Input: ad7877 - implement EV_KEY:BTN_TOUCH reporting

Some input users such as Android or X require BTN_TOUCH events.
Implement EV_KEY:BTN_TOUCH and make sure that the release event
is not erroneous scheduled without a preceding valid touch.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 12 insertions, 5 deletions

diff --git a/drivers/input/touchscreen/ad7877.c b/drivers/input/touchscreen/ad7877.c
index 53f4d79ee530..96c0a0d4b69c 100644
--- a/drivers/input/touchscreen/ad7877.c
+++ b/drivers/input/touchscreen/ad7877.c
@@ -333,7 +333,7 @@ static int ad7877_read_adc(struct spi_device *spi, unsigned command)
         return status ? : sample;
 }
 
-static void ad7877_rx(struct ad7877 *ts)
+static int ad7877_rx(struct ad7877 *ts)
 {
         struct input_dev *input_dev = ts->input;
         unsigned Rt;
@@ -360,11 +360,17 @@ static void ad7877_rx(struct ad7877 *ts)
                 Rt /= z1;
                 Rt = (Rt + 2047) >> 12;
 
+                if (!timer_pending(&ts->timer))
+                        input_report_key(input_dev, BTN_TOUCH, 1);
+
                 input_report_abs(input_dev, ABS_X, x);
                 input_report_abs(input_dev, ABS_Y, y);
                 input_report_abs(input_dev, ABS_PRESSURE, Rt);
                 input_sync(input_dev);
+                return 0;
         }
+
+        return -EINVAL;
 }
 
 static inline void ad7877_ts_event_release(struct ad7877 *ts)
@@ -372,6 +378,7 @@ static inline void ad7877_ts_event_release(struct ad7877 *ts)
         struct input_dev *input_dev = ts->input;
 
         input_report_abs(input_dev, ABS_PRESSURE, 0);
+        input_report_key(input_dev, BTN_TOUCH, 0);
         input_sync(input_dev);
 }
 
@@ -413,11 +420,9 @@ static void ad7877_callback(void *_ts)
         struct ad7877 *ts = _ts;
 
         spin_lock_irq(&ts->lock);
-
-        ad7877_rx(ts);
+        if (!ad7877_rx(ts))
+                mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
         ts->pending = 0;
-        mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT);
-
         spin_unlock_irq(&ts->lock);
 }
 
@@ -728,6 +733,8 @@ static int __devinit ad7877_probe(struct spi_device *spi)
         input_dev->phys = ts->phys;
         input_dev->dev.parent = &spi->dev;
 
+        __set_bit(EV_KEY, input_dev->evbit);
+        __set_bit(BTN_TOUCH, input_dev->keybit);
         __set_bit(EV_ABS, input_dev->evbit);
         __set_bit(ABS_X, input_dev->absbit);
         __set_bit(ABS_Y, input_dev->absbit);