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[v2,1/2,RFT] dt-bindings: leds: Add cznic,turris1x-leds.yaml binding

Message ID 20220705155929.25565-1-pali@kernel.org
State Changes Requested, archived
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Series [v2,1/2,RFT] dt-bindings: leds: Add cznic,turris1x-leds.yaml binding | expand

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Commit Message

Pali Rohár July 5, 2022, 3:59 p.m. UTC 
Add device-tree bindings documentation for Turris 1.x RGB LEDs.

Signed-off-by: Pali Rohár <pali@kernel.org>

---
Changes in v2:
* Fix schema errors
---
 .../bindings/leds/cznic,turris1x-leds.yaml    | 118 ++++++++++++++++++
 1 file changed, 118 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/cznic,turris1x-leds.yaml

Comments

Marek Behún July 5, 2022, 5:30 p.m. UTC | #1 
On Tue,  5 Jul 2022 17:59:29 +0200
Pali Rohár <pali@kernel.org> wrote:

> This adds support for the RGB LEDs found on the front panel of the
> Turris 1.x routers. There are 8 RGB LEDs that are controlled by
> CZ.NIC CPLD firmware running on Lattice FPGA.
> 
> CPLD firmware provides HW triggering mode for all LEDs except WiFi LED
> which is automatically enabled after power on reset. LAN LEDs share HW
> registers for RGB colors settings, so it is not possible to set different
> colors for individual LAN LEDs.
> 
> CZ.NIC CPLD firmware is open source and available at:
> https://gitlab.nic.cz/turris/hw/turris_cpld/-/blob/master/CZ_NIC_Router_CPLD.v
> 
> This driver uses the multicolor LED framework and HW led triggers.
> 
> Signed-off-by: Pali Rohár <pali@kernel.org>

Reviewed-by: Marek Behún <kabel@kernel.org>
Krzysztof Kozlowski July 5, 2022, 5:51 p.m. UTC | #2 
On 05/07/2022 17:59, Pali Rohár wrote:
> Add device-tree bindings documentation for Turris 1.x RGB LEDs.

The patchset is difficult to find because you attached it to some older
thread. Don't.

> 
> Signed-off-by: Pali Rohár <pali@kernel.org>
> 
> ---
> Changes in v2:
> * Fix schema errors
> ---
>  .../bindings/leds/cznic,turris1x-leds.yaml    | 118 ++++++++++++++++++
>  1 file changed, 118 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/leds/cznic,turris1x-leds.yaml
> 
> diff --git a/Documentation/devicetree/bindings/leds/cznic,turris1x-leds.yaml b/Documentation/devicetree/bindings/leds/cznic,turris1x-leds.yaml
> new file mode 100644
> index 000000000000..bcaab5b03128
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/cznic,turris1x-leds.yaml
> @@ -0,0 +1,118 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/cznic,turris1x-leds.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: CZ.NIC's Turris 1.x LEDs driver
> +
> +maintainers:
> +  - Pali Rohár <pali@kernel.org>
> +
> +description:
> +  This module adds support for the RGB LEDs found on the front panel of the
> +  Turris 1.x routers. There are 8 RGB LEDs that are controlled by CZ.NIC CPLD
> +  firmware running on Lattice FPGA. Firmware is open source and available at
> +  https://gitlab.nic.cz/turris/hw/turris_cpld/-/blob/master/CZ_NIC_Router_CPLD.v
> +
> +properties:
> +  compatible:
> +    const: cznic,turris1x-leds
> +
> +  reg:
> +    description: CPLD address range where LED registers are mapped
> +    maxItems: 1
> +
> +  "#address-cells":
> +    const: 1
> +
> +  "#size-cells":
> +    const: 0
> +
> +patternProperties:
> +  "^multi-led@[0-7]$":
> +    type: object
> +    $ref: leds-class-multicolor.yaml#
> +    unevaluatedProperties: false
> +
> +    properties:
> +      reg:
> +        minimum: 0
> +        maximum: 7
> +
> +    required:
> +      - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/leds/common.h>
> +
> +    cpld@3,0 {
> +        #address-cells = <1>;
> +        #size-cells = <1>;
> +        ranges = <0x0 0x3 0x0 0x00020000>;
> +
> +        led-controller@13 {
> +            compatible = "cznic,turris1x-leds";
> +            reg = <0x13 0x1d>;
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            multi-led@0 {
> +                    reg = <0x0>;
You have some weird indentation here. In other places of DTS example it
is correct four spaces, so here should be four spaces as well.

Best regards,
Krzysztof
Andy Shevchenko July 5, 2022, 6:40 p.m. UTC | #3 
On Tue, Jul 5, 2022 at 6:11 PM Pali Rohár <pali@kernel.org> wrote:
>
> This adds support for the RGB LEDs found on the front panel of the
> Turris 1.x routers. There are 8 RGB LEDs that are controlled by
> CZ.NIC CPLD firmware running on Lattice FPGA.
>
> CPLD firmware provides HW triggering mode for all LEDs except WiFi LED
> which is automatically enabled after power on reset. LAN LEDs share HW
> registers for RGB colors settings, so it is not possible to set different
> colors for individual LAN LEDs.
>
> CZ.NIC CPLD firmware is open source and available at:
> https://gitlab.nic.cz/turris/hw/turris_cpld/-/blob/master/CZ_NIC_Router_CPLD.v
>
> This driver uses the multicolor LED framework and HW led triggers.

Pardon me, but this driver seems like 3 years old by the APIs it's
using... I have to say this, because I was surprised a lot to see some
calls.

...

> +config LEDS_TURRIS_1X
> +       tristate "LED support for CZ.NIC's Turris 1.x"
> +       depends on LEDS_CLASS_MULTICOLOR

> +       depends on OF

Why?

If it's a functional (not compile time) dependency, make it

  depends on OF || COMPILE_TEST

> +       select LEDS_TRIGGERS
> +       help
> +         This option enables support for LEDs found on the front side of
> +         CZ.NIC's Turris 1.x routers.

...

> +#include <linux/i2c.h>
> +#include <linux/led-class-multicolor.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>

> +#include <linux/of.h>

Rather property.h. See below how.

...

> +/* LEDs 1-5 share common register for setting brightness */
> +#define TURRIS1X_LED_BRIGHTNESS_OFF(idx)       ({ const u8 _idx = (idx) & 7; \

Can you start with the GCC expression on a new line? I may give a much
shorter next line and increase readability.

> +                                                  (_idx == 0) ? 0 : \
> +                                                  (_idx <= 5) ? 1 : \
> +                                                  (_idx - 4); })
> +
> +#define TURRIS1X_LED_BRIGHTNESS_REG(idx, color)        TURRIS1X_LED_REG_OFF(0x13 + \
> +                                                 3 * TURRIS1X_LED_BRIGHTNESS_OFF(idx) + \
> +                                                 ((color) & 3))

Ditto.

...

> +static enum led_brightness turris1x_led_brightness_get(struct led_classdev *cdev)
> +{
> +       struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
> +       struct turris1x_leds *leds = dev_get_drvdata(cdev->dev->parent);
> +       struct turris1x_led *led = to_turris1x_led(mc_cdev);
> +
> +       if (!(readb(leds->regs + TURRIS1X_LED_SW_OVERRIDE_REG) & BIT(led->reg)))
> +               return 1;
> +       else if (!(readb(leds->regs + TURRIS1X_LED_SW_DISABLE_REG) & BIT(led->reg)))
> +               return 1;
> +       else

Redundant 'else' in both cases.

> +               return 0;
> +}

...

> +               /*
> +                * LEDs 1-5 (LAN) share common color settings in same sets
> +                * of HW registers and therefore it is not possible to set
> +                * different colors. So when chaning color of one LED then

chaining

> +                * reflect color change for all of them.
> +                */

> +               if (led->reg >= 1 && led->reg <= 5) {

Same is used in the macro above. Maybe you can provide a shortcut for
this instead of duplicating?

> +                       for (j = 0; j < ARRAY_SIZE(leds->leds); j++) {

> +                               if (leds->leds[j].reg < 1 ||
> +                                   leds->leds[j].reg > 5 ||

Ditto.

