From 2be001739242fac1083f3b21898158492844699d Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Mon, 21 Jul 2014 11:12:16 -0700 Subject: [PATCH] gpio: Add support for GPIOF_ACTIVE_LOW to gpio_request_one functions 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. This can cause problems in at least two areas: First, the same API can be used to auto-export pins to user space. The missing support for GPIOF_ACTIVE_LOW results in unexpected behavior for such auto-exported pins. Second, the requested gpio pin can be convered for use by gpiod functions with gpio_to_desc(). While gpio API functions do not support GPIOF_ACTIVE_LOW, gpiod functions do, which again results in unexpected behavior. Check the flag in gpio_request_one and set the gpio internal flag FLAG_ACTIVE_LOW if it is set to address those problems. Signed-off-by: Guenter Roeck Reviewed-by: Alexandre Courbot Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib-legacy.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpio/gpiolib-legacy.c b/drivers/gpio/gpiolib-legacy.c index eb5a4e2cee85..c684d94cdbb4 100644 --- a/drivers/gpio/gpiolib-legacy.c +++ b/drivers/gpio/gpiolib-legacy.c @@ -34,6 +34,9 @@ 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