platform/x86: intel/rst: 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
platform/x86 intel/rst driver.

Fixes: 163a68a31f74 ("platform/x86: intel/rst: Convert ACPI driver to a platform one")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/2051525.PYKUYFuaPT@rafael.j.wysocki
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

diff --git a/drivers/platform/x86/intel/rst.c b/drivers/platform/x86/intel/rst.c
index 4bd10927aad99551c664e5e6e13e3242ca29f97b..bb19f0d89305095ed89223af05058bf7c0df5e57 100644 (file)
--- a/drivers/platform/x86/intel/rst.c
+++ b/drivers/platform/x86/intel/rst.c
@@ -102,9 +102,13 @@ static struct device_attribute irst_timeout_attr = {
 
 static int irst_probe(struct platform_device *pdev)
 {
-       struct acpi_device *acpi = ACPI_COMPANION(&pdev->dev);
+       struct acpi_device *acpi;
        int error;
 
+       acpi = ACPI_COMPANION(&pdev->dev);
+       if (!acpi)
+               return -ENODEV;
+
        error = device_create_file(&acpi->dev, &irst_timeout_attr);
        if (unlikely(error))
                return error;