From: Timur Tabi timur@codeaurora.org
[ Upstream commit 1ca2a92b2a99323f666f1b669b7484df4bda05e4 ]
This reverts commit 72d3200061776264941be1b5a9bb8e926b3b30a5.
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 Signed-off-by: Lee Jones lee.jones@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpio/gpiolib.c | 31 +++++++------------------------ 1 file changed, 7 insertions(+), 24 deletions(-)
--- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1232,31 +1232,14 @@ int gpiochip_add_data(struct gpio_chip * 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. - */ - - 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); - } + /* 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. + */ + desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0; }
#ifdef CONFIG_PINCTRL