[v4,2/4] gpiolib: add gpiod_get_array and gpiod_put_array functions
diff mbox

Message ID 1592036.ZMHnOUhaPf@pcimr
State New
Headers show

Commit Message

Rojhalat Ibrahim Feb. 10, 2015, 1:40 p.m. UTC
Introduce new functions for conveniently obtaining and disposing of an entire
array of GPIOs with one function call.

Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Suggested-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
---
Change log:
  v4: - use shorter names for members of struct gpio_descs
      - rename lut_gpio_count to platform_gpio_count for clarity
      - add check for successful memory allocation
      - use ERR_CAST()
  v3: - rebase on current linux-gpio devel branch
      - fix ACPI GPIO counting
      - allow for zero-sized arrays
      - make the flags argument mandatory for the new functions
      - clarify documentation
  v2: change interface

 Documentation/gpio/consumer.txt |   33 +++++
 drivers/gpio/gpiolib.c          |  233 ++++++++++++++++++++++++++++++++++++++++
 include/linux/gpio/consumer.h   |   46 +++++++
 3 files changed, 309 insertions(+), 3 deletions(-)

Comments

Mika Westerberg Feb. 11, 2015, 10:30 a.m. UTC | #1
On Tue, Feb 10, 2015 at 02:40:52PM +0100, Rojhalat Ibrahim wrote:
> +#ifdef CONFIG_ACPI
> +
> +static unsigned int acpi_gpio_package_count(const union acpi_object *obj)
> +{
> +	const union acpi_object *element = obj->package.elements;
> +	const union acpi_object *end = element + obj->package.count;
> +	unsigned int count = 0;
> +
> +	while (element < end) {
> +		if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
> +			count++;
> +
> +		element++;
> +	}
> +	return count;
> +}
> +
> +static int acpi_find_gpio_count(struct acpi_resource *ares, void *data)
> +{
> +	unsigned int *count = data;
> +
> +	if (ares->type == ACPI_RESOURCE_TYPE_GPIO)
> +		*count += ares->data.gpio.pin_table_length;
> +
> +	return 1;
> +}
> +
> +static int acpi_gpio_count(struct device *dev, const char *con_id)
> +{
> +	struct acpi_device *adev = ACPI_COMPANION(dev);
> +	const union acpi_object *obj;
> +	const struct acpi_gpio_mapping *gm;
> +	int count = -ENOENT;
> +	int ret;
> +	char propname[32];
> +	unsigned int i;
> +
> +	/* Try first from _DSD */
> +	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
> +		if (con_id && strcmp(con_id, "gpios"))
> +			snprintf(propname, sizeof(propname), "%s-%s",
> +				 con_id, gpio_suffixes[i]);
> +		else
> +			snprintf(propname, sizeof(propname), "%s",
> +				 gpio_suffixes[i]);
> +
> +		ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_ANY,
> +					    &obj);
> +		if (ret == 0) {
> +			if (obj->type == ACPI_TYPE_LOCAL_REFERENCE)
> +				count = 1;
> +			else if (obj->type == ACPI_TYPE_PACKAGE)
> +				count = acpi_gpio_package_count(obj);
> +		} else if (adev->driver_gpios) {
> +			for (gm = adev->driver_gpios; gm->name; gm++)
> +				if (strcmp(propname, gm->name) == 0) {
> +					count = gm->size;
> +					break;
> +				}
> +		}
> +		if (count >= 0)
> +			break;
> +	}
> +
> +	/* Then from plain _CRS GPIOs */
> +	if (count < 0) {
> +		struct list_head resource_list;
> +		unsigned int crs_count = 0;
> +
> +		INIT_LIST_HEAD(&resource_list);
> +		acpi_dev_get_resources(adev, &resource_list,
> +				       acpi_find_gpio_count, &crs_count);
> +		acpi_dev_free_resource_list(&resource_list);
> +		if (crs_count > 0)
> +			count = crs_count;
> +	}
> +	return count;
> +}
> +
> +#else
> +
> +static int acpi_gpio_count(struct device *dev, const char *con_id)
> +{
> +	return -ENODEV;
> +}
> +
> +#endif

It just occured to me that it would be better to put this code to
gpiolib-acpi.c and declare acpi_gpio_count() in drivers/gpio/gpiolib.h.

That said, I tested this code on Lenovo Thinkpad10 by converting
drivers/input/misc/soc_button_array.c to fetch its GPIOs using this new
API -- it works just fine (and looks better).