> +                                   leds->leds[j].reg == led->reg)
> +                                       continue;
> +                               for (i = 0; i < ARRAY_SIZE(led->subled_info); i++)
> +                                       leds->leds[j].mc_cdev.subled_info[i].intensity =
> +                                               mc_cdev->subled_info[i].intensity;
> +                       }
> +               }
> +       }

...

> +       ret = of_property_read_u32(np, "reg", &reg);
> +       if (ret || reg >= ARRAY_SIZE(leds->leds)) {
> +               dev_err(dev,
> +                       "Node %pOF: must contain 'reg' property with values between 0 and %u\n",
> +                       np, (unsigned int)ARRAY_SIZE(leds->leds) - 1);
> +               return -EINVAL;
> +       }
> +
> +       ret = of_property_read_u32(np, "color", &color);
> +       if (ret || color != LED_COLOR_ID_RGB) {
> +               dev_err(dev,
> +                       "Node %pOF: must contain 'color' property with value LED_COLOR_ID_RGB\n",
> +                       np);
> +               return -EINVAL;
> +       }
> +
> +       led = &leds->leds[reg];
> +
> +       if (led->registered) {
> +               dev_err(dev, "Node %pOF: duplicate 'reg' property %u\n",
> +                            np, reg);
> +               return -EINVAL;
> +       }

> +       init_data.fwnode = &np->fwnode;

Oh, no. We do not dereference fwnode, we have helpers for that.
Moreover, why not use fwnode to begin with?

> +       ret = devm_led_classdev_multicolor_register_ext(dev, &led->mc_cdev,
> +                                                       &init_data);
> +       if (ret) {
> +               dev_err(dev, "Cannot register LED %pOF: %i\n", np, ret);
> +               return ret;
> +       }
> +
> +       return 0;
> +}

...

> +static ssize_t brightness_show(struct device *dev, struct device_attribute *a,
> +                              char *buf)
> +{
> +       struct turris1x_leds *leds = dev_get_drvdata(dev);
> +       unsigned int brightness;
> +
> +       /*
> +        * Current brightness value is available in read-only register
> +        * TURRIS1X_LED_GET_GLOBAL_BRIGHTNESS_REG. Equivalent code is:
> +        * level = readb(leds->regs + TURRIS1X_LED_GLOBAL_LEVEL_REG) & 7;
> +        * brightness = readb(leds->regs + TURRIS1X_LED_GLOBAL_BRIGHTNESS_REG(level));
> +        */
> +       brightness = readb(leds->regs + TURRIS1X_LED_GET_GLOBAL_BRIGHTNESS_REG);
> +
> +       return sprintf(buf, "%u\n", brightness);

sysfs_emit()

> +}

...

> +       if (kstrtoul(buf, 10, &brightness))
> +               return -EINVAL;

Why shadow the error code from kstrtoul()? Note it might return
something different.

Do you really need unsigned long? Can't you use u8 and kstrtou8() respectively?

> +       if (brightness > 255)
> +               return -EINVAL;

Yeah, read above about u8.

...

> +       /*
> +        * Brightness can be set only to one of 8 predefined value levels
> +        * available in TURRIS1X_LED_GLOBAL_BRIGHTNESS_REG(level) registers.
> +        * Choose level which has nearest value to the specified brightness.

a level
the nearest

> +        */

...

> +               error = abs(value - (int)brightness);

Why casting?!

...

> +static ssize_t brightness_level_show(struct device *dev,
> +                                    struct device_attribute *a, char *buf)
> +{
> +       struct turris1x_leds *leds = dev_get_drvdata(dev);
> +       unsigned int level;
> +
> +       level = readb(leds->regs + TURRIS1X_LED_GLOBAL_LEVEL_REG) & 7;
> +
> +       return sprintf(buf, "%u\n", level);

sysfs_emit()

> +}

...

> +       if (kstrtoul(buf, 10, &level))
> +               return -EINVAL;

As per above.

...

> +static ssize_t brightness_values_show(struct device *dev,
> +                                     struct device_attribute *a, char *buf)
> +{
> +       struct turris1x_leds *leds = dev_get_drvdata(dev);
> +       unsigned int vals[8];
> +       int i;
> +
> +       for (i = 0; i < 8; i++)
> +               vals[i] = readb(leds->regs +
> +                               TURRIS1X_LED_GLOBAL_BRIGHTNESS_REG(i));
> +
> +       return sprintf(buf, "%u %u %u %u %u %u %u %u\n", vals[0], vals[1],
> +                      vals[2], vals[3], vals[4], vals[5], vals[6], vals[7]);

sysfs_emit()
Wouldn't it be better to have CSV instead? I think for such cases we
usually have this kind of format.

> +}

...

> +static struct attribute *turris1x_leds_controller_attrs[] = {
> +       &dev_attr_brightness.attr,
> +       &dev_attr_brightness_level.attr,
> +       &dev_attr_brightness_values.attr,

> +       NULL,

No comma for terminator.

> +};

...

> +static int turris1x_leds_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;

> +       struct device_node *np = dev_of_node(dev);
> +       struct device_node *child;

Why not use fwnode to begin with?

> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

> +       if (!res)
> +               return -ENODEV;

Besides dup code, which actually does not print a message...

> +       regs = devm_ioremap_resource(dev, res);

...we have devm_platform_ioremap_resource() to combine two above into one.

> +       if (IS_ERR(regs))
> +               return PTR_ERR(regs);

...

> +       ret = devm_led_trigger_register(dev, &turris1x_hw_trigger);
> +       if (ret) {
> +               dev_err(dev, "Cannot register private LED trigger: %d\n", ret);
> +               return ret;

return dev_err_probe(...);

> +       }

...

> +       for_each_available_child_of_node(np, child) {

device_for_each_child_node()

> +               ret = turris1x_led_register(dev, leds, child,
> +                                           val_sw_override, val_sw_disable);
> +               if (ret) {

> +                       of_node_put(child);

fwnode_handle_put()

> +                       return ret;
> +               }
> +       }

...

> +       ret = devm_device_add_groups(dev, turris1x_leds_controller_groups);
> +       if (ret) {
> +               dev_err(dev, "Could not add attribute group!\n");
> +               return ret;

return dev_err_probe(...);

> +       }
> +
> +       return 0;
> +}

...

> +       /*
> +        * LED registers are persisent across board resets.

persistent

> +        * So reset LEDs to default state before kernel reboots.
> +        */

...

> +                       writeb(0xff,

GENMASK() ?

> +                              leds->regs + TURRIS1X_LED_BRIGHTNESS_REG(i, j));
> +       }
> +}

...

> +static const struct of_device_id of_turris1x_leds_match[] = {
> +       { .compatible = "cznic,turris1x-leds" },
> +       {},

No comma for terminator.

> +};
Pali Rohár July 5, 2022, 6:46 p.m. UTC | #4 
On Tuesday 05 July 2022 20:40:26 Andy Shevchenko wrote:
> On Tue, Jul 5, 2022 at 6:11 PM Pali Rohár <pali@kernel.org> wrote:
> >
> > This adds support for the RGB LEDs found on the front panel of the
> > Turris 1.x routers. There are 8 RGB LEDs that are controlled by
> > CZ.NIC CPLD firmware running on Lattice FPGA.
> >
> > CPLD firmware provides HW triggering mode for all LEDs except WiFi LED
> > which is automatically enabled after power on reset. LAN LEDs share HW
> > registers for RGB colors settings, so it is not possible to set different
> > colors for individual LAN LEDs.
> >
> > CZ.NIC CPLD firmware is open source and available at:
> > https://gitlab.nic.cz/turris/hw/turris_cpld/-/blob/master/CZ_NIC_Router_CPLD.v
> >
> > This driver uses the multicolor LED framework and HW led triggers.
> 
> Pardon me, but this driver seems like 3 years old by the APIs it's
> using... I have to say this, because I was surprised a lot to see some
> calls.

I wrote it just recently according to other omnia multicolor driver.
Andy Shevchenko July 5, 2022, 6:58 p.m. UTC | #5 
On Tue, Jul 5, 2022 at 8:47 PM Pali Rohár <pali@kernel.org> wrote:
>
> On Tuesday 05 July 2022 20:40:26 Andy Shevchenko wrote:
> > On Tue, Jul 5, 2022 at 6:11 PM Pali Rohár <pali@kernel.org> wrote:
> > >
> > > This adds support for the RGB LEDs found on the front panel of the
> > > Turris 1.x routers. There are 8 RGB LEDs that are controlled by
> > > CZ.NIC CPLD firmware running on Lattice FPGA.
> > >
> > > CPLD firmware provides HW triggering mode for all LEDs except WiFi LED
> > > which is automatically enabled after power on reset. LAN LEDs share HW
> > > registers for RGB colors settings, so it is not possible to set different
> > > colors for individual LAN LEDs.
> > >
> > > CZ.NIC CPLD firmware is open source and available at:
> > > https://gitlab.nic.cz/turris/hw/turris_cpld/-/blob/master/CZ_NIC_Router_CPLD.v
> > >
> > > This driver uses the multicolor LED framework and HW led triggers.
> >
> > Pardon me, but this driver seems like 3 years old by the APIs it's
> > using... I have to say this, because I was surprised a lot to see some
> > calls.
>
> I wrote it just recently according to other omnia multicolor driver.

I see. I hope you will find my review useful then.
Rob Herring (Arm) July 5, 2022, 7:18 p.m. UTC | #6 
On Tue, 05 Jul 2022 17:59:28 +0200, Pali Rohár wrote:
> Add device-tree bindings documentation for Turris 1.x RGB LEDs.
> 
> Signed-off-by: Pali Rohár <pali@kernel.org>
> 
> ---
> Changes in v2:
> * Fix schema errors
> ---
>  .../bindings/leds/cznic,turris1x-leds.yaml    | 118 ++++++++++++++++++
>  1 file changed, 118 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/leds/cznic,turris1x-leds.yaml
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
Documentation/devicetree/bindings/leds/cznic,turris1x-leds.example.dts:23.13-47: Warning (ranges_format): /example-0/cpld@3,0:ranges: "ranges" property has invalid length (16 bytes) (parent #address-cells == 1, child #address-cells == 1, #size-cells == 1)

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/patch/

This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit.
Marek Behún July 6, 2022, 11:15 a.m. UTC | #7 
On Tue,  5 Jul 2022 17:59:28 +0200
Pali Rohár <pali@kernel.org> wrote:

> +examples:
> +  - |
> +    #include <dt-bindings/leds/common.h>
> +
> +    cpld@3,0 {

The generic node name should be just "bus". That it is a CPLD
implementation should come from compatible string.

This is similar to how we have generic names like "led-controller",
"switch", "ethernet-phy", ...

Pali, I can take over this and get it merged if you are getting
frustrated here.

Marek
Pali Rohár July 6, 2022, 11:19 a.m. UTC | #8 
On Wednesday 06 July 2022 13:15:07 Marek Behún wrote:
> On Tue,  5 Jul 2022 17:59:28 +0200
> Pali Rohár <pali@kernel.org> wrote:
> 
> > +examples:
> > +  - |
> > +    #include <dt-bindings/leds/common.h>
> > +
> > +    cpld@3,0 {
> 
> The generic node name should be just "bus". That it is a CPLD
> implementation should come from compatible string.

Sorry, I do not understand why "bus". Why other memory chips are named
e.g. "nand" or "nor" and not "bus" too? By this logic should not be
_every_ node called just "bus"? Hm... and are names needed at all then?
Marek Behún July 6, 2022, 3:27 p.m. UTC | #9 
On Wed, 6 Jul 2022 13:19:12 +0200
Pali Rohár <pali@kernel.org> wrote:

> On Wednesday 06 July 2022 13:15:07 Marek Behún wrote:
> > On Tue,  5 Jul 2022 17:59:28 +0200
> > Pali Rohár <pali@kernel.org> wrote:
> >   
> > > +examples:
> > > +  - |
> > > +    #include <dt-bindings/leds/common.h>
> > > +
> > > +    cpld@3,0 {  
> > 
> > The generic node name should be just "bus". That it is a CPLD
> > implementation should come from compatible string.  
> 
> Sorry, I do not understand why "bus". Why other memory chips are named
> e.g. "nand" or "nor" and not "bus" too?

As far as I understand this is because that is the preferred name for
busses and this is a bus, since there is also the simple-bus compatible.

> By this logic should not be _every_ node called just "bus"? Hm... and 
> are names needed at all then?

:-)

The schema
  https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/simple-bus.yaml
allows for different names (soc|axi|ahb|*-bus) to avoid warnings on
existing old dts files.

The preferred way is to not have the implementation in nodename,
similar to how we use 'switch' instead of 'mv88e6xxx', or
'ethernet-phy' instead of 'mv88e151x', or 'led-controller', ...

I wasn't there when people started requesting for this to be that way,
but I guess it makes some sense to make it more readable and less
redundant (the generic name in nodename and the implementation in
compatible string...).

Marek
Krzysztof Kozlowski July 6, 2022, 3:36 p.m. UTC | #10 
On 06/07/2022 17:27, Marek Behún wrote:
> On Wed, 6 Jul 2022 13:19:12 +0200
> Pali Rohár <pali@kernel.org> wrote:
> 
>> On Wednesday 06 July 2022 13:15:07 Marek Behún wrote:
>>> On Tue,  5 Jul 2022 17:59:28 +0200
>>> Pali Rohár <pali@kernel.org> wrote:
>>>   
>>>> +examples:
>>>> +  - |
>>>> +    #include <dt-bindings/leds/common.h>
>>>> +
>>>> +    cpld@3,0 {  
>>>
>>> The generic node name should be just "bus". That it is a CPLD
>>> implementation should come from compatible string.  
>>
>> Sorry, I do not understand why "bus". Why other memory chips are named
>> e.g. "nand" or "nor" and not "bus" too?
> 
> As far as I understand this is because that is the preferred name for
> busses and this is a bus, since there is also the simple-bus compatible.
> 
>> By this logic should not be _every_ node called just "bus"? Hm... and 
>> are names needed at all then?
> 
> :-)
> 
> The schema
>   https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/simple-bus.yaml
> allows for different names (soc|axi|ahb|*-bus) to avoid warnings on
> existing old dts files.
> 
> The preferred way is to not have the implementation in nodename,
> similar to how we use 'switch' instead of 'mv88e6xxx', or
> 'ethernet-phy' instead of 'mv88e151x', or 'led-controller', ...

Thanks Marek for detailed explanation.
The cases above rather trigger my comments and this one here, after
Pali's explanation, do not fit them. pld is a generic class of a device,
so it is okay here. cpld probably as well (although one could argue that
it is a subset of pld, so the generic name is pld, but then one would
say fpga also should be called pld). For me it does not have to be bus,
just don't want mv88e6xxx or any other vendor/model names. Therefore
cpld is fine.

> 
> I wasn't there when people started requesting for this to be that way,
> but I guess it makes some sense to make it more readable and less
> redundant (the generic name in nodename and the implementation in
> compatible string...).




