media: ov9734: Enable runtime PM before registering async sub-device

As the sensor device maybe accessible right after its async sub-device is
registered, such as ipu-bridge will try to power up sensor by sensor's
client device's runtime PM from the async notifier callback, if runtime PM
is not enabled, it will fail.

So runtime PM should be ready before its async sub-device is registered
and accessible by others.

Fixes: d3f863a6 ("media: i2c: Add ov9734 image sensor driver")
Cc: stable@vger.kernel.org
Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/media/i2c/ov9734.c

@@ -893,6 +893,7 @@ static void ov9734_remove(struct i2c_client *client)
 	media_entity_cleanup(&sd->entity);
 	v4l2_ctrl_handler_free(sd->ctrl_handler);
 	pm_runtime_disable(&client->dev);
+	pm_runtime_set_suspended(&client->dev);
 	mutex_destroy(&ov9734->mutex);
 }
 
@@ -938,13 +939,6 @@ static int ov9734_probe(struct i2c_client *client)
 		goto probe_error_v4l2_ctrl_handler_free;
 	}
 
-	ret = v4l2_async_register_subdev_sensor(&ov9734->sd);
-	if (ret < 0) {
-		dev_err(&client->dev, "failed to register V4L2 subdev: %d",
-			ret);
-		goto probe_error_media_entity_cleanup;
-	}
-
 	/*
 	 * Device is already turned on by i2c-core with ACPI domain PM.
 	 * Enable runtime PM and turn off the device.
@@ -953,9 +947,18 @@ static int ov9734_probe(struct i2c_client *client)
 	pm_runtime_enable(&client->dev);
 	pm_runtime_idle(&client->dev);
 
+	ret = v4l2_async_register_subdev_sensor(&ov9734->sd);
+	if (ret < 0) {
+		dev_err(&client->dev, "failed to register V4L2 subdev: %d",
+			ret);
+		goto probe_error_media_entity_cleanup_pm;
+	}
+
 	return 0;
 
-probe_error_media_entity_cleanup:
+probe_error_media_entity_cleanup_pm:
+	pm_runtime_disable(&client->dev);
+	pm_runtime_set_suspended(&client->dev);
 	media_entity_cleanup(&ov9734->sd.entity);
 
 probe_error_v4l2_ctrl_handler_free: