Re: [PATCH v2 11/12] media: mt9m114: Return -EPROBE_DEFER if no endpoint is found

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

Hi Hans,

Thank you for the patch.

On Sat, May 31, 2025 at 06:31:46PM +0200, Hans de Goede wrote:
> With IPU# bridges, endpoints may only be created when the IPU bridge is
> initialized. This may happen after the sensor driver's first probe().
> 
> Signed-off-by: Hans de Goede <hansg@kernel.org>
> ---
>  drivers/media/i2c/mt9m114.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c
> index c4d3122d698e..72914c47ec9a 100644
> --- a/drivers/media/i2c/mt9m114.c
> +++ b/drivers/media/i2c/mt9m114.c
> @@ -2399,11 +2399,14 @@ static int mt9m114_parse_dt(struct mt9m114 *sensor)
>  	struct fwnode_handle *ep;
>  	int ret;
>  
> +	/*
> +	 * Sometimes the fwnode graph is initialized by the bridge driver,
> +	 * wait for this.
> +	 */
>  	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
> -	if (!ep) {
> -		dev_err(&sensor->client->dev, "No endpoint found\n");
> -		return -EINVAL;
> -	}
> +	if (!ep)
> +		return dev_err_probe(&sensor->client->dev, -EPROBE_DEFER,
> +				     "waiting for fwnode graph endpoint\n");

That's a bit annoying, as in non-ACPI systems we'll then get probe
deferral, making the issue more difficult to debug.

Is there a way, on IPU-based systems, to delay probing the sensor until
the bridge has been initialized ? I suppose this is a question for
Sakari too.

>  
>  	sensor->bus_cfg.bus_type = V4L2_MBUS_UNKNOWN;
>  	ret = v4l2_fwnode_endpoint_alloc_parse(ep, &sensor->bus_cfg);

-- 
Regards,

Laurent Pinchart