Best regards,
Krzysztof
Marek Behún July 6, 2022, 4:43 p.m. UTC | #11 
On Wed, 6 Jul 2022 17:36:43 +0200
Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> wrote:

> On 06/07/2022 17:27, Marek Behún wrote:
> > On Wed, 6 Jul 2022 13:19:12 +0200
> > Pali Rohár <pali@kernel.org> wrote:
> >   
> >> On Wednesday 06 July 2022 13:15:07 Marek Behún wrote:  
> >>> On Tue,  5 Jul 2022 17:59:28 +0200
> >>> Pali Rohár <pali@kernel.org> wrote:
> >>>     
> >>>> +examples:
> >>>> +  - |
> >>>> +    #include <dt-bindings/leds/common.h>
> >>>> +
> >>>> +    cpld@3,0 {    
> >>>
> >>> The generic node name should be just "bus". That it is a CPLD
> >>> implementation should come from compatible string.    
> >>
> >> Sorry, I do not understand why "bus". Why other memory chips are named
> >> e.g. "nand" or "nor" and not "bus" too?  
> > 
> > As far as I understand this is because that is the preferred name for
> > busses and this is a bus, since there is also the simple-bus compatible.
> >   
> >> By this logic should not be _every_ node called just "bus"? Hm... and 
> >> are names needed at all then?  
> > 
> > :-)
> > 
> > The schema
> >   https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/simple-bus.yaml
> > allows for different names (soc|axi|ahb|*-bus) to avoid warnings on
> > existing old dts files.
> > 
> > The preferred way is to not have the implementation in nodename,
> > similar to how we use 'switch' instead of 'mv88e6xxx', or
> > 'ethernet-phy' instead of 'mv88e151x', or 'led-controller', ...  
> 
> Thanks Marek for detailed explanation.
> The cases above rather trigger my comments and this one here, after
> Pali's explanation, do not fit them. pld is a generic class of a device,
> so it is okay here. cpld probably as well (although one could argue that
> it is a subset of pld, so the generic name is pld, but then one would
> say fpga also should be called pld). For me it does not have to be bus,
> just don't want mv88e6xxx or any other vendor/model names. Therefore
> cpld is fine.

What about cpld-bus? It is used as a bus (simple-bus compatible) and
would work with the *-bus pattern in dt-schema.

Marek
Krzysztof Kozlowski July 6, 2022, 6:16 p.m. UTC | #12 
On 06/07/2022 18:43, Marek Behún wrote:
> On Wed, 6 Jul 2022 17:36:43 +0200
> Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> wrote:
> 
>> On 06/07/2022 17:27, Marek Behún wrote:
>>> On Wed, 6 Jul 2022 13:19:12 +0200
>>> Pali Rohár <pali@kernel.org> wrote:
>>>   
>>>> On Wednesday 06 July 2022 13:15:07 Marek Behún wrote:  
>>>>> On Tue,  5 Jul 2022 17:59:28 +0200
>>>>> Pali Rohár <pali@kernel.org> wrote:
>>>>>     
>>>>>> +examples:
>>>>>> +  - |
>>>>>> +    #include <dt-bindings/leds/common.h>
>>>>>> +
>>>>>> +    cpld@3,0 {    
>>>>>
>>>>> The generic node name should be just "bus". That it is a CPLD
>>>>> implementation should come from compatible string.    
>>>>
>>>> Sorry, I do not understand why "bus". Why other memory chips are named
>>>> e.g. "nand" or "nor" and not "bus" too?  
>>>
>>> As far as I understand this is because that is the preferred name for
>>> busses and this is a bus, since there is also the simple-bus compatible.
>>>   
>>>> By this logic should not be _every_ node called just "bus"? Hm... and 
>>>> are names needed at all then?  
>>>
>>> :-)
>>>
>>> The schema
>>>   https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/simple-bus.yaml
>>> allows for different names (soc|axi|ahb|*-bus) to avoid warnings on
>>> existing old dts files.
>>>
>>> The preferred way is to not have the implementation in nodename,
>>> similar to how we use 'switch' instead of 'mv88e6xxx', or
>>> 'ethernet-phy' instead of 'mv88e151x', or 'led-controller', ...  
>>
>> Thanks Marek for detailed explanation.
>> The cases above rather trigger my comments and this one here, after
>> Pali's explanation, do not fit them. pld is a generic class of a device,
>> so it is okay here. cpld probably as well (although one could argue that
>> it is a subset of pld, so the generic name is pld, but then one would
>> say fpga also should be called pld). For me it does not have to be bus,
>> just don't want mv88e6xxx or any other vendor/model names. Therefore
>> cpld is fine.
> 
> What about cpld-bus? It is used as a bus (simple-bus compatible) and
> would work with the *-bus pattern in dt-schema.

If we talk about the example - it does not use any compatible, so we are
focusing on unimportant piece. Anyway using a simple-bus compatible does
not necessarily mean it is a bus. "soc" nodes also use it, but these are
not buses.


Best regards,
Krzysztof
Pali Rohár July 8, 2022, 4:05 p.m. UTC | #13 
On Wednesday 06 July 2022 17:36:43 Krzysztof Kozlowski wrote:
> On 06/07/2022 17:27, Marek Behún wrote:
> > On Wed, 6 Jul 2022 13:19:12 +0200
> > Pali Rohár <pali@kernel.org> wrote:
> > 
> >> On Wednesday 06 July 2022 13:15:07 Marek Behún wrote:
> >>> On Tue,  5 Jul 2022 17:59:28 +0200
> >>> Pali Rohár <pali@kernel.org> wrote:
> >>>   
> >>>> +examples:
> >>>> +  - |
> >>>> +    #include <dt-bindings/leds/common.h>
> >>>> +
> >>>> +    cpld@3,0 {  
> >>>
> >>> The generic node name should be just "bus". That it is a CPLD
> >>> implementation should come from compatible string.  
> >>
> >> Sorry, I do not understand why "bus". Why other memory chips are named
> >> e.g. "nand" or "nor" and not "bus" too?
> > 
> > As far as I understand this is because that is the preferred name for
> > busses and this is a bus, since there is also the simple-bus compatible.
> > 
> >> By this logic should not be _every_ node called just "bus"? Hm... and 
> >> are names needed at all then?
> > 
> > :-)
> > 
> > The schema
> >   https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/simple-bus.yaml
> > allows for different names (soc|axi|ahb|*-bus) to avoid warnings on
> > existing old dts files.
> > 
> > The preferred way is to not have the implementation in nodename,
> > similar to how we use 'switch' instead of 'mv88e6xxx', or
> > 'ethernet-phy' instead of 'mv88e151x', or 'led-controller', ...
> 
> Thanks Marek for detailed explanation.
> The cases above rather trigger my comments and this one here, after
> Pali's explanation, do not fit them. pld is a generic class of a device,
> so it is okay here. cpld probably as well (although one could argue that
> it is a subset of pld, so the generic name is pld, but then one would
> say fpga also should be called pld). For me it does not have to be bus,
> just don't want mv88e6xxx or any other vendor/model names. Therefore
> cpld is fine.

Exactly. cpld, fpga, nor, nand, soc... all of them are not real buses.

simple-bus here is just name invented by device tree and without which
existing kernel drivers refuse to work.

> > 
> > I wasn't there when people started requesting for this to be that way,
> > but I guess it makes some sense to make it more readable and less
> > redundant (the generic name in nodename and the implementation in
> > compatible string...).
> 
> 
> 
> 
> Best regards,
> Krzysztof
Marek Behún July 8, 2022, 4:29 p.m. UTC | #14 
On Fri, 8 Jul 2022 18:05:28 +0200
Pali Rohár <pali@kernel.org> wrote:

> On Wednesday 06 July 2022 17:36:43 Krzysztof Kozlowski wrote:
> > On 06/07/2022 17:27, Marek Behún wrote:  
> > > On Wed, 6 Jul 2022 13:19:12 +0200
> > > Pali Rohár <pali@kernel.org> wrote:
> > >   
> > >> On Wednesday 06 July 2022 13:15:07 Marek Behún wrote:  
> > >>> On Tue,  5 Jul 2022 17:59:28 +0200
> > >>> Pali Rohár <pali@kernel.org> wrote:
> > >>>     
> > >>>> +examples:
> > >>>> +  - |
> > >>>> +    #include <dt-bindings/leds/common.h>
> > >>>> +
> > >>>> +    cpld@3,0 {    
> > >>>
> > >>> The generic node name should be just "bus". That it is a CPLD
> > >>> implementation should come from compatible string.    
> > >>
> > >> Sorry, I do not understand why "bus". Why other memory chips are named
> > >> e.g. "nand" or "nor" and not "bus" too?  
> > > 
> > > As far as I understand this is because that is the preferred name for
> > > busses and this is a bus, since there is also the simple-bus compatible.
> > >   
> > >> By this logic should not be _every_ node called just "bus"? Hm... and 
> > >> are names needed at all then?  
> > > 
> > > :-)
> > > 
> > > The schema
> > >   https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/simple-bus.yaml
> > > allows for different names (soc|axi|ahb|*-bus) to avoid warnings on
> > > existing old dts files.
> > > 
> > > The preferred way is to not have the implementation in nodename,
> > > similar to how we use 'switch' instead of 'mv88e6xxx', or
> > > 'ethernet-phy' instead of 'mv88e151x', or 'led-controller', ...  
> > 
> > Thanks Marek for detailed explanation.
> > The cases above rather trigger my comments and this one here, after
> > Pali's explanation, do not fit them. pld is a generic class of a device,
> > so it is okay here. cpld probably as well (although one could argue that
> > it is a subset of pld, so the generic name is pld, but then one would
> > say fpga also should be called pld). For me it does not have to be bus,
> > just don't want mv88e6xxx or any other vendor/model names. Therefore
> > cpld is fine.  
> 
> Exactly. cpld, fpga, nor, nand, soc... all of them are not real buses.
> 
> simple-bus here is just name invented by device tree and without which
> existing kernel drivers refuse to work.

