linux-kernel - [PATCH 3.14 56/83] pinctrl: as3722: fix handling of GPIO invert bit

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Date:	Sun, 11 May 2014 21:19:57 +0200
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Andrew Bresticker <abrestic@...omium.org>,
	Stephen Warren <swarren@...dia.com>,
	Laxman Dewangan <ldewangan@...dia.com>,
	Linus Walleij <linus.walleij@...aro.org>
Subject: [PATCH 3.14 56/83] pinctrl: as3722: fix handling of GPIO invert bit

3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andrew Bresticker <abrestic@...omium.org>

commit a73d2e30b46787d478275db36c19222020e29dc5 upstream.

The AS3722_GPIO_INV bit will always be blindly overwritten by
as3722_pinctrl_gpio_set_direction() and will be ignored when
setting the value of the GPIO in as3722_gpio_set() since the
enable_gpio_invert flag is never set.  This will cause an
initially inverted GPIO to toggle when requested as an output,
which could be problematic if, for example, the GPIO controls
a critical regulator.

Instead of setting up the enable_gpio_invert flag, just leave
the invert bit alone and check it before setting the GPIO value.

Signed-off-by: Andrew Bresticker <abrestic@...omium.org>
Reviewed-by: Stephen Warren <swarren@...dia.com>
Tested-by: Stephen Warren <swarren@...dia.com>
Acked-by: Laxman Dewangan <ldewangan@...dia.com>
Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/pinctrl/pinctrl-as3722.c |   17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

--- a/drivers/pinctrl/pinctrl-as3722.c
+++ b/drivers/pinctrl/pinctrl-as3722.c
@@ -64,7 +64,6 @@ struct as3722_pin_function {
 };
 
 struct as3722_gpio_pin_control {
-	bool enable_gpio_invert;
 	unsigned mode_prop;
 	int io_function;
 };
@@ -320,10 +319,8 @@ static int as3722_pinctrl_gpio_set_direc
 		return mode;
 	}
 
-	if (as_pci->gpio_control[offset].enable_gpio_invert)
-		mode |= AS3722_GPIO_INV;
-
-	return as3722_write(as3722, AS3722_GPIOn_CONTROL_REG(offset), mode);
+	return as3722_update_bits(as3722, AS3722_GPIOn_CONTROL_REG(offset),
+				AS3722_GPIO_MODE_MASK, mode);
 }
 
 static const struct pinmux_ops as3722_pinmux_ops = {
@@ -496,10 +493,18 @@ static void as3722_gpio_set(struct gpio_
 {
 	struct as3722_pctrl_info *as_pci = to_as_pci(chip);
 	struct as3722 *as3722 = as_pci->as3722;
-	int en_invert = as_pci->gpio_control[offset].enable_gpio_invert;
+	int en_invert;
 	u32 val;
 	int ret;
 
+	ret = as3722_read(as3722, AS3722_GPIOn_CONTROL_REG(offset), &val);
+	if (ret < 0) {
+		dev_err(as_pci->dev,
+			"GPIO_CONTROL%d_REG read failed: %d\n", offset, ret);
+		return;
+	}
+	en_invert = !!(val & AS3722_GPIO_INV);
+
 	if (value)
 		val = (en_invert) ? 0 : AS3722_GPIOn_SIGNAL(offset);
 	else


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