From: David Jander <da...@protonic.nl>

[ Upstream commit e52cd628a03f72a547dbf90ccb703ee64800504a ]

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: f5a28a7d4858f94a ("Input: ads7846 - avoid pen up/down when reading 
hwmon")
Co-developed-by: Oleksij Rempel <o.rem...@pengutronix.de>
Signed-off-by: David Jander <da...@protonic.nl>
Signed-off-by: Oleksij Rempel <o.rem...@pengutronix.de>
Link: https://lore.kernel.org/r/20201027105416.18773-1-o.rem...@pengutronix.de
Signed-off-by: Dmitry Torokhov <dmitry.torok...@gmail.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/input/touchscreen/ads7846.c | 44 +++++++++++++++++------------
 1 file changed, 26 insertions(+), 18 deletions(-)

diff --git a/drivers/input/touchscreen/ads7846.c 
b/drivers/input/touchscreen/ads7846.c
index a2f45aefce08a..0fbad337e45a3 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -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)
 {
 }
@@ -871,16 +887,8 @@ 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;
 }
-- 
2.27.0



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