[PATCH v2 2/2] HID: logitech-hidpp: enable reprogrammable buttons on Signature M650

[Elliot Douglas]

The Bluetooth Signature M650 exposes its side buttons through the normal
mouse report, but the observed events are short click-like events emitted
around release rather than physical press/release state.

The device appears to use the held side-button state for its built-in
gesture and side-button + wheel horizontal-scroll mode. As a result,
holding a side button long enough can prevent the normal mouse report from
emitting a usable button event at all.

HID++ REPROG_CONTROLS_V4 diversion for control IDs 0x0053 and 0x0056
provides real press and release timing for those same controls. Logitech
documents the Signature M650 side buttons as Back/Forward buttons, so
report the diverted controls as BTN_BACK and BTN_FORWARD.

The HID++ 0x1b04 documentation lists those control IDs as Back and
Forward. The driver still verifies that the controls are present in the
device control table and advertised as divertable before changing their
reporting mode.

Link: https://support.logi.com/hc/en-nz/articles/4414473810583-Getting-Started-Signature-M650
Signed-off-by: Elliot Douglas <edouglas7358@xxxxxxxxx>
---
 drivers/hid/hid-logitech-hidpp.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index f9189e14fb78..e71dd2457e80 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -3624,14 +3624,30 @@ static int hidpp10_extra_mouse_buttons_raw_event(struct hidpp_device *hidpp,
 
 #define HIDPP_REPROG_CONTROLS_EVENT_DIVERTED		0x00
 
+#define HIDPP_REPROG_CONTROL_BACK			0x0053
+#define HIDPP_REPROG_CONTROL_FORWARD			0x0056
+
+#define HIDPP_PRODUCT_SIGNATURE_M650			0xb02a
+
 struct hidpp_reprog_control_mapping {
 	u16 control;
 	u16 code;
 };
 
+static const struct hidpp_reprog_control_mapping m650_reprog_control_mappings[] = {
+	{ HIDPP_REPROG_CONTROL_BACK, BTN_BACK },
+	{ HIDPP_REPROG_CONTROL_FORWARD, BTN_FORWARD },
+	{ }
+};
+
 static const struct hidpp_reprog_control_mapping *
 hidpp20_reprog_controls_get_mappings(struct hidpp_device *hidpp)
 {
+	switch (hidpp->hid_dev->product) {
+	case HIDPP_PRODUCT_SIGNATURE_M650:
+		return m650_reprog_control_mappings;
+	}
+
 	return NULL;
 }
 
@@ -4911,7 +4927,9 @@ static const struct hid_device_id hidpp_devices[] = {
 	{ /* MX Vertical mouse over Bluetooth */
 	  HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_LOGITECH, 0xb020) },
 	{ /* Signature M650 over Bluetooth */
-	  HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_LOGITECH, 0xb02a) },
+	  HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_LOGITECH,
+			       HIDPP_PRODUCT_SIGNATURE_M650),
+	  .driver_data = HIDPP_QUIRK_HIDPP_REPROG_CONTROLS_BTNS },
 	{ /* MX Master 3 mouse over Bluetooth */
 	  HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_LOGITECH, 0xb023) },
 	{ /* MX Anywhere 3 mouse over Bluetooth */
-- 
2.54.0