[PATCH v1] hwmon: (acpi_power_meter) Check ACPI_COMPANION() against NULL

["Rafael J. Wysocki" <rafael@kernel.org>]

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

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
acpi_power_meter hwmon driver.

Fixes: afc6c4aedea5 ("hwmon: (acpi_power_meter) Convert ACPI driver to a platform one")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/hwmon/acpi_power_meter.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/hwmon/acpi_power_meter.c
+++ b/drivers/hwmon/acpi_power_meter.c
@@ -884,10 +884,14 @@ static void acpi_power_meter_notify(acpi
 
 static int acpi_power_meter_probe(struct platform_device *pdev)
 {
-	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
 	struct acpi_power_meter_resource *resource;
+	struct acpi_device *device;
 	int res;
 
+	device = ACPI_COMPANION(&pdev->dev);
+	if (!device)
+		return -ENODEV;
+
 	resource = kzalloc_obj(*resource);
 	if (!resource)
 		return -ENOMEM;