Re: [PATCH v1 08/15] media: i2c: imx290: Factor out DT parsing to separate function

[Alexander Stein <alexander.stein@ew.tq-group.com>]

Hello Laurent,

thanks for working on this.

Am Dienstag, 22. November 2022, 23:32:43 CET schrieb Laurent Pinchart:
> Make the probe() function more readable by factoring out the DT parsing
> code to a separate function. No functional change intended.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
>  drivers/media/i2c/imx290.c | 97 +++++++++++++++++++++-----------------
>  1 file changed, 53 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/media/i2c/imx290.c b/drivers/media/i2c/imx290.c
> index d9fc6c44b0f0..655f676df3d2 100644
> --- a/drivers/media/i2c/imx290.c
> +++ b/drivers/media/i2c/imx290.c
> @@ -1139,112 +1139,125 @@ static s64 imx290_check_link_freqs(const struct
> imx290 *imx290, return 0;
>  }
> 
> -static int imx290_probe(struct i2c_client *client)
> +static int imx290_parse_dt(struct imx290 *imx290)
>  {
> -	struct device *dev = &client->dev;
> -	struct fwnode_handle *endpoint;
>  	/* Only CSI2 is supported for now: */
>  	struct v4l2_fwnode_endpoint ep = {
>  		.bus_type = V4L2_MBUS_CSI2_DPHY
>  	};
> -	struct imx290 *imx290;
> -	u32 xclk_freq;
> -	u32 chip_id;

I assume your patch for reading the chip ID slipped into this series.
Either add it to the series or rearrange your patches.

> +	struct fwnode_handle *endpoint;
> +	int ret;
>  	s64 fq;
> -	int ret;
> 
> -	imx290 = devm_kzalloc(dev, sizeof(*imx290), GFP_KERNEL);
> -	if (!imx290)
> -		return -ENOMEM;
> -
> -	imx290->dev = dev;
> -	imx290->regmap = devm_regmap_init_i2c(client, 
&imx290_regmap_config);
> -	if (IS_ERR(imx290->regmap)) {
> -		dev_err(dev, "Unable to initialize I2C\n");
> -		return -ENODEV;
> -	}
> -
> -	endpoint = fwnode_graph_get_next_endpoint(dev_fwnode(dev), NULL);
> +	endpoint = fwnode_graph_get_next_endpoint(dev_fwnode(imx290->dev), 
NULL);
>  	if (!endpoint) {
> -		dev_err(dev, "Endpoint node not found\n");
> +		dev_err(imx290->dev, "Endpoint node not found\n");
>  		return -EINVAL;
>  	}
> 
>  	ret = v4l2_fwnode_endpoint_alloc_parse(endpoint, &ep);
>  	fwnode_handle_put(endpoint);
>  	if (ret == -ENXIO) {
> -		dev_err(dev, "Unsupported bus type, should be CSI2\n");
> -		goto err_endpoint;
> +		dev_err(imx290->dev, "Unsupported bus type, should be 
CSI2\n");
> +		goto done;
>  	} else if (ret) {
> -		dev_err(dev, "Parsing endpoint node failed\n");
> -		goto err_endpoint;
> +		dev_err(imx290->dev, "Parsing endpoint node failed\n");
> +		goto done;
>  	}
> 
>  	/* Get number of data lanes */
>  	imx290->nlanes = ep.bus.mipi_csi2.num_data_lanes;
>  	if (imx290->nlanes != 2 && imx290->nlanes != 4) {
> -		dev_err(dev, "Invalid data lanes: %d\n", imx290->nlanes);
> +		dev_err(imx290->dev, "Invalid data lanes: %d\n", imx290-
>nlanes);
>  		ret = -EINVAL;
> -		goto err_endpoint;
> +		goto done;
>  	}
> 
> -	dev_dbg(dev, "Using %u data lanes\n", imx290->nlanes);
> +	dev_dbg(imx290->dev, "Using %u data lanes\n", imx290->nlanes);
> 
>  	if (!ep.nr_of_link_frequencies) {
> -		dev_err(dev, "link-frequency property not found in DT\n");
> +		dev_err(imx290->dev, "link-frequency property not found in 
DT\n");
>  		ret = -EINVAL;
> -		goto err_endpoint;
> +		goto done;
>  	}
> 
>  	/* Check that link frequences for all the modes are in device tree 
*/
>  	fq = imx290_check_link_freqs(imx290, &ep);
>  	if (fq) {
> -		dev_err(dev, "Link frequency of %lld is not supported\n", 
fq);
> +		dev_err(imx290->dev, "Link frequency of %lld is not 
supported\n",
> +			fq);
>  		ret = -EINVAL;
> -		goto err_endpoint;
> +		goto done;
>  	}
> 
> +	ret = 0;
> +
> +done:
> +	v4l2_fwnode_endpoint_free(&ep);
> +	return ret;
> +}
> +
> +static int imx290_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct imx290 *imx290;
> +	u32 xclk_freq;
> +	u32 chip_id;
> +	int ret;
> +
> +	imx290 = devm_kzalloc(dev, sizeof(*imx290), GFP_KERNEL);
> +	if (!imx290)
> +		return -ENOMEM;
> +
> +	imx290->dev = dev;
> +	imx290->regmap = devm_regmap_init_i2c(client, 
&imx290_regmap_config);
> +	if (IS_ERR(imx290->regmap)) {
> +		dev_err(dev, "Unable to initialize I2C\n");
> +		return -ENODEV;
> +	}
> +
> +	ret = imx290_parse_dt(imx290);
> +	if (ret)
> +		return ret;
> +
>  	/* get system clock (xclk) */
>  	imx290->xclk = devm_clk_get(dev, "xclk");
>  	if (IS_ERR(imx290->xclk)) {
>  		dev_err(dev, "Could not get xclk");
> -		ret = PTR_ERR(imx290->xclk);
> -		goto err_endpoint;
> +		return PTR_ERR(imx290->xclk);

