On 07/16/2014 11:09 PM, Alexandre Courbot wrote:
On Thu, Jul 17, 2014 at 8:11 AM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
The gpio include file and the gpio documentation declare and document
GPIOF_ACTIVE_LOW as one of the flags to be passed to gpio_request_one
and related functions. However, the flag is not evaluated or used.
Check the flag in gpio_request_one and set the gpio internal flag
FLAG_ACTIVE_LOW if it is set.
What is the point since the integer GPIO API has no clue of the
active-low status of a GPIO? It is only used by the gpiod and sysfs
interfaces.
One can use gpio_request_one() to export a gpio pin to user space from
the kernel. That code path does use the flag, as you point out yourself above.
One could also argue that the integer gpio API _should_ support this as well,
but that is a different question.
Guenter
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
drivers/gpio/gpiolib.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 2ebc907..43d9e34 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1842,6 +1842,9 @@ int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
if (flags & GPIOF_OPEN_SOURCE)
set_bit(FLAG_OPEN_SOURCE, &desc->flags);
+ if (flags & GPIOF_ACTIVE_LOW)
+ set_bit(FLAG_ACTIVE_LOW, &desc->flags);
+
if (flags & GPIOF_DIR_IN)
err = gpiod_direction_input(desc);
else
--
1.9.1
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