Re: [PATCH v6 3/8] media: qcom: camss: Prepare CSID for C-PHY support

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] State leak: `csid->phy.cphy` is not explicitly reset when linking to the Test Pattern Generator (TPG), leading to stale hardware configuration.
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commit 0af85d683a316522712652086dfff4934fe24c0c
Author: David Heidelberg <david@ixit.cz>
Subject: media: qcom: camss: Prepare CSID for C-PHY support

Inherit C-PHY information from CSIPHY, so we can configure CSID properly.
CSI2_RX_CFG0_PHY_TYPE_SEL must be set to 1, when C-PHY mode is used.

> diff --git a/drivers/media/platform/qcom/camss/camss-csid.c b/drivers/media/platform/qcom/camss/camss-csid.c
> --- a/drivers/media/platform/qcom/camss/camss-csid.c
> +++ b/drivers/media/platform/qcom/camss/camss-csid.c
> @@ -1291,6 +1291,7 @@ static int csid_link_setup(struct media_entity *entity,
>  
>  			lane_cfg = &csiphy->cfg.csi2->lane_cfg;
>  			csid->phy.lane_cnt = lane_cfg->num_data;
> +			csid->phy.cphy = (lane_cfg->phy_cfg == V4L2_MBUS_CSI2_CPHY);

[Severity: Medium]
Does this leave stale state when linking to the Test Pattern Generator (TPG)
later?

If a C-PHY sensor is linked, csid->phy.cphy is set to true here. If that
sensor is later unlinked and the TPG is linked, the TPG link logic updates
other PHY parameters but does not reset cphy:

        if (sd->grp_id == TPG_GRP_ID) {
                tpg = v4l2_get_subdevdata(sd);
                csid->phy.lane_cnt = tpg->res->lane_cnt;
                csid->phy.csiphy_id = tpg->id;
                csid->phy.lane_assign = csid_get_lane_assign(NULL, csid->phy.lane_cnt);
                csid->tpg_linked = true;
        }

When __csid_configure_rx() is called, it writes this leftover value into
CSI2_RX_CFG0_PHY_TYPE_SEL. Could this cause the TPG stream data to be garbled
by configuring the hardware to expect 3-phase C-PHY encoding instead of D-PHY?

>  			csid->phy.lane_assign = csid_get_lane_assign(lane_cfg, lane_cfg->num_data);
>  			csid->tpg_linked = false;
>  		}

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Sashiko AI review · https://sashiko.dev/#/patchset/20260603-qcom-cphy-v6-0-e50de0b557a8@ixit.cz?part=3