From: Linus Walleij <linus.walleij@linaro.org>
Date: Thu, 10 Dec 2015 14:55:29 +0000 (+0100)
Subject: gpio: generic: clamp values from bgpio_get_set()
X-Git-Tag: v4.4-rc6~7^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=67a76aafec00db46fbd65d7d17a1cde1adde70c5;p=platform%2Fkernel%2Flinux-exynos.git

gpio: generic: clamp values from bgpio_get_set()

The bgpio_get_set() call should return a value clamped to [0,1],
the current code will return a negative value if reading
bit 31, which turns the value negative as this is a signed value
and thus gets interpreted as an error by the gpiolib core.
Found on the gpio-mxc but applies to any MMIO driver.

Cc: stable@vger.kernel.org # 4.3+
Cc: kernel@pengutronix.de
Cc: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Fixes:  e20538b82f1f ("gpio: Propagate errors from chip->get()")
Reported-by: Clemens Gruber <clemens.gruber@pqgruber.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---

diff --git a/drivers/gpio/gpio-generic.c b/drivers/gpio/gpio-generic.c
index bd5193c..88ae70d 100644
--- a/drivers/gpio/gpio-generic.c
+++ b/drivers/gpio/gpio-generic.c
@@ -141,9 +141,9 @@ static int bgpio_get_set(struct gpio_chip *gc, unsigned int gpio)
 	unsigned long pinmask = bgc->pin2mask(bgc, gpio);
 
 	if (bgc->dir & pinmask)
-		return bgc->read_reg(bgc->reg_set) & pinmask;
+		return !!(bgc->read_reg(bgc->reg_set) & pinmask);
 	else
-		return bgc->read_reg(bgc->reg_dat) & pinmask;
+		return !!(bgc->read_reg(bgc->reg_dat) & pinmask);
 }
 
 static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)