Customize camera (CSI / MIPI / GMSL sensor bring-up)

Overview

Tegra264 (Thor) and Tegra234 (Orin) expose a single tegra-capture-vi controller fronted by NVCSI and a fixed set of CSI ports. Camera bring-up is:

1. Sensor selection — picked from the set NVIDIA ships in-tree .dtsi references for on the active platform.
2. Carrier + module support check — verified against the Camera Development Guide, Adaptation Guide §Camera, carrier schematic, Module TRM, and carrier pinmap.
3. Wiring — derived from the in-tree tegra<soc>-camera-<sensor>*.dtsi when one exists (the DTSI IS the wiring source of truth); captured per-sensor from the user when the sensor is custom.
4. Kernel-DT overlay — cpp-expand the in-tree DTSI, extract its fragment@N body, append into the composite custom overlay .dts for the active target (per ../../references/bsp-customization-kernel-dtb.md), verify the composite with fdtoverlay. /jetson-build-source compiles the composite and owns the carrier conf’s OVERLAY_DTB_FILE+= registration.

Agentic, not table-driven — sensor list is built at runtime by globbing in-tree per-sensor dtbos. No _THOR_CAMERAS dict, no questions.json, no Python renderer in the question path.

No ODMDATA edit — cameras don’t consume UPHY lanes (CSI is a separate PHY pool). The skill emits only a kernel-DT overlay; the ODMDATA line in the carrier conf is untouched by this skill.

The output is one commit:

• Camera fragment@N block (plus jetson-header-name on the composite root if not already present) appended to the composite custom overlay .dts per ../../references/bsp-customization-kernel-dtb.md → committed to the bsp_sources/ hardware repo. /jetson-build-source compiles the composite to .dtbo and owns its Makefile + flash-conf registration.

When to invoke

• The user says “enable camera”, “configure CSI”, “wire a Hawk / Owl / IMX sensor”, “MIPI camera”, “GMSL camera”, or asks to bring up tegra-capture-vi / NVCSI on a custom carrier.
• Flash boots but v4l2-ctl --list-devices shows no tegra-capture-vi channels, OR sensor enumeration on a fresh daughter-card needs to be confirmed.
• A sensor was previously enabled and the user wants to add another (multi-sensor bring-up).

Prerequisites:

• Active profile with reference_devkit: + custom_carrier: blocks.
• <source.root_path>/Linux_for_Tegra/.git exists (/jetson-init-source).
• /jetson-derive-carrier has run — the carrier flash-conf fork is in the overlay tracker.
• <source.root_path>/bsp_sources/hardware/nvidia/<chip-dir>/nv-public/overlay/ exists and contains the in-tree per-sensor .dtsi files (sourced by /jetson-init-source’s Branch A archive extract).
• <source.root_path>/bsp_sources/kernel/kernel-noble/include/dt-bindings/ contains the macro headers cpp needs (source_sync.sh may need to run if Branch B was used — see Step 5a.i below).
• Source-of-truth docs registered or supplied at prompt: Camera Development Guide (in bsp_developer_guide mirror or separate path), Adaptation Guide §Camera, carrier schematic, SoC TRM, Module Design Guide.
• dtc, cpp, fdtoverlay on PATH.

Procedure

Detailed step-by-step procedure (Steps 1–7, with all tables, code blocks, and gates) lives in references/procedure.md. Summary:

1. Step 1 — Resolve active target + open source-of-truth docs.
2. Step 2 — Enumerate supported sensors by globbing in-tree per-platform camera dtbos; classify as DPHY-direct / GMSL / custom. Never invent sensors.
3. Step 3 / 3a — Cross-check carrier + module support against DTSI, Camera Development Guide, Adaptation Guide §Camera, SoC TRM, Module Design Guide, schematic, and carrier pinmap. Render the wiring table FIRST, then issue the confirm-or-customize gate.
4. Step 4 (custom path only) — Batched per-sensor wiring questions auto-filled from the carrier pinmap.
5. Step 5 — Append exactly ONE /* custom-bsp: camera:<sensor> */ fragment to the composite custom overlay .dts (see ../../references/bsp-customization-kernel-dtb.md). Clone path cpp-expands the in-tree DTSI; custom path splices Step-4 answers + mode tables in-place. Idempotently set jetson-header-name on the composite root. Verify with dtc + fdtoverlay (pre-compile single-fragment gate; post-compile deep-tree uniqueness gate). Commit via the workflow’s commit-message preview gate.
6. Step 6 — Verify ancillary CAM pin SFIOs (cam_i2c_*, extperiph<m>_clk, reset/PWDN/PWR_EN GPIOs) via pin_verifier.py; route mismatches to /jetson-customize-pinmux.
7. Step 7 — Atomic-write run-state JSON sidecar at <workspace>/target-platform/<profile-stem>.jetson-customize-camera.json and emit the headline, then drive the downstream next-step chain via sequential AskUserQuestion prompts per references/procedure.md Step 7. The chain is a documented workflow gate, not a clarifying question — auto-mode does NOT exempt it. Never substitute a printed “Next step: …” line for the prompts.

