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gpiolib: Document that GPIO line names are not globally unique

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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: f881bab038 ("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>
This commit is contained in:
Geert Uytterhoeven 2020-05-11 12:18:28 +02:00 committed by Linus Walleij
parent ed43f2b4e7
commit 582838ea5b
1 changed files with 8 additions and 3 deletions
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11
drivers/gpio/gpiolib.c
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@ -296,6 +296,9 @@ static int gpiodev_add_to_list(struct gpio_device *gdev)
/* /*
* Convert a GPIO name to its descriptor * 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) 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 * Take the names from gc->names and assign them to their GPIO descriptors.
* are, they are assigned 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) static int gpiochip_set_desc_names(struct gpio_chip *gc)
{ {