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Message-ID: <20180308045525.7662-61-alexander.levin@microsoft.com>
Date: Thu, 8 Mar 2018 04:56:28 +0000
From: Sasha Levin <Alexander.Levin@...rosoft.com>
To: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"stable@...r.kernel.org" <stable@...r.kernel.org>
CC: Brian Norris <briannorris@...omium.org>,
Linus Walleij <linus.walleij@...aro.org>,
Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL for 4.15 61/78] pinctrl: rockchip: enable clock when
reading pin direction register
From: Brian Norris <briannorris@...omium.org>
[ 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@...omium.org>
Reviewed-by: Heiko Stuebner <heiko@...ech.de>
Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
drivers/pinctrl/pinctrl-rockchip.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/pinctrl/pinctrl-rockchip.c b/drivers/pinctrl/pinctrl-rockchip.c
index 2ba17548ad5b..073de6a9ed34 100644
--- a/drivers/pinctrl/pinctrl-rockchip.c
+++ b/drivers/pinctrl/pinctrl-rockchip.c
@@ -2014,8 +2014,16 @@ 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));
}
--
2.14.1
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