Re: [PATCH] media: i2c: imx219: Add support for 'clock-frequency' parsing

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Mehdi,

Thank you for the patch.

On Thu, Feb 20, 2025 at 04:49:09PM +0100, Mehdi Djait wrote:
> Make the clock producer reference lookup optional
> 
> Add support for ACPI-based platforms by parsing the 'clock-frequency'
> property when no clock producer is available
> 
> Signed-off-by: Mehdi Djait <mehdi.djait@linux.intel.com>
> ---
>  drivers/media/i2c/imx219.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/i2c/imx219.c b/drivers/media/i2c/imx219.c
> index 2d54cea113e1..a876a6d80a47 100644
> --- a/drivers/media/i2c/imx219.c
> +++ b/drivers/media/i2c/imx219.c
> @@ -1103,12 +1103,22 @@ static int imx219_probe(struct i2c_client *client)
>  				     "failed to initialize CCI\n");
>  
>  	/* Get system clock (xclk) */
> -	imx219->xclk = devm_clk_get(dev, NULL);
> +	imx219->xclk = devm_clk_get_optional(dev, NULL);
>  	if (IS_ERR(imx219->xclk))
>  		return dev_err_probe(dev, PTR_ERR(imx219->xclk),
>  				     "failed to get xclk\n");
>  
> -	imx219->xclk_freq = clk_get_rate(imx219->xclk);
> +	if (imx219->xclk) {
> +		imx219->xclk_freq = clk_get_rate(imx219->xclk);
> +	} else {
> +		ret = fwnode_property_read_u32(dev_fwnode(dev),
> +					       "clock-frequency",
> +					       &imx219->xclk_freq);
> +		if (ret)
> +			return dev_err_probe(dev, ret,
> +					     "failed to get clock frequency");
> +	}
> +

This doesn't seem specific to the imx219 driver. Could you turn this
into a generic V4L2 sensor helper that would take a struct device and a
clock name, and return the frequency, either retrieved from the clock,
or from the clock-frequency property as a fallback ?

Some drivers will also need to control the clock, so the clock should
probably be returned too.

>  	if (imx219->xclk_freq != IMX219_XCLK_FREQ)
>  		return dev_err_probe(dev, -EINVAL,
>  				     "xclk frequency not supported: %d Hz\n",

-- 
Regards,

Laurent Pinchart