platform/x86: fujitsu-tablet: 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 requisite ACPI_COMPANION() checks against NULL to the
platform/x86 fujitsu-tablet driver.

Fixes: bd13b265d386 ("platform/x86: fujitsu-tablet: 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/10861611.nUPlyArG6x@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/fujitsu-tablet.c b/drivers/platform/x86/fujitsu-tablet.c
index 8319df28e9b8a64d80333f558225b3bfe49771f3..2f8c1b89cbca17b213d8e576f579884b5ac1cbd1 100644 (file)
--- a/drivers/platform/x86/fujitsu-tablet.c
+++ b/drivers/platform/x86/fujitsu-tablet.c
@@ -445,10 +445,14 @@ static acpi_status fujitsu_walk_resources(struct acpi_resource *res, void *data)
 
 static int acpi_fujitsu_probe(struct platform_device *pdev)
 {
-       struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
+       struct acpi_device *adev;
        acpi_status status;
        int error;
 
+       adev = ACPI_COMPANION(&pdev->dev);
+       if (!adev)
+               return -ENODEV;
+
        status = acpi_walk_resources(adev->handle, METHOD_NAME__CRS,
                        fujitsu_walk_resources, NULL);
        if (ACPI_FAILURE(status) || !fujitsu.irq || !fujitsu.io_base)