[BUG] - incorrect max exposure and others for arducam-pivariety (IMX462)

[Eric Claeys]

Describe the bug
Running rpicam-still --list-cameras produces the following. Notice the "ExposureTime" is [14..0] which is incorrect - the maximum time isn't specified and should be.

Available cameras
-----------------
0 : arducam-pivariety [1920x1080 10-bit RGGB] (/base/soc/i2c0mux/i2c@1/arducam_pivariety@c)
    Modes: 'SRGGB10_CSI2P' : 1920x1080 [60.00 fps - (0, 0)/1920x1080 crop]

    Available controls for 1920x1080 SRGGB10_CSI2P mode:
    ----------------------------------------------------
    AeConstraintMode : [0..3]
    AeEnable : [false..true]
    AeExposureMode : [0..3]
    AeMeteringMode : [0..3]
    AnalogueGain : [1.000000..200.000000]
    AwbEnable : [false..true]
    AwbMode : [0..7]
    Brightness : [-1.000000..1.000000]
    ColourGains : [0.000000..32.000000]
    Contrast : [0.000000..32.000000]
    ExposureTime : [14..0]
    ExposureValue : [-8.000000..8.000000]
    FrameDurationLimits : [16666..15534444]
    NoiseReductionMode : [0..4]
    Saturation : [0.000000..32.000000]
    ScalerCrop : [(0, 0)/64x64..(0, 0)/1920x1080]
    Sharpness : [0.000000..16.000000]

Further, running rpicam-still -v --shutter 5000 --metadata SOME_FILE ... produces the following. Note that no default Brightness, Saturation, or Sharpness were given:

{
    "ExposureTime": 5000000,
    "FocusFoM": 1351,
    "AnalogueGain": 1.330000,
    "ColourCorrectionMatrix": [ 1.831948, -0.820011, -0.011936, -0.430259, 1.753510, -0.323250, -0.071906, -0.713727, 1.785643 ],
    "FrameDuration": 5000059,
    "Lux": 0.090005,
    "AeLocked": false,
    "ColourGains": [ 1.000000, 1.000000 ],
    "DigitalGain": 1.891665,
    "ColourTemperature": 4500,
    "SensorBlackLevels": [ 4096, 4096, 4096, 4096 ],
    "ScalerCrop": "(0, 0)/1920x1080",
    "SensorTimestamp": 805369547000
}

IMHO it this output should always contain ALL the values used

[6by9]

Support for Arducam's PiVariety cameras has never been upstreamed by them, therefore they do not run with the Raspberry Pi libcamera or this repo for rpicam-apps.

Arducam's branches are at https://github.com/Arducam/libcamera and https://github.com/ArduCAM/libcamera-apps/, although I note they have disabled issues on those repos.
Support for Arducam products is through their support channels at https://forum.arducam.com/ or https://www.arducam.com/contact-arducam/

I suspect because of the way that PiVariety has been implemented that the max exposure time is not known as the microcontroller on the sensor board may not provide that information.