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gpio: generic: clamp values from bgpio_get_set()

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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>
This commit is contained in:
Linus Walleij 2015-12-10 15:55:29 +01:00
parent 3a57e74162
commit 67a76aafec
1 changed files with 2 additions and 2 deletions
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4
drivers/gpio/gpio-generic.c
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@ -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)