Re: [PATCH v6 0/8] media: camss: Add support for C-PHY configuration on Qualcomm platforms

[Bryan O'Donoghue <bod@kernel.org>]

On 03/06/2026 00:30, David Heidelberg via B4 Relay wrote:
> Note: WIP tag added, as not everything from the previous review round has
> been addressed.
> 
> # Short summary
> 
> This patch series extends the Qualcomm CAMSS (Camera Subsystem),
> including CSID and CSIPHY components, to support C-PHY mode configuration.
> 
> # Background and motivation
> 
> Modern smartphone cameras increasingly rely on MIPI C-PHY rather than
> D-PHY, thanks to its higher data throughput and signal efficiency.
> As a result, many OEMs adopt C-PHY interfaces for main (rear) cameras on
> Qualcomm-based devices.
> 
> Until now, mainline Linux lacked C-PHY configuration support for Qualcomm
> chipsets, preventing bring-up of primary camera sensors on several
> Snapdragon platforms. This series closes that gap.
> 
>   - Introduces C-PHY configuration support for the CAMSS driver stack,
>     covering both CSID and CSIPHY blocks.
>   - Successfully enables C-PHY operation on the Snapdragon 845 platform.
>   - Tested on OnePlus 6 and 6T phones running mainline Linux,
>     using the Sony IMX519 main camera sensor.
>   - The new configuration allows other chipsets versionsto enable C-PHY by
>     simply adding corresponding sensor driver support and csiphy
>     initialization data, following the example set for sdm845.
> 
> With this patch series, mainline Linux gains working C-PHY support for
> Snapdragon 845, paving the way for improved main camera functionality
> across many Qualcomm-based devices. The groundwork also simplifies
> future enablement efforts for additional SoCs and sensors.
> 
> Until merged, the series will be also available at:
>    https://codeberg.org/sdm845/linux/commits/branch/b4/qcom-cphy
> 
> Signed-off-by: David Heidelberg <david@ixit.cz>
> ---
> Changes in v6:
> - lanes_enable now uses WARN_ONCE instead of return values. (Sakari)
> - Dropped Kodiak patch until it gets better documented.
> - Document the 3ph C-PHY sdm845 registers a bit.
> - Link to v5: https://lore.kernel.org/r/20260531-qcom-cphy-v5-0-6be0f62b4d65@ixit.cz
> 
> Changes in v5:
> - Split first patch enabling C-PHY part into last patch. (Bryan)
> - Fix the camss_get_link_freq crash. (Cory)
> - Dropped patch whitelisting C-PHY, instead use nullptr check. (Bryan)
> - Dropped A-b/R-b from
>   "media: qcom: camss: Initialize lanes after lane configuration is available"
>   and changed Petr to Co-developed by and owned the patch.
> - Link to v4: https://lore.kernel.org/r/20260301-qcom-cphy-v4-0-e53316d2cc65@ixit.cz
> 
> Changes in v4:
> - Documented cphy parametr to camss_get_link_freq.
> - Use BIT() macro for lane_mask. (Bryan)
> - Correct lane_mask calculation. (Kieran + me)
> - Removed comment for the D/C-PHY sequences init. (Bryan)
> - Pass &csid->phy for calculate freq. (Bryan)
> - Added missing cphy description to camss_get_link_freq. (kernel test robot)
> - Gen2 v1.1 MIPI CSI-2 CPHY init hex to lowercase.
> - Added back missed commit with improved electrical for sdm845 3ph.
> - NOT addressed yet:
>    - Proliferating special cases in switch statements on a per-SoC basis is verboten.
>    - is it possible to set clock_lane to say 0xff in DT ?
> - Link to v3: https://lore.kernel.org/r/20260117-qcom-cphy-v3-0-8ce76a06f7db@ixit.cz
> 
> Changes in v3:
> - Make lanes_enable return sucess or error, since I couldn't move the
>    configuration to the _init.
> - Dropped R-b tags on
>    "media: qcom: camss: Initialize lanes after lane configuration is available"
>    as I changed formatting.
> - Link to v2: https://lore.kernel.org/r/20251204-qcom-cphy-v2-0-6b35ef8b071e@ixit.cz
> 
> Changes in v2:
> - This is still WIP patch series, thus I wanted to publish already
>    changed parts to get feedback regarding to the direction of patchset.
> - When switch to using odd bits, zeroed val which was left unitialized in v1.
> - Accidentally missed archs added back in the commit moving lane regs to
>    new location.
> - Remove commit with reverting check for only D-PHY is supported and
>    adjusted the check to also account for C-PHY.
> - Documented link frequency calculation with defines. (Casey)
> - Changed the cphy boolean to phy_cfg enum in the camss/camss-csiphy.
>    (Brian)
> - Added patch for csiphy-3ph enablement for sm7280 from Luca as I'm
>    meanwhile trying to bring up the C-PHY sensor on FairPhone 5.
> - Merged these two commits together
>      csiphy-3ph: Enable sdm845 C-PHY sequence
>      csiphy-3ph: Add Gen2 v1.1 MIPI CSI-2 CPHY init
>    merged R-b.
> - Link to v1: https://lore.kernel.org/r/20251109-qcom-cphy-v1-0-165f7e79b0e1@ixit.cz
> 
> ---
> David Heidelberg (8):
>        media: qcom: camss: csiphy: Introduce PHY configuration
>        media: qcom: camss: csiphy-3ph: Use odd bits for configuring C-PHY lanes
>        media: qcom: camss: Prepare CSID for C-PHY support
>        media: qcom: camss: Initialize lanes after lane configuration is available
>        media: qcom: camss: csiphy-3ph: Add Gen2 v1.1 MIPI CSI-2 C-PHY init
>        media: qcom: camss: csiphy-3ph: Update Gen2 v1.1 MIPI CSI-2 C-PHY init
>        media: qcom: camss: Account for C-PHY when calculating link frequency
>        media: qcom: camss: Enable C-PHY where available
> 
>   .../media/platform/qcom/camss/camss-csid-gen2.c    |   1 +
>   drivers/media/platform/qcom/camss/camss-csid.c     |   8 +-
>   drivers/media/platform/qcom/camss/camss-csid.h     |   1 +
>   .../platform/qcom/camss/camss-csiphy-3ph-1-0.c     | 243 +++++++++++++++++----
>   drivers/media/platform/qcom/camss/camss-csiphy.c   |   6 +-
>   drivers/media/platform/qcom/camss/camss-csiphy.h   |   2 +
>   drivers/media/platform/qcom/camss/camss.c          |  36 ++-
>   drivers/media/platform/qcom/camss/camss.h          |   2 +-
>   8 files changed, 236 insertions(+), 63 deletions(-)
> ---
> base-commit: b7bee4ca5688e30ca50fbc87b1b8f7eed7006c17
> change-id: 20251109-qcom-cphy-bb8cbda1c644
> 
> Best regards,

I'd like to see a dts to go with this ideally for upstream ...

---
bod