[PATCH v18 5/5] media: qcom: camss: Use data-lanes starting at 1 for new CSIPHY mode

[Loic Poulain]

On Thu, Sep 17, 2026 at 1:08 PM Bryan O'Donoghue
<bryan.odonoghue at linaro.org> 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 at linaro.org>

Reviewed-by: Loic Poulain <loic.poulain at oss.qualcomm.com>

> ---
>  drivers/media/platform/qcom/camss/camss-csiphy.h |  1 +
>  drivers/media/platform/qcom/camss/camss.c        | 15 ++++++++++++---
>  2 files changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/platform/qcom/camss/camss-csiphy.h b/drivers/media/platform/qcom/camss/camss-csiphy.h
> index 7a357044b9fdb..8c3319f2ca1cf 100644
> --- a/drivers/media/platform/qcom/camss/camss-csiphy.h
> +++ b/drivers/media/platform/qcom/camss/camss-csiphy.h
> @@ -21,6 +21,7 @@
>  #define MSM_CSIPHY_PAD_SINK 0
>  #define MSM_CSIPHY_PAD_SRC 1
>  #define MSM_CSIPHY_PADS_NUM 2
> +#define MSM_CSIPHY_MAX_DATA_LANE 4
>
>  #define CSIPHY_GRP_ID 1
>
> diff --git a/drivers/media/platform/qcom/camss/camss.c b/drivers/media/platform/qcom/camss/camss.c
> index 84097d82d99c9..6f58e729eaceb 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 >= MSM_CSIPHY_MAX_DATA_LANE) {
> +                       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;
>         }
>
> --
> 2.55.0
>