Once you have done the above change you can add for the ACPI parts,

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
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Rojhalat Ibrahim Feb. 11, 2015, 12:14 p.m. UTC | #2
On Wednesday 11 February 2015 12:30:01 Mika Westerberg wrote:
> On Tue, Feb 10, 2015 at 02:40:52PM +0100, Rojhalat Ibrahim wrote:
> > +#ifdef CONFIG_ACPI
> > +
> > +static unsigned int acpi_gpio_package_count(const union acpi_object *obj)
> > +{
> > +	const union acpi_object *element = obj->package.elements;
> > +	const union acpi_object *end = element + obj->package.count;
> > +	unsigned int count = 0;
> > +
> > +	while (element < end) {
> > +		if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
> > +			count++;
> > +
> > +		element++;
> > +	}
> > +	return count;
> > +}
> > +
> > +static int acpi_find_gpio_count(struct acpi_resource *ares, void *data)
> > +{
> > +	unsigned int *count = data;
> > +
> > +	if (ares->type == ACPI_RESOURCE_TYPE_GPIO)
> > +		*count += ares->data.gpio.pin_table_length;
> > +
> > +	return 1;
> > +}
> > +
> > +static int acpi_gpio_count(struct device *dev, const char *con_id)
> > +{
> > +	struct acpi_device *adev = ACPI_COMPANION(dev);
> > +	const union acpi_object *obj;
> > +	const struct acpi_gpio_mapping *gm;
> > +	int count = -ENOENT;
> > +	int ret;
> > +	char propname[32];
> > +	unsigned int i;
> > +
> > +	/* Try first from _DSD */
> > +	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
> > +		if (con_id && strcmp(con_id, "gpios"))
> > +			snprintf(propname, sizeof(propname), "%s-%s",
> > +				 con_id, gpio_suffixes[i]);
> > +		else
> > +			snprintf(propname, sizeof(propname), "%s",
> > +				 gpio_suffixes[i]);
> > +
> > +		ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_ANY,
> > +					    &obj);
> > +		if (ret == 0) {
> > +			if (obj->type == ACPI_TYPE_LOCAL_REFERENCE)
> > +				count = 1;
> > +			else if (obj->type == ACPI_TYPE_PACKAGE)
> > +				count = acpi_gpio_package_count(obj);
> > +		} else if (adev->driver_gpios) {
> > +			for (gm = adev->driver_gpios; gm->name; gm++)
> > +				if (strcmp(propname, gm->name) == 0) {
> > +					count = gm->size;
> > +					break;
> > +				}
> > +		}
> > +		if (count >= 0)
> > +			break;
> > +	}
> > +
> > +	/* Then from plain _CRS GPIOs */
> > +	if (count < 0) {
> > +		struct list_head resource_list;
> > +		unsigned int crs_count = 0;
> > +
> > +		INIT_LIST_HEAD(&resource_list);
> > +		acpi_dev_get_resources(adev, &resource_list,
> > +				       acpi_find_gpio_count, &crs_count);
> > +		acpi_dev_free_resource_list(&resource_list);
> > +		if (crs_count > 0)
> > +			count = crs_count;
> > +	}
> > +	return count;
> > +}
> > +
> > +#else
> > +
> > +static int acpi_gpio_count(struct device *dev, const char *con_id)
> > +{
> > +	return -ENODEV;
> > +}
> > +
> > +#endif
> 
> It just occured to me that it would be better to put this code to
> gpiolib-acpi.c and declare acpi_gpio_count() in drivers/gpio/gpiolib.h.
> 

Ok. I will also have to move the definition of gpio_suffixes[] (PATCH 1/4)
to drivers/gpio/gpiolib.h since it is needed by both the OF and the ACPI
portions of the code.

> That said, I tested this code on Lenovo Thinkpad10 by converting
> drivers/input/misc/soc_button_array.c to fetch its GPIOs using this new
> API -- it works just fine (and looks better).
> 
> Once you have done the above change you can add for the ACPI parts,
> 
> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> 

Great. Thanks.



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Alexandre Courbot Feb. 11, 2015, 1:31 p.m. UTC | #3
On Wed, Feb 11, 2015 at 9:14 PM, Rojhalat Ibrahim <imr@rtschenk.de> wrote:
> On Wednesday 11 February 2015 12:30:01 Mika Westerberg wrote:
>> On Tue, Feb 10, 2015 at 02:40:52PM +0100, Rojhalat Ibrahim wrote:
>> > +#ifdef CONFIG_ACPI
>> > +
>> > +static unsigned int acpi_gpio_package_count(const union acpi_object *obj)
>> > +{
>> > +   const union acpi_object *element = obj->package.elements;
>> > +   const union acpi_object *end = element + obj->package.count;
>> > +   unsigned int count = 0;
>> > +
>> > +   while (element < end) {
>> > +           if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
>> > +                   count++;
>> > +
>> > +           element++;
>> > +   }
>> > +   return count;
>> > +}
>> > +
>> > +static int acpi_find_gpio_count(struct acpi_resource *ares, void *data)
>> > +{
>> > +   unsigned int *count = data;
>> > +
>> > +   if (ares->type == ACPI_RESOURCE_TYPE_GPIO)
>> > +           *count += ares->data.gpio.pin_table_length;
>> > +
>> > +   return 1;
>> > +}
>> > +
>> > +static int acpi_gpio_count(struct device *dev, const char *con_id)
>> > +{
>> > +   struct acpi_device *adev = ACPI_COMPANION(dev);
>> > +   const union acpi_object *obj;
>> > +   const struct acpi_gpio_mapping *gm;
>> > +   int count = -ENOENT;
>> > +   int ret;
>> > +   char propname[32];
>> > +   unsigned int i;
>> > +
>> > +   /* Try first from _DSD */
>> > +   for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
>> > +           if (con_id && strcmp(con_id, "gpios"))
>> > +                   snprintf(propname, sizeof(propname), "%s-%s",
>> > +                            con_id, gpio_suffixes[i]);
>> > +           else
>> > +                   snprintf(propname, sizeof(propname), "%s",
>> > +                            gpio_suffixes[i]);
>> > +
>> > +           ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_ANY,
>> > +                                       &obj);
>> > +           if (ret == 0) {
>> > +                   if (obj->type == ACPI_TYPE_LOCAL_REFERENCE)
>> > +                           count = 1;
>> > +                   else if (obj->type == ACPI_TYPE_PACKAGE)
>> > +                           count = acpi_gpio_package_count(obj);
>> > +           } else if (adev->driver_gpios) {
>> > +                   for (gm = adev->driver_gpios; gm->name; gm++)
>> > +                           if (strcmp(propname, gm->name) == 0) {
>> > +                                   count = gm->size;
>> > +                                   break;
>> > +                           }
>> > +           }
>> > +           if (count >= 0)
>> > +                   break;
>> > +   }
>> > +
>> > +   /* Then from plain _CRS GPIOs */
>> > +   if (count < 0) {
>> > +           struct list_head resource_list;
>> > +           unsigned int crs_count = 0;
>> > +
>> > +           INIT_LIST_HEAD(&resource_list);
>> > +           acpi_dev_get_resources(adev, &resource_list,
>> > +                                  acpi_find_gpio_count, &crs_count);
>> > +           acpi_dev_free_resource_list(&resource_list);
>> > +           if (crs_count > 0)
>> > +                   count = crs_count;
>> > +   }
>> > +   return count;
>> > +}
>> > +
>> > +#else
>> > +
>> > +static int acpi_gpio_count(struct device *dev, const char *con_id)
>> > +{
>> > +   return -ENODEV;
>> > +}
>> > +
>> > +#endif
>>
>> It just occured to me that it would be better to put this code to
>> gpiolib-acpi.c and declare acpi_gpio_count() in drivers/gpio/gpiolib.h.
>>
>
> Ok. I will also have to move the definition of gpio_suffixes[] (PATCH 1/4)
> to drivers/gpio/gpiolib.h since it is needed by both the OF and the ACPI
> portions of the code.

