Re: [PATCH v2 1/3] hid-multitouch: add support for trackpads

On Fri, Jan 20, 2012 at 05:09:48PM +0100, Henrik Rydberg wrote:

Hi Benjamin,

quoted

@@ -389,9 +404,19 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 				td->last_field_index = field->index;
 			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;
 
+	case HID_UP_BUTTON:
+		code = ((usage->hid - 1) & HID_USAGE) + BTN_MOUSE;

Why '+' here instead of '|' is  beyond me...

Because it is an offset for the range. The fact that it is on power 2
boundary and we can use "|" is purely coincidential here.

Maybe we should even write it as:

		code = BTN_MOUSE + ((usage->hid - 1) & HID_USAGE);

Thanks,
Dmitry

-- 
Dmitry