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gpiolib: safer implementation of desc_to_gpio()

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The current implementation of desc_to_gpio() relies on the chip pointer
to be set to a valid value in order to compute the GPIO number. This
was done in the hope that we can get rid of the gpio_desc global array,
but this is not happening anytime soon.

This patch reimplements desc_to_gpio() in a fashion similar to that of
gpio_to_desc(). As a result, desc_to_gpio(gpio_to_desc(gpio)) == gpio is
now always true. This allows to call desc_to_gpio() on non-initialized
descriptors as some error-handling code currently does.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Reported-by: Dr. H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Alexandre Courbot 2013-10-04 10:59:57 -07:00 committed by Linus Walleij
parent 03d152d558
commit 8c0fca8153
1 changed files with 1 additions and 1 deletions
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2
drivers/gpio/gpiolib.c
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@ -136,7 +136,7 @@ static struct gpio_desc *gpio_to_desc(unsigned gpio)
*/
static int desc_to_gpio(const struct gpio_desc *desc)
{
return desc->chip->base + gpio_chip_hwgpio(desc);
return desc - &gpio_desc[0];
}