From aca5ce14eb773a75e5d935968b2e390dc5bd29c3 Mon Sep 17 00:00:00 2001 From: Laxman Dewangan Date: Fri, 17 Feb 2012 20:26:21 +0530 Subject: gpio: gpiolib: Support for open drain/collector gpios Adding support for the open drain gpio on which client can specify the open drain property through GPIO flag GPIOF_OPEN_DRAIN at the time of gpio request. The open drain pins are normally pulled high and it cannot be driven to output with value of 1 and so when client request for setting the pin to HIGH, the gpio will be set to input direction to make pin in tristate and hence PULL-UP on pins will make the state to HIGH. The open drain pin can be driven to LOW by setting output with value of 0. Signed-off-by: Laxman Dewangan Reviwed-by: Mark Brown Acked-by: Linus Walleij Signed-off-by: Grant Likely --- include/linux/gpio.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/gpio.h') diff --git a/include/linux/gpio.h b/include/linux/gpio.h index 38ac48b7d3a8..66a5b2e9d35a 100644 --- a/include/linux/gpio.h +++ b/include/linux/gpio.h @@ -14,6 +14,9 @@ #define GPIOF_OUT_INIT_LOW (GPIOF_DIR_OUT | GPIOF_INIT_LOW) #define GPIOF_OUT_INIT_HIGH (GPIOF_DIR_OUT | GPIOF_INIT_HIGH) +/* Gpio pin is open drain */ +#define GPIOF_OPEN_DRAIN (1 << 2) + /** * struct gpio - a structure describing a GPIO with configuration * @gpio: the GPIO number -- cgit v1.2.3