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gpiolib: request the gpio before querying its direction

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Before querying a GPIO to determine its direction, the GPIO should be
formally requested.  This allows the GPIO driver to block access to
unavailable GPIOs, which makes it easier for some drivers to support
sparse GPIO maps.

Signed-off-by: Timur Tabi <timur@codeaurora.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Timur Tabi 2017-07-27 13:19:23 -05:00 committed by Linus Walleij
parent b2dc4110cb
commit 108d23e322
1 changed files with 11 additions and 0 deletions
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11
drivers/gpio/gpiolib.c
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@ -1201,6 +1201,14 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data)
struct gpio_desc *desc = &gdev->descs[i];
desc->gdev = gdev;
if (chip->request) {
status = chip->request(chip, i);
if (status < 0)
/* The GPIO is unavailable, so skip it */
continue;
}
/*
* REVISIT: most hardware initializes GPIOs as inputs
* (often with pullups enabled) so power usage is
@ -1226,6 +1234,9 @@ int gpiochip_add_data(struct gpio_chip *chip, void *data)
*/
set_bit(FLAG_IS_OUT, &desc->flags);
}
if (chip->free)
chip->free(chip, i);
}
#ifdef CONFIG_PINCTRL