Input: ad7879 - add option to correct xy axis

Sebastian Zenker reported that driver swaps x and y samples when the
touchscreen leads are connected in accordance with the datasheet
specification.  Transposed axis can be typically corrected by touch
screen calibration however this bug also negatively influences touch
pressure measurements.

Add an option to correct x and y axis.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Reported-and-tested-by: Sebastian Zenker <sebastian.zenker@gmx.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/ad7879.c b/drivers/input/touchscreen/ad7879.c
index e2482b40da51..e60709261951 100644
--- a/drivers/input/touchscreen/ad7879.c
+++ b/drivers/input/touchscreen/ad7879.c
@@ -118,6 +118,7 @@ struct ad7879 {
         unsigned int            irq;
         bool                    disabled;       /* P: input->mutex */
         bool                    suspended;      /* P: input->mutex */
+        bool                    swap_xy;
         u16                     conversion_data[AD7879_NR_SENSE];
         char                    phys[32];
         u8                      first_conversion_delay;
@@ -161,6 +162,9 @@ static int ad7879_report(struct ad7879 *ts)
         z1 = ts->conversion_data[AD7879_SEQ_Z1] & MAX_12BIT;
         z2 = ts->conversion_data[AD7879_SEQ_Z2] & MAX_12BIT;
 
+        if (ts->swap_xy)
+                swap(x, y);
+
         /*
          * The samples processed here are already preprocessed by the AD7879.
          * The preprocessing function consists of a median and an averaging
@@ -520,6 +524,7 @@ struct ad7879 *ad7879_probe(struct device *dev, u8 devid, unsigned int irq,
         ts->dev = dev;
         ts->input = input_dev;
         ts->irq = irq;
+        ts->swap_xy = pdata->swap_xy;
 
         setup_timer(&ts->timer, ad7879_timer, (unsigned long) ts);