From 8c550e94b8835170593169a45b5ba30d3fc72a70 Mon Sep 17 00:00:00 2001 From: Drew Fustini Date: Sat, 21 Sep 2019 12:25:23 +0200 Subject: [PATCH] gpio: expose pull-up/pull-down line flags to userspace Add pull-up/pull-down flags to the gpio line get and set ioctl() calls. Use cases include a push button that does not have an external resistor. Addition use cases described by Limor Fried (ladyada) of Adafruit in this PR for Adafruit_Blinka Python lib: https://github.com/adafruit/Adafruit_Blinka/pull/59 Signed-off-by: Drew Fustini Link: https://lore.kernel.org/r/20190921102522.8970-1-drew@pdp7.com Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib.c | 12 ++++++++++++ include/uapi/linux/gpio.h | 4 ++++ 2 files changed, 16 insertions(+) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 2342deaace17..921f76d2f5c4 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -421,6 +421,8 @@ struct linehandle_state { (GPIOHANDLE_REQUEST_INPUT | \ GPIOHANDLE_REQUEST_OUTPUT | \ GPIOHANDLE_REQUEST_ACTIVE_LOW | \ + GPIOHANDLE_REQUEST_PULL_UP | \ + GPIOHANDLE_REQUEST_PULL_DOWN | \ GPIOHANDLE_REQUEST_OPEN_DRAIN | \ GPIOHANDLE_REQUEST_OPEN_SOURCE) @@ -592,6 +594,10 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip) set_bit(FLAG_OPEN_DRAIN, &desc->flags); if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE) set_bit(FLAG_OPEN_SOURCE, &desc->flags); + if (lflags & GPIOHANDLE_REQUEST_PULL_DOWN) + set_bit(FLAG_PULL_DOWN, &desc->flags); + if (lflags & GPIOHANDLE_REQUEST_PULL_UP) + set_bit(FLAG_PULL_UP, &desc->flags); ret = gpiod_set_transitory(desc, false); if (ret < 0) @@ -1097,6 +1103,10 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) lineinfo.flags |= (GPIOLINE_FLAG_OPEN_SOURCE | GPIOLINE_FLAG_IS_OUT); + if (test_bit(FLAG_PULL_DOWN, &desc->flags)) + lineinfo.flags |= GPIOLINE_FLAG_PULL_DOWN; + if (test_bit(FLAG_PULL_UP, &desc->flags)) + lineinfo.flags |= GPIOLINE_FLAG_PULL_UP; if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) return -EFAULT; @@ -2770,6 +2780,8 @@ static bool gpiod_free_commit(struct gpio_desc *desc) clear_bit(FLAG_REQUESTED, &desc->flags); clear_bit(FLAG_OPEN_DRAIN, &desc->flags); clear_bit(FLAG_OPEN_SOURCE, &desc->flags); + clear_bit(FLAG_PULL_UP, &desc->flags); + clear_bit(FLAG_PULL_DOWN, &desc->flags); clear_bit(FLAG_IS_HOGGED, &desc->flags); ret = true; } diff --git a/include/uapi/linux/gpio.h b/include/uapi/linux/gpio.h index 4ebfe0ac6c5b..c2d1f7d908d6 100644 --- a/include/uapi/linux/gpio.h +++ b/include/uapi/linux/gpio.h @@ -33,6 +33,8 @@ struct gpiochip_info { #define GPIOLINE_FLAG_ACTIVE_LOW (1UL << 2) #define GPIOLINE_FLAG_OPEN_DRAIN (1UL << 3) #define GPIOLINE_FLAG_OPEN_SOURCE (1UL << 4) +#define GPIOLINE_FLAG_PULL_UP (1UL << 5) +#define GPIOLINE_FLAG_PULL_DOWN (1UL << 6) /** * struct gpioline_info - Information about a certain GPIO line @@ -62,6 +64,8 @@ struct gpioline_info { #define GPIOHANDLE_REQUEST_ACTIVE_LOW (1UL << 2) #define GPIOHANDLE_REQUEST_OPEN_DRAIN (1UL << 3) #define GPIOHANDLE_REQUEST_OPEN_SOURCE (1UL << 4) +#define GPIOHANDLE_REQUEST_PULL_UP (1UL << 5) +#define GPIOHANDLE_REQUEST_PULL_DOWN (1UL << 6) /** * struct gpiohandle_request - Information about a GPIO handle request -- 2.45.2