[PATCH v3 4/9] HID: multitouch: support getting the tip state from HID_DG_TOUCH fields

Aditya Garg
2024-08-08T13:53:12Z

This is necessary on Apple Touch Bars, where the tip state is contained
in fields with the HID_DG_TOUCH usage. This feature is gated by a quirk
in order to prevent breaking other devices, see commit c2ef8f21ea8f
("HID: multitouch: add support for trackpads").

Signed-off-by: Kerem Karabay <kekrby@gmail.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
---
drivers/hid/hid-multitouch.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 3e92789ed..571435da5 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -72,6 +72,7 @@ MODULE_LICENSE("GPL");
#define MT_QUIRK_FORCE_MULTI_INPUT BIT(20)
#define MT_QUIRK_DISABLE_WAKEUP BIT(21)
#define MT_QUIRK_ORIENTATION_INVERT BIT(22)
+#define MT_QUIRK_TOUCH_IS_TIPSTATE BIT(23)

#define MT_INPUTMODE_TOUCHSCREEN 0x02
#define MT_INPUTMODE_TOUCHPAD 0x03
@@ -809,6 +810,15 @@ static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,

MT_STORE_FIELD(confidence_state);
return 1;
+ case HID_DG_TOUCH:
+ /*
+ * Legacy devices use TIPSWITCH and not TOUCH.
+ * Let's just ignore this field unless the quirk is set.
+ */
+ if (!(cls->quirks & MT_QUIRK_TOUCH_IS_TIPSTATE))
+ return -1;
+
+ fallthrough;
case HID_DG_TIPSWITCH:
if (field->application != HID_GD_SYSTEM_MULTIAXIS)
input_set_capability(hi->input,
@@ -872,10 +882,6 @@ static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,
case HID_DG_CONTACTMAX:
/* contact max are global to the report */
return -1;
- case HID_DG_TOUCH:
- /* Legacy devices use TIPSWITCH and not TOUCH.
- * Let's just ignore this field. */
- return -1;
}
/* let hid-input decide for the others */
return 0;
--
2.43.0