media: qcom: add X1E80100 C-PHY camera receive support

[ooaklee]

Summary

• add an explicit MIPI C-PHY mode to the generic PHY API and the Qualcomm X1E80100 combo PHY
• program the bounded X1E80100 one-trio receive, interrupt-clear, and shutdown sequences at 2.406 Gsymbol/s
• propagate the endpoint bus type through Qualcomm CAMSS CSIPHY and CSID
• route the validated one-trio C-PHY path through the X1E80100 CAMSS clocks and CSID receiver fields

Dependency and status

This PR is intended to target jg/ubuntu-qcom-x1e-7.2.y directly. Review it after #82, #83, and the preceding IMX681 sensor topic:

• IMX681 sensor prerequisite: media: i2c: add Sony IMX681 sensor support #85

The head is stacked on x/sp11-camera-imx681, so its GitHub diff is cumulative until the sensor topic is merged into the release branch. The C-PHY-specific portion is the two commits after ddc5bc6c2804. It does not merge the broad -sp11 staging branch or replay the correction already merged through #81.

This PR is a draft. The Denali OLED camera graph follows separately, and both the exact cumulative SP11 stack and an existing non-SP11 X1E D-PHY camera need hardware testing before this shared-driver topic is ready.

Containment

• C-PHY endpoint acceptance is limited to the qcom,x1e80100-camss compatible
• the Qualcomm combo-PHY sequence is selected only for the X1E80100 capability data, PHY_MODE_MIPI_CPHY, trio 0, one data lane/trio, and the exact 2.406 Gsymbol/s rate
• CAMSS accepts only the matching 1.203 GHz V4L2 link frequency for this C-PHY path
• the existing D-PHY endpoint parsing, clock selection, lane programming, receiver programming, and shutdown paths remain the default for existing devices
• the generic PHY_MODE_MIPI_CPHY enum addition is inert until a consumer explicitly requests that mode
• this topic adds no board device tree and no sensor driver beyond the cumulative prerequisite
• the staging source's VFE write-mode, CSID crop/drop-engine, status-logging, CCS, and sensor-format experiments are excluded

Provenance

The two C-PHY commits are authored by Leon Silcott, carry the authorized Signed-off-by: Leon Silcott <leon@boasi.io>, and preserve source links to the final integration state in d915d679423e.

The receiver work builds on @turbineBMW's public camera review patch at immutable revision 05e5335bc724 and credits @geocausa's Windows/QTI parity analysis in the commit messages. These are source and analysis credits; no contributor Signed-off-by or Co-authored-by trailer has been invented for the rewritten commits.

Validation

• git diff --check ddc5bc6c2804..HEAD for the incremental C-PHY topic
• strict checkpatch: no errors or checks; only the generic new-file/MAINTAINERS prompt for the X1E80100 register-table header, which is covered by the existing QUALCOMM MIPI CSI2 PHY DRIVER entry
• ARM64 ubuntu_x1e_defconfig W=1 builds of the two Qualcomm MIPI CSI-2 PHY objects and the four affected CAMSS/CSIPHY/CSID objects
• source audit confirms C-PHY acceptance is limited to X1E80100 and the validated topology/rate
• source audit confirms existing D-PHY endpoints continue through the pre-existing configuration paths
• the cumulative series builds without the excluded VFE, crop/drop, CCS, logging, or sensor-format experiments

Hardware checks still required

• boot the exact cumulative camera stack on an X1E Surface Pro 11 OLED and verify CSIPHY2/CSID0 C-PHY stream setup
• verify repeated and continuous raw capture without CSIPHY, CSID ECC/CRC, or VFE transport errors
• verify repeated stream start/stop and suspend/resume exercise the C-PHY shutdown and reconfiguration paths
• run a camera stream smoke test on a non-SP11 X1E device that uses the existing D-PHY path
• confirm that non-X1E CAMSS devices continue rejecting C-PHY endpoints and retain their existing D-PHY behavior