[PATCH 0/3] Enable the front camera on the Dell Latitude 7320 Detachable

[Sahan Nissanka <adee.sahan@gmail.com>]

This series enables the user-facing 5MP camera on the Dell Latitude 7320
Detachable, which has never worked on Linux. Two open reports ask for it:
intel/ipu6-drivers issues #24 (2022) and #402 (2025), the latter blocked
waiting for "OV5678 sensor specifications (clock rates, power requirements)".

Those specifications turned out not to be needed. ACPI describes the front
sensor as OVTI5678 and no driver has ever claimed that id. The part reports
chip id 0x005675 at register 0x300a, and the values ov5675.c is sensitive to
were read from the machine's ACPI SSDB before the sensor was ever powered and
both agree - 2 CSI-2 data lanes and a 19.2 MHz external clock. The advertised
5MP also matches the driver's native 2592x1944. So no new sensor driver and no
new register tables are required to make it stream.

One caveat, set out in full in 2/3: this part is not a plain Bayer sensor. It
carries a 4x4 RGB-IR colour filter array, one pixel in four being infrared.
That is confirmed from Intel's own Windows IPU6 configuration for this exact
module, from measurements on the sensor at full resolution, and from the
module's tuning data, which agree with each other. The SGRBG10 that ov5675
declares is therefore inaccurate, and colour is wrong in a way white balance
cannot correct.

That cannot be fixed in this series: the V4L2 ABI has no RGB-IR media bus
code at all, and ox05b1s already carries the same inaccuracy for an RGB-IR
sensor of the same class and resolution. I intend to propose RGB-IR media bus
codes separately. Until such support exists, this series takes hardware that
does not work at all to hardware that works with imperfect colour, which
seemed worth having in the meantime. I am happy to hold 2/3 if maintainers
would rather not add the id before the format can be described honestly.

That leaves three small pieces:

  1/3 gives the TPS68470 PMIC board data, without which the sensors are not
      even enumerated - they declare an ACPI _DEP on the control logic, so no
      i2c client is created until it probes.
  2/3 adds the OVTI5678 id to ov5675.
  3/3 adds the ipu-bridge entry so a software node is created for it.

The patches touch two subsystems: 1/3 is platform-driver-x86, 2/3 and 3/3 are
media. They are independent of each other in build terms, but none of them
does anything useful alone, so they are sent together for context. Happy to
split them if maintainers prefer.

Tested on a Dell Latitude 7320 Detachable, BIOS 1.48.0, kernel 7.0.0. With
all three applied:

  intel-ipu6 0000:00:05.0: Found supported sensor OVTI5678:00
  intel-ipu6 0000:00:05.0: Found supported sensor OVTI8856:00
  intel-ipu6 0000:00:05.0: Connected 2 cameras
  ov5675 1-0036: ... appears in the media graph

and libcamera captures 2584x1944 at 29.95 fps.

The rear OVTI8856 sensor shares the same PMIC. Its rails are described by the
same board data, but its reset/powerdown GPIO assignment is not yet known, so
it is deliberately left out here.

Sahan Nissanka (3):
  platform/x86: int3472: Add TPS68470 board data for Dell 7320
    Detachable
  media: i2c: ov5675: Add OVTI5678 ACPI id
  media: ipu-bridge: Add sensor configuration for OV5675 (OVTI5678)

 drivers/media/i2c/ov5675.c                    | 11 ++
 drivers/media/pci/intel/ipu-bridge.c          |  2 +
 .../x86/intel/int3472/tps68470_board_data.c   | 92 +++++++++++++++++++
 3 files changed, 105 insertions(+)

-- 
2.53.0