[PATCH v2 1/2] watchdog: w83627hf_wdt: Add support for Nuvoton NCT6126

[Paul Louvel]

Add support for the hardware watchdog integrated in the Nuvoton NCT6126
Super I/O chip. This device is used on a number of x86 single-board
computers and is compatible with the w83627hf_wdt driver.

Unlike most supported chips, the NCT6126 shares the same high-byte chip
ID as the NCT6116. Read the low byte of the chip ID as well to
distinguish between the two devices and identify the NCT6126 correctly.

Signed-off-by: Paul Louvel <paul.louvel@xxxxxxxxxxx>
---
 drivers/watchdog/w83627hf_wdt.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/watchdog/w83627hf_wdt.c b/drivers/watchdog/w83627hf_wdt.c
index bc33b63c5a5d..1f649fda8a81 100644
--- a/drivers/watchdog/w83627hf_wdt.c
+++ b/drivers/watchdog/w83627hf_wdt.c
@@ -49,7 +49,7 @@ static int wdt_cfg_leave = 0xAA;/* key to lock configuration space */
 enum chips { w83627hf, w83627s, w83697hf, w83697ug, w83637hf, w83627thf,
 	     w83687thf, w83627ehf, w83627dhg, w83627uhg, w83667hg, w83627dhg_p,
 	     w83667hg_b, nct6775, nct6776, nct6779, nct6791, nct6792, nct6793,
-	     nct6795, nct6796, nct6102, nct6116 };
+	     nct6795, nct6796, nct6102, nct6116, nct6126 };
 
 static int timeout;			/* in seconds */
 module_param(timeout, int, 0);
@@ -94,7 +94,9 @@ MODULE_PARM_DESC(early_disable, "Disable watchdog at boot time (default=0)");
 #define NCT6775_ID		0xb4
 #define NCT6776_ID		0xc3
 #define NCT6102_ID		0xc4
-#define NCT6116_ID		0xd2
+#define NCT6116_ID		0xd2	/* also NCT6126D */
+#define NCT6126_VER_A_LOW_ID	0x83	/* ... version A */
+#define NCT6126_VER_B_LOW_ID	0x84	/* ... version B */
 #define NCT6779_ID		0xc5
 #define NCT6791_ID		0xc8
 #define NCT6792_ID		0xc9
@@ -428,7 +430,12 @@ static int wdt_find(int addr)
 		cr_wdt_csr = NCT6102D_WDT_CSR;
 		break;
 	case NCT6116_ID:
-		ret = nct6116;
+		val = superio_inb(0x21);
+		if (val == NCT6126_VER_A_LOW_ID || val == NCT6126_VER_B_LOW_ID)
+			ret = nct6126;
+		else
+			ret = nct6116;
+
 		cr_wdt_timeout = NCT6102D_WDT_TIMEOUT;
 		cr_wdt_control = NCT6102D_WDT_CONTROL;
 		cr_wdt_csr = NCT6102D_WDT_CSR;
@@ -499,6 +506,7 @@ static int __init wdt_init(void)
 		"NCT6796",
 		"NCT6102",
 		"NCT6116",
+		"NCT6126"
 	};
 
 	/* Apply system-specific quirks */

-- 
2.55.0