dev, "No supply name defined\n");
> >> +		return -ENODEV;
> >> +	}
> >> +
> >> +	init_data.constraints.valid_ops_mask = REGULATOR_CHANGE_STATUS;
> >> +	init_data.num_consumer_supplies = 1;
> >> +	sensor_config->supply_map.dev_name = int3472->sensor_name;
> >> +	init_data.consumer_supplies = &sensor_config->supply_map;
> >> +
> >> +	snprintf(int3472->regulator.regulator_name,
> >> +		 sizeof(int3472->regulator.regulator_name), "%s-regulator",
> >> +		 acpi_dev_name(int3472->adev));
> >> +	snprintf(int3472->regulator.supply_name,
> >> +		 GPIO_REGULATOR_SUPPLY_NAME_LENGTH, "supply-0");
> >> +
> >> +	int3472->regulator.rdesc = INT3472_REGULATOR(
> >> +						int3472->regulator.regulator_name,
> >> +						int3472->regulator.supply_name,
> >> +						&int3472_gpio_regulator_ops);
> >> +
> >> +	int3472->regulator.gpio = acpi_get_gpiod(path,
> >> +						 ares->data.gpio.pin_table[0],
> >> +						 "int3472,regulator");
> >> +	if (IS_ERR(int3472->regulator.gpio)) {
> >> +		dev_err(int3472->dev, "Failed to get regulator GPIO lines\n");
> >
> > s/lines/line/ (sorry, it was a typo in my review of v2)
> 
> No problem!
> 
> >> +static int skl_int3472_parse_crs(struct int3472_discrete_device *int3472)
> >> +{
> >> +	struct list_head resource_list;
> >> +	int ret;
> >> +
> >> +	INIT_LIST_HEAD(&resource_list);
> >> +
> >> +	int3472->sensor_config = skl_int3472_get_sensor_module_config(int3472);
> >
> > I have forgotten some of the context I'm afraid :-/ Are there valid use
> > cases for not checking for an error here, or should we do so and drop
> > the error checks in other functions above ?
> 
> Not all platforms need a sensor_config; only those which have either a
> regulator pin or need a GPIO function to be remapped; the rest will do
> without it.
> 
> So, we need to not check for an error here because the absence of a
> sensor_config isn't necessarily an error, we won't know till later.
> 
> >> +int skl_int3472_discrete_probe(struct platform_device *pdev)
> >> +{
> >> +	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
> >> +	struct int3472_discrete_device *int3472;
> >> +	struct int3472_cldb cldb;
> >> +	int ret;
> >> +
> >> +	ret = skl_int3472_fill_cldb(adev, &cldb);
> >> +	if (ret) {
> >> +		dev_err(&pdev->dev, "Couldn't fill CLDB structure\n");
> >> +		return ret;
> >> +	}
> >> +
> >> +	if (cldb.control_logic_type != 1) {
> >> +		dev_err(&pdev->dev, "Unsupported control logic type %u\n",
> >> +			cldb.control_logic_type);
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	/* Max num GPIOs we've seen plus a terminator */
> >> +	int3472 = kzalloc(struct_size(int3472, gpios.table,
> >> +			  INT3472_MAX_SENSOR_GPIOS + 1), GFP_KERNEL);
> >> +	if (!int3472)
> >> +		return -ENOMEM;
> >> +
> >> +	int3472->adev = adev;
> >> +	int3472->dev = &pdev->dev;
> >> +	platform_set_drvdata(pdev, int3472);
> >> +
> >> +	int3472->sensor = acpi_dev_get_dependent_dev(adev);
> >> +	if (IS_ERR_OR_NULL(int3472->sensor)) {
> >> +		dev_err(&pdev->dev,
> >> +			"INT3472 seems to have no dependents.\n");
> >> +		ret = -ENODEV;
> >> +		goto err_free_int3472;
> >> +	}
> >> +	get_device(&int3472->sensor->dev);
> >
> > I see no corresponding put_device(), am I missing something ? I'm also
> > not sure why this is needed.
> 
> The put is acpi_dev_put() in skl_int3472_discrete_remove(); there seems
> to be no acpi_dev_get() for some reason. We use the sensor acpi_device
> to get the clock frequency, and to fetch the sensor module string, so I
> thought it ought to hold a reference on those grounds.

Shouldn't acpi_dev_get_dependent_dev() increase the reference count
then, instead of doing it manually here ?