We will really need to factorize this lookup code. I will give it a
look, but first I'd like to merge this good stuff.

I am mixed about moving these declarations into gpiolib.h - maybe have
one static declaration per file instead, especially since lookup on
ACPI is not necessarily the same as lookup on DT. It makes sense to
have it that way.

>
>> That said, I tested this code on Lenovo Thinkpad10 by converting
>> drivers/input/misc/soc_button_array.c to fetch its GPIOs using this new
>> API -- it works just fine (and looks better).
>>
>> Once you have done the above change you can add for the ACPI parts,
>>
>> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
>> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
>>
>
> Great. Thanks.

Hopefully the next revision will be the right one! :)
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Rojhalat Ibrahim Feb. 11, 2015, 2 p.m. UTC | #4
On Wednesday 11 February 2015 22:31:12 Alexandre Courbot wrote:
> On Wed, Feb 11, 2015 at 9:14 PM, Rojhalat Ibrahim <imr@rtschenk.de> wrote:
> > On Wednesday 11 February 2015 12:30:01 Mika Westerberg wrote:
> >> On Tue, Feb 10, 2015 at 02:40:52PM +0100, Rojhalat Ibrahim wrote:
> >> > +#ifdef CONFIG_ACPI
> >> > +
> >> > +static unsigned int acpi_gpio_package_count(const union acpi_object *obj)
> >> > +{
> >> > +   const union acpi_object *element = obj->package.elements;
> >> > +   const union acpi_object *end = element + obj->package.count;
> >> > +   unsigned int count = 0;
> >> > +
> >> > +   while (element < end) {
> >> > +           if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
> >> > +                   count++;
> >> > +
> >> > +           element++;
> >> > +   }
> >> > +   return count;
> >> > +}
> >> > +
> >> > +static int acpi_find_gpio_count(struct acpi_resource *ares, void *data)
> >> > +{
> >> > +   unsigned int *count = data;
> >> > +
> >> > +   if (ares->type == ACPI_RESOURCE_TYPE_GPIO)
> >> > +           *count += ares->data.gpio.pin_table_length;
> >> > +
> >> > +   return 1;
> >> > +}
> >> > +
> >> > +static int acpi_gpio_count(struct device *dev, const char *con_id)
> >> > +{
> >> > +   struct acpi_device *adev = ACPI_COMPANION(dev);
> >> > +   const union acpi_object *obj;
> >> > +   const struct acpi_gpio_mapping *gm;
> >> > +   int count = -ENOENT;
> >> > +   int ret;
> >> > +   char propname[32];
> >> > +   unsigned int i;
> >> > +
> >> > +   /* Try first from _DSD */
> >> > +   for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
> >> > +           if (con_id && strcmp(con_id, "gpios"))
> >> > +                   snprintf(propname, sizeof(propname), "%s-%s",
> >> > +                            con_id, gpio_suffixes[i]);
> >> > +           else
> >> > +                   snprintf(propname, sizeof(propname), "%s",
> >> > +                            gpio_suffixes[i]);
> >> > +
> >> > +           ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_ANY,
> >> > +                                       &obj);
> >> > +           if (ret == 0) {
> >> > +                   if (obj->type == ACPI_TYPE_LOCAL_REFERENCE)
> >> > +                           count = 1;
> >> > +                   else if (obj->type == ACPI_TYPE_PACKAGE)
> >> > +                           count = acpi_gpio_package_count(obj);
> >> > +           } else if (adev->driver_gpios) {
> >> > +                   for (gm = adev->driver_gpios; gm->name; gm++)
> >> > +                           if (strcmp(propname, gm->name) == 0) {
> >> > +                                   count = gm->size;
> >> > +                                   break;
> >> > +                           }
> >> > +           }
> >> > +           if (count >= 0)
> >> > +                   break;
> >> > +   }
> >> > +
> >> > +   /* Then from plain _CRS GPIOs */
> >> > +   if (count < 0) {
> >> > +           struct list_head resource_list;
> >> > +           unsigned int crs_count = 0;
> >> > +
> >> > +           INIT_LIST_HEAD(&resource_list);
> >> > +           acpi_dev_get_resources(adev, &resource_list,
> >> > +                                  acpi_find_gpio_count, &crs_count);
> >> > +           acpi_dev_free_resource_list(&resource_list);
> >> > +           if (crs_count > 0)
> >> > +                   count = crs_count;
> >> > +   }
> >> > +   return count;
> >> > +}
> >> > +
> >> > +#else
> >> > +
> >> > +static int acpi_gpio_count(struct device *dev, const char *con_id)
> >> > +{
> >> > +   return -ENODEV;
> >> > +}
> >> > +
> >> > +#endif
> >>
> >> It just occured to me that it would be better to put this code to
> >> gpiolib-acpi.c and declare acpi_gpio_count() in drivers/gpio/gpiolib.h.
> >>
> >
> > Ok. I will also have to move the definition of gpio_suffixes[] (PATCH 1/4)
> > to drivers/gpio/gpiolib.h since it is needed by both the OF and the ACPI
> > portions of the code.
> 
> We will really need to factorize this lookup code. I will give it a
> look, but first I'd like to merge this good stuff.
> 
> I am mixed about moving these declarations into gpiolib.h - maybe have
> one static declaration per file instead, especially since lookup on
> ACPI is not necessarily the same as lookup on DT. It makes sense to
> have it that way.
> 

