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 v3 2/5] gpiolib: add support for pull up/down to lineevent_create
Date: Sun, 20 Oct 2019 22:42:35 +0800 [thread overview]
Message-ID: <20191020144238.14080-3-warthog618@gmail.com> (raw)
In-Reply-To: <20191020144238.14080-1-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.
The patch also restricts 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 604dc17b3207..eef964417521 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_PULL_UP) ||
+ (lflags & GPIOHANDLE_REQUEST_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_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
next prev parent reply other threads:[~2019-10-20 14:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-20 14:42 [PATCH v3 0/5] gpio: expose line bias flags to userspace Kent Gibson
2019-10-20 14:42 ` [PATCH v3 1/5] gpio: expose pull-up/pull-down line " Kent Gibson
2019-10-20 14:42 ` Kent Gibson [this message]
2019-10-20 14:42 ` [PATCH v3 3/5] gpio: mockup: add set_config to support pull up/down Kent Gibson
2019-10-20 14:42 ` [PATCH v3 4/5] gpiolib: add support for disabling line bias Kent Gibson
2019-10-20 14:42 ` [PATCH v3 5/5] gpiolib: add support for biasing output lines Kent Gibson
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