OK, then cpld seems correct. I thought it was considered a bus in a way,
since "simple-bus" is used in compatible.

Marek
Rob Herring (Arm) July 12, 2022, 9:28 p.m. UTC | #15 
On Fri, Jul 08, 2022 at 06:05:28PM +0200, Pali Rohár wrote:
> On Wednesday 06 July 2022 17:36:43 Krzysztof Kozlowski wrote:
> > On 06/07/2022 17:27, Marek Behún wrote:
> > > On Wed, 6 Jul 2022 13:19:12 +0200
> > > Pali Rohár <pali@kernel.org> wrote:
> > > 
> > >> On Wednesday 06 July 2022 13:15:07 Marek Behún wrote:
> > >>> On Tue,  5 Jul 2022 17:59:28 +0200
> > >>> Pali Rohár <pali@kernel.org> wrote:
> > >>>   
> > >>>> +examples:
> > >>>> +  - |
> > >>>> +    #include <dt-bindings/leds/common.h>
> > >>>> +
> > >>>> +    cpld@3,0 {  
> > >>>
> > >>> The generic node name should be just "bus". That it is a CPLD
> > >>> implementation should come from compatible string.  
> > >>
> > >> Sorry, I do not understand why "bus". Why other memory chips are named
> > >> e.g. "nand" or "nor" and not "bus" too?
> > > 
> > > As far as I understand this is because that is the preferred name for
> > > busses and this is a bus, since there is also the simple-bus compatible.
> > > 
> > >> By this logic should not be _every_ node called just "bus"? Hm... and 
> > >> are names needed at all then?
> > > 
> > > :-)
> > > 
> > > The schema
> > >   https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/simple-bus.yaml
> > > allows for different names (soc|axi|ahb|*-bus) to avoid warnings on
> > > existing old dts files.
> > > 
> > > The preferred way is to not have the implementation in nodename,
> > > similar to how we use 'switch' instead of 'mv88e6xxx', or
> > > 'ethernet-phy' instead of 'mv88e151x', or 'led-controller', ...
> > 
> > Thanks Marek for detailed explanation.
> > The cases above rather trigger my comments and this one here, after
> > Pali's explanation, do not fit them. pld is a generic class of a device,
> > so it is okay here. cpld probably as well (although one could argue that
> > it is a subset of pld, so the generic name is pld, but then one would
> > say fpga also should be called pld). For me it does not have to be bus,
> > just don't want mv88e6xxx or any other vendor/model names. Therefore
> > cpld is fine.
> 
> Exactly. cpld, fpga, nor, nand, soc... all of them are not real buses.

I guess you could (and we do) have 'cpld' and 'fpga' as devices where 
the OS can reprogram them and such. But if the implementation is fixed 
with no implementation specific controls, I don't think naming how it's 
implemented adds too much. If there's nothing else to identify the 
device though, having 'cpld' in there does have some value I guess.

Same could be argued for soc too perhaps, but that's in the list largely 
to avoid a bunch of s/soc/bus/ on dts files.
 
> simple-bus here is just name invented by device tree and without which
> existing kernel drivers refuse to work.

Everything is just names invented by DT.

simple-bus means 'a bus containing MMIO devices without any bus 
configuration'. You want to add a clock to it?, then no longer a 
simple-bus. Based on that definition, the kernel can enumerate child 
devices without platform specific help. 

Just use 'cpld-bus' and lets move on with our lives.

Rob
Pali Rohár Nov. 2, 2022, 12:25 a.m. UTC | #16 
Hello! What with this driver? Its DTS part was already merged and ready to serve.

On Tuesday 05 July 2022 17:59:29 Pali Rohár wrote:
> This adds support for the RGB LEDs found on the front panel of the
> Turris 1.x routers. There are 8 RGB LEDs that are controlled by
> CZ.NIC CPLD firmware running on Lattice FPGA.
> 
> CPLD firmware provides HW triggering mode for all LEDs except WiFi LED
> which is automatically enabled after power on reset. LAN LEDs share HW
> registers for RGB colors settings, so it is not possible to set different
> colors for individual LAN LEDs.
> 
> CZ.NIC CPLD firmware is open source and available at:
> https://gitlab.nic.cz/turris/hw/turris_cpld/-/blob/master/CZ_NIC_Router_CPLD.v
> 
> This driver uses the multicolor LED framework and HW led triggers.
> 
> Signed-off-by: Pali Rohár <pali@kernel.org>
> 
> ---
> Changes in v2:
> * Use 0/1 instead of LED_OFF/LED_ON
> * Add brightness_level device attribute
> * Implement callback brightness_set instead of brightness_set_blocking
> * Reset LEDs to default state before kernel reboots
> ---
>  .../testing/sysfs-class-led-driver-turris1x   |  31 ++
>  drivers/leds/Kconfig                          |   9 +
>  drivers/leds/Makefile                         |   1 +
>  drivers/leds/leds-turris-1x.c                 | 474 ++++++++++++++++++
>  4 files changed, 515 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-class-led-driver-turris1x
>  create mode 100644 drivers/leds/leds-turris-1x.c
> 
> diff --git a/Documentation/ABI/testing/sysfs-class-led-driver-turris1x b/Documentation/ABI/testing/sysfs-class-led-driver-turris1x
> new file mode 100644
> index 000000000000..bb8b82b43165
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-led-driver-turris1x
> @@ -0,0 +1,31 @@
> +What:		/sys/class/leds/<led>/device/brightness
> +Date:		July 2022
> +KernelVersion:	5.20
> +Contact:	Pali Rohár <pali@kernel.org>
> +Description:	(RW) On the back size of the Turris 1.x routers there is also
> +		a button which can be used to control the intensity of all the
> +		LEDs at once, so that if they are too bright, user can dim them.
> +
> +		The CPLD firmware cycles between 8 levels of this global
> +		brightness (from 100% to 0%), but this setting can have any
> +		integer value between 0 and 255. It is therefore convenient to be
> +		able to change this setting from software.
> +
> +		Format: %u
> +
> +What:		/sys/class/leds/<led>/device/brightness_level
> +Date:		July 2022
> +KernelVersion:	5.20
> +Contact:	Pali Rohár <pali@kernel.org>
> +Description:	(RW) Current brightness level value (0-7).
> +
> +		Format: %u
> +
> +What:		/sys/class/leds/<led>/device/brightness_values
> +Date:		July 2022
> +KernelVersion:	5.20
> +Contact:	Pali Rohár <pali@kernel.org>
> +Description:	(RW) Values of all 8 levels between which CPLD firmware cycles
> +		when brightness button is pressed.
> +
> +		Format: %u %u %u %u %u %u %u %u
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index a49979f41eee..71caf45c8ac3 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -157,6 +157,15 @@ config LEDS_EL15203000
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called leds-el15203000.
>  
> +config LEDS_TURRIS_1X
> +	tristate "LED support for CZ.NIC's Turris 1.x"
> +	depends on LEDS_CLASS_MULTICOLOR
> +	depends on OF
> +	select LEDS_TRIGGERS
> +	help
> +	  This option enables support for LEDs found on the front side of
> +	  CZ.NIC's Turris 1.x routers.
> +
>  config LEDS_TURRIS_OMNIA
>  	tristate "LED support for CZ.NIC's Turris Omnia"
>  	depends on LEDS_CLASS_MULTICOLOR
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index 4fd2f92cd198..de08083dbbca 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -82,6 +82,7 @@ obj-$(CONFIG_LEDS_TCA6507)		+= leds-tca6507.o
>  obj-$(CONFIG_LEDS_TI_LMU_COMMON)	+= leds-ti-lmu-common.o
>  obj-$(CONFIG_LEDS_TLC591XX)		+= leds-tlc591xx.o
>  obj-$(CONFIG_LEDS_TPS6105X)		+= leds-tps6105x.o
> +obj-$(CONFIG_LEDS_TURRIS_1X)		+= leds-turris-1x.o
>  obj-$(CONFIG_LEDS_TURRIS_OMNIA)		+= leds-turris-omnia.o
>  obj-$(CONFIG_LEDS_WM831X_STATUS)	+= leds-wm831x-status.o
>  obj-$(CONFIG_LEDS_WM8350)		+= leds-wm8350.o
> diff --git a/drivers/leds/leds-turris-1x.c b/drivers/leds/leds-turris-1x.c
> new file mode 100644
> index 000000000000..cf7567b64306
> --- /dev/null
> +++ b/drivers/leds/leds-turris-1x.c
> @@ -0,0 +1,474 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// (C) 2022 Pali Rohár <pali@kernel.org>
> +//
> +// CZ.NIC's Turris 1.x LEDs driver, controlled by CPLD firmware:
> +// https://gitlab.nic.cz/turris/hw/turris_cpld/-/blob/master/CZ_NIC_Router_CPLD.v
> +
> +#include <linux/i2c.h>
> +#include <linux/led-class-multicolor.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include "leds.h"
> +
> +/* LED registers starts at byte 0x13 in CPLD memory map */
> +#define TURRIS1X_LED_REG_OFF(reg) ((reg)-0x13)
> +
> +/* LEDs 1-5 share common register for setting brightness */
> +#define TURRIS1X_LED_BRIGHTNESS_OFF(idx)	({ const u8 _idx = (idx) & 7; \
> +						   (_idx == 0) ? 0 : \
> +						   (_idx <= 5) ? 1 : \
> +						   (_idx - 4); })
> +
> +#define TURRIS1X_LED_BRIGHTNESS_REG(idx, color)	TURRIS1X_LED_REG_OFF(0x13 + \
> +						  3 * TURRIS1X_LED_BRIGHTNESS_OFF(idx) + \
> +						  ((color) & 3))
> +#define TURRIS1X_LED_GLOBAL_LEVEL_REG		TURRIS1X_LED_REG_OFF(0x20)
> +#define TURRIS1X_LED_GET_GLOBAL_BRIGHTNESS_REG	TURRIS1X_LED_REG_OFF(0x21)
> +#define TURRIS1X_LED_SW_OVERRIDE_REG		TURRIS1X_LED_REG_OFF(0x22)
> +#define TURRIS1X_LED_SW_DISABLE_REG		TURRIS1X_LED_REG_OFF(0x23)
> +#define TURRIS1X_LED_GLOBAL_BRIGHTNESS_REG(lvl)	TURRIS1X_LED_REG_OFF(0x28 + ((lvl) & 7))
> +
> +struct turris1x_led {
> +	struct led_classdev_mc mc_cdev;
> +	struct mc_subled subled_info[3];
> +	u32 reg;
> +	bool registered;
> +};
> +
> +#define to_turris1x_led(l)	container_of(l, struct turris1x_led, mc_cdev)
> +
> +struct turris1x_leds {
> +	void __iomem *regs;
> +	struct mutex lock;
> +	struct turris1x_led leds[8];
> +};
> +
> +static struct led_hw_trigger_type turris1x_hw_trigger_type;
> +
> +static int turris1x_hwtrig_activate(struct led_classdev *cdev)
> +{
> +	struct turris1x_leds *leds = dev_get_drvdata(cdev->dev->parent);
> +	struct turris1x_led *led = to_turris1x_led(lcdev_to_mccdev(cdev));
> +	u8 val;
> +
> +	/* Disable software control of LED */
> +	mutex_lock(&leds->lock);
> +	val = readb(leds->regs + TURRIS1X_LED_SW_OVERRIDE_REG);
> +	val &= ~BIT(led->reg);
> +	writeb(val, leds->regs + TURRIS1X_LED_SW_OVERRIDE_REG);
> +	mutex_unlock(&leds->lock);
> +
> +	return 0;
> +}
> +
> +static void turris1x_hwtrig_deactivate(struct led_classdev *cdev)
> +{
> +	struct turris1x_leds *leds = dev_get_drvdata(cdev->dev->parent);
> +	struct turris1x_led *led = to_turris1x_led(lcdev_to_mccdev(cdev));
> +	u8 val;
> +
> +	/* Enable software control of LED */
> +	mutex_lock(&leds->lock);
> +	val = readb(leds->regs + TURRIS1X_LED_SW_OVERRIDE_REG);
> +	val |= BIT(led->reg);
> +	writeb(val, leds->regs + TURRIS1X_LED_SW_OVERRIDE_REG);
> +	mutex_unlock(&leds->lock);
> +}
> +
> +static struct led_trigger turris1x_hw_trigger = {
> +	.name		= "turris1x-cpld",
> +	.activate	= turris1x_hwtrig_activate,
> +	.deactivate	= turris1x_hwtrig_deactivate,
> +	.trigger_type	= &turris1x_hw_trigger_type,
> +};
> +
> +static enum led_brightness turris1x_led_brightness_get(struct led_classdev *cdev)
> +{
> +	struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
> +	struct turris1x_leds *leds = dev_get_drvdata(cdev->dev->parent);
> +	struct turris1x_led *led = to_turris1x_led(mc_cdev);
> +
> +	if (!(readb(leds->regs + TURRIS1X_LED_SW_OVERRIDE_REG) & BIT(led->reg)))
> +		return 1;
> +	else if (!(readb(leds->regs + TURRIS1X_LED_SW_DISABLE_REG) & BIT(led->reg)))
> +		return 1;
> +	else
> +		return 0;
> +}
> +
> +static void turris1x_led_brightness_set(struct led_classdev *cdev,
> +					enum led_brightness brightness)
> +{
> +	struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
> +	struct turris1x_leds *leds = dev_get_drvdata(cdev->dev->parent);
> +	struct turris1x_led *led = to_turris1x_led(mc_cdev);
> +	int i, j;
> +	u8 val;
> +
> +	mutex_lock(&leds->lock);
> +
> +	/* Set new brightness value for each color when LED is enabled */
> +	if (brightness) {
> +		led_mc_calc_color_components(mc_cdev, brightness);
> +		for (i = 0; i < ARRAY_SIZE(led->subled_info); i++)
> +			writeb(mc_cdev->subled_info[i].brightness,
> +			       leds->regs + TURRIS1X_LED_BRIGHTNESS_REG(led->reg, i));
> +
> +		/*
> +		 * LEDs 1-5 (LAN) share common color settings in same sets
> +		 * of HW registers and therefore it is not possible to set
> +		 * different colors. So when chaning color of one LED then
> +		 * reflect color change for all of them.
> +		 */
> +		if (led->reg >= 1 && led->reg <= 5) {
> +			for (j = 0; j < ARRAY_SIZE(leds->leds); j++) {
> +				if (leds->leds[j].reg < 1 ||
> +				    leds->leds[j].reg > 5 ||
> +				    leds->leds[j].reg == led->reg)
> +					continue;
> +				for (i = 0; i < ARRAY_SIZE(led->subled_info); i++)
> +					leds->leds[j].mc_cdev.subled_info[i].intensity =
> +						mc_cdev->subled_info[i].intensity;
> +			}
> +		}
> +	}
> +
> +	/* Enable / disable LED for software control */
> +	val = readb(leds->regs + TURRIS1X_LED_SW_DISABLE_REG);
> +	if (brightness && (val & BIT(led->reg)))
> +		writeb(val & ~BIT(led->reg),
> +		       leds->regs + TURRIS1X_LED_SW_DISABLE_REG);
> +	else if (!brightness && !(val & BIT(led->reg)))
> +		writeb(val | BIT(led->reg),
> +		       leds->regs + TURRIS1X_LED_SW_DISABLE_REG);
> +
> +	mutex_unlock(&leds->lock);
> +}
> +
> +static int turris1x_led_register(struct device *dev, struct turris1x_leds *leds,
> +				 struct device_node *np, u8 val_sw_override,
> +				 u8 val_sw_disable)
> +{
> +	struct led_init_data init_data = {};
> +	struct led_classdev *cdev;
> +	struct turris1x_led *led;
> +	int ret, color;
> +	u32 reg;
> +	int i;
> +
> +	const unsigned int colors[ARRAY_SIZE(led->subled_info)] = {
> +		LED_COLOR_ID_RED, LED_COLOR_ID_GREEN, LED_COLOR_ID_BLUE
> +	};
> +
> +	ret = of_property_read_u32(np, "reg", &reg);
> +	if (ret || reg >= ARRAY_SIZE(leds->leds)) {
> +		dev_err(dev,
> +			"Node %pOF: must contain 'reg' property with values between 0 and %u\n",
> +			np, (unsigned int)ARRAY_SIZE(leds->leds) - 1);
> +		return -EINVAL;
> +	}
> +
> +	ret = of_property_read_u32(np, "color", &color);
> +	if (ret || color != LED_COLOR_ID_RGB) {
> +		dev_err(dev,
> +			"Node %pOF: must contain 'color' property with value LED_COLOR_ID_RGB\n",
> +			np);
> +		return -EINVAL;
> +	}
> +
> +	led = &leds->leds[reg];
> +
> +	if (led->registered) {
> +		dev_err(dev, "Node %pOF: duplicate 'reg' property %u\n",
> +			     np, reg);
> +		return -EINVAL;
> +	}
> +
> +	led->registered = true;
> +	led->reg = reg;
> +
> +	/* Set initial colors to what are currently in use */
> +	for (i = 0; i < ARRAY_SIZE(led->subled_info); i++) {
> +		led->subled_info[i].intensity =
> +			readb(leds->regs + TURRIS1X_LED_BRIGHTNESS_REG(reg, i));
> +		led->subled_info[i].color_index = colors[i];
> +		led->subled_info[i].channel = i;
> +	}
> +
> +	led->mc_cdev.subled_info = led->subled_info;
> +	led->mc_cdev.num_colors = ARRAY_SIZE(led->subled_info);
> +
> +	init_data.fwnode = &np->fwnode;
> +
> +	cdev = &led->mc_cdev.led_cdev;
> +	cdev->max_brightness = 1;
> +	cdev->brightness_get = turris1x_led_brightness_get;
> +	cdev->brightness_set = turris1x_led_brightness_set;
> +
> +	/* All LEDs except LED 6 (WiFi) can be controller by hardware trigger */
> +	if (reg != 6)
> +		cdev->trigger_type = &turris1x_hw_trigger_type;
> +
> +	/* Disable hardware trigger for LED 6 (WiFi) - allow software control */
> +	if (reg == 6 && !(val_sw_override & BIT(6))) {
> +		if (!(val_sw_disable & BIT(6))) {
> +			val_sw_disable |= BIT(6);
> +			writeb(val_sw_disable,
> +			       leds->regs + TURRIS1X_LED_SW_DISABLE_REG);
> +		}
> +		val_sw_override |= BIT(6);
> +		writeb(val_sw_override,
> +		       leds->regs + TURRIS1X_LED_SW_OVERRIDE_REG);
> +	}
> +
> +	if (!(val_sw_override & BIT(reg)))
> +		cdev->default_trigger = turris1x_hw_trigger.name;
> +
> +	if (!(val_sw_override & BIT(reg)) || !(val_sw_disable & BIT(reg)))
> +		cdev->brightness = 1;
> +
> +	ret = devm_led_classdev_multicolor_register_ext(dev, &led->mc_cdev,
> +							&init_data);
> +	if (ret) {
> +		dev_err(dev, "Cannot register LED %pOF: %i\n", np, ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static ssize_t brightness_show(struct device *dev, struct device_attribute *a,
> +			       char *buf)
> +{
> +	struct turris1x_leds *leds = dev_get_drvdata(dev);
> +	unsigned int brightness;
> +
> +	/*
> +	 * Current brightness value is available in read-only register
> +	 * TURRIS1X_LED_GET_GLOBAL_BRIGHTNESS_REG. Equivalent code is:
> +	 * level = readb(leds->regs + TURRIS1X_LED_GLOBAL_LEVEL_REG) & 7;
> +	 * brightness = readb(leds->regs + TURRIS1X_LED_GLOBAL_BRIGHTNESS_REG(level));
> +	 */
> +	brightness = readb(leds->regs + TURRIS1X_LED_GET_GLOBAL_BRIGHTNESS_REG);
> +
> +	return sprintf(buf, "%u\n", brightness);
> +}
> +
> +static ssize_t brightness_store(struct device *dev, struct device_attribute *a,
> +				const char *buf, size_t count)
> +{
> +	struct turris1x_leds *leds = dev_get_drvdata(dev);
> +	int best_error, error, level, value;
> +	unsigned long brightness;
> +	u8 best_level;
> +
> +	if (kstrtoul(buf, 10, &brightness))
> +		return -EINVAL;
> +
> +	if (brightness > 255)
> +		return -EINVAL;
> +
> +	/*
> +	 * Brightness can be set only to one of 8 predefined value levels
> +	 * available in TURRIS1X_LED_GLOBAL_BRIGHTNESS_REG(level) registers.
> +	 * Choose level which has nearest value to the specified brightness.
> +	 */
> +	best_level = 0;
> +	best_error = INT_MAX;
> +	for (level = 0; level < 8; level++) {
> +		value = readb(leds->regs +
> +			      TURRIS1X_LED_GLOBAL_BRIGHTNESS_REG(level));
> +		error = abs(value - (int)brightness);
> +		if (best_error > error) {
> +			best_error = error;
> +			best_level = level;
> +		}
> +	}
> +
> +	writeb(best_level, leds->regs + TURRIS1X_LED_GLOBAL_LEVEL_REG);
> +
> +	return count;
> +}
> +static DEVICE_ATTR_RW(brightness);
> +
> +static ssize_t brightness_level_show(struct device *dev,
> +				     struct device_attribute *a, char *buf)
> +{
> +	struct turris1x_leds *leds = dev_get_drvdata(dev);
> +	unsigned int level;
> +
> +	level = readb(leds->regs + TURRIS1X_LED_GLOBAL_LEVEL_REG) & 7;
> +
> +	return sprintf(buf, "%u\n", level);
> +}
> +
> +static ssize_t brightness_level_store(struct device *dev,
> +				      struct device_attribute *a,
> +				      const char *buf, size_t count)
> +{
> +	struct turris1x_leds *leds = dev_get_drvdata(dev);
> +	unsigned long level;
> +
> +	if (kstrtoul(buf, 10, &level))
> +		return -EINVAL;
> +
> +	if (level > 7)
> +		return -EINVAL;
> +
> +	writeb(level, leds->regs + TURRIS1X_LED_GLOBAL_LEVEL_REG);
> +
> +	return count;
> +}
> +static DEVICE_ATTR_RW(brightness_level);
> +
> +static ssize_t brightness_values_show(struct device *dev,
> +				      struct device_attribute *a, char *buf)
> +{
> +	struct turris1x_leds *leds = dev_get_drvdata(dev);
