diff --git a/drivers/watchdog/sp5100_tco.c b/drivers/watchdog/sp5100_tco.c
index e02399ea8730..86ffb58fbc85 100644
--- a/drivers/watchdog/sp5100_tco.c
+++ b/drivers/watchdog/sp5100_tco.c
@@ -86,6 +86,10 @@ static enum tco_reg_layout tco_reg_layout(struct pci_dev *dev)
 	    dev->device == PCI_DEVICE_ID_ATI_SBX00_SMBUS &&
 	    dev->revision < 0x40) {
 		return sp5100;
+	} else if (dev->vendor == PCI_VENDOR_ID_AMD &&
+	    sp5100_tco_pci->device == PCI_DEVICE_ID_AMD_KERNCZ_SMBUS &&
+	    sp5100_tco_pci->revision >= AMD_ZEN_SMBUS_PCI_REV) {
+		return efch_mmio;
 	} else if (dev->vendor == PCI_VENDOR_ID_AMD &&
 	    ((dev->device == PCI_DEVICE_ID_AMD_HUDSON2_SMBUS &&
 	     dev->revision >= 0x41) ||
@@ -459,18 +463,6 @@ static int sp5100_tco_setupdevice(struct device *dev,
 		break;
 	case efch:
 		dev_name = SB800_DEVNAME;
-		/*
-		 * On Family 17h devices, the EFCH_PM_DECODEEN_WDT_TMREN bit of
-		 * EFCH_PM_DECODEEN not only enables the EFCH_PM_WDT_ADDR memory
-		 * region, it also enables the watchdog itself.
-		 */
-		if (boot_cpu_data.x86 == 0x17) {
-			val = sp5100_tco_read_pm_reg8(EFCH_PM_DECODEEN);
-			if (!(val & EFCH_PM_DECODEEN_WDT_TMREN)) {
-				sp5100_tco_update_pm_reg8(EFCH_PM_DECODEEN, 0xff,
-							  EFCH_PM_DECODEEN_WDT_TMREN);
-			}
-		}
 		val = sp5100_tco_read_pm_reg8(EFCH_PM_DECODEEN);
 		if (val & EFCH_PM_DECODEEN_WDT_TMREN)
 			mmio_addr = EFCH_PM_WDT_ADDR;
diff --git a/drivers/watchdog/sp5100_tco.h b/drivers/watchdog/sp5100_tco.h
index 8ca1b215e3ce..6a0986d2c94b 100644
--- a/drivers/watchdog/sp5100_tco.h
+++ b/drivers/watchdog/sp5100_tco.h
@@ -89,3 +89,4 @@
 #define EFCH_PM_ACPI_MMIO_PM_ADDR	(EFCH_PM_ACPI_MMIO_ADDR +	\
 					 EFCH_PM_ACPI_MMIO_PM_OFFSET)
 #define EFCH_PM_ACPI_MMIO_PM_SIZE	8
+#define AMD_ZEN_SMBUS_PCI_REV		0x51