From: Thierry Reding Date: Fri, 25 Apr 2014 15:10:06 +0000 (+0200) Subject: gpio: Add helpers for optional GPIOs X-Git-Tag: next-20140516~12^2^2~7 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=29a1f2333e07bbbecb920cc78fd035fe8f53207a;p=karo-tx-linux.git 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 Reviewed-by: Alexandre Courbot Signed-off-by: Linus Walleij --- diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt index 8ff1167cfedf..10b8c5d2c797 100644 --- a/Documentation/driver-model/devres.txt +++ b/Documentation/driver-model/devres.txt @@ -312,4 +312,6 @@ SPI 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 @@ -51,6 +51,22 @@ 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 @@ -86,6 +102,33 @@ 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 4ad110e793c5..d9c9cb4665db 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2737,6 +2737,22 @@ 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 @@ -2799,6 +2815,33 @@ 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 bed128e8f4b1..6a37ef0dc59c 100644 --- a/include/linux/gpio/consumer.h +++ b/include/linux/gpio/consumer.h @@ -23,6 +23,12 @@ 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, @@ -30,6 +36,12 @@ 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); @@ -73,6 +85,20 @@ 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(); @@ -93,6 +119,20 @@ 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();