From bae48da237fcedd7ad09569025483b988635efb7 Mon Sep 17 00:00:00 2001 From: Alexandre Courbot Date: Thu, 17 Oct 2013 10:21:38 -0700 Subject: gpiolib: add gpiod_get() and gpiod_put() functions Add gpiod_get(), gpiod_get_index() and gpiod_put() functions that provide safer management of GPIOs. These functions put the GPIO framework in line with the conventions of other frameworks in the kernel, and help ensure every GPIO is declared properly and valid while it is used. Signed-off-by: Alexandre Courbot Signed-off-by: Linus Walleij --- drivers/gpio/devres.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) (limited to 'drivers/gpio/devres.c') diff --git a/drivers/gpio/devres.c b/drivers/gpio/devres.c index 3e7812f0405..2caa2571734 100644 --- a/drivers/gpio/devres.c +++ b/drivers/gpio/devres.c @@ -19,6 +19,89 @@ #include #include +static void devm_gpiod_release(struct device *dev, void *res) +{ + struct gpio_desc **desc = res; + + gpiod_put(*desc); +} + +static int devm_gpiod_match(struct device *dev, void *res, void *data) +{ + struct gpio_desc **this = res, **gpio = data; + + return *this == *gpio; +} + +/** + * devm_gpiod_get - Resource-managed gpiod_get() + * @dev: GPIO consumer + * @con_id: function within the GPIO consumer + * + * Managed gpiod_get(). GPIO descriptors returned from this function are + * automatically disposed on driver detach. See gpiod_get() for detailed + * information about behavior and return values. + */ +struct gpio_desc *__must_check devm_gpiod_get(struct device *dev, + const char *con_id) +{ + return devm_gpiod_get_index(dev, con_id, 0); +} +EXPORT_SYMBOL(devm_gpiod_get); + +/** + * devm_gpiod_get_index - Resource-managed gpiod_get_index() + * @dev: GPIO consumer + * @con_id: function within the GPIO consumer + * @idx: index of the GPIO to obtain in the consumer + * + * Managed gpiod_get_index(). GPIO descriptors returned from this function are + * automatically disposed on driver detach. See gpiod_get_index() for detailed + * information about behavior and return values. + */ +struct gpio_desc *__must_check devm_gpiod_get_index(struct device *dev, + const char *con_id, + unsigned int idx) +{ + struct gpio_desc **dr; + struct gpio_desc *desc; + + dr = devres_alloc(devm_gpiod_release, sizeof(struct gpiod_desc *), + GFP_KERNEL); + if (!dr) + return ERR_PTR(-ENOMEM); + + desc = gpiod_get_index(dev, con_id, idx); + if (IS_ERR(desc)) { + devres_free(dr); + return desc; + } + + *dr = desc; + devres_add(dev, dr); + + return 0; +} +EXPORT_SYMBOL(devm_gpiod_get_index); + +/** + * devm_gpiod_put - Resource-managed gpiod_put() + * @desc: GPIO descriptor to dispose of + * + * Dispose of a GPIO descriptor obtained with devm_gpiod_get() or + * devm_gpiod_get_index(). Normally this function will not be called as the GPIO + * will be disposed of by the resource management code. + */ +void devm_gpiod_put(struct device *dev, struct gpio_desc *desc) +{ + WARN_ON(devres_release(dev, devm_gpiod_release, devm_gpiod_match, + &desc)); +} +EXPORT_SYMBOL(devm_gpiod_put); + + + + static void devm_gpio_release(struct device *dev, void *res) { unsigned *gpio = res; -- cgit v1.2.3-70-g09d2