Patch "pinctrl: rockchip: enable clock when reading pin direction register" has been added to the 4.15-stable tree

This is a note to let you know that I've just added the patch titled

pinctrl: rockchip: enable clock when reading pin direction register

to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
pinctrl-rockchip-enable-clock-when-reading-pin-direction-register.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Brian Norris <[email protected]>
Date: Tue, 12 Dec 2017 09:43:43 -0800
Subject: pinctrl: rockchip: enable clock when reading pin direction register

From: Brian Norris <[email protected]>

[ 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".

---
 drivers/pinctrl/pinctrl-rockchip.c |    8 ++++++++
 1 file changed, 8 insertions(+)

@@ -2014,8 +2014,16 @@ static int rockchip_gpio_get_direction(s
 {
 	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));
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/pinctrl-rockchip-enable-clock-when-reading-pin-direction-register.patch queue-4.15/platform-chrome-use-proper-protocol-transfer-function.patch