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authorLinus Torvalds <torvalds@linux-foundation.org>2014-09-05 08:04:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-09-05 08:04:29 -0700
commit5e6c72396c2c514a761d990011ce1560f0eb71c9 (patch)
tree99ccd36c79fee77d9a7187b3c63aa6256f5dd30a /Documentation
parentcaa552358eb3de5d1cb0f473e92c91d8a875b7f3 (diff)
parent0dbc8b7afef6e4fddcfebcbacbeb269a0a3b06d5 (diff)
Merge tag 'gpio-v3.17-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio
Pull GPIO fixes from Linus Walleij: - some documentation sync - resource leak in the bt8xx driver - again fix the way varargs are used to handle the optional flags on the gpiod_* accessors. Now hopefully nailed the entire problem. * tag 'gpio-v3.17-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: gpio: move varargs hack outside #ifdef GPIOLIB gpio: bt8xx: fix release of managed resources Documentation: gpio: documentation for optional getters functions
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/gpio/consumer.txt24
1 files changed, 23 insertions, 1 deletions
diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt
index 76546324e968..6ce544191ca6 100644
--- a/Documentation/gpio/consumer.txt
+++ b/Documentation/gpio/consumer.txt
@@ -53,7 +53,20 @@ with IS_ERR() (they will never return a NULL pointer). -ENOENT will be returned
if and only if no GPIO has been assigned to the device/function/index triplet,
other error codes are used for cases where a GPIO has been assigned but an error
occurred while trying to acquire it. This is useful to discriminate between mere
-errors and an absence of GPIO for optional GPIO parameters.
+errors and an absence of GPIO for optional GPIO parameters. For the common
+pattern where a GPIO is optional, the gpiod_get_optional() and
+gpiod_get_index_optional() functions can be used. These functions return NULL
+instead of -ENOENT if no GPIO has been assigned to the requested function:
+
+
+ struct gpio_desc *gpiod_get_optional(struct device *dev,
+ const char *con_id,
+ enum gpiod_flags flags)
+
+ struct gpio_desc *gpiod_get_index_optional(struct device *dev,
+ const char *con_id,
+ unsigned int index,
+ enum gpiod_flags flags)
Device-managed variants of these functions are also defined:
@@ -65,6 +78,15 @@ Device-managed variants of these functions are also defined:
unsigned int idx,
enum gpiod_flags flags)
+ struct gpio_desc *devm_gpiod_get_optional(struct device *dev,
+ const char *con_id,
+ enum gpiod_flags flags)
+
+ struct gpio_desc * devm_gpiod_get_index_optional(struct device *dev,
+ const char *con_id,
+ unsigned int index,
+ enum gpiod_flags flags)
+
A GPIO descriptor can be disposed of using the gpiod_put() function:
void gpiod_put(struct gpio_desc *desc)