platform/surface: aggregator_tabletsw: Add support for book mode in KIP subsystem

Devices with a type-cover have an additional "book" mode, deactivating
type-cover input and turning off its backlight. This is currently
unsupported, leading to the warning

  surface_aggregator_tablet_mode_switch 01:0e:01:00:01: unknown KIP cover state: 6

Therefore, add support for this state and map it to enable tablet-mode.

Fixes: 9f794056 ("platform/surface: Add KIP/POS tablet-mode switch driver")
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Link: https://lore.kernel.org/r/20230525213218.2797480-2-luzmaximilian@gmail.comReviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/surface/surface_aggregator_tabletsw.c

@@ -210,6 +210,7 @@ enum ssam_kip_cover_state {
 	SSAM_KIP_COVER_STATE_LAPTOP        = 0x03,
 	SSAM_KIP_COVER_STATE_FOLDED_CANVAS = 0x04,
 	SSAM_KIP_COVER_STATE_FOLDED_BACK   = 0x05,
+	SSAM_KIP_COVER_STATE_BOOK          = 0x06,
 };
 
 static const char *ssam_kip_cover_state_name(struct ssam_tablet_sw *sw,
@@ -231,6 +232,9 @@ static const char *ssam_kip_cover_state_name(struct ssam_tablet_sw *sw,
 	case SSAM_KIP_COVER_STATE_FOLDED_BACK:
 		return "folded-back";
 
+	case SSAM_KIP_COVER_STATE_BOOK:
+		return "book";
+
 	default:
 		dev_warn(&sw->sdev->dev, "unknown KIP cover state: %u\n", state->state);
 		return "<unknown>";
@@ -244,6 +248,7 @@ static bool ssam_kip_cover_state_is_tablet_mode(struct ssam_tablet_sw *sw,
 	case SSAM_KIP_COVER_STATE_DISCONNECTED:
 	case SSAM_KIP_COVER_STATE_FOLDED_CANVAS:
 	case SSAM_KIP_COVER_STATE_FOLDED_BACK:
+	case SSAM_KIP_COVER_STATE_BOOK:
 		return true;
 
 	case SSAM_KIP_COVER_STATE_CLOSED: