[PATCH v1] iio: light: acpi-als: Check ACPI_COMPANION() against NULL

[Rafael J. Wysocki]

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

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-als IIO driver.

Fixes: d4243cb08a27 ("iio: light: acpi-als: Convert ACPI driver to a platform one")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
 drivers/iio/light/acpi-als.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/iio/light/acpi-als.c
+++ b/drivers/iio/light/acpi-als.c
@@ -179,11 +179,15 @@ out:
 static int acpi_als_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
-	struct acpi_device *device = ACPI_COMPANION(dev);
+	struct acpi_device *device;
 	struct iio_dev *indio_dev;
 	struct acpi_als *als;
 	int ret;
 
+	device = ACPI_COMPANION(dev);
+	if (!device)
+		return -ENODEV;
+
 	indio_dev = devm_iio_device_alloc(dev, sizeof(*als));
 	if (!indio_dev)
 		return -ENOMEM;