From 33fc16fd8aa3684e19b1d1f0a712593e2e570ab1 Mon Sep 17 00:00:00 2001

From: Hans de Goede <hdegoede@redhat.com>

Date: Sun, 11 Jun 2017 21:24:50 +0200

Subject: [PATCH 10/16] Input: silead: Add support for capactive home button

 found on some x86 tablets

On some x86 tablets with a silead touchscreen the windows logo on the

front is a capacitive home button. Touching this button results in a touch

with bits 12-15 of the Y coordinates set, while normally only the lower 12

are used.

Detect this and report a KEY_LEFTMETA press when this happens. Note for

now we only respond to the Y coordinate bits 12-15 containing 0x01, on some

tablets *without* a capacative button I've noticed these bits containing

0x04 when crossing the edges of the screen.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

---

 drivers/input/touchscreen/silead.c | 45 ++++++++++++++++++++++++++++----------

 1 file changed, 34 insertions(+), 11 deletions(-)

diff --git a/drivers/input/touchscreen/silead.c b/drivers/input/touchscreen/silead.c

index 0dbcf105f7db..c0ba40c09699 100644

--- a/drivers/input/touchscreen/silead.c

+++ b/drivers/input/touchscreen/silead.c

@@ -56,7 +56,7 @@

 #define SILEAD_POINT_Y_MSB_OFF	0x01

 #define SILEAD_POINT_X_OFF	0x02

 #define SILEAD_POINT_X_MSB_OFF	0x03

-#define SILEAD_TOUCH_ID_MASK	0xF0

+#define SILEAD_EXTRA_DATA_MASK	0xF0

 #define SILEAD_CMD_SLEEP_MIN	10000

 #define SILEAD_CMD_SLEEP_MAX	20000

@@ -109,6 +109,8 @@ static int silead_ts_request_input_dev(struct silead_ts_data *data)

 			    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED |

 			    INPUT_MT_TRACK);

+	input_set_capability(data->input, EV_KEY, KEY_LEFTMETA);

+

 	data->input->name = SILEAD_TS_NAME;

 	data->input->phys = "input/ts";

 	data->input->id.bustype = BUS_I2C;

@@ -139,7 +141,8 @@ static void silead_ts_read_data(struct i2c_client *client)

 	struct input_dev *input = data->input;

 	struct device *dev = &client->dev;

 	u8 *bufp, buf[SILEAD_TS_DATA_LEN];

-	int touch_nr, error, i;

+	int touch_nr, softbutton, error, i;

+	bool softbutton_pressed = false;

 	error = i2c_smbus_read_i2c_block_data(client, SILEAD_REG_DATA,

 					      SILEAD_TS_DATA_LEN, buf);

@@ -148,21 +151,40 @@ static void silead_ts_read_data(struct i2c_client *client)

 		return;

 	}

-	touch_nr = buf[0];

-	if (touch_nr > data->max_fingers) {

+	if (buf[0] > data->max_fingers) {

 		dev_warn(dev, "More touches reported then supported %d > %d\n",

-			 touch_nr, data->max_fingers);

-		touch_nr = data->max_fingers;

+			 buf[0], data->max_fingers);

+		buf[0] = data->max_fingers;

 	}

+	touch_nr = 0;

 	bufp = buf + SILEAD_POINT_DATA_LEN;

-	for (i = 0; i < touch_nr; i++, bufp += SILEAD_POINT_DATA_LEN) {

-		/* Bits 4-7 are the touch id */

-		data->id[i] = (bufp[SILEAD_POINT_X_MSB_OFF] &

-			       SILEAD_TOUCH_ID_MASK) >> 4;

-		touchscreen_set_mt_pos(&data->pos[i], &data->prop,

+	for (i = 0; i < buf[0]; i++, bufp += SILEAD_POINT_DATA_LEN) {

+		softbutton = (bufp[SILEAD_POINT_Y_MSB_OFF] &

+			      SILEAD_EXTRA_DATA_MASK) >> 4;

+

+		if (softbutton) {

+			/*

+			 * For now only respond to softbutton == 0x01, some

+			 * tablets *without* a capacative button send 0x04

+			 * when crossing the edges of the screen.

+			 */

+			if (softbutton == 0x01)

+				softbutton_pressed = true;

+

+			continue;

+		}

+

+		/*

+		 * Bits 4-7 are the touch id, note not all models have

+		 * hardware touch ids so atm we don't use these.

+		 */

+		data->id[touch_nr] = (bufp[SILEAD_POINT_X_MSB_OFF] &

+				      SILEAD_EXTRA_DATA_MASK) >> 4;

+		touchscreen_set_mt_pos(&data->pos[touch_nr], &data->prop,

 			get_unaligned_le16(&bufp[SILEAD_POINT_X_OFF]) & 0xfff,

 			get_unaligned_le16(&bufp[SILEAD_POINT_Y_OFF]) & 0xfff);

+		touch_nr++;

 	}

 	input_mt_assign_slots(input, data->slots, data->pos, touch_nr, 0);

@@ -178,6 +200,7 @@ static void silead_ts_read_data(struct i2c_client *client)

 	}

 	input_mt_sync_frame(input);

+	input_report_key(input, KEY_LEFTMETA, softbutton_pressed);

 	input_sync(input);

 }

-- 

2.13.0