watchdog: it87_wdt: Add support for IT8728F watchdog.

This works the same way IT8721F works, but it supports WDT_PWROK
(checked on the datasheet).

Signed-off-by: Diego Elio Pettenò <flameeyes@flameeyes.eu>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 0542314..66e77ad 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -596,7 +596,12 @@
 	depends on X86 && EXPERIMENTAL
 	---help---
 	  This is the driver for the hardware watchdog on the ITE IT8702,
-	  IT8712, IT8716, IT8718, IT8720, IT8721, IT8726 Super I/O chips.
+	  IT8712, IT8716, IT8718, IT8720, IT8721, IT8726 and IT8728
+	  Super I/O chips.
+
+	  If the driver does not work, then make sure that the game port in
+	  the BIOS is enabled.
+
 	  This watchdog simply watches your kernel to make sure it doesn't
 	  freeze, and if it does, it reboots your computer after a certain
 	  amount of time.
diff --git a/drivers/watchdog/it87_wdt.c b/drivers/watchdog/it87_wdt.c
index 8a741bc..d3dcc69 100644
--- a/drivers/watchdog/it87_wdt.c
+++ b/drivers/watchdog/it87_wdt.c
@@ -12,7 +12,8 @@
  *		    http://www.ite.com.tw/
  *
  *	Support of the watchdog timers, which are available on
- *	IT8702, IT8712, IT8716, IT8718, IT8720, IT8721 and IT8726.
+ *	IT8702, IT8712, IT8716, IT8718, IT8720, IT8721, IT8726
+ *	and IT8728.
  *
  *	This program is free software; you can redistribute it and/or
  *	modify it under the terms of the GNU General Public License
@@ -84,6 +85,7 @@
 #define IT8720_ID	0x8720
 #define IT8721_ID	0x8721
 #define IT8726_ID	0x8726	/* the data sheet suggest wrongly 0x8716 */
+#define IT8728_ID	0x8728
 
 /* GPIO Configuration Registers LDN=0x07 */
 #define WDTCTRL		0x71
@@ -95,7 +97,7 @@
 #define WDT_CIRINT	0x80
 #define WDT_MOUSEINT	0x40
 #define WDT_KYBINT	0x20
-#define WDT_GAMEPORT	0x10 /* not in it8718, it8720, it8721 */
+#define WDT_GAMEPORT	0x10 /* not in it8718, it8720, it8721, it8728 */
 #define WDT_FORCE	0x02
 #define WDT_ZERO	0x01
 
@@ -616,6 +618,7 @@
 	case IT8718_ID:
 	case IT8720_ID:
 	case IT8721_ID:
+	case IT8728_ID:
 		max_units = 65535;
 		try_gameport = 0;
 		break;