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authorGeert Uytterhoeven <geert+renesas@glider.be>2020-05-11 13:18:28 +0300
committerLinus Walleij <linus.walleij@linaro.org>2020-05-16 12:37:35 +0300
commit582838ea5bea41258d136c82a6c493a95cda652c (patch)
tree1e79ffd92747744ab3717b63289f702af28ce7ea /drivers/gpio
parented43f2b4e78069ee02687e5a562e1ecd15cbef4f (diff)
downloadlinux-582838ea5bea41258d136c82a6c493a95cda652c.tar.xz
gpiolib: Document that GPIO line names are not globally unique
gpiochip_set_desc_names() no longer rejects GPIO line name collisions. Hence GPIO line names are not guaranteed to be globally unique. In case of multiple GPIO lines with the same name, gpio_name_to_desc() will return the first match found. Update the comments for gpio_name_to_desc() and gpiochip_set_desc_names() to match reality. Fixes: f881bab038c9667d ("gpio: keep the GPIO line names internal") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Link: https://lore.kernel.org/r/20200511101828.30046-1-geert+renesas@glider.be Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/gpio')
-rw-r--r--drivers/gpio/gpiolib.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 48b4f70e2898..fe5f14a417bd 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -296,6 +296,9 @@ static int gpiodev_add_to_list(struct gpio_device *gdev)
/*
* Convert a GPIO name to its descriptor
+ * Note that there is no guarantee that GPIO names are globally unique!
+ * Hence this function will return, if it exists, a reference to the first GPIO
+ * line found that matches the given name.
*/
static struct gpio_desc *gpio_name_to_desc(const char * const name)
{
@@ -329,10 +332,12 @@ static struct gpio_desc *gpio_name_to_desc(const char * const name)
}
/*
- * Takes the names from gc->names and checks if they are all unique. If they
- * are, they are assigned to their gpio descriptors.
+ * Take the names from gc->names and assign them to their GPIO descriptors.
+ * Warn if a name is already used for a GPIO line on a different GPIO chip.
*
- * Warning if one of the names is already used for a different GPIO.
+ * Note that:
+ * 1. Non-unique names are still accepted,
+ * 2. Name collisions within the same GPIO chip are not reported.
*/
static int gpiochip_set_desc_names(struct gpio_chip *gc)
{