[PATCH] gpiolib: return 0 or 1 in gpiod_get_value*() functions

[Jose Diaz de Grenu de Pedro]

Commit 79a9becda894 moved the awareness of active low state
into the gpiod_get_value*() functions, but it only inverts the
GPIO's raw value when it is active low. If the GPIO is active
high, the gpiod_get_value*() functions return the raw value of
the register, which can be any positive value.

This patch does a double inversion when the GPIO is active high
to make sure either a 0 or 1 is returned by these functions.

Signed-off-by: Jose Diaz de Grenu de Pedro <Jose.Diazde...@digi.com>
Signed-off-by: Hector Palacios <hector....@digi.com>
---
drivers/gpio/gpiolib.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 50c4922fe53a..20f472a25b55 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1981,9 +1981,9 @@ int gpiod_get_value(const struct gpio_desc *desc)

value = _gpiod_get_raw_value(desc);
if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
- value = !value;
-
- return value;
+ return !value;
+ else
+ return !!value
}
EXPORT_SYMBOL_GPL(gpiod_get_value);

@@ -2224,9 +2224,9 @@ int gpiod_get_value_cansleep(const struct gpio_desc *desc)

value = _gpiod_get_raw_value(desc);
if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
- value = !value;
-
- return value;
+ return !value;
+ else
+ return !!value;
}
EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep);

--
2.6.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majo...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

[Jose Diaz de Grenu de Pedro]

Commit 79a9becda894 moved the awareness of active low state
into the gpiod_get_value*() functions, but it only inverts the
GPIO's raw value when it is active low. If the GPIO is active
high, the gpiod_get_value*() functions return the raw value of
the register, which can be any positive value.

This patch does a double inversion when the GPIO is active high

to make sure either 0 or 1 is returned by these functions.

Signed-off-by: Jose Diaz de Grenu de Pedro <Jose.Diazde...@digi.com>
Signed-off-by: Hector Palacios <hector....@digi.com>
---

change in v2:
- add missing semicolon

---
drivers/gpio/gpiolib.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c

index 50c4922fe53a..bd96f0457ba8 100644

[Bjorn Andersson]

On linux-next (at least) _gpiod_get_raw_value() returns the following value:

value = value < 0 ? value : !!value;

So this should already be negative errno, 0 or 1.

Regards,
Bjorn

[Linus Walleij]

On Mon, Nov 30, 2015 at 6:30 PM, Jose Diaz de Grenu de Pedro
<Jose.Diazde...@digi.com> wrote:

> Commit 79a9becda894 moved the awareness of active low state
> into the gpiod_get_value*() functions, but it only inverts the
> GPIO's raw value when it is active low. If the GPIO is active
> high, the gpiod_get_value*() functions return the raw value of
> the register, which can be any positive value.

No, because:

static int _gpiod_get_raw_value(const struct gpio_desc *desc)
{
struct gpio_chip *chip;
int offset;
int value;

chip = desc->chip;
offset = gpio_chip_hwgpio(desc);
value = chip->get ? chip->get(chip, offset) : -EIO;

value = value < 0 ? value : !!value;

trace_gpio_value(desc_to_gpio(desc), 1, value);
return value;
}

This returns a negative error code or the value clamped to [0,1]

Yours,
Linus Walleij