If we do one static declaration per file then acpi_find_gpio() in gpiolib.c
is going to use potentially different suffixes from acpi_gpio_count() in
gpiolib-acpi.c. That can't be good.

Furthermore it seems to me that while the suffixes do not necessarily have to
be the same for ACPI and DT, they are now, and it may even be desirable to
keep them consistent as long as there is no reason for not doing so.

> >
> >> That said, I tested this code on Lenovo Thinkpad10 by converting
> >> drivers/input/misc/soc_button_array.c to fetch its GPIOs using this new
> >> API -- it works just fine (and looks better).
> >>
> >> Once you have done the above change you can add for the ACPI parts,
> >>
> >> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> >> Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> >>
> >
> > Great. Thanks.
> 
> Hopefully the next revision will be the right one! :)
> 

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Mika Westerberg Feb. 11, 2015, 2:19 p.m. UTC | #5
On Wed, Feb 11, 2015 at 03:00:16PM +0100, Rojhalat Ibrahim wrote:
> On Wednesday 11 February 2015 22:31:12 Alexandre Courbot wrote:
> > On Wed, Feb 11, 2015 at 9:14 PM, Rojhalat Ibrahim <imr@rtschenk.de> wrote:
> > > On Wednesday 11 February 2015 12:30:01 Mika Westerberg wrote:
> > >> On Tue, Feb 10, 2015 at 02:40:52PM +0100, Rojhalat Ibrahim wrote:
> > >> > +#ifdef CONFIG_ACPI
> > >> > +
> > >> > +static unsigned int acpi_gpio_package_count(const union acpi_object *obj)
> > >> > +{
> > >> > +   const union acpi_object *element = obj->package.elements;
> > >> > +   const union acpi_object *end = element + obj->package.count;
> > >> > +   unsigned int count = 0;
> > >> > +
> > >> > +   while (element < end) {
> > >> > +           if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
> > >> > +                   count++;
> > >> > +
> > >> > +           element++;
> > >> > +   }
> > >> > +   return count;
> > >> > +}
> > >> > +
> > >> > +static int acpi_find_gpio_count(struct acpi_resource *ares, void *data)
> > >> > +{
> > >> > +   unsigned int *count = data;
> > >> > +
> > >> > +   if (ares->type == ACPI_RESOURCE_TYPE_GPIO)
> > >> > +           *count += ares->data.gpio.pin_table_length;
> > >> > +
> > >> > +   return 1;
> > >> > +}
> > >> > +
> > >> > +static int acpi_gpio_count(struct device *dev, const char *con_id)
> > >> > +{
> > >> > +   struct acpi_device *adev = ACPI_COMPANION(dev);
> > >> > +   const union acpi_object *obj;
> > >> > +   const struct acpi_gpio_mapping *gm;
> > >> > +   int count = -ENOENT;
> > >> > +   int ret;
> > >> > +   char propname[32];
> > >> > +   unsigned int i;
> > >> > +
> > >> > +   /* Try first from _DSD */
> > >> > +   for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
> > >> > +           if (con_id && strcmp(con_id, "gpios"))
> > >> > +                   snprintf(propname, sizeof(propname), "%s-%s",
> > >> > +                            con_id, gpio_suffixes[i]);
> > >> > +           else
> > >> > +                   snprintf(propname, sizeof(propname), "%s",
> > >> > +                            gpio_suffixes[i]);
> > >> > +
> > >> > +           ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_ANY,
> > >> > +                                       &obj);
> > >> > +           if (ret == 0) {
> > >> > +                   if (obj->type == ACPI_TYPE_LOCAL_REFERENCE)
> > >> > +                           count = 1;
> > >> > +                   else if (obj->type == ACPI_TYPE_PACKAGE)
> > >> > +                           count = acpi_gpio_package_count(obj);
> > >> > +           } else if (adev->driver_gpios) {
> > >> > +                   for (gm = adev->driver_gpios; gm->name; gm++)
> > >> > +                           if (strcmp(propname, gm->name) == 0) {
> > >> > +                                   count = gm->size;
> > >> > +                                   break;
> > >> > +                           }
> > >> > +           }
> > >> > +           if (count >= 0)
> > >> > +                   break;
> > >> > +   }
> > >> > +
> > >> > +   /* Then from plain _CRS GPIOs */
> > >> > +   if (count < 0) {
> > >> > +           struct list_head resource_list;
> > >> > +           unsigned int crs_count = 0;
> > >> > +
> > >> > +           INIT_LIST_HEAD(&resource_list);
> > >> > +           acpi_dev_get_resources(adev, &resource_list,
> > >> > +                                  acpi_find_gpio_count, &crs_count);
> > >> > +           acpi_dev_free_resource_list(&resource_list);
> > >> > +           if (crs_count > 0)
> > >> > +                   count = crs_count;
> > >> > +   }
> > >> > +   return count;
> > >> > +}
> > >> > +
> > >> > +#else
> > >> > +
> > >> > +static int acpi_gpio_count(struct device *dev, const char *con_id)
> > >> > +{
> > >> > +   return -ENODEV;
> > >> > +}
> > >> > +
> > >> > +#endif
> > >>
> > >> It just occured to me that it would be better to put this code to
> > >> gpiolib-acpi.c and declare acpi_gpio_count() in drivers/gpio/gpiolib.h.
> > >>
> > >
> > > Ok. I will also have to move the definition of gpio_suffixes[] (PATCH 1/4)
> > > to drivers/gpio/gpiolib.h since it is needed by both the OF and the ACPI
> > > portions of the code.
> > 
> > We will really need to factorize this lookup code. I will give it a
> > look, but first I'd like to merge this good stuff.
> > 
> > I am mixed about moving these declarations into gpiolib.h - maybe have
> > one static declaration per file instead, especially since lookup on
> > ACPI is not necessarily the same as lookup on DT. It makes sense to
> > have it that way.
> > 
> 
> If we do one static declaration per file then acpi_find_gpio() in gpiolib.c
> is going to use potentially different suffixes from acpi_gpio_count() in
> gpiolib-acpi.c. That can't be good.
> 
> Furthermore it seems to me that while the suffixes do not necessarily have to
> be the same for ACPI and DT, they are now, and it may even be desirable to
> keep them consistent as long as there is no reason for not doing so.

Yeah, I didn't realize that by moving stuff to gpiolib-acpi.c you need
to duplicate gpio_suffixes as well.

So either leave it as is now or then we can have a bit stricter suffixes
for ACPI (which I would prefer). In other words we only accept
"foo-gpios" or "gpios". The only user currently is rfkill-gpio.c and
that already has "-gpios" there.

I think Alexandre suggested that already some time ago when we were
discussing about ACPI properties wrt. GPIOs.
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Alexandre Courbot Feb. 11, 2015, 2:24 p.m. UTC | #6
On Wed, Feb 11, 2015 at 11:00 PM, Rojhalat Ibrahim <imr@rtschenk.de> wrote:
> On Wednesday 11 February 2015 22:31:12 Alexandre Courbot wrote:
>> On Wed, Feb 11, 2015 at 9:14 PM, Rojhalat Ibrahim <imr@rtschenk.de> wrote:
>> > On Wednesday 11 February 2015 12:30:01 Mika Westerberg wrote:
>> >> On Tue, Feb 10, 2015 at 02:40:52PM +0100, Rojhalat Ibrahim wrote:
>> >> > +#ifdef CONFIG_ACPI
>> >> > +
>> >> > +static unsigned int acpi_gpio_package_count(const union acpi_object *obj)
>> >> > +{
>> >> > +   const union acpi_object *element = obj->package.elements;
>> >> > +   const union acpi_object *end = element + obj->package.count;
>> >> > +   unsigned int count = 0;
>> >> > +
>> >> > +   while (element < end) {
>> >> > +           if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
>> >> > +                   count++;
>> >> > +
>> >> > +           element++;
>> >> > +   }
>> >> > +   return count;
>> >> > +}
>> >> > +
>> >> > +static int acpi_find_gpio_count(struct acpi_resource *ares, void *data)
>> >> > +{
>> >> > +   unsigned int *count = data;
>> >> > +
>> >> > +   if (ares->type == ACPI_RESOURCE_TYPE_GPIO)
>> >> > +           *count += ares->data.gpio.pin_table_length;
>> >> > +
>> >> > +   return 1;
>> >> > +}
>> >> > +
>> >> > +static int acpi_gpio_count(struct device *dev, const char *con_id)
>> >> > +{
>> >> > +   struct acpi_device *adev = ACPI_COMPANION(dev);
>> >> > +   const union acpi_object *obj;
>> >> > +   const struct acpi_gpio_mapping *gm;
>> >> > +   int count = -ENOENT;
>> >> > +   int ret;
>> >> > +   char propname[32];
>> >> > +   unsigned int i;
>> >> > +
>> >> > +   /* Try first from _DSD */
>> >> > +   for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
>> >> > +           if (con_id && strcmp(con_id, "gpios"))
>> >> > +                   snprintf(propname, sizeof(propname), "%s-%s",
>> >> > +                            con_id, gpio_suffixes[i]);
>> >> > +           else
>> >> > +                   snprintf(propname, sizeof(propname), "%s",
>> >> > +                            gpio_suffixes[i]);
>> >> > +
>> >> > +           ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_ANY,
>> >> > +                                       &obj);
>> >> > +           if (ret == 0) {
>> >> > +                   if (obj->type == ACPI_TYPE_LOCAL_REFERENCE)
>> >> > +                           count = 1;
>> >> > +                   else if (obj->type == ACPI_TYPE_PACKAGE)
>> >> > +                           count = acpi_gpio_package_count(obj);
>> >> > +           } else if (adev->driver_gpios) {
>> >> > +                   for (gm = adev->driver_gpios; gm->name; gm++)
>> >> > +                           if (strcmp(propname, gm->name) == 0) {
>> >> > +                                   count = gm->size;
>> >> > +                                   break;
>> >> > +                           }
>> >> > +           }
>> >> > +           if (count >= 0)
>> >> > +                   break;
>> >> > +   }
>> >> > +
>> >> > +   /* Then from plain _CRS GPIOs */
>> >> > +   if (count < 0) {
>> >> > +           struct list_head resource_list;
>> >> > +           unsigned int crs_count = 0;
>> >> > +
>> >> > +           INIT_LIST_HEAD(&resource_list);
>> >> > +           acpi_dev_get_resources(adev, &resource_list,
>> >> > +                                  acpi_find_gpio_count, &crs_count);
>> >> > +           acpi_dev_free_resource_list(&resource_list);
>> >> > +           if (crs_count > 0)
>> >> > +                   count = crs_count;
>> >> > +   }
>> >> > +   return count;
>> >> > +}
>> >> > +
>> >> > +#else
>> >> > +
>> >> > +static int acpi_gpio_count(struct device *dev, const char *con_id)
>> >> > +{
>> >> > +   return -ENODEV;
>> >> > +}
>> >> > +
>> >> > +#endif
>> >>
>> >> It just occured to me that it would be better to put this code to
>> >> gpiolib-acpi.c and declare acpi_gpio_count() in drivers/gpio/gpiolib.h.
>> >>
>> >
>> > Ok. I will also have to move the definition of gpio_suffixes[] (PATCH 1/4)
>> > to drivers/gpio/gpiolib.h since it is needed by both the OF and the ACPI
>> > portions of the code.
>>
>> We will really need to factorize this lookup code. I will give it a
>> look, but first I'd like to merge this good stuff.
>>
>> I am mixed about moving these declarations into gpiolib.h - maybe have
>> one static declaration per file instead, especially since lookup on
>> ACPI is not necessarily the same as lookup on DT. It makes sense to
>> have it that way.
>>
>
> If we do one static declaration per file then acpi_find_gpio() in gpiolib.c
> is going to use potentially different suffixes from acpi_gpio_count() in
> gpiolib-acpi.c. That can't be good.

