sm7125: input: touchscreen: fts5cu56a: limit physical proximity sense range

* On stock ROM proximity only changes if changes occur near to the sensor. However on AOSP proximity already changes if a finger is placed somewhere between the upper half and the middle of the screen, making it impossible to for example pull down the notification panel during a phone call because the screen constantly turnes off. Samsung seems to apply something remotely similar on their stock ROM by creating a whole new virtual sensor.
* We now check if the area around the sensor (1400-2800 on the X axis, 0-700 on the Y axis) is touched and only then report proximity changes.
* To not break proximity reporting during screen off we also check if the panel is in LPM state

Change-Id: I22cb2f15cbb8a852b416642b47e1eb2799053d7e

drivers/input/touchscreen/stm/fts5cu56a/fts_ts.c

@@ -1820,10 +1820,20 @@ static u8 fts_event_handler_type_b(struct fts_ts_info *info)
 			if (p_event_status->stype == FTS_EVENT_STATUSTYPE_VENDORINFO) {
 				if (info->board->support_ear_detect) {
 					if (p_event_status->status_id == 0x6A) {
-						p_event_status->status_data_1 = p_event_status->status_data_1 == 5 || !p_event_status->status_data_1;
-						info->hover_event = p_event_status->status_data_1;
-						input_report_abs(info->input_dev_proximity, ABS_MT_CUSTOM, p_event_status->status_data_1);
-						input_sync(info->input_dev_proximity);
+						if (info->fts_power_state == FTS_POWER_STATE_LOWPOWER || info->finger[TouchID].y < 700 && info->finger[TouchID].x > 900
+						    && info->finger[TouchID].x < 3000) {
+							// Report actual range when either the area around the sensor is touched or if panel is in LPM state
+							p_event_status->status_data_1 = p_event_status->status_data_1 == 5 || !p_event_status->status_data_1;
+							info->hover_event = p_event_status->status_data_1;
+							input_report_abs(info->input_dev_proximity, ABS_MT_CUSTOM, p_event_status->status_data_1);
+							input_sync(info->input_dev_proximity);
+						} else {
+							// Properly reset to 1cm
+							p_event_status->status_data_1 = 1;
+							info->hover_event = p_event_status->status_data_1;
+							input_report_abs(info->input_dev_proximity, ABS_MT_CUSTOM, p_event_status->status_data_1);
+							input_sync(info->input_dev_proximity);
+						}
 						input_info(true, &info->client->dev, "%s: proximity: %d\n", __func__, p_event_status->status_data_1);
 					}
 				}