Input: wacom - add LED support for Cintiq 24HD

The Cintiq 24HD has three LEDs on the left side of the tablet and
three LEDs on the right side of the tablet. Switching to LED 0,
1, or 2 will enable the top, middle, or bottom LED for the respective
side. Switching to LED 3 turns off the LEDs on the respective side.

Signed-off-by: Jason Gerecke <killertofu@gmail.com>
Reviewed-by: Ping Cheng <pingc@wacom.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

Documentation/ABI/testing/sysfs-driver-wacom

@@ -15,9 +15,9 @@ Contact:	linux-input@vger.kernel.org
 Description:
 		Attribute group for control of the status LEDs and the OLEDs.
 		This attribute group is only available for Intuos 4 M, L,
-		and XL (with LEDs and OLEDs) and Cintiq 21UX2 (LEDs only).
-		Therefore its presence implicitly signifies the presence of
-		said LEDs and OLEDs on the tablet device.
+		and XL (with LEDs and OLEDs) and Cintiq 21UX2 and Cintiq 24HD
+		(LEDs only). Therefore its presence implicitly signifies the
+		presence of said LEDs and OLEDs on the tablet device.
 
 What:		/sys/bus/usb/devices/<busnum>-<devnum>:<cfg>.<intf>/wacom_led/status0_luminance
 Date:		August 2011
@@ -41,16 +41,17 @@ Date:		August 2011
 Contact:	linux-input@vger.kernel.org
 Description:
 		Writing to this file sets which one of the four (for Intuos 4)
-		or of the right four (for Cintiq 21UX2) status LEDs is active (0..3).
-		The other three LEDs on the same side are always inactive.
+		or of the right four (for Cintiq 21UX2 and Cintiq 24HD) status
+		LEDs is active (0..3). The other three LEDs on the same side are
+		always inactive.
 
 What:		/sys/bus/usb/devices/<busnum>-<devnum>:<cfg>.<intf>/wacom_led/status_led1_select
 Date:		September 2011
 Contact:	linux-input@vger.kernel.org
 Description:
-		Writing to this file sets which one of the left four (for Cintiq 21UX2)
-		status LEDs is active (0..3). The other three LEDs on the left are always
-		inactive.
+		Writing to this file sets which one of the left four (for Cintiq 21UX2
+		and Cintiq 24HD) status LEDs is active (0..3). The other three LEDs on
+		the left are always inactive.
 
 What:		/sys/bus/usb/devices/<busnum>-<devnum>:<cfg>.<intf>/wacom_led/buttons_luminance
 Date:		August 2011

drivers/input/tablet/wacom_sys.c

@@ -563,7 +563,8 @@ static int wacom_led_control(struct wacom *wacom)
 	if (!buf)
 		return -ENOMEM;
 
-	if (wacom->wacom_wac.features.type == WACOM_21UX2)
+	if (wacom->wacom_wac.features.type == WACOM_21UX2 ||
+	    wacom->wacom_wac.features.type == WACOM_24HD)
 		led = (wacom->led.select[1] << 4) | 0x40;
 
 	led |=  wacom->led.select[0] | 0x4;
@@ -782,6 +783,7 @@ static int wacom_initialize_leds(struct wacom *wacom)
 					   &intuos4_led_attr_group);
 		break;
 
+	case WACOM_24HD:
 	case WACOM_21UX2:
 		wacom->led.select[0] = 0;
 		wacom->led.select[1] = 0;
@@ -816,6 +818,7 @@ static void wacom_destroy_leds(struct wacom *wacom)
 				   &intuos4_led_attr_group);
 		break;
 
+	case WACOM_24HD:
 	case WACOM_21UX2:
 		sysfs_remove_group(&wacom->intf->dev.kobj,
 				   &cintiq_led_attr_group);