[PATCH v1 3/3] platform/chrome: wilco_ec: event: Check ACPI_COMPANION()

["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
wilco_ec event driver.

Fixes: 27d58498f690 ("platform/chrome: wilco_ec: event: Convert to a platform driver")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/platform/chrome/wilco_ec/event.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/platform/chrome/wilco_ec/event.c
+++ b/drivers/platform/chrome/wilco_ec/event.c
@@ -452,8 +452,13 @@ static void hangup_device(struct event_d
 static int event_device_probe(struct platform_device *pdev)
 {
 	struct event_device_data *dev_data;
+	struct acpi_device *adev;
 	int error, minor;
 
+	adev = ACPI_COMPANION(&pdev->dev);
+	if (!adev)
+		return -ENODEV;
+
 	minor = ida_alloc_max(&event_ida, EVENT_MAX_DEV-1, GFP_KERNEL);
 	if (minor < 0) {
 		error = minor;
@@ -494,8 +499,7 @@ static int event_device_probe(struct pla
 		goto free_dev_data;
 
 	/* Install an ACPI notify handler. */
-	error = acpi_dev_install_notify_handler(ACPI_COMPANION(&pdev->dev),
-						ACPI_DEVICE_NOTIFY,
+	error = acpi_dev_install_notify_handler(adev, ACPI_DEVICE_NOTIFY,
 						event_device_notify, &pdev->dev);
 	if (error)
 		goto free_cdev;