Yeah it's a bit of a mess, I really need to reorganize that code...

I'm not going to mind how you do it - just do whatever seems good to
you, I will revisit it later anyway. For now I'd like this
well-implemented and tested interface to be merged for everyone to
enjoy.
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Patch
diff mbox

diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt
index d85fbae..2924f2f 100644
--- a/Documentation/gpio/consumer.txt
+++ b/Documentation/gpio/consumer.txt
@@ -58,7 +58,6 @@  pattern where a GPIO is optional, the gpiod_get_optional() and
 gpiod_get_index_optional() functions can be used. These functions return NULL
 instead of -ENOENT if no GPIO has been assigned to the requested function:
 
-
 	struct gpio_desc *gpiod_get_optional(struct device *dev,
 					     const char *con_id,
 					     enum gpiod_flags flags)
@@ -68,6 +67,27 @@  instead of -ENOENT if no GPIO has been assigned to the requested function:
 						   unsigned int index,
 						   enum gpiod_flags flags)
 
+For a function using multiple GPIOs all of those can be obtained with one call:
+
+	struct gpio_descs *gpiod_get_array(struct device *dev,
+					   const char *con_id,
+					   enum gpiod_flags flags)
+
+This function returns a struct gpio_descs which contains an array of
+descriptors:
+
+	struct gpio_descs {
+		unsigned int ndescs;
+		struct gpio_desc *desc[];
+	}
+
+The following function returns NULL instead of -ENOENT if no GPIOs have been
+assigned to the requested function:
+
+	struct gpio_descs *gpiod_get_array_optional(struct device *dev,
+						    const char *con_id,
+						    enum gpiod_flags flags)
+
 Device-managed variants of these functions are also defined:
 
 	struct gpio_desc *devm_gpiod_get(struct device *dev, const char *con_id,
@@ -91,8 +111,15 @@  A GPIO descriptor can be disposed of using the gpiod_put() function:
 
 	void gpiod_put(struct gpio_desc *desc)
 
-It is strictly forbidden to use a descriptor after calling this function. The
-device-managed variant is, unsurprisingly:
+For an array of GPIOs this function can be used:
+
+	void gpiod_put_array(struct gpio_descs *descs)
+
+It is strictly forbidden to use a descriptor after calling these functions.
+It is also not allowed to individually release descriptors (using gpiod_put())
+from an array acquired with gpiod_get_array().
+
+The device-managed variant is, unsurprisingly:
 
 	void devm_gpiod_put(struct device *dev, struct gpio_desc *desc)
 
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index ff2b80d..3f78a7b 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1804,6 +1804,158 @@  static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
 	return desc;
 }
 
