Re: [PATCH v10 3/3] media: i2c: Add support for alvium camera

[Christophe JAILLET <christophe.jaillet@wanadoo.fr>]

Le 20/10/2023 à 16:13, Tommaso Merciai a écrit :
> The Alvium camera is shipped with sensor + isp in the same housing.
> The camera can be equipped with one out of various sensor and abstract
> the user from this. Camera is connected via MIPI CSI-2.
> 
> Most of the camera module features are supported, with the main exception
> being fw update.
> 
> The driver provides all mandatory, optional and recommended V4L2 controls
> for maximum compatibility with libcamera
> 
> References:
>   - https://www.alliedvision.com/en/products/embedded-vision-solutions
> 
> Signed-off-by: Tommaso Merciai <tomm.merciai@gmail.com>
> ---

Hi, a few nits and a question at the end.

> +static int alvium_setup_mipi_fmt(struct alvium_dev *alvium)
> +{
> +	int avail_fmt_cnt = 0;
> +	int sz = 0;
> +	int fmt = 0;
> +
> +	alvium->alvium_csi2_fmt = NULL;
> +
> +	/* calculate fmt array size */
> +	for (fmt = 0; fmt < ALVIUM_NUM_SUPP_MIPI_DATA_FMT; fmt++) {
> +		if (alvium->is_mipi_fmt_avail[alvium_csi2_fmts[fmt].fmt_av_bit])
> +			if ((!alvium_csi2_fmts[fmt].is_raw) ||
> +				  (alvium->is_bay_avail[alvium_csi2_fmts[fmt].bay_av_bit]))
> +				sz++;
> +	}
> +
> +	/* init alvium_csi2_fmt array */
> +	alvium->alvium_csi2_fmt_n = sz;
> +	alvium->alvium_csi2_fmt = kmalloc_array(sz,
> +						     sizeof(struct alvium_pixfmt),

This could be on the previous line.

> +						     GFP_KERNEL);
> +
> +	/* Create the alvium_csi2 fmt array from formats available */
> +	for (fmt = 0; fmt < ALVIUM_NUM_SUPP_MIPI_DATA_FMT; fmt++) {
> +		if (!alvium->is_mipi_fmt_avail[alvium_csi2_fmts[fmt].fmt_av_bit])
> +			continue;
> +
> +		if ((!alvium_csi2_fmts[fmt].is_raw) ||
> +				(alvium->is_bay_avail[alvium_csi2_fmts[fmt].bay_av_bit])) {
> +			alvium->alvium_csi2_fmt[avail_fmt_cnt] =
> +					alvium_csi2_fmts[fmt];
> +			avail_fmt_cnt++;
> +		}
> +	}
> +
> +	return 0;
> +}

...

> +static int alvium_s_frame_interval(struct v4l2_subdev *sd,
> +				   struct v4l2_subdev_frame_interval *fi)
> +{
> +	struct alvium_dev *alvium = sd_to_alvium(sd);
> +	int ret;
> +
> +	if (alvium->streaming)
> +		return -EBUSY;
> +
> +	ret = alvium_set_frame_interval(alvium, fi);
> +	if (!ret) {
> +		ret = alvium_set_frame_rate(alvium);
> +		if (ret)
> +			return -EIO;

Why not ret?

> +	}
> +
> +	return ret;
> +}

...

> +static int alvium_get_dt_data(struct alvium_dev *alvium)
> +{
> +	struct device *dev = &alvium->i2c_client->dev;
> +	struct fwnode_handle *fwnode = dev_fwnode(dev);
> +	struct fwnode_handle *endpoint;
> +	int ret = -EINVAL;
> +
> +	if (!fwnode)
> +		return -EINVAL;
> +
> +	/* Only CSI2 is supported for now: */
> +	alvium->ep.bus_type = V4L2_MBUS_CSI2_DPHY;
> +
> +	endpoint = fwnode_graph_get_endpoint_by_id(fwnode, 0, 0, 0);
> +	if (!endpoint) {
> +		dev_err(dev, "endpoint node not found\n");
> +		return -EINVAL;
> +	}
> +
> +	if (v4l2_fwnode_endpoint_alloc_parse(endpoint, &alvium->ep)) {
> +		dev_err(dev, "could not parse endpoint\n");
> +		goto error_out;

This could go to another label to be less confusing, but 
v4l2_fwnode_endpoint_free() looks to be a no-op here, so good enough.

