diff options
author | Thierry Reding <treding@nvidia.com> | 2014-04-25 17:10:06 +0200 |
---|---|---|
committer | Marcel Ziswiler <marcel.ziswiler@toradex.com> | 2015-09-18 08:45:10 +0200 |
commit | 8e23cf5068fd4c43d379cf5dd56cd9962aaf3241 (patch) | |
tree | 47471d1e5e271028bdfb69f94807a2c6904b58b5 | |
parent | e9ad022e2f350086fda798bed07128f22e59d7b1 (diff) |
gpio: Add helpers for optional GPIOs
Introduce gpiod_get_optional() and gpiod_get_index_optional() helpers
that make it easier for drivers to handle optional GPIOs.
Currently in order to handle optional GPIOs, a driver needs to special
case error handling for -ENOENT, such as this:
gpio = gpiod_get(dev, "foo");
if (IS_ERR(gpio)) {
if (PTR_ERR(gpio) != -ENOENT)
return PTR_ERR(gpio);
gpio = NULL;
}
if (gpio) {
/* set up GPIO */
}
With these new helpers the above is reduced to:
gpio = gpiod_get_optional(dev, "foo");
if (IS_ERR(gpio))
return PTR_ERR(gpio);
if (gpio) {
/* set up GPIO */
}
While at it, device-managed variants of these functions are also
provided.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
(cherry picked from commit 29a1f2333e07bbbecb920cc78fd035fe8f53207a)
-rw-r--r-- | Documentation/driver-model/devres.txt | 7 | ||||
-rw-r--r-- | drivers/gpio/devres.c | 43 | ||||
-rw-r--r-- | drivers/gpio/gpiolib.c | 43 | ||||
-rw-r--r-- | include/linux/gpio/consumer.h | 40 |
4 files changed, 133 insertions, 0 deletions
diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt index 4f7897e99cba..10b8c5d2c797 100644 --- a/Documentation/driver-model/devres.txt +++ b/Documentation/driver-model/devres.txt @@ -308,3 +308,10 @@ SLAVE DMA ENGINE SPI devm_spi_register_master() + +GPIO + devm_gpiod_get() + devm_gpiod_get_index() + devm_gpiod_get_optional() + devm_gpiod_get_index_optional() + devm_gpiod_put() diff --git a/drivers/gpio/devres.c b/drivers/gpio/devres.c index 307464fd015f..65978cf85f79 100644 --- a/drivers/gpio/devres.c +++ b/drivers/gpio/devres.c @@ -52,6 +52,22 @@ struct gpio_desc *__must_check devm_gpiod_get(struct device *dev, EXPORT_SYMBOL(devm_gpiod_get); /** + * devm_gpiod_get_optional - Resource-managed gpiod_get_optional() + * @dev: GPIO consumer + * @con_id: function within the GPIO consumer + * + * Managed gpiod_get_optional(). GPIO descriptors returned from this function + * are automatically disposed on driver detach. See gpiod_get_optional() for + * detailed information about behavior and return values. + */ +struct gpio_desc *__must_check devm_gpiod_get_optional(struct device *dev, + const char *con_id) +{ + return devm_gpiod_get_index_optional(dev, con_id, 0); +} +EXPORT_SYMBOL(devm_gpiod_get_optional); + +/** * devm_gpiod_get_index - Resource-managed gpiod_get_index() * @dev: GPIO consumer * @con_id: function within the GPIO consumer @@ -87,6 +103,33 @@ struct gpio_desc *__must_check devm_gpiod_get_index(struct device *dev, EXPORT_SYMBOL(devm_gpiod_get_index); /** + * devm_gpiod_get_index_optional - Resource-managed gpiod_get_index_optional() + * @dev: GPIO consumer + * @con_id: function within the GPIO consumer + * @index: index of the GPIO to obtain in the consumer + * + * Managed gpiod_get_index_optional(). GPIO descriptors returned from this + * function are automatically disposed on driver detach. See + * gpiod_get_index_optional() for detailed information about behavior and + * return values. + */ +struct gpio_desc *__must_check devm_gpiod_get_index_optional(struct device *dev, + const char *con_id, + unsigned int index) +{ + struct gpio_desc *desc; + + desc = devm_gpiod_get_index(dev, con_id, index); + if (IS_ERR(desc)) { + if (PTR_ERR(desc) == -ENOENT) + return NULL; + } + + return desc; +} +EXPORT_SYMBOL(devm_gpiod_get_index_optional); + +/** * devm_gpiod_put - Resource-managed gpiod_put() * @desc: GPIO descriptor to dispose of * diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index d0ca0a3348dd..6a51530d2df8 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2435,6 +2435,22 @@ struct gpio_desc *__must_check gpiod_get(struct device *dev, const char *con_id) EXPORT_SYMBOL_GPL(gpiod_get); /** + * gpiod_get_optional - obtain an optional GPIO for a given GPIO function + * @dev: GPIO consumer, can be NULL for system-global GPIOs + * @con_id: function within the GPIO consumer + * + * This is equivalent to gpiod_get(), except that when no GPIO was assigned to + * the requested function it will return NULL. This is convenient for drivers + * that need to handle optional GPIOs. + */ +struct gpio_desc *__must_check gpiod_get_optional(struct device *dev, + const char *con_id) +{ + return gpiod_get_index_optional(dev, con_id, 0); +} +EXPORT_SYMBOL_GPL(gpiod_get_optional); + +/** * gpiod_get_index - obtain a GPIO from a multi-index GPIO function * @dev: GPIO consumer, can be NULL for system-global GPIOs * @con_id: function within the GPIO consumer @@ -2497,6 +2513,33 @@ struct gpio_desc *__must_check gpiod_get_index(struct device *dev, EXPORT_SYMBOL_GPL(gpiod_get_index); /** + * gpiod_get_index_optional - obtain an optional GPIO from a multi-index GPIO + * function + * @dev: GPIO consumer, can be NULL for system-global GPIOs + * @con_id: function within the GPIO consumer + * @index: index of the GPIO to obtain in the consumer + * + * This is equivalent to gpiod_get_index(), except that when no GPIO with the + * specified index was assigned to the requested function it will return NULL. + * This is convenient for drivers that need to handle optional GPIOs. + */ +struct gpio_desc *__must_check gpiod_get_index_optional(struct device *dev, + const char *con_id, + unsigned int index) +{ + struct gpio_desc *desc; + + desc = gpiod_get_index(dev, con_id, index); + if (IS_ERR(desc)) { + if (PTR_ERR(desc) == -ENOENT) + return NULL; + } + + return desc; +} +EXPORT_SYMBOL_GPL(gpiod_get_index_optional); + +/** * gpiod_put - dispose of a GPIO descriptor * @desc: GPIO descriptor to dispose of * diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h index 7a8144fef406..c349021e8e4f 100644 --- a/include/linux/gpio/consumer.h +++ b/include/linux/gpio/consumer.h @@ -24,6 +24,12 @@ struct gpio_desc *__must_check gpiod_get(struct device *dev, struct gpio_desc *__must_check gpiod_get_index(struct device *dev, const char *con_id, unsigned int idx); +struct gpio_desc *__must_check gpiod_get_optional(struct device *dev, + const char *con_id); +struct gpio_desc *__must_check gpiod_get_index_optional(struct device *dev, + const char *con_id, + unsigned int index); + void gpiod_put(struct gpio_desc *desc); struct gpio_desc *__must_check devm_gpiod_get(struct device *dev, @@ -31,6 +37,12 @@ struct gpio_desc *__must_check devm_gpiod_get(struct device *dev, struct gpio_desc *__must_check devm_gpiod_get_index(struct device *dev, const char *con_id, unsigned int idx); +struct gpio_desc *__must_check devm_gpiod_get_optional(struct device *dev, + const char *con_id); +struct gpio_desc *__must_check +devm_gpiod_get_index_optional(struct device *dev, const char *con_id, + unsigned int index); + void devm_gpiod_put(struct device *dev, struct gpio_desc *desc); int gpiod_get_direction(const struct gpio_desc *desc); @@ -74,6 +86,20 @@ static inline struct gpio_desc *__must_check gpiod_get_index(struct device *dev, { return ERR_PTR(-ENOSYS); } + +static inline struct gpio_desc *__must_check +gpiod_get_optional(struct device *dev, const char *con_id) +{ + return ERR_PTR(-ENOSYS); +} + +static inline struct gpio_desc *__must_check +gpiod_get_index_optional(struct device *dev, const char *con_id, + unsigned int index) +{ + return ERR_PTR(-ENOSYS); +} + static inline void gpiod_put(struct gpio_desc *desc) { might_sleep(); @@ -94,6 +120,20 @@ struct gpio_desc *__must_check devm_gpiod_get_index(struct device *dev, { return ERR_PTR(-ENOSYS); } + +static inline struct gpio_desc *__must_check +devm_gpiod_get_optional(struct device *dev, const char *con_id) +{ + return ERR_PTR(-ENOSYS); +} + +static inline struct gpio_desc *__must_check +devm_gpiod_get_index_optional(struct device *dev, const char *con_id, + unsigned int index) +{ + return ERR_PTR(-ENOSYS); +} + static inline void devm_gpiod_put(struct device *dev, struct gpio_desc *desc) { might_sleep(); |