On Tue, Feb 10, 2015 at 2:07 AM, Rojhalat Ibrahim <[email protected]> wrote:
> Introduce new functions for conveniently obtaining and disposing of an entire
> array of GPIOs with one function call.
>
> Suggested-by: Alexandre Courbot <[email protected]>
> Signed-off-by: Rojhalat Ibrahim <[email protected]>
> ---
> Change log:
> 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 | 231
> ++++++++++++++++++++++++++++++++++++++++
> include/linux/gpio/consumer.h | 46 ++++++++
> 3 files changed, 307 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt
> index d85fbae..85a7e30 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 array_size;
> + struct gpio_desc *desc_array[];
I missed this in the previous revision, but how about having shorter
names for these members? Like
array_size -> ndescs
desc_array -> desc
These would be more comfortable to work with I believe.
> + }
> +
> +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..d4153e0 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;
> +}
Mika, does the ACPI part look good to you?
> +
> +#else
> +
> +static int acpi_gpio_count(struct device *dev, const char *con_id)
> +{
> + return -ENODEV;
> +}
> +
> +#endif
> +
> +static int lut_gpio_count(struct device *dev, const char *con_id)
I did not reply to your previous comment, but I'd prefer if this was
named platform_gpio_count, for clarity.
These are my last nits - after they are fixed, please feel free to add my
Reviewed-by: Alexandre Courbot <[email protected]>
to the next revision.
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