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From: Kent Gibson <warthog618@gmail.com>
To: linux-gpio@vger.kernel.org, bgolaszewski@baylibre.com,
	linus.walleij@linaro.org, bamv2005@gmail.com
Cc: drew@pdp7.com, Kent Gibson <warthog618@gmail.com>
Subject: [PATCH v4 2/5] gpiolib: add support for pull up/down to lineevent_create
Date: Mon, 28 Oct 2019 15:37:10 +0800	[thread overview]
Message-ID: <20191028073713.25664-3-warthog618@gmail.com> (raw)
In-Reply-To: <20191028073713.25664-1-warthog618@gmail.com>

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

Also restrict the application of bias to lines
explicitly requested as inputs to prevent bias being applied
to as-is line requests.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
---
 drivers/gpio/gpiolib.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e80e689be2cc..7dfbb3676ee0 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -554,6 +554,12 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 	     (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_BIAS_PULL_UP) ||
+	     (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
+		return -EINVAL;
+
 	lh = kzalloc(sizeof(*lh), GFP_KERNEL);
 	if (!lh)
 		return -ENOMEM;
@@ -944,6 +950,10 @@ 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_BIAS_PULL_DOWN)
+		set_bit(FLAG_PULL_DOWN, &desc->flags);
+	if (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)
+		set_bit(FLAG_PULL_UP, &desc->flags);
 
 	ret = gpiod_direction_input(desc);
 	if (ret)
-- 
2.23.0


  parent reply	other threads:[~2019-10-28  7:38 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-28  7:37 [PATCH v4 0/5] gpio: expose line bias flags to userspace Kent Gibson
2019-10-28  7:37 ` [PATCH v4 1/5] gpio: expose pull-up/pull-down line " Kent Gibson
2019-10-28  7:37 ` Kent Gibson [this message]
2019-10-31  7:11   ` [PATCH v4 2/5] gpiolib: add support for pull up/down to lineevent_create Bartosz Golaszewski
2019-10-31  7:24     ` Kent Gibson
2019-10-28  7:37 ` [PATCH v4 3/5] gpio: mockup: add set_config to support pull up/down Kent Gibson
2019-10-28  7:37 ` [PATCH v4 4/5] gpiolib: add support for disabling line bias Kent Gibson
2019-10-28  7:37 ` [PATCH v4 5/5] gpiolib: add support for biasing output lines Kent Gibson
2019-10-31  7:10 ` [PATCH v4 0/5] gpio: expose line bias flags to userspace Bartosz Golaszewski
2019-11-04  0:26   ` Linus Walleij
2019-11-04  1:07     ` Kent Gibson
2019-11-04 10:14       ` Bartosz Golaszewski
2019-11-04 11:11         ` Kent Gibson
2019-11-04 11:48           ` Bartosz Golaszewski
2019-11-04 14:22             ` Kent Gibson
2019-11-04 15:20               ` Bartosz Golaszewski
2019-11-04 15:35                 ` Kent Gibson

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