Messages in this thread | | | From | Linus Walleij <> | Date | Tue, 18 Sep 2018 15:40:10 -0700 | Subject | Re: [PATCH] gpiolib: Show correct direction from the beginning |
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On Fri, Sep 14, 2018 at 12:08 AM Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> wrote:
> Current code assumes that the direction is input if direction_input > function is set. > This might not be the case on GPIOs with programmable direction. > > Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> > --- > drivers/gpio/gpiolib.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > index a57300c1d649..af853749e0bb 100644 > --- a/drivers/gpio/gpiolib.c > +++ b/drivers/gpio/gpiolib.c > @@ -1352,7 +1352,12 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data, > * 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; > + if (chip->get_direction) > + desc->flags = !chip->get_direction(chip, i) ? > + (1 << FLAG_IS_OUT) : 0; > + else > + desc->flags = !chip->direction_input ? > + (1 << FLAG_IS_OUT) : 0;
We used to do this.
But it breaks Qualcomm hardware.
commit 1ca2a92b2a99323f666f1b669b7484df4bda05e4 Author: Timur Tabi <timur@codeaurora.org> Date: Wed Dec 20 13:10:31 2017 -0600
Revert "gpio: set up initial state from .get_direction()"
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>
Yours, Linus Walleij
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