Input: elan_i2c - handle physical middle button

Some models have a middle button, we should export it as well.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/elan_i2c_core.c

@@ -99,6 +99,7 @@ struct elan_tp_data {
 	u8			max_baseline;
 	bool			baseline_ready;
 	u8			clickpad;
+	bool			middle_button;
 };
 
 static int elan_get_fwinfo(u16 ic_type, u16 *validpage_count,
@@ -420,6 +421,9 @@ static int elan_query_device_parameters(struct elan_tp_data *data)
 	if (device_property_read_bool(&client->dev, "elan,clickpad"))
 		data->clickpad = 1;
 
+	if (device_property_read_bool(&client->dev, "elan,middle-button"))
+		data->middle_button = true;
+
 	return 0;
 }
 
@@ -958,8 +962,9 @@ static void elan_report_absolute(struct elan_tp_data *data, u8 *packet)
 			finger_data += ETP_FINGER_DATA_LEN;
 	}
 
-	input_report_key(input, BTN_LEFT, tp_info & 0x01);
-	input_report_key(input, BTN_RIGHT, tp_info & 0x02);
+	input_report_key(input, BTN_LEFT,   tp_info & BIT(0));
+	input_report_key(input, BTN_MIDDLE, tp_info & BIT(2));
+	input_report_key(input, BTN_RIGHT,  tp_info & BIT(1));
 	input_report_abs(input, ABS_DISTANCE, hover_event != 0);
 	input_mt_report_pointer_emulation(input, true);
 	input_sync(input);
@@ -1093,10 +1098,13 @@ static int elan_setup_input_device(struct elan_tp_data *data)
 
 	__set_bit(EV_ABS, input->evbit);
 	__set_bit(INPUT_PROP_POINTER, input->propbit);
-	if (data->clickpad)
+	if (data->clickpad) {
 		__set_bit(INPUT_PROP_BUTTONPAD, input->propbit);
-	else
+	} else {
 		__set_bit(BTN_RIGHT, input->keybit);
+		if (data->middle_button)
+			__set_bit(BTN_MIDDLE, input->keybit);
+	}
 	__set_bit(BTN_LEFT, input->keybit);
 
 	/* Set up ST parameters */