Mh, using dev_err_probe this can be a one-liner.

>  	}
> 
>  	ret = fwnode_property_read_u32(dev_fwnode(dev), "clock-frequency",
>  				       &xclk_freq);
>  	if (ret) {
>  		dev_err(dev, "Could not get xclk frequency\n");
> -		goto err_endpoint;
> +		return ret;
>  	}
> 
>  	/* external clock must be 37.125 MHz */
>  	if (xclk_freq != 37125000) {
>  		dev_err(dev, "External clock frequency %u is not 
supported\n",
>  			xclk_freq);
> -		ret = -EINVAL;
> -		goto err_endpoint;
> +		return -EINVAL;
>  	}
> 
>  	ret = clk_set_rate(imx290->xclk, xclk_freq);
>  	if (ret) {
>  		dev_err(dev, "Could not set xclk frequency\n");
> -		goto err_endpoint;
> +		return ret;
>  	}
> 
>  	ret = imx290_get_regulators(dev, imx290);
>  	if (ret < 0) {
>  		dev_err(dev, "Cannot get regulators\n");
> -		goto err_endpoint;
> +		return ret;

Using dev_err_probe this can be a one-liner as well.

>  	}
> 
>  	imx290->rst_gpio = devm_gpiod_get_optional(dev, "reset",
>  						   
GPIOD_OUT_HIGH);
>  	if (IS_ERR(imx290->rst_gpio)) {
>  		dev_err(dev, "Cannot get reset gpio\n");
> -		ret = PTR_ERR(imx290->rst_gpio);
> -		goto err_endpoint;
> +		return PTR_ERR(imx290->rst_gpio);

Using dev_err_probe this can be a one-liner as well.

Regards,
Alexander

>  	}
> 
>  	mutex_init(&imx290->lock);
> @@ -1279,16 +1292,12 @@ static int imx290_probe(struct i2c_client *client)
>  	pm_runtime_enable(dev);
>  	pm_runtime_idle(dev);
> 
> -	v4l2_fwnode_endpoint_free(&ep);
> -
>  	return 0;
> 
>  err_subdev:
>  	imx290_subdev_cleanup(imx290);
>  err_mutex:
>  	mutex_destroy(&imx290->lock);
> -err_endpoint:
> -	v4l2_fwnode_endpoint_free(&ep);
> 
>  	return ret;
>  }