In the past, no elantech was known with 3 touchpad mouse buttons.
Fujitsu H730 is the first known elantech with a middle button. This commit
enables this middle button.

Reported-by: Stefan Valouch <redacted>
Tested-by: Stefan Valouch <redacted>
Tested-by: Alfredo Gemma <redacted>
Signed-off-by: Ulrik De Bie <redacted>
---
 drivers/input/mouse/elantech.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index 67d56c0..e86bbd7 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c

@@ -563,6 +563,7 @@ static void elantech_input_sync_v4(struct psmouse *psmouse)
 	} else {
 		input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
 		input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
+		input_report_key(dev, BTN_MIDDLE, packet[0] & 0x04);
 	}
 
 	input_mt_report_pointer_emulation(dev, true);

@@ -1150,6 +1151,7 @@ static int elantech_set_input_params(struct psmouse *psmouse)
 	__clear_bit(EV_REL, dev->evbit);
 
 	__set_bit(BTN_LEFT, dev->keybit);
+	__set_bit(BTN_MIDDLE, dev->keybit);