+static int dt_gpio_count(struct device *dev, const char *con_id)
+{
+	int ret;
+	char propname[32];
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
+		if (con_id)
+			snprintf(propname, sizeof(propname), "%s-%s",
+				 con_id, gpio_suffixes[i]);
+		else
+			snprintf(propname, sizeof(propname), "%s",
+				 gpio_suffixes[i]);
+
+		ret = of_gpio_named_count(dev->of_node, propname);
+		if (ret >= 0)
+			break;
+	}
+	return ret;
+}
+
+#ifdef CONFIG_ACPI
+
+static unsigned int acpi_gpio_package_count(const union acpi_object *obj)
+{
+	const union acpi_object *element = obj->package.elements;
+	const union acpi_object *end = element + obj->package.count;
+	unsigned int count = 0;
+
+	while (element < end) {
+		if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
+			count++;
+
+		element++;
+	}
+	return count;
+}
+
+static int acpi_find_gpio_count(struct acpi_resource *ares, void *data)
+{
+	unsigned int *count = data;
+
+	if (ares->type == ACPI_RESOURCE_TYPE_GPIO)
+		*count += ares->data.gpio.pin_table_length;
+
+	return 1;
+}
+
+static int acpi_gpio_count(struct device *dev, const char *con_id)
+{
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+	const union acpi_object *obj;
+	const struct acpi_gpio_mapping *gm;
+	int count = -ENOENT;
+	int ret;
+	char propname[32];
+	unsigned int i;
+
+	/* Try first from _DSD */
+	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
+		if (con_id && strcmp(con_id, "gpios"))
+			snprintf(propname, sizeof(propname), "%s-%s",
+				 con_id, gpio_suffixes[i]);
+		else
+			snprintf(propname, sizeof(propname), "%s",
+				 gpio_suffixes[i]);
+
+		ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_ANY,
+					    &obj);
+		if (ret == 0) {
+			if (obj->type == ACPI_TYPE_LOCAL_REFERENCE)
+				count = 1;
+			else if (obj->type == ACPI_TYPE_PACKAGE)
+				count = acpi_gpio_package_count(obj);
+		} else if (adev->driver_gpios) {
+			for (gm = adev->driver_gpios; gm->name; gm++)
+				if (strcmp(propname, gm->name) == 0) {
+					count = gm->size;
+					break;
+				}
+		}
+		if (count >= 0)
+			break;
+	}
+
+	/* Then from plain _CRS GPIOs */
+	if (count < 0) {
+		struct list_head resource_list;
+		unsigned int crs_count = 0;
+
+		INIT_LIST_HEAD(&resource_list);
+		acpi_dev_get_resources(adev, &resource_list,
+				       acpi_find_gpio_count, &crs_count);
+		acpi_dev_free_resource_list(&resource_list);
+		if (crs_count > 0)
+			count = crs_count;
+	}
+	return count;
+}
+
+#else
+
+static int acpi_gpio_count(struct device *dev, const char *con_id)
+{
+	return -ENODEV;
+}
+
+#endif
+
+static int platform_gpio_count(struct device *dev, const char *con_id)
+{
+	struct gpiod_lookup_table *table;
+	struct gpiod_lookup *p;
+	unsigned int count = 0;
+
+	table = gpiod_find_lookup_table(dev);
+	if (!table)
+		return -ENOENT;
+
+	for (p = &table->table[0]; p->chip_label; p++) {
+		if ((con_id && p->con_id && !strcmp(con_id, p->con_id)) ||
+		    (!con_id && !p->con_id))
+			count++;
+	}
+	if (!count)
+		return -ENOENT;
+
+	return count;
+}
+
+/**
+ * gpiod_count - return the number of GPIOs associated with a device / function
+ *		or -ENOENT if no GPIO has been assigned to the requested function
+ * @dev:	GPIO consumer, can be NULL for system-global GPIOs
+ * @con_id:	function within the GPIO consumer
+ */
+int gpiod_count(struct device *dev, const char *con_id)
+{
+	int count = -ENOENT;
+
+	if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
+		count = dt_gpio_count(dev, con_id);
+	else if (IS_ENABLED(CONFIG_ACPI) && dev && ACPI_HANDLE(dev))
+		count = acpi_gpio_count(dev, con_id);
+
+	if (count < 0)
+		count = platform_gpio_count(dev, con_id);
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(gpiod_count);
+
 /**
  * gpiod_get - obtain a GPIO for a given GPIO function
  * @dev:	GPIO consumer, can be NULL for system-global GPIOs
@@ -2005,6 +2157,72 @@  struct gpio_desc *__must_check __gpiod_get_index_optional(struct device *dev,
 EXPORT_SYMBOL_GPL(__gpiod_get_index_optional);
 
