Commit f03b94ef authored Dec 12, 2017 by Brian Norris Committed by Greg Kroah-Hartman Mar 24, 2018

pinctrl: rockchip: enable clock when reading pin direction register




[ Upstream commit 5c9d8c4f6b8168738a26bcf288516cc3a0886810 ]

We generally leave the GPIO clock disabled, unless an interrupt is
requested or we're accessing IO registers. We forgot to do this for the
->get_direction() callback, which means we can sometimes [1] get
incorrect results [2] from, e.g., /sys/kernel/debug/gpio.

Enable the clock, so we get the right results!

[1] Sometimes, because many systems have 1 or mor interrupt requested on
each GPIO bank, so they always leave their clock on.

[2] Incorrect, meaning the register returns 0, and so we interpret that
as "input".

Signed-off-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent bd6552cf

drivers/pinctrl/pinctrl-rockchip.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -1278,8 +1278,16 @@ static int rockchip_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
		{
		struct rockchip_pin_bank *bank = gpiochip_get_data(chip);
		u32 data;
		int ret;

		ret = clk_enable(bank->clk);
		if (ret < 0) {
		dev_err(bank->drvdata->dev,
		"failed to enable clock for bank %s\n", bank->name);
		return ret;
		}
		data = readl_relaxed(bank->reg_base + GPIO_SWPORT_DDR);
		clk_disable(bank->clk);

		return !(data & BIT(offset));
		}