> +	}
> +
> +	if (!alvium->ep.nr_of_link_frequencies) {
> +		dev_err(dev, "no link frequencies defined");
> +		goto error_out;
> +	}
> +
> +	return 0;
> +
> +error_out:
> +	v4l2_fwnode_endpoint_free(&alvium->ep);
> +	fwnode_handle_put(endpoint);
> +
> +	return ret;
> +}
> +
> +static int alvium_power_on(struct alvium_dev *alvium, bool on)
> +{
> +	int ret = 0;

Useless init.

> +
> +	if (!on)
> +		return regulator_disable(alvium->reg_vcc);
> +
> +	ret = regulator_enable(alvium->reg_vcc);
> +	if (ret)
> +		return ret;
> +
> +	/* alvium boot time 7s*/

space missing before */

> +	msleep(7000);
> +	return 0;
> +}

...

> +static int alvium_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct alvium_dev *alvium;
> +	int ret;
> +
> +	alvium = devm_kzalloc(dev, sizeof(*alvium), GFP_KERNEL);
> +	if (!alvium)
> +		return -ENOMEM;
> +
> +	alvium->i2c_client = client;
> +
> +	alvium->regmap = devm_cci_regmap_init_i2c(client, 16);
> +	if (IS_ERR(alvium->regmap))
> +		return PTR_ERR(alvium->regmap);
> +
> +	ret = alvium_get_dt_data(alvium);
> +	if (ret)
> +		return ret;
> +
> +	alvium->reg_vcc = devm_regulator_get_optional(dev, "vcc-ext-in");
> +	if (IS_ERR(alvium->reg_vcc))
> +		return dev_err_probe(dev, PTR_ERR(alvium->reg_vcc),
> +			"no vcc-ext-in regulator provided\n");
> +
> +	ret = alvium_power_on(alvium, true);
> +	if (ret)
> +		goto err_powerdown;
> +
> +	if (!alvium_is_alive(alvium)) {
> +		dev_err(dev, "Device detection failed: %d\n", ret);

Nit: Here and below, dev_err_probe() could also be used to display the 
error code in a human readable way.

> +		ret = -ENODEV;
> +		goto err_powerdown;
> +	}
> +
> +	ret = alvium_get_hw_info(alvium);
> +	if (ret) {
> +		dev_err(dev, "get_hw_info fail %d\n", ret);
> +		goto err_powerdown;
> +	}
> +
> +	ret = alvium_hw_init(alvium);
> +	if (ret) {
> +		dev_err(dev, "hw_init fail %d\n", ret);
> +		goto err_powerdown;
> +	}
> +
> +	ret = alvium_setup_mipi_fmt(alvium);
> +	if (ret) {
> +		dev_err(dev, "setup_mipi_fmt fail %d\n", ret);
> +		goto err_powerdown;
> +	}
> +
> +	/*
> +	 * Enable runtime PM without autosuspend:
> +	 *
> +	 * Don't use pm autosuspend (alvium have ~7s boot time).
> +	 * Alvium has been powered manually:
> +	 *  - mark it as active
> +	 *  - increase the usage count without resuming the device.
> +	 */
> +	pm_runtime_set_active(dev);
> +	pm_runtime_get_noresume(dev);
> +	pm_runtime_enable(dev);
> +
> +	/* Initialize the V4L2 subdev. */
> +	ret = alvium_subdev_init(alvium);
> +	if (ret)
> +		goto err_pm;
> +
> +	ret = v4l2_async_register_subdev(&alvium->sd);
> +	if (ret < 0) {
> +		dev_err(dev, "Could not register v4l2 device\n");
> +		goto err_subdev;
> +	}
> +
> +	return 0;
> +
> +err_subdev:
> +	alvium_subdev_cleanup(alvium);

Should this also be called by the remove function?
Or is it already handled by an un-register mechanism?

CJ

> +err_pm:
> +	pm_runtime_disable(dev);
> +	pm_runtime_put_noidle(dev);
> +err_powerdown:
> +	alvium_power_on(alvium, false);
> +
> +	return ret;
> +}
> +

...