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From:   Johnny Chuang <johnny.chuang.emc@gmail.com>
To:     Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        Peter Hutterer <peter.hutterer@who-t.net>,
        linux-kernel@vger.kernel.org, linux-input@vger.kernel.org,
        Rob Schonberger <robsc@google.com>,
        Johnny Chuang <johnny.chuang@emc.com.tw>
Cc:     James Chen <james.chen@emc.com.tw>,
        Jennifer Tsai <jennifer.tsai@emc.com.tw>,
        Paul Liang <paul.liang@emc.com.tw>,
        Jeff Chuang <jeff.chuang@emc.com.tw>
Subject: [PATCH] Input: elants_i2c - support palm detection
Date:   Thu, 26 Mar 2020 15:58:45 +0800
Message-Id: <1585209525-6047-1-git-send-email-johnny.chuang.emc@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Johnny Chuang <johnny.chuang@emc.com.tw>

Elan define finger/palm detection on the least significant bit of byte 33.
The default value is 1 for all firmwares, which report as MT_TOOL_FINGER.
If firmware support palm detection, the bit will change to 0 and
report as MT_TOOL_PALM when firmware detecting palm.

Signed-off-by: Johnny Chuang <johnny.chuang@emc.com.tw>
---
 drivers/input/touchscreen/elants_i2c.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/input/touchscreen/elants_i2c.c b/drivers/input/touchscreen/elants_i2c.c
index 14c577c..3b4d9eb3 100644
--- a/drivers/input/touchscreen/elants_i2c.c
+++ b/drivers/input/touchscreen/elants_i2c.c
@@ -73,6 +73,7 @@
 #define FW_POS_STATE		1
 #define FW_POS_TOTAL		2
 #define FW_POS_XY		3
+#define FW_POS_TOOL_TYPE	33
 #define FW_POS_CHECKSUM		34
 #define FW_POS_WIDTH		35
 #define FW_POS_PRESSURE		45
@@ -842,6 +843,7 @@ static void elants_i2c_mt_event(struct elants_data *ts, u8 *buf)
 {
 	struct input_dev *input = ts->input;
 	unsigned int n_fingers;
+	unsigned int tool_type;
 	u16 finger_state;
 	int i;
 
@@ -852,6 +854,12 @@ static void elants_i2c_mt_event(struct elants_data *ts, u8 *buf)
 	dev_dbg(&ts->client->dev,
 		"n_fingers: %u, state: %04x\n",  n_fingers, finger_state);
 
+	/* Note: all fingers have the same tool type */
+	if (buf[FW_POS_TOOL_TYPE] & 0x01)
+		tool_type = MT_TOOL_FINGER;
+	else
+		tool_type = MT_TOOL_PALM;
+
 	for (i = 0; i < MAX_CONTACT_NUM && n_fingers; i++) {
 		if (finger_state & 1) {
 			unsigned int x, y, p, w;
@@ -867,7 +875,7 @@ static void elants_i2c_mt_event(struct elants_data *ts, u8 *buf)
 				i, x, y, p, w);
 
 			input_mt_slot(input, i);
-			input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
+			input_mt_report_slot_state(input, tool_type, true);
 			input_event(input, EV_ABS, ABS_MT_POSITION_X, x);
 			input_event(input, EV_ABS, ABS_MT_POSITION_Y, y);
 			input_event(input, EV_ABS, ABS_MT_PRESSURE, p);
@@ -1307,6 +1315,7 @@ static int elants_i2c_probe(struct i2c_client *client,
 	input_set_abs_params(ts->input, ABS_MT_POSITION_Y, 0, ts->y_max, 0, 0);
 	input_set_abs_params(ts->input, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
 	input_set_abs_params(ts->input, ABS_MT_PRESSURE, 0, 255, 0, 0);
+	input_set_abs_params(ts->input, ABS_MT_TOOL_TYPE, 0, MT_TOOL_MAX, 0, 0);
 	input_abs_set_res(ts->input, ABS_MT_POSITION_X, ts->x_res);
 	input_abs_set_res(ts->input, ABS_MT_POSITION_Y, ts->y_res);
 	input_abs_set_res(ts->input, ABS_MT_TOUCH_MAJOR, 1);
-- 
2.7.4