Hi Pavel,

On Tue, May 17, 2016 at 08:19:27PM +0200, Pavel Machek wrote:

+static int ad5820_set_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct ad5820_device *coil =
+		container_of(ctrl->handler, struct ad5820_device, ctrls);
+	u32 code;
+	int r = 0;
+
+	switch (ctrl->id) {
+	case V4L2_CID_FOCUS_ABSOLUTE:
+		coil->focus_absolute = ctrl->val;
+		return ad5820_update_hw(coil);
+
+	case V4L2_CID_FOCUS_AD5820_RAMP_TIME:
+		code = RAMP_US_TO_CODE(ctrl->val);
+		ctrl->val = CODE_TO_RAMP_US(code);
+		coil->focus_ramp_time = ctrl->val;
+		break;
+
+	case V4L2_CID_FOCUS_AD5820_RAMP_MODE:
+		coil->focus_ramp_mode = ctrl->val;
+		break;
+	}
+
+	return r;

Just return 0 instead, r is not used.

+static int ad5820_registered(struct v4l2_subdev *subdev)
+{
+	static const int CHECK_VALUE = 0x3FF0;

CHECK_VALUE is not used?

+static int ad5820_probe(struct i2c_client *client,
+			const struct i2c_device_id *devid)
+{
+	struct ad5820_device *coil;
+	int ret = 0;
+
+	coil = kzalloc(sizeof(*coil), GFP_KERNEL);
+	if (coil == NULL)
+		return -ENOMEM;
+
+	mutex_init(&coil->power_lock);
+
+	v4l2_i2c_subdev_init(&coil->subdev, client, &ad5820_ops);
+	coil->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	coil->subdev.internal_ops = &ad5820_internal_ops;
+	strcpy(coil->subdev.name, "ad5820 focus");
+
+	ret = media_entity_pads_init(&coil->subdev.entity, 0, NULL);
+	if (ret < 0) {
+		kfree(coil);
+		return ret;
+	}
+
+	ret = v4l2_async_register_subdev(&coil->subdev);
+	if (ret < 0)

Do we need to call media_entity_cleanup() here?

+static int __init ad5820_init(void)
+{
+	int rval;
+
+	rval = i2c_add_driver(&ad5820_i2c_driver);
+	if (rval)
+		printk(KERN_INFO "%s: failed registering " AD5820_NAME "\n",
+		       __func__);
+
+	return rval;
+}
+
+static void __exit ad5820_exit(void)
+{
+	i2c_del_driver(&ad5820_i2c_driver);
+}
+
+
+module_init(ad5820_init);
+module_exit(ad5820_exit);

Use module_i2c_driver() instead.


Cheers
Marcus Folkesson