Re: [PATCH] media: v4l2-common: Always register clock with device-specific name

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

On Fri, Mar 27, 2026 at 06:52:12PM +0100, Paul Cercueil wrote:
> If we need to register a dummy fixed-frequency clock, always register it
> using a device-specific name.
> 
> This supports the use case where a system has two of the same sensor,
> meaning two instances of the same driver, which previously both tried
> (and failed) to create a clock with the same name.
> 
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> ---
>  drivers/media/v4l2-core/v4l2-common.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
> index 554c591e1113..5f3295c3122a 100644
> --- a/drivers/media/v4l2-core/v4l2-common.c
> +++ b/drivers/media/v4l2-core/v4l2-common.c
> @@ -792,14 +792,11 @@ struct clk *__devm_v4l2_sensor_clk_get(struct device *dev, const char *id,
>  	if (ret)
>  		return ERR_PTR(ret == -EINVAL ? -EPROBE_DEFER : ret);
>  
> -	if (!id) {
> -		clk_id = kasprintf(GFP_KERNEL, "clk-%s", dev_name(dev));
> -		if (!clk_id)
> -			return ERR_PTR(-ENOMEM);
> -		id = clk_id;
> -	}
> +	clk_id = kasprintf(GFP_KERNEL, "clk-%s", dev_name(dev));

This will now fail if the same device needs to register two clocks. You
need to include the id in the name. Maybe something like

	clk_id = kasprintf(GFP_KERNEL, "clk-%s-%s", dev_name(dev), id);

> +	if (!clk_id)
> +		return ERR_PTR(-ENOMEM);
>  
> -	clk_hw = devm_clk_hw_register_fixed_rate(dev, id, NULL, 0, rate);
> +	clk_hw = devm_clk_hw_register_fixed_rate(dev, clk_id, NULL, 0, rate);
>  	if (IS_ERR(clk_hw))
>  		return ERR_CAST(clk_hw);
>  

-- 
Regards,

Laurent Pinchart