Messages in this thread Patch in this message | | | From | Linus Walleij <> | Subject | [PATCH 11/15 v3] gpio: Add devm_gpiod_unhinge() | Date | Wed, 5 Dec 2018 13:47:17 +0100 |
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This adds a function named devm_gpiod_unhinge() that removes the resource management from a GPIO descriptor.
I am not sure if this is the best anglosaxon name for the function, no other managed resources have an equivalent currently, but I chose "unhinge" as the closest intuitive thing I could imagine that fits Rusty Russell's API design criterions "the obvious use is the correct one" and "the name tells you how to use it".
The idea came out of a remark from Mark Brown that it should be possible to handle over management of a resource from devres to the regulator core, and indeed we can do that.
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> --- ChangeLog v2->v3: - Make sure to bail out of gpiod_unhinge() if the descritor passed in is NULL or an error pointer. - Accept of devres_destroy() returns -ENOENT: if we have nonexclusive GPIOs, we may attempt to remove resource management from the same descriptor multiple times. ChangeLog v1->v2: - New patch to be able to hand over GPIO descriptors to the regulator core. - Mark: feel free to apply this to the regulator tree with the regulator tree with the rest. --- Documentation/driver-model/devres.txt | 1 + drivers/gpio/gpiolib-devres.c | 30 +++++++++++++++++++++++++++ include/linux/gpio/consumer.h | 10 +++++++++ 3 files changed, 41 insertions(+)
diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt index 43681ca0837f..fc4cc24dfb97 100644 --- a/Documentation/driver-model/devres.txt +++ b/Documentation/driver-model/devres.txt @@ -254,6 +254,7 @@ GPIO devm_gpiod_get_index_optional() devm_gpiod_get_optional() devm_gpiod_put() + devm_gpiod_unhinge() devm_gpiochip_add_data() devm_gpiochip_remove() devm_gpio_request() diff --git a/drivers/gpio/gpiolib-devres.c b/drivers/gpio/gpiolib-devres.c index a57e968025a8..e9a17ec4de02 100644 --- a/drivers/gpio/gpiolib-devres.c +++ b/drivers/gpio/gpiolib-devres.c @@ -346,6 +346,36 @@ void devm_gpiod_put(struct device *dev, struct gpio_desc *desc) } EXPORT_SYMBOL(devm_gpiod_put); +/** + * devm_gpiod_unhinge - Remove resource management from a gpio descriptor + * @dev: GPIO consumer + * @desc: GPIO descriptor to remove resource management from + * + * Remove resource management from a GPIO descriptor. This is needed when + * you want to hand over lifecycle management of a descriptor to another + * mechanism. + */ + +void devm_gpiod_unhinge(struct device *dev, struct gpio_desc *desc) +{ + int ret; + + if (IS_ERR_OR_NULL(desc)) + return; + ret = devres_destroy(dev, devm_gpiod_release, + devm_gpiod_match, desc); + /* + * If the GPIO descriptor is requested as nonexclusive, we + * may call this function several times on the same descriptor + * so it is OK if devres_destroy() returns -ENOENT. + */ + if (ret == -ENOENT) + return; + /* Anything else we should warn about */ + WARN_ON(ret); +} +EXPORT_SYMBOL(devm_gpiod_unhinge); + /** * devm_gpiod_put_array - Resource-managed gpiod_put_array() * @dev: GPIO consumer diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h index 348885f2f3d3..8aebcf822082 100644 --- a/include/linux/gpio/consumer.h +++ b/include/linux/gpio/consumer.h @@ -104,6 +104,7 @@ struct gpio_descs *__must_check devm_gpiod_get_array_optional(struct device *dev, const char *con_id, enum gpiod_flags flags); void devm_gpiod_put(struct device *dev, struct gpio_desc *desc); +void devm_gpiod_unhinge(struct device *dev, struct gpio_desc *desc); void devm_gpiod_put_array(struct device *dev, struct gpio_descs *descs); int gpiod_get_direction(struct gpio_desc *desc); @@ -249,6 +250,15 @@ static inline void gpiod_put(struct gpio_desc *desc) WARN_ON(1); } +static inline void devm_gpiod_unhinge(struct device *dev, + struct gpio_desc *desc) +{ + might_sleep(); + + /* GPIO can never have been requested */ + WARN_ON(1); +} + static inline void gpiod_put_array(struct gpio_descs *descs) { might_sleep(); -- 2.19.2
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