Re: [PATCH v17 5/5] media: qcom: camss: Use data-lanes starting at 1 for new CSIPHY mode

[Nihal Kumar Gupta]

On 06-09-2026 19:47, Bryan O'Donoghue wrote:
> Introducing a dedicated CSIPHY driver community feedback was both to move
> to data-lanes starting at index 1 on the PHY side and also to match that
> indexing scheme in the CSI decoder - CSID.
> 
> CSID consumes the data-lanes property to determine which CSID lanes to
> switch on. For indexes starting at 1 we need to amend the logic somewhere.
> The PHY side code normalises the input data to register level meanings so,
> replicate that logic on the CSID side.
> 
> Introduce a simple flag to differentiate between legacy indexing @ 0 and
> new indexing @ 1.
> 
> Existing bindings are not affected.
> 
> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
> ---
>  drivers/media/platform/qcom/camss/camss.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/media/platform/qcom/camss/camss.c b/drivers/media/platform/qcom/camss/camss.c
> index 84097d82d99c9..07b3cddca5840 100644
> --- a/drivers/media/platform/qcom/camss/camss.c
> +++ b/drivers/media/platform/qcom/camss/camss.c
> @@ -4742,7 +4742,8 @@ static const struct parent_dev_ops vfe_parent_dev_ops = {
>   */
>  static int camss_parse_endpoint_node(struct device *dev,
>  				     struct fwnode_handle *ep,
> -				     struct camss_async_subdev *csd)
> +				     struct camss_async_subdev *csd,
> +				     u8 lane_base)
>  {
>  	struct csiphy_lanes_cfg *lncfg = &csd->interface.csi2.lane_cfg;
>  	struct v4l2_mbus_config_mipi_csi2 *mipi_csi2;
> @@ -4777,7 +4778,14 @@ static int camss_parse_endpoint_node(struct device *dev,
>  		return -ENOMEM;
>  
>  	for (i = 0; i < lncfg->num_data; i++) {
> -		lncfg->data[i].pos = mipi_csi2->data_lanes[i];
> +		u8 lane = mipi_csi2->data_lanes[i];
> +
> +		if (lane < lane_base || lane - lane_base >= lncfg->num_data) {
> +			dev_err(dev, "invalid data-lane %u\n", lane);
> +			return -EINVAL;
> +		}
> +
> +		lncfg->data[i].pos = mipi_csi2->data_lanes[i] - lane_base;
>  		lncfg->data[i].pol = mipi_csi2->lane_polarities[i + 1];
>  	}
>  
> @@ -4794,6 +4802,7 @@ static int camss_parse_ports(struct camss *camss)
>  {
>  	struct device *dev = camss->dev;
>  	struct fwnode_handle *fwnode = dev_fwnode(dev), *ep;
> +	u8 lane_base = camss->legacy_phy ? 0 : 1;
>  	int ret;
>  
>  	fwnode_graph_for_each_endpoint(fwnode, ep) {
> @@ -4841,7 +4850,7 @@ static int camss_parse_ports(struct camss *camss)
>  			goto err_cleanup;
>  		}
>  
> -		ret = camss_parse_endpoint_node(dev, ep, csd);
> +		ret = camss_parse_endpoint_node(dev, ep, csd, lane_base);
>  		if (ret < 0)
>  			goto err_cleanup;
>  	}
> 
Reviewed-by: Nihal Kumar Gupta <nihal.gupta@xxxxxxxxxxxxxxxx>
Tested-by: Nihal Kumar Gupta <nihal.gupta@xxxxxxxxxxxxxxxx> # Glymur CRD

---
Regards,
Nihal Kumar Gupta