Input: elantech - report the middle button of the touchpad

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. For backwards compatibility, the Fujitsu is
detected via DMI, and only for this one 3 buttons will be announced.

Reported-by: Stefan Valouch <stefan@valouch.com>
Signed-off-by: Ulrik De Bie <ulrik.debie-os@e2big.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index ce699eba9adc..6d628f155c08 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);
@@ -1132,6 +1133,22 @@ static void elantech_set_buttonpad_prop(struct psmouse *psmouse)
 }
 
 /*
+ * Some hw_version 4 models do have a middle button
+ */
+static const struct dmi_system_id elantech_dmi_has_middle_button[] = {
+#if defined(CONFIG_DMI) && defined(CONFIG_X86)
+        {
+                /* Fujitsu H730 has a middle button */
+                .matches = {
+                        DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+                        DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS H730"),
+                },
+        },
+#endif
+        { }
+};
+
+/*
  * Set the appropriate event bits for the input subsystem
  */
 static int elantech_set_input_params(struct psmouse *psmouse)
@@ -1150,6 +1167,8 @@ static int elantech_set_input_params(struct psmouse *psmouse)
         __clear_bit(EV_REL, dev->evbit);
 
         __set_bit(BTN_LEFT, dev->keybit);
+        if (dmi_check_system(elantech_dmi_has_middle_button))
+                __set_bit(BTN_MIDDLE, dev->keybit);
         __set_bit(BTN_RIGHT, dev->keybit);
 
         __set_bit(BTN_TOUCH, dev->keybit);