[PATCH v6 0/2] media: Add Himax HM1092 mono NIR sensor driver

[Ramshouriesh R <rshouriesh@gmail.com>]

This adds a V4L2 subdev driver and DT binding for the Himax HM1092, a
1 megapixel monochrome near-infrared image sensor. On laptops it sits
behind the IR camera used for face unlock. It speaks a single MIPI CSI-2
data lane and outputs 10-bit RAW at 560x360.

The driver exposes that one fixed mode, test patterns, exposure, analogue
gain and digital gain controls, pixel-array selection targets and the
standard fwnode properties. It has been tested on an ASUS Zenbook A14:
the sensor probes, streams, changes brightness across the full exposure
and analogue gain ranges, accepts digital gain endpoint updates while
streaming, and returns to runtime suspend after capture.

The exposure default is 500 lines, selected from unstretched illuminated
captures on the ASUS system. The init sequence programs the same value so
the sensor state and V4L2 control default remain consistent.

The register programming was extracted from
com.qti.sensormodule.hm1092.bin in the Qualcomm camera stack shipped for
the ASUS system. Jake Steinman independently identified the exposure,
analogue gain, digital gain and group-hold registers from Dell's
hm1092.sys. The available documentation does not identify the
test-pattern modes, so their menu names are based on output observed
during hardware testing.

The ASUS Windows configuration supplies a 24 MHz external clock. The
programmed PLL divide-by-12 pre-divider and multiply-by-90 multiplier
give a 180 MHz CSI-2 DDR link frequency, a 360 Mbit/s lane rate and a
36 MHz pixel rate. With HTS 1616 and VTS 750, the resulting frame rate is
approximately 29.7 frames per second. The driver reports the 1296x736
native pixel array, the 1280x720 active array and the mode's 1150x718
crop.

The sensor driver and its binding are SoC-neutral, so they are sent on
their own through the media tree. The board-level device tree and PHY
work that wires this camera up on the ASUS Zenbook A14 will be sent as
its own series.

Signed-off-by: Ramshouriesh R <rshouriesh@gmail.com>
---
Changes in v6:
- dt-bindings: update the example to the PLL-derived 180 MHz link
  frequency.
- hm1092: replace the inconsistent 400 MHz link frequency and derived
  80 MHz pixel rate with 180 MHz and 36 MHz. The new values are derived
  from the ASUS Windows configuration's 24 MHz external clock and the
  sensor PLL dividers.
- hm1092: report the 1296x736 native array, 1280x720 active array and
  1150x718 mode crop as distinct selection targets.
- hm1092: add exposure, analogue gain and digital gain controls using the
  register map supplied by Jake Steinman. Keep multi-byte controls as
  separate writes, use group hold, derive the exposure maximum from VTS,
  and program the hardware-tested 500-line exposure default in both the
  init table and control. Hardware-test the controls on the 560x360 mode.
- hm1092: do not power the sensor on in probe(). There is no I2C access
  during probe, so leave it suspended and let runtime PM power it for
  streaming.
- Link to v5: https://patch.msgid.link/20260709-hm1092-driver-v5-0-a1f5baa6fe08@gmail.com

Changes in v5:
- dt-bindings: drop the data-lanes property entirely; the fixed
  single-lane wiring is not configurable, so it does not belong in DT.
- hm1092: implement the get_selection pad op (CROP, CROP_DEFAULT,
  CROP_BOUNDS and NATIVE_SIZE) reporting the sensor's pixel-array
  geometry, as required by libcamera.
- Link to v4: https://patch.msgid.link/20260705-hm1092-driver-v4-0-0a13ec274d89@gmail.com

Changes in v4:
- dt-bindings: make data-lanes optional for the fixed single-lane sensor,
  constrain explicit values to <1>, and omit it from the example.
- hm1092: add the copyright notice.
- hm1092: replace the private register representation and write helper
  with CCI register sequences and direct CCI writes.
- hm1092: use descriptive test-pattern names based on hardware captures;
  the available documentation does not identify these modes.
- hm1092: parse fwnode properties before creating controls and set
  read-only flags after validating control creation.
- hm1092: use the generic get_fmt callback for the fixed sensor mode.
- hm1092: initialize endpoint parsing with the fixed one-lane default,
  reject other lane configurations, and remove the redundant endpoint
  presence check.
- hm1092: use fsleep() and null-safe GPIO calls, and apply the requested
  declaration, brace, return-value and error-path formatting cleanups.
- Link to v3: https://patch.msgid.link/20260702-hm1092-driver-v3-0-85faa7ff4fec@gmail.com

Changes in v3:
- dt-bindings: add the Reviewed-by tag from Conor Dooley.
- hm1092: initialize RAW colorimetry fields in the pad format helper so
  userspace values cannot leak into subdevice state.
- hm1092: return -ENXIO when the required firmware graph endpoint is
  absent instead of deferring probe indefinitely.
- Link to v2: https://patch.msgid.link/20260702-hm1092-driver-v2-0-4f9f369d6a48@gmail.com

Changes in v2:
- hm1092: use pm_ptr() instead of pm_sleep_ptr() for the dev_pm_ops
  pointer. The ops come from DEFINE_RUNTIME_DEV_PM_OPS(), so gating them
  on CONFIG_PM_SLEEP dropped runtime PM on a CONFIG_PM=y, PM_SLEEP=n
  build.
- hm1092: free the control handler on the error paths in
  hm1092_init_controls(); the fwnode-parse and ctrl_hdlr->error returns
  leaked the handler.
- Link to v1: https://patch.msgid.link/20260701-hm1092-driver-v1-0-d1bd81e233b5@gmail.com

---
Ramshouriesh R (2):
      media: dt-bindings: Add Himax HM1092 NIR sensor
      media: i2c: hm1092: add Himax HM1092 mono NIR sensor driver

 .../bindings/media/i2c/himax,hm1092.yaml           | 101 +++
 MAINTAINERS                                        |   7 +
 drivers/media/i2c/Kconfig                          |  11 +
 drivers/media/i2c/Makefile                         |   1 +
 drivers/media/i2c/hm1092.c                         | 863 +++++++++++++++++++++
 5 files changed, 983 insertions(+)
---
base-commit: be5c93fa674f0fc3c8f359c2143abce6bbb422e6
change-id: 20260618-hm1092-driver-a6f2aaddf201

Best regards,
--  
Ramshouriesh R <rshouriesh@gmail.com>