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Input: ads7846 - fix race that causes missing releases

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[ Upstream commit e52cd628a0 ]

If touchscreen is released while busy reading HWMON device, the release
can be missed. The IRQ thread is not started because no touch is active
and BTN_TOUCH release event is never sent.

Fixes: f5a28a7d48 ("Input: ads7846 - avoid pen up/down when reading hwmon")
Co-developed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: David Jander <david@protonic.nl>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20201027105416.18773-1-o.rempel@pengutronix.de
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
David Jander 2020-11-11 11:00:59 -08:00 committed by Greg Kroah-Hartman
parent 86398df4b2
commit c7ac509273
1 changed files with 26 additions and 18 deletions
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44
drivers/input/touchscreen/ads7846.c
View file

@ -199,6 +199,26 @@ struct ads7846 {
#define REF_ON (READ_12BIT_DFR(x, 1, 1))
#define REF_OFF (READ_12BIT_DFR(y, 0, 0))
static int get_pendown_state(struct ads7846 *ts)
{
if (ts->get_pendown_state)
return ts->get_pendown_state();
return !gpio_get_value(ts->gpio_pendown);
}
static void ads7846_report_pen_up(struct ads7846 *ts)
{
struct input_dev *input = ts->input;
input_report_key(input, BTN_TOUCH, 0);
input_report_abs(input, ABS_PRESSURE, 0);
input_sync(input);
ts->pendown = false;
dev_vdbg(&ts->spi->dev, "UP\n");
}
/* Must be called with ts->lock held */
static void ads7846_stop(struct ads7846 *ts)
{
@ -215,6 +235,10 @@ static void ads7846_stop(struct ads7846 *ts)
static void ads7846_restart(struct ads7846 *ts)
{
if (!ts->disabled && !ts->suspended) {
/* Check if pen was released since last stop */
if (ts->pendown && !get_pendown_state(ts))
ads7846_report_pen_up(ts);
/* Tell IRQ thread that it may poll the device. */
ts->stopped = false;
mb();
@ -605,14 +629,6 @@ static const struct attribute_group ads784x_attr_group = {
/*--------------------------------------------------------------------------*/
static int get_pendown_state(struct ads7846 *ts)
{
if (ts->get_pendown_state)
return ts->get_pendown_state();
return !gpio_get_value(ts->gpio_pendown);
}
static void null_wait_for_sync(void)
{
}
@ -867,16 +883,8 @@ static irqreturn_t ads7846_irq(int irq, void *handle)
msecs_to_jiffies(TS_POLL_PERIOD));
}
if (ts->pendown && !ts->stopped) {
struct input_dev *input = ts->input;
input_report_key(input, BTN_TOUCH, 0);
input_report_abs(input, ABS_PRESSURE, 0);
input_sync(input);
ts->pendown = false;
dev_vdbg(&ts->spi->dev, "UP\n");
}
if (ts->pendown && !ts->stopped)
ads7846_report_pen_up(ts);
return IRQ_HANDLED;
}