Gotchas

• Dual-fragment trap. Contribute exactly ONE camera-tagged fragment@N to the composite. A second one carrying status overrides triggers dtc deep-merge → duplicate sibling subtrees (e.g. two tca9546@70) → runtime first-match drops the dtsi- supplied deep tree → camera silently doesn’t enumerate. Gate on this skill’s marker only (Step 5c).
• Composite root compatible is owned globally, not by this skill. Don’t widen from any in-tree per-sensor dtbo’s compatible (devkit-SKU-gated). Fix the composite root if needed.
• jetson-header-name from any in-tree per-sensor dtbo. Fixed, carrier-agnostic; read once, paste onto the metadata root.
• DO NOT also append the in-tree per-sensor dtbo to OVERLAY_DTB_FILE. Registering both your rendered overlay AND the in-tree tegra<soc>-p3971-camera-<sensor>-overlay.dtbo produces a phantom subdev bind that bricks camera enumeration.
• Stub overlay is a known footgun. Committing tegra-capture-vi { status="okay"; num-channels=<N>; } with no ports / sensor / nvcsi body bricks the camera (all channel init failed). Splice the FULL sensor body via cpp + dtc.
• Sensor mode tables must be spliced, never hand-authored. mode<N>, sensor_modes, pixel_phase — copy verbatim from the closest in-tree DTSI.
• camera_common_regulator_get (null) ERR: -EINVAL = missing avdd-reg / iovdd-reg / dvdd-reg strings — splice the FULL sensor body; always-on rails fall back to dummy regulator.
• External &label refs must exist in base DTB’s __symbols__. Use target-path = "/tegra-capture-vi" when the label is absent; fdtoverlay exits non-zero with FDT_ERR_NOTFOUND otherwise.
• cpp failure on dt-bindings/gpio/gpio.h: No such file = L4T source tree isn’t staged. Re-run /jetson-init-source (Branch B’s source_sync.sh fetches the headers). Never fabricate the macro expansion.
• No ODMDATA edit, no flash-conf edit. Camera doesn’t consume UPHY lanes. The carrier conf’s ODMDATA="..." is untouched. OVERLAY_DTB_FILE+= is owned by /jetson-build-source Step 5.0a — this skill never touches the carrier flash conf.
• Don’t touch the upstream BSP at <bsp_image.root_path>. All edits land in <source.root_path>/Linux_for_Tegra/ (overlay tracker) and <source.root_path>/bsp_sources/ (overlay .dts) under the pristine + customization commit pattern.

References

• references/procedure.md — full step-by-step Steps 1–7 procedure (extracted from this SKILL.md).
• references/csi-dt-bindings.md — CSI / nvcsi / vi DT binding reference notes.
• references/overlay-template.md — guidance on the metadata-root + clone-body overlay shape.
• references/camera-overlay-templates/ — starter .dts.tmpl templates: dphy-direct.dts.tmpl, gmsl-serdes.dts.tmpl.
• ../../scripts/pin_verifier.py — shared HSIO pin verifier (Step 6).
• ../../references/platform_template.yaml — documents: block consumed by Step 1.
• ../../context/bsp-customization-workflow.md — overlay edit protocol.
• ../jetson-customize-pinmux/SKILL.md — sibling skill auto-invoked by Step 6 to fix HSIO pin SFIO mismatches (CAM I²C, MCLK, reset GPIOs).
• ../jetson-derive-carrier/SKILL.md — must run first; produces the carrier base overlay (the *-dynamic.dtbo) this skill’s composite stacks after.
• ../jetson-init-source/SKILL.md — produces the overlay tracker + bsp_sources repo (with the hardware/nvidia/<chip-dir>/ per-sensor DTSI tree) this skill reads and commits into.