goodix_ts_data structure contains abs_x_max and abs_y_max members,
which contain already swapped maximum ranges. That causes reporting
touch events with invalid position (out of range values).

Problem occurs for example when ts->inverted_x and ts->swapped_x_y are
true, but ts->inverted_y is false. Assuming we have 720x1280 touch
panel, ts->abs_x_max == 1279 and ts->abs_y_max == 719 (because we
inverted that in goodix_read_config()). Now let's assume that we
received event from (0:0) position (in touch panel original
coordinates). In function goodix_ts_report_touch() we calculate
input_x as 1279, but after swapping input_y takes that value (which is
more that maximum 719 value reported during initialization).

Take into account that abs_x_max and abs_y_max are already swapped
in goodix_ts_report_touch(), so position for inverted axes will be
calculated correctly.

Signed-off-by: Marcin Niestroj <redacted>
Fixes: ad48cf5e9597 ("Input: goodix - add axis swapping and axis inversion support")
---
Changes v2 -> v3 (suggested by Bastien):
 - add explanation about when the problem occurs

Changes v1 -> v2 (suggested by Bastien):
 - patch splitted off from patch 3

 drivers/input/touchscreen/goodix.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
index 7896097ca69b..dc832890f6d3 100644
--- a/drivers/input/touchscreen/goodix.c
+++ b/drivers/input/touchscreen/goodix.c

@@ -296,12 +296,18 @@ static void goodix_ts_report_touch(struct goodix_ts_data *ts, u8 *coor_data)
 	int input_w = get_unaligned_le16(&coor_data[5]);
 
 	/* Inversions have to happen before axis swapping */
-	if (ts->inverted_x)
-		input_x = ts->abs_x_max - input_x;
-	if (ts->inverted_y)
-		input_y = ts->abs_y_max - input_y;
-	if (ts->swapped_x_y)
+	if (!ts->swapped_x_y) {
+		if (ts->inverted_x)
+			input_x = ts->abs_x_max - input_x;
+		if (ts->inverted_y)
+			input_y = ts->abs_y_max - input_y;
+	} else {
+		if (ts->inverted_x)
+			input_x = ts->abs_y_max - input_x;
+		if (ts->inverted_y)
+			input_y = ts->abs_x_max - input_y;
 		swap(input_x, input_y);
+	}
 
 	input_mt_slot(ts->input_dev, id);
 	input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, true);

-- 
2.16.1