> >> diff --git a/drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c b/drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c
> >> new file mode 100644
> >> index 000000000000..d0d2391e263f
> >> --- /dev/null
> >> +++ b/drivers/platform/x86/intel-int3472/intel_skl_int3472_tps68470.c
> >> @@ -0,0 +1,113 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +/* Author: Dan Scally <djrscally@gmail.com> */
> >> +
> >> +#include <linux/i2c.h>
> >> +#include <linux/mfd/core.h>
> >> +#include <linux/mfd/tps68470.h>
> >> +#include <linux/platform_device.h>
> >> +#include <linux/regmap.h>
> >> +
> >> +#include "intel_skl_int3472_common.h"
> >> +
> >> +static const struct mfd_cell tps68470_c[] = {
> >> +	{ .name = "tps68470-gpio" },
> >> +	{ .name = "tps68470_pmic_opregion" },
> >> +};
> >> +
> >> +static const struct mfd_cell tps68470_w[] = {
> >
> > Maybe more explicit names than _c and _w could be nice ?
> 
> _chrome and _windows was in my mind - sound ok?

As Andy mentioned, _cros is better, and _windows_ or _win both work for
me.

On Wed, Feb 24, 2021 at 12:16 PM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
> On Tue, Feb 23, 2021 at 10:36:18PM +0000, Daniel Scally wrote:
> > On 23/02/2021 20:04, Laurent Pinchart wrote:

...

> > >> +  get_device(&int3472->sensor->dev);
> > >
> > > I see no corresponding put_device(), am I missing something ? I'm also
> > > not sure why this is needed.
> >
> > The put is acpi_dev_put() in skl_int3472_discrete_remove(); there seems
> > to be no acpi_dev_get() for some reason. We use the sensor acpi_device
> > to get the clock frequency, and to fetch the sensor module string, so I
> > thought it ought to hold a reference on those grounds.
>
> Shouldn't acpi_dev_get_dependent_dev() increase the reference count
> then, instead of doing it manually here ?

That's what I expected as well.
We have plenty of acpi_dev_get_*() and they do increase the reference
counter one way or the other.

Hi Andy, Laurent

On 24/02/2021 10:18, Andy Shevchenko wrote:
> On Wed, Feb 24, 2021 at 12:16 PM Laurent Pinchart
> <laurent.pinchart@ideasonboard.com> wrote:
>> On Tue, Feb 23, 2021 at 10:36:18PM +0000, Daniel Scally wrote:
>>> On 23/02/2021 20:04, Laurent Pinchart wrote:
> ...
>
>>>>> +  get_device(&int3472->sensor->dev);
>>>> I see no corresponding put_device(), am I missing something ? I'm also
>>>> not sure why this is needed.
>>> The put is acpi_dev_put() in skl_int3472_discrete_remove(); there seems
>>> to be no acpi_dev_get() for some reason. We use the sensor acpi_device
>>> to get the clock frequency, and to fetch the sensor module string, so I
>>> thought it ought to hold a reference on those grounds.
>> Shouldn't acpi_dev_get_dependent_dev() increase the reference count
>> then, instead of doing it manually here ?
> That's what I expected as well.
> We have plenty of acpi_dev_get_*() and they do increase the reference
> counter one way or the other.
>
Okedokey, I'll move the get() to that function and drop it from here.

Hi Andy

On 22/02/2021 14:58, Andy Shevchenko wrote
>> +#include <linux/clk-provider.h>
> 
> This is definitely not for *.h. (Not all C files needed this)
> 
>> +#include <linux/gpio/machine.h>
> 
> Ditto.
> 
>> +#include <linux/regulator/driver.h>
>> +#include <linux/regulator/machine.h>
> 
> Ditto.

Bit more delayed than I wanted to be, but I'm just finishing off the v4
of this. For these includes, I'm using the actual structs from them
rather than pointers, so removing these would mean moving the definition
of struct int3472_discrete_device into one of the source files; you're
happy with that?

On Tue, May 18, 2021 at 12:43 AM Daniel Scally <djrscally@gmail.com> wrote:
>
> Hi Andy
>
> On 22/02/2021 14:58, Andy Shevchenko wrote
> >> +#include <linux/clk-provider.h>
> >
> > This is definitely not for *.h. (Not all C files needed this)
> >
> >> +#include <linux/gpio/machine.h>
> >
> > Ditto.
> >
> >> +#include <linux/regulator/driver.h>
> >> +#include <linux/regulator/machine.h>
> >
> > Ditto.
>
> Bit more delayed than I wanted to be, but I'm just finishing off the v4
> of this. For these includes, I'm using the actual structs from them
> rather than pointers, so removing these would mean moving the definition
> of struct int3472_discrete_device into one of the source files; you're
> happy with that?

Either way, please send a v4 and we start over from a fresh view.

Thanks!