IMX577 DOL HDR Device Tree

Autonomous Machines Jetson & Embedded Systems Jetson AGX Xavier
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4

For WDR you still need create camera_overrides.isp file at /var/nvidia/nvcam/settings and change mode to 664
And add below to the overrides file.
wdr.DOL.v4.EnableDOL = TRUE;
ae.wdr.DreMin = FER;
ae.wdr.DreMax = FER;

Check the FER from below

Also the exposure ratio needs to be fixed value, preferably a power of 2.
This fixed exposure ratio needs to obeys the following constraints:
a. Short exposure time lower limit * fixed exposure ratio >= Long exposure time lower limit.
b. Short exposure time upper limit * fixed exposure ratio <= Long exposure time upper limit.

The limits for short exposure time and long exposure time can be derived from the data sheet.
The above constraints will ensure