 /**
+ * gpiod_get_array - obtain multiple GPIOs from a multi-index GPIO function
+ * @dev:	GPIO consumer, can be NULL for system-global GPIOs
+ * @con_id:	function within the GPIO consumer
+ * @flags:	optional GPIO initialization flags
+ *
+ * This function acquires all the GPIOs defined under a given function.
+ *
+ * Return a struct gpio_descs containing an array of descriptors, -ENOENT if
+ * no GPIO has been assigned to the requested function, or another IS_ERR()
+ * code if an error occurred while trying to acquire the GPIOs.
+ */
+struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
+						const char *con_id,
+						enum gpiod_flags flags)
+{
+	struct gpio_desc *desc;
+	struct gpio_descs *descs;
+	int count;
+
+	count = gpiod_count(dev, con_id);
+	if (count < 0)
+		return ERR_PTR(count);
+
+	descs = kzalloc(sizeof(*descs) + sizeof(descs->desc[0]) * count,
+			GFP_KERNEL);
+	if (!descs)
+		return ERR_PTR(-ENOMEM);
+
+	for (descs->ndescs = 0; descs->ndescs < count; ) {
+		desc = gpiod_get_index(dev, con_id, descs->ndescs, flags);
+		if (IS_ERR(desc)) {
+			gpiod_put_array(descs);
+			return ERR_CAST(desc);
+		}
+		descs->desc[descs->ndescs] = desc;
+		descs->ndescs++;
+	}
+	return descs;
+}
+EXPORT_SYMBOL_GPL(gpiod_get_array);
+
+/**
+ * gpiod_get_array_optional - obtain multiple GPIOs from a multi-index GPIO
+ *                            function
+ * @dev:	GPIO consumer, can be NULL for system-global GPIOs
+ * @con_id:	function within the GPIO consumer
+ * @flags:	optional GPIO initialization flags
+ *
+ * This is equivalent to gpiod_get_array(), except that when no GPIO was
+ * assigned to the requested function it will return NULL.
+ */
+struct gpio_descs *__must_check gpiod_get_array_optional(struct device *dev,
+							const char *con_id,
+							enum gpiod_flags flags)
+{
+	struct gpio_descs *descs;
+
+	descs = gpiod_get_array(dev, con_id, flags);
+	if (IS_ERR(descs) && (PTR_ERR(descs) == -ENOENT))
+		return NULL;
+
+	return descs;
+}
+EXPORT_SYMBOL_GPL(gpiod_get_array_optional);
+
+/**
  * gpiod_put - dispose of a GPIO descriptor
  * @desc:	GPIO descriptor to dispose of
  *
@@ -2016,6 +2234,21 @@  void gpiod_put(struct gpio_desc *desc)
 }
 EXPORT_SYMBOL_GPL(gpiod_put);
 
+/**
+ * gpiod_put_array - dispose of multiple GPIO descriptors
+ * @descs:	struct gpio_descs containing an array of descriptors
+ */
+void gpiod_put_array(struct gpio_descs *descs)
+{
+	unsigned int i;
+
+	for (i = 0; i < descs->ndescs; i++)
+		gpiod_put(descs->desc[i]);
+
+	kfree(descs);
+}
+EXPORT_SYMBOL_GPL(gpiod_put_array);
+
 #ifdef CONFIG_DEBUG_FS
 
 static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index 45afc2d..f71cad6 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -16,6 +16,15 @@  struct device;
  */
 struct gpio_desc;
 
+/**
+ * Struct containing an array of descriptors that can be obtained using
+ * gpiod_get_array().
+ */
+struct gpio_descs {
+	unsigned int ndescs;
+	struct gpio_desc *desc[];
+};
+
 #define GPIOD_FLAGS_BIT_DIR_SET		BIT(0)
 #define GPIOD_FLAGS_BIT_DIR_OUT		BIT(1)
 #define GPIOD_FLAGS_BIT_DIR_VAL		BIT(2)
@@ -34,6 +43,9 @@  enum gpiod_flags {
 
 #ifdef CONFIG_GPIOLIB
 
+/* Return the number of GPIOs associated with a device / function */
+int gpiod_count(struct device *dev, const char *con_id);
+
 /* Acquire and dispose GPIOs */
 struct gpio_desc *__must_check __gpiod_get(struct device *dev,
 					 const char *con_id,
@@ -49,7 +61,14 @@  struct gpio_desc *__must_check __gpiod_get_index_optional(struct device *dev,
 							const char *con_id,
 							unsigned int index,
 							enum gpiod_flags flags);
+struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
+						const char *con_id,
+						enum gpiod_flags flags);
+struct gpio_descs *__must_check gpiod_get_array_optional(struct device *dev,
+							const char *con_id,
+							enum gpiod_flags flags);
 void gpiod_put(struct gpio_desc *desc);
+void gpiod_put_array(struct gpio_descs *descs);
 
 struct gpio_desc *__must_check __devm_gpiod_get(struct device *dev,
 					      const char *con_id,
@@ -113,6 +132,11 @@  struct gpio_desc *devm_get_gpiod_from_child(struct device *dev,
 					    struct fwnode_handle *child);
 #else /* CONFIG_GPIOLIB */
 
+static inline int gpiod_count(struct device *dev, const char *con_id)
+{
+	return 0;
+}
+
 static inline struct gpio_desc *__must_check __gpiod_get(struct device *dev,
 						const char *con_id,
 						enum gpiod_flags flags)
@@ -142,6 +166,20 @@  __gpiod_get_index_optional(struct device *dev, const char *con_id,
 	return ERR_PTR(-ENOSYS);
 }
 
+static inline struct gpio_descs *__must_check
+gpiod_get_array(struct device *dev, const char *con_id,
+		enum gpiod_flags flags)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
+static inline struct gpio_descs *__must_check
+gpiod_get_array_optional(struct device *dev, const char *con_id,
+			 enum gpiod_flags flags)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
 static inline void gpiod_put(struct gpio_desc *desc)
 {
 	might_sleep();
@@ -150,6 +188,14 @@  static inline void gpiod_put(struct gpio_desc *desc)
 	WARN_ON(1);
 }
 
+static inline void gpiod_put_array(struct gpio_descs *descs)
+{
+	might_sleep();
+
+	/* GPIO can never have been requested */
+	WARN_ON(1);
+}
+
 static inline struct gpio_desc *__must_check
 __devm_gpiod_get(struct device *dev,
 		 const char *con_id,