[PATCH] Input: goodix-berlin: report a resolution of 10 units/mm

[Val Packett <val@packett.cool>]

Without a reported resolution, userspace was assuming 1 unit/mm which
is wildly wrong: a regular smartphone is clearly not 2.4 meters tall.
Most applications do not care much for this kind of raw mm value,
but Phosh's on-screen keyboard would accidentally trigger swipe-to-close
gestures due to misinterpreting small movements as huge ones.

Do what the older goodix.c driver does and set the resolution to 10
units/mm to make sure the numbers calculated by userspace are reasonable.

Signed-off-by: Val Packett <val@packett.cool>
---
 drivers/input/touchscreen/goodix_berlin_core.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/input/touchscreen/goodix_berlin_core.c b/drivers/input/touchscreen/goodix_berlin_core.c
index 83f28b870531..b0938a4f3fec 100644
--- a/drivers/input/touchscreen/goodix_berlin_core.c
+++ b/drivers/input/touchscreen/goodix_berlin_core.c
@@ -628,6 +628,14 @@ static int goodix_berlin_input_dev_config(struct goodix_berlin_core *cd,
 
 	touchscreen_parse_properties(cd->input_dev, true, &cd->props);
 
+	/*
+	 * The resolution of these touchscreens is about 10 units/mm, the actual
+	 * resolution does not matter much since we set INPUT_PROP_DIRECT.
+	 * Set it to 10 to ensure userspace isn't off by an order of magnitude.
+	 */
+	input_abs_set_res(cd->input_dev, ABS_MT_POSITION_X, 10);
+	input_abs_set_res(cd->input_dev, ABS_MT_POSITION_Y, 10);
+
 	error = input_mt_init_slots(cd->input_dev, GOODIX_BERLIN_MAX_TOUCH,
 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
 	if (error)
-- 
2.53.0