HID: Add map_msc() to avoid boilerplate code

Since we are going to have more MSC events too, add map_msc() that can
be used to fill in necessary fields and avoid boilerplate code.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Tero Kristo <tero.kristo@linux.intel.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20211210111138.1248187-2-tero.kristo@linux.intel.com

drivers/hid/hid-input.c

@@ -52,6 +52,7 @@ static const struct {
 #define map_rel(c)	hid_map_usage(hidinput, usage, &bit, &max, EV_REL, (c))
 #define map_key(c)	hid_map_usage(hidinput, usage, &bit, &max, EV_KEY, (c))
 #define map_led(c)	hid_map_usage(hidinput, usage, &bit, &max, EV_LED, (c))
+#define map_msc(c)	hid_map_usage(hidinput, usage, &bit, &max, EV_MSC, (c))
 
 #define map_abs_clear(c)	hid_map_usage_clear(hidinput, usage, &bit, \
 		&max, EV_ABS, (c))
@@ -874,10 +875,7 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
 
 		case 0x5b: /* TransducerSerialNumber */
 		case 0x6e: /* TransducerSerialNumber2 */
-			usage->type = EV_MSC;
-			usage->code = MSC_SERIAL;
-			bit = input->mscbit;
-			max = MSC_MAX;
+			map_msc(MSC_SERIAL);
 			break;
 
 		default:  goto unknown;

include/linux/hid.h

@@ -1010,6 +1010,10 @@ static inline void hid_map_usage(struct hid_input *hidinput,
 		bmap = input->ledbit;
 		limit = LED_MAX;
 		break;
+	case EV_MSC:
+		bmap = input->mscbit;
+		limit = MSC_MAX;
+		break;
 	}
 
 	if (unlikely(c > limit || !bmap)) {