HID: uclogic: Always shift touch reports to zero

Always decrement touch report values to have the range start with zero,
regardless if flipped or not. This fixes the future non-flipped touch
strip reports.

Signed-off-by: Nikolai Kondrashov <spbnick@gmail.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Author: spbnick

drivers/hid/hid-uclogic-core.c

@@ -386,15 +386,16 @@ static int uclogic_raw_event_frame(
 	}
 
 	/* If need to, and can, transform the touch ring reports */
-	if (frame->touch_byte > 0 && frame->touch_byte < size &&
-	    frame->touch_flip_at != 0) {
+	if (frame->touch_byte > 0 && frame->touch_byte < size) {
 		__s8 value = data[frame->touch_byte];
-		if (value != 0) {
-			value = frame->touch_flip_at - value;
-			if (value < 0)
-				value = frame->touch_max + value;
 
-			data[frame->touch_byte] = value;
+		if (value != 0) {
+			if (frame->touch_flip_at != 0) {
+				value = frame->touch_flip_at - value;
+				if (value <= 0)
+					value = frame->touch_max + value;
+			}
+			data[frame->touch_byte] = value - 1;
 		}
 	}
 

drivers/hid/hid-uclogic-params.c

@@ -889,7 +889,7 @@ static int uclogic_params_huion_init(struct uclogic_params *params,
 				UCLOGIC_RDESC_V2_FRAME_TOUCH_DEV_ID_BYTE;
 			p.frame_list[1].touch_byte = 5;
 			p.frame_list[1].touch_max = 12;
-			p.frame_list[1].touch_flip_at = 6;
+			p.frame_list[1].touch_flip_at = 7;
 
 			/* Create v2 frame dial parameters */
 			rc = uclogic_params_frame_init_with_desc(