linux-kernel - [PATCH RFC 3/4] Input: melfas-mip4 - initialize touch events only if the device is a touchscreen

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Message-Id: <20250503-mip4-touchkey-v1-3-b483cda29a5b@disroot.org>
Date: Sat, 03 May 2025 14:38:29 +0530
From: Kaustabh Chakraborty <kauschluss@...root.org>
To: Sangwon Jee <jeesw@...fas.com>, 
 Dmitry Torokhov <dmitry.torokhov@...il.com>, Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Henrik Rydberg <rydberg@...math.org>
Cc: linux-input@...r.kernel.org, devicetree@...r.kernel.org, 
 linux-kernel@...r.kernel.org, Kaustabh Chakraborty <kauschluss@...root.org>
Subject: [PATCH RFC 3/4] Input: melfas-mip4 - initialize touch events only
 if the device is a touchscreen

Certain MIP4 devices report zero values when enquired for its touchscreen
dimensions (MIP4_R1_INFO_RESOLUTION_X and MIP4_R1_INFO_RESOLUTION_Y),
which is indicative of the fact that those devices are not touchscreens.

While registering for touch events for the device, always check - and
proceed - only if the device reports a non-zero resolution.

Signed-off-by: Kaustabh Chakraborty <kauschluss@...root.org>
---
 drivers/input/touchscreen/melfas_mip4.c | 50 ++++++++++++++++++---------------
 1 file changed, 27 insertions(+), 23 deletions(-)

diff --git a/drivers/input/touchscreen/melfas_mip4.c b/drivers/input/touchscreen/melfas_mip4.c
index 061ac353bc7a2e28f17581411af81f35c89733a1..57b657694a420220be135c2f78d3ddad3ef6f520 100644
--- a/drivers/input/touchscreen/melfas_mip4.c
+++ b/drivers/input/touchscreen/melfas_mip4.c
@@ -1146,14 +1146,16 @@ static int mip4_flash_fw(struct mip4_ts *ts,
 	mip4_query_device(ts);
 
 	/* Refresh device parameters */
-	input_set_abs_params(ts->input, ABS_MT_POSITION_X, 0, ts->max_x, 0, 0);
-	input_set_abs_params(ts->input, ABS_MT_POSITION_Y, 0, ts->max_y, 0, 0);
-	input_set_abs_params(ts->input, ABS_X, 0, ts->max_x, 0, 0);
-	input_set_abs_params(ts->input, ABS_Y, 0, ts->max_y, 0, 0);
-	input_abs_set_res(ts->input, ABS_MT_POSITION_X, ts->ppm_x);
-	input_abs_set_res(ts->input, ABS_MT_POSITION_Y, ts->ppm_y);
-	input_abs_set_res(ts->input, ABS_X, ts->ppm_x);
-	input_abs_set_res(ts->input, ABS_Y, ts->ppm_y);
+	if (ts->max_x && ts->max_y) {
+		input_set_abs_params(ts->input, ABS_MT_POSITION_X, 0, ts->max_x, 0, 0);
+		input_set_abs_params(ts->input, ABS_MT_POSITION_Y, 0, ts->max_y, 0, 0);
+		input_set_abs_params(ts->input, ABS_X, 0, ts->max_x, 0, 0);
+		input_set_abs_params(ts->input, ABS_Y, 0, ts->max_y, 0, 0);
+		input_abs_set_res(ts->input, ABS_MT_POSITION_X, ts->ppm_x);
+		input_abs_set_res(ts->input, ABS_MT_POSITION_Y, ts->ppm_y);
+		input_abs_set_res(ts->input, ABS_X, ts->ppm_x);
+		input_abs_set_res(ts->input, ABS_Y, ts->ppm_y);
+	}
 
 	for (i = 0; i < ts->key_num; i++) {
 		if (ts->key_code[i])
@@ -1498,21 +1500,23 @@ static int mip4_probe(struct i2c_client *client)
 	input->keycodesize = sizeof(*ts->key_code);
 	input->keycodemax = ts->key_num;
 
-	input_set_abs_params(input, ABS_MT_TOOL_TYPE, 0, MT_TOOL_PALM, 0, 0);
-	input_set_abs_params(input, ABS_MT_POSITION_X, 0, ts->max_x, 0, 0);
-	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, ts->max_y, 0, 0);
-	input_set_abs_params(input, ABS_MT_PRESSURE,
-			     MIP4_PRESSURE_MIN, MIP4_PRESSURE_MAX, 0, 0);
-	input_set_abs_params(input, ABS_MT_TOUCH_MAJOR,
-			     MIP4_TOUCH_MAJOR_MIN, MIP4_TOUCH_MAJOR_MAX, 0, 0);
-	input_set_abs_params(input, ABS_MT_TOUCH_MINOR,
-			     MIP4_TOUCH_MINOR_MIN, MIP4_TOUCH_MINOR_MAX, 0, 0);
-	input_abs_set_res(ts->input, ABS_MT_POSITION_X, ts->ppm_x);
-	input_abs_set_res(ts->input, ABS_MT_POSITION_Y, ts->ppm_y);
-
-	error = input_mt_init_slots(input, MIP4_MAX_FINGERS, INPUT_MT_DIRECT);
-	if (error)
-		return error;
+	if (ts->max_x && ts->max_y) {
+		input_set_abs_params(input, ABS_MT_TOOL_TYPE, 0, MT_TOOL_PALM, 0, 0);
+		input_set_abs_params(input, ABS_MT_POSITION_X, 0, ts->max_x, 0, 0);
+		input_set_abs_params(input, ABS_MT_POSITION_Y, 0, ts->max_y, 0, 0);
+		input_set_abs_params(input, ABS_MT_PRESSURE,
+				     MIP4_PRESSURE_MIN, MIP4_PRESSURE_MAX, 0, 0);
+		input_set_abs_params(input, ABS_MT_TOUCH_MAJOR,
+				     MIP4_TOUCH_MAJOR_MIN, MIP4_TOUCH_MAJOR_MAX, 0, 0);
+		input_set_abs_params(input, ABS_MT_TOUCH_MINOR,
+				     MIP4_TOUCH_MINOR_MIN, MIP4_TOUCH_MINOR_MAX, 0, 0);
+		input_abs_set_res(ts->input, ABS_MT_POSITION_X, ts->ppm_x);
+		input_abs_set_res(ts->input, ABS_MT_POSITION_Y, ts->ppm_y);
+
+		error = input_mt_init_slots(input, MIP4_MAX_FINGERS, INPUT_MT_DIRECT);
+		if (error)
+			return error;
+	}
 
 	for (i = 0; i < ts->key_num; i++) {
 		if (ts->key_code[i])

-- 
2.49.0