linux-kernel - Re: [PATCH v4 2/2] media: i2c: Add support for the OV5648 image sensor

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Date:   Wed, 9 Dec 2020 01:34:36 +0200
From:   Sakari Ailus <sakari.ailus@...ux.intel.com>
To:     Paul Kocialkowski <paul.kocialkowski@...tlin.com>
Cc:     linux-media@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Maxime Ripard <mripard@...nel.org>,
        Hans Verkuil <hverkuil@...all.nl>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH v4 2/2] media: i2c: Add support for the OV5648 image
 sensor

Hi Paul,

On Sat, Nov 28, 2020 at 03:33:50PM +0100, Paul Kocialkowski wrote:
...
> +	if (ret)
> +		goto error_ctrls;
> +
> +	/* V4L2 subdev register */
> +
> +	ret = v4l2_async_register_subdev_sensor_common(subdev);

The driver's device node may be already available to the user here...

> +	if (ret)
> +		goto error_ctrls;
> +
> +	/* Runtime PM */
> +
> +	pm_runtime_enable(sensor->dev);
> +	pm_runtime_set_suspended(sensor->dev);

but runtime PM is enabled here.

This needs to be done in a different order. Otherwise chances are that the
device node is accessed before the device is powered on.

> +
> +	return 0;
> +
> +error_ctrls:
> +	v4l2_ctrl_handler_free(&sensor->ctrls.handler);
> +
> +error_mutex:
> +	mutex_destroy(&sensor->mutex);
> +
> +error_entity:
> +	media_entity_cleanup(&sensor->subdev.entity);
> +
> +error_endpoint:
> +	v4l2_fwnode_endpoint_free(&sensor->endpoint);
> +
> +	return ret;
> +}
> +
> +static int ov5648_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *subdev = i2c_get_clientdata(client);
> +	struct ov5648_sensor *sensor = ov5648_subdev_sensor(subdev);
> +
> +	clk_rate_exclusive_put(sensor->xvclk);
> +
> +	v4l2_async_unregister_subdev(subdev);
> +	mutex_destroy(&sensor->mutex);
> +	media_entity_cleanup(&subdev->entity);
> +	v4l2_device_unregister_subdev(subdev);
> +	pm_runtime_disable(sensor->dev);
> +
> +	ov5648_sensor_power(sensor, false);

This needs to go, too, as there's no corresponding operation that powered
on the device.

Also don't forget to release the control handler.

I believe these apply to both of the two drivers.

-- 
Kind regards,

Sakari Ailus