Commit 1ca2a92b authored by Timur Tabi's avatar Timur Tabi Committed by Linus Walleij
Browse files

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



This reverts commit 72d32000.

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: default avatarTimur Tabi <timur@codeaurora.org>
Reviewed-by: default avatarStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent caa92ee8

drivers/gpio/gpiolib.c

+7 −24
Original line number Diff line number Diff line
@@ -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.

		 */



		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.

		/* 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.

		 */

			set_bit(FLAG_IS_OUT, &desc->flags);

		}

		desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;

	}



#ifdef CONFIG_PINCTRL

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