[+Rafael]
On Mon, Feb 09, 2015 at 06:07:10PM +0100, Rojhalat Ibrahim 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]>
Can you please next time CC me the whole series? Now it fails with:
drivers/gpio/gpiolib.c: In function ‘dt_gpio_count’:
drivers/gpio/gpiolib.c:1812:29: error: ‘gpio_suffixes’ undeclared (first
use in this function)
for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
^
include/linux/kernel.h:54:33: note: in definition of macro ‘ARRAY_SIZE’
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) +
__must_be_array(arr))
and so on.
> ---
> 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[];
> + }
> +
> +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);
Should you check that the ACPI companion device actually exists here or
is it checked somewhere before already?
> + 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]);
I'm assuming some previous patch added gpio_suffixes[].
> + 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;
> +}
Otherwise the ACPI parts look good to me. I still want to test this,
though.
> +
> +#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)
> +{
> + 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);
Aha, so you here you checked for the ACPI compation, all right then.
> +
> + if (count < 0)
> + count = lut_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 +2157,70 @@ 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_array[0]) * count,
> + GFP_KERNEL);
Should you return ERR_PTR(-ENOMEM) here if the allocation fails?
> +
> + for (descs->array_size = 0; descs->array_size < count; ) {
^
|
+-- extra
whitespace
> + desc = gpiod_get_index(dev, con_id, descs->array_size, flags);
> + if (IS_ERR(desc)) {
> + gpiod_put_array(descs);
> + return ERR_PTR(PTR_ERR(desc));
Uh, why not
return desc
?
> + }
> + descs->desc_array[descs->array_size] = desc;
> + descs->array_size++;
> + }
> + 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;
The caller still needs to handle other error codes (than -ENOENT), so
would it be better to just have only gpiod_get_array()?
> +
> + return descs;
> +}
> +EXPORT_SYMBOL_GPL(gpiod_get_array_optional);
> +
> +/**
> * gpiod_put - dispose of a GPIO descriptor
> * @desc: GPIO descriptor to dispose of
> *
> @@ -2016,6 +2232,21 @@ 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->array_size; i++)
> + gpiod_put(descs->desc_array[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..6b1c389 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 array_size;
> + struct gpio_desc *desc_array[];
> +};
> +
> #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);
That should be -ENXIO.
> +}
> +
> +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);
Ditto.
> +}
> +
> 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,
> --
> 2.0.5
>
--
To unsubscribe from this list: send the line "unsubscribe linux-gpio" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
