[PATCH 1/5] gpiolib: add support for pull up/down to lineevent_create

[Kent Gibson <warthog618@gmail.com>]

This patch adds support for pull up/down to lineevent_create.
Use cases include receiving asynchronous presses from a
push button without an external pull up/down.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
---
 drivers/gpio/gpiolib.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 994e5d71375d..0912a00b2960 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -920,8 +920,20 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 	/* This is just wrong: we don't look for events on output lines */
 	if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
 	    (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
-	    (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE) ||
-	    (lflags & GPIOHANDLE_REQUEST_PULL_UP) ||
+	    (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
+		return -EINVAL;
+
+	/* PULL_UP and PULL_DOWN flags only make sense for input mode. */
+	if (!(lflags & GPIOHANDLE_REQUEST_INPUT) &&
+	    ((lflags & GPIOHANDLE_REQUEST_PULL_UP) ||
+	     (lflags & GPIOHANDLE_REQUEST_PULL_DOWN)))
+		return -EINVAL;
+
+	/*
+	 * Do not allow both pull-up and pull-down flags to be set as they
+	 *  are contradictory.
+	 */
+	if ((lflags & GPIOHANDLE_REQUEST_PULL_UP) &&
 	    (lflags & GPIOHANDLE_REQUEST_PULL_DOWN))
 		return -EINVAL;
 
@@ -951,6 +963,10 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 
 	if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW)
 		set_bit(FLAG_ACTIVE_LOW, &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_direction_input(desc);
 	if (ret)
-- 
2.23.0