Re: [PATCH 1/2] media: i2c: hm1092: Add ACPI enumeration and the 19.2 MHz configuration

[Eduard Kulyk <kulikeduard89@gmail.com>]

Hi Jake,

Tested v6 plus this patch on a Dell Latitude 7350 (Meteor Lake, IPU6),
kernel 7.2.3, with an out-of-tree ipu-bridge that has the HIMX1092
entry. Patch 2 is not needed there, IPU6 already has Y10.

The sensor binds as hm1092 i2c-HIMX1092:00 and streams Y10 648x368
(1344 bytes per line) through IPU6 CSI2 4 at link frequency 180480000.

- v4l2-compliance 1.32.0 on the subdev: 46 tests, 0 failures,
  0 warnings
- 300 frames at 30.11 fps, 20 start/stop cycles without errors
- runtime PM: suspended when idle, active while streaming
- streams again after s2idle suspend/resume
- exposure and analogue gain behave as expected (analogue gain
  0/32/64/128/255 gives mean levels 16/31/45/73/113)
- IR flood LED (INT3472) off/on/off at exposure 700: mean levels
  9/117/9, clean IR image with the LED on
- the crop rectangle reads (0,0)/1294x734 against bounds
  (8,8)/1280x720, as you described

One issue, which I think comes from v6 rather than this patch:
digital_gain is advertised as 256..4095, but only the low 10 bits
seem to take effect. At exposure 100:

  256  -> 15     1024 -> 8 (black frame)
  512  -> 22     1280 -> 15
  768  -> 29     2048 -> 8 (black frame)
  1023 -> 36     4095 -> 35

So 1024 behaves like 0 and 1280 like 256. Perhaps the maximum should
be 0x3ff, but I don't have the datasheet to confirm.

Thanks a lot for your work on this. If you need anything else tested on
this machine, feel free to contact me.

Tested-by: Eduard Kulyk <kulikeduard89@gmail.com> # Dell Latitude 7350 (IPU6)

Regards,
Eduard