From 43fd7b19845667fb66cc7f80641c1387c5b1494e Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Fri, 25 Apr 2014 17:10:06 +0200 Subject: [PATCH] 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 (cherry picked from commit 29a1f2333e07bbbecb920cc78fd035fe8f53207a) Signed-off-by: Simon Horman --- Documentation/driver-model/devres.txt | 2 ++ drivers/gpio/devres.c | 43 +++++++++++++++++++++++++++++++++++ drivers/gpio/gpiolib.c | 43 +++++++++++++++++++++++++++++++++++ include/linux/gpio/consumer.h | 40 ++++++++++++++++++++++++++++++++ 4 files changed, 128 insertions(+) diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt index 8ff1167c..10b8c5d 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 307464f..65978cf 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 09550cb..8cbaf69 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2459,6 +2459,22 @@ 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 @@ -2521,6 +2537,33 @@ 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 bed128e..6a37ef0 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(); -- 2.7.4