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Revert "gpio: set up initial state from .get_direction()" 

This reverts commit 72d3200061.

We cannot blindly query the direction of all GPIOs when the pins are
first registered.  The get_direction callback normally triggers a
read/write to hardware, but we shouldn't be touching the hardware for
an individual GPIO until after it's been properly claimed.

Signed-off-by: Timur Tabi <timur@codeaurora.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Timur Tabi 2017-12-20 13:10:31 -06:00 committed by Linus Walleij
parent caa92ee84b
commit 1ca2a92b2a
1 changed files with 7 additions and 24 deletions
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31
drivers/gpio/gpiolib.c
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@ -1217,31 +1217,14 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
struct gpio_desc *desc = &gdev->descs[i];
desc->gdev = gdev;
/*
* REVISIT: most hardware initializes GPIOs as inputs
* (often with pullups enabled) so power usage is
* minimized. Linux code should set the gpio direction
* first thing; but until it does, and in case
* chip->get_direction is not set, we may expose the
* wrong direction in sysfs.
/* REVISIT: most hardware initializes GPIOs as inputs (often
* with pullups enabled) so power usage is minimized. Linux
* code should set the gpio direction first thing; but until
* it does, and in case chip->get_direction is not set, we may
* expose the wrong direction in sysfs.
*/
if (chip->get_direction) {
/*
* If we have .get_direction, set up the initial
* direction flag from the hardware.
*/
int dir = chip->get_direction(chip, i);
if (!dir)
set_bit(FLAG_IS_OUT, &desc->flags);
} else if (!chip->direction_input) {
/*
* If the chip lacks the .direction_input callback
* we logically assume all lines are outputs.
*/
set_bit(FLAG_IS_OUT, &desc->flags);
}
desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
}
#ifdef CONFIG_PINCTRL