[PATCH 2/3] watchdog: iTCO_wdt: Make ICH_RES_IO_SMI optional

[Mika Westerberg <mika.westerberg@linux.intel.com>]

The iTCO_wdt driver only needs ICH_RES_IO_SMI I/O resource when either
turn_SMI_watchdog_clear_off module parameter is set to match ->iTCO_version
(or higher), and when legacy iTCO_vendorsupport is set. Modify the driver
so that ICH_RES_IO_SMI is optional if the two conditions are not met.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/watchdog/iTCO_wdt.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
index 156360e37714..f1692452bc25 100644
--- a/drivers/watchdog/iTCO_wdt.c
+++ b/drivers/watchdog/iTCO_wdt.c
@@ -460,7 +460,7 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
 		return -ENODEV;
 
 	p->smi_res = platform_get_resource(pdev, IORESOURCE_IO, ICH_RES_IO_SMI);
-	if (!p->smi_res)
+	if (!p->smi_res && iTCO_vendorsupport)
 		return -ENODEV;
 
 	p->iTCO_version = pdata->version;
@@ -492,15 +492,19 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
 	/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
 	p->update_no_reboot_bit(p->no_reboot_priv, true);
 
-	/* The TCO logic uses the TCO_EN bit in the SMI_EN register */
-	if (!devm_request_region(dev, p->smi_res->start,
-				 resource_size(p->smi_res),
-				 pdev->name)) {
-		pr_err("I/O address 0x%04llx already in use, device disabled\n",
-		       (u64)SMI_EN(p));
-		return -EBUSY;
-	}
 	if (turn_SMI_watchdog_clear_off >= p->iTCO_version) {
+		if (!p->smi_res) {
+			pr_err("SMI I/O resource is missing\n");
+			return -EINVAL;
+		}
+		/* The TCO logic uses the TCO_EN bit in the SMI_EN register */
+		if (!devm_request_region(dev, p->smi_res->start,
+					 resource_size(p->smi_res),
+					 pdev->name)) {
+			pr_err("I/O address 0x%04llx already in use, device disabled\n",
+			       (u64)SMI_EN(p));
+			return -EBUSY;
+		}
 		/*
 		 * Bit 13: TCO_EN -> 0
 		 * Disables TCO logic generating an SMI#
-- 
2.25.0