watchdog: ni903x_wdt: Check ACPI_COMPANION() against NULL

Every platform driver can be forced to match a device that doesn't match
its list of device IDs because of device_match_driver_override(), so
platform drivers that rely on the existence of a device's ACPI companion
object need to verify its presence.

Accordingly, add a requisite ACPI_COMPANION() check against NULL to the
ni903x_wdt watchdog driver.

Fixes: d37ec2fbab55 ("watchdog: ni903x_wdt: Convert to a platform driver")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/2280455.irdbgypaU6@rafael.j.wysocki
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/watchdog/ni903x_wdt.c b/drivers/watchdog/ni903x_wdt.c
index 8b1b9baa914e5f5219706dd75aa5874b01b05be2..c72a9ee9cb8e19a80e2005d972738643a9d39ffe 100644 (file)
--- a/drivers/watchdog/ni903x_wdt.c
+++ b/drivers/watchdog/ni903x_wdt.c
@@ -183,9 +183,14 @@ static int ni903x_acpi_probe(struct platform_device *pdev)
        struct device *dev = &pdev->dev;
        struct watchdog_device *wdd;
        struct ni903x_wdt *wdt;
+       acpi_handle handle;
        acpi_status status;
        int ret;
 
+       handle = ACPI_HANDLE(dev);
+       if (!handle)
+               return -ENODEV;
+
        wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
        if (!wdt)
                return -ENOMEM;
@@ -193,7 +198,7 @@ static int ni903x_acpi_probe(struct platform_device *pdev)
        platform_set_drvdata(pdev, wdt);
        wdt->dev = dev;
 
-       status = acpi_walk_resources(ACPI_HANDLE(dev), METHOD_NAME__CRS,
+       status = acpi_walk_resources(handle, METHOD_NAME__CRS,
                                     ni903x_resources, wdt);
        if (ACPI_FAILURE(status) || wdt->io_base == 0) {
                dev_err(dev, "failed to get resources\n");