> +	unsigned int vals[8];
> +	int i;
> +
> +	for (i = 0; i < 8; i++)
> +		vals[i] = readb(leds->regs +
> +				TURRIS1X_LED_GLOBAL_BRIGHTNESS_REG(i));
> +
> +	return sprintf(buf, "%u %u %u %u %u %u %u %u\n", vals[0], vals[1],
> +		       vals[2], vals[3], vals[4], vals[5], vals[6], vals[7]);
> +}
> +
> +static ssize_t brightness_values_store(struct device *dev,
> +				       struct device_attribute *a,
> +				       const char *buf, size_t count)
> +{
> +	struct turris1x_leds *leds = dev_get_drvdata(dev);
> +	unsigned int vals[8];
> +	int nchars;
> +	int i;
> +
> +	if (sscanf(buf, "%u %u %u %u %u %u %u %u%n", &vals[0], &vals[1],
> +		   &vals[2], &vals[3], &vals[4], &vals[5], &vals[6], &vals[7],
> +		   &nchars) != 8 || nchars + 1 < count)
> +		return -EINVAL;
> +
> +	for (i = 0; i < 8; i++)
> +		writeb(vals[i],
> +		       leds->regs + TURRIS1X_LED_GLOBAL_BRIGHTNESS_REG(i));
> +
> +	return count;
> +}
> +static DEVICE_ATTR_RW(brightness_values);
> +
> +static struct attribute *turris1x_leds_controller_attrs[] = {
> +	&dev_attr_brightness.attr,
> +	&dev_attr_brightness_level.attr,
> +	&dev_attr_brightness_values.attr,
> +	NULL,
> +};
> +ATTRIBUTE_GROUPS(turris1x_leds_controller);
> +
> +static int turris1x_leds_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev_of_node(dev);
> +	struct device_node *child;
> +	struct turris1x_leds *leds;
> +	struct resource *res;
> +	void __iomem *regs;
> +	u8 val_sw_override;
> +	u8 val_sw_disable;
> +	int ret;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res)
> +		return -ENODEV;
> +
> +	regs = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(regs))
> +		return PTR_ERR(regs);
> +
> +	leds = devm_kzalloc(dev, sizeof(*leds), GFP_KERNEL);
> +	if (!leds)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, leds);
> +
> +	leds->regs = regs;
> +	mutex_init(&leds->lock);
> +
> +	ret = devm_led_trigger_register(dev, &turris1x_hw_trigger);
> +	if (ret) {
> +		dev_err(dev, "Cannot register private LED trigger: %d\n", ret);
> +		return ret;
> +	}
> +
> +	val_sw_override = readb(leds->regs + TURRIS1X_LED_SW_OVERRIDE_REG);
> +	val_sw_disable = readb(leds->regs + TURRIS1X_LED_SW_DISABLE_REG);
> +
> +	for_each_available_child_of_node(np, child) {
> +		ret = turris1x_led_register(dev, leds, child,
> +					    val_sw_override, val_sw_disable);
> +		if (ret) {
> +			of_node_put(child);
> +			return ret;
> +		}
> +	}
> +
> +	ret = devm_device_add_groups(dev, turris1x_leds_controller_groups);
> +	if (ret) {
> +		dev_err(dev, "Could not add attribute group!\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void turris1x_leds_shutdown(struct platform_device *pdev)
> +{
> +	struct turris1x_leds *leds = platform_get_drvdata(pdev);
> +	int i, j;
> +	u8 val;
> +
> +	/*
> +	 * LED registers are persisent across board resets.
> +	 * So reset LEDs to default state before kernel reboots.
> +	 */
> +
> +	/* Disable software control of all LEDs except LED 6 (WiFi) */
> +	writeb(BIT(6), leds->regs + TURRIS1X_LED_SW_OVERRIDE_REG);
> +
> +	/* Turn off LED 6 (WiFi) as there is no hardware trigger for it */
> +	val = readb(leds->regs + TURRIS1X_LED_SW_DISABLE_REG);
> +	writeb(val | BIT(6), leds->regs + TURRIS1X_LED_SW_DISABLE_REG);
> +
> +	/* Reset colors of all LEDs to default values */
> +	for (i = 0; i < ARRAY_SIZE(leds->leds); i++) {
> +		/* Skip LAN2-LAN5 LEDs which share color register with LAN1 */
> +		if (i >= 2 && i <= 5)
> +			continue;
> +		for (j = 0; j < ARRAY_SIZE(leds->leds[i].subled_info); j++)
> +			writeb(0xff,
> +			       leds->regs + TURRIS1X_LED_BRIGHTNESS_REG(i, j));
> +	}
> +}
> +
> +static const struct of_device_id of_turris1x_leds_match[] = {
> +	{ .compatible = "cznic,turris1x-leds" },
> +	{},
> +};
> +
> +static struct platform_driver turris1x_leds_driver = {
> +	.probe = turris1x_leds_probe,
> +	.shutdown = turris1x_leds_shutdown,
> +	.driver = {
> +		.name = "turris1x_leds",
> +		.of_match_table = of_turris1x_leds_match,
> +	},
> +};
> +module_platform_driver(turris1x_leds_driver);
> +
> +MODULE_AUTHOR("Pali Rohár <pali@kernel.org>");
> +MODULE_DESCRIPTION("CZ.NIC's Turris 1.x LEDs");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:turris1x_leds");
> -- 
> 2.20.1
>
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/leds/cznic,turris1x-leds.yaml b/Documentation/devicetree/bindings/leds/cznic,turris1x-leds.yaml
new file mode 100644
index 000000000000..bcaab5b03128
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/cznic,turris1x-leds.yaml
@@ -0,0 +1,118 @@ 
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/cznic,turris1x-leds.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: CZ.NIC's Turris 1.x LEDs driver
+
+maintainers:
+  - Pali Rohár <pali@kernel.org>
+
+description:
+  This module adds support for the RGB LEDs found on the front panel of the
+  Turris 1.x routers. There are 8 RGB LEDs that are controlled by CZ.NIC CPLD
+  firmware running on Lattice FPGA. Firmware is open source and available at
+  https://gitlab.nic.cz/turris/hw/turris_cpld/-/blob/master/CZ_NIC_Router_CPLD.v
+
+properties:
+  compatible:
+    const: cznic,turris1x-leds
+
+  reg:
+    description: CPLD address range where LED registers are mapped
+    maxItems: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+patternProperties:
+  "^multi-led@[0-7]$":
+    type: object
+    $ref: leds-class-multicolor.yaml#
+    unevaluatedProperties: false
+
+    properties:
+      reg:
+        minimum: 0
+        maximum: 7
+
+    required:
+      - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/leds/common.h>
+
+    cpld@3,0 {
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges = <0x0 0x3 0x0 0x00020000>;
+
+        led-controller@13 {
+            compatible = "cznic,turris1x-leds";
+            reg = <0x13 0x1d>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            multi-led@0 {
+                    reg = <0x0>;
+                    color = <LED_COLOR_ID_RGB>;
+                    function = LED_FUNCTION_WAN;
+            };
+
+            multi-led@1 {
+                    reg = <0x1>;
+                    color = <LED_COLOR_ID_RGB>;
+                    function = LED_FUNCTION_LAN;
+                    function-enumerator = <5>;
+            };
+
+            multi-led@2 {
+                    reg = <0x2>;
+                    color = <LED_COLOR_ID_RGB>;
+                    function = LED_FUNCTION_LAN;
+                    function-enumerator = <4>;
+            };
+
+            multi-led@3 {
+                    reg = <0x3>;
+                    color = <LED_COLOR_ID_RGB>;
+                    function = LED_FUNCTION_LAN;
+                    function-enumerator = <3>;
+            };
+
+            multi-led@4 {
+                    reg = <0x4>;
+                    color = <LED_COLOR_ID_RGB>;
+                    function = LED_FUNCTION_LAN;
+                    function-enumerator = <2>;
+            };
+
+            multi-led@5 {
+                    reg = <0x5>;
+                    color = <LED_COLOR_ID_RGB>;
+                    function = LED_FUNCTION_LAN;
+                    function-enumerator = <1>;
+            };
+
+            multi-led@6 {
+                    reg = <0x6>;
+                    color = <LED_COLOR_ID_RGB>;
+                    function = LED_FUNCTION_WLAN;
+            };
+
+            multi-led@7 {
+                    reg = <0x7>;
+                    color = <LED_COLOR_ID_RGB>;
+                    function = LED_FUNCTION_POWER;
+            };
+        };
+    };
+
+...