watchdog: f71808e_wdt: Add F81803 support

This adds watchdog support for the Fintek F81803 Super I/O chip.

Testing was done on the Seneca XK-QUAD.

Signed-off-by: Jaret Cantu <jaret.cantu@timesys.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20190912175550.9340-1-jaret.cantu@timesys.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
diff --git a/drivers/watchdog/f71808e_wdt.c b/drivers/watchdog/f71808e_wdt.c
index ff5cf1b..e46104c 100644
--- a/drivers/watchdog/f71808e_wdt.c
+++ b/drivers/watchdog/f71808e_wdt.c
@@ -31,8 +31,10 @@
 #define SIO_REG_DEVID		0x20	/* Device ID (2 bytes) */
 #define SIO_REG_DEVREV		0x22	/* Device revision */
 #define SIO_REG_MANID		0x23	/* Fintek ID (2 bytes) */
+#define SIO_REG_CLOCK_SEL	0x26	/* Clock select */
 #define SIO_REG_ROM_ADDR_SEL	0x27	/* ROM address select */
 #define SIO_F81866_REG_PORT_SEL	0x27	/* F81866 Multi-Function Register */
+#define SIO_REG_TSI_LEVEL_SEL	0x28	/* TSI Level select */
 #define SIO_REG_MFUNCT1		0x29	/* Multi function select 1 */
 #define SIO_REG_MFUNCT2		0x2a	/* Multi function select 2 */
 #define SIO_REG_MFUNCT3		0x2b	/* Multi function select 3 */
@@ -49,6 +51,7 @@
 #define SIO_F71869A_ID		0x1007	/* Chipset ID */
 #define SIO_F71882_ID		0x0541	/* Chipset ID */
 #define SIO_F71889_ID		0x0723	/* Chipset ID */
+#define SIO_F81803_ID		0x1210	/* Chipset ID */
 #define SIO_F81865_ID		0x0704	/* Chipset ID */
 #define SIO_F81866_ID		0x1010	/* Chipset ID */
 
@@ -108,7 +111,7 @@ MODULE_PARM_DESC(start_withtimeout, "Start watchdog timer on module load with"
 	" given initial timeout. Zero (default) disables this feature.");
 
 enum chips { f71808fg, f71858fg, f71862fg, f71868, f71869, f71882fg, f71889fg,
-	     f81865, f81866};
+	     f81803, f81865, f81866};
 
 static const char *f71808e_names[] = {
 	"f71808fg",
@@ -118,6 +121,7 @@ static const char *f71808e_names[] = {
 	"f71869",
 	"f71882fg",
 	"f71889fg",
+	"f81803",
 	"f81865",
 	"f81866",
 };
@@ -370,6 +374,14 @@ static int watchdog_start(void)
 			superio_inb(watchdog.sioaddr, SIO_REG_MFUNCT3) & 0xcf);
 		break;
 
+	case f81803:
+		/* Enable TSI Level register bank */
+		superio_clear_bit(watchdog.sioaddr, SIO_REG_CLOCK_SEL, 3);
+		/* Set pin 27 to WDTRST# */
+		superio_outb(watchdog.sioaddr, SIO_REG_TSI_LEVEL_SEL, 0x5f &
+			superio_inb(watchdog.sioaddr, SIO_REG_TSI_LEVEL_SEL));
+		break;
+
 	case f81865:
 		/* Set pin 70 to WDTRST# */
 		superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT3, 5);
@@ -809,6 +821,9 @@ static int __init f71808e_find(int sioaddr)
 		/* Confirmed (by datasheet) not to have a watchdog. */
 		err = -ENODEV;
 		goto exit;
+	case SIO_F81803_ID:
+		watchdog.type = f81803;
+		break;
 	case SIO_F81865_ID:
 		watchdog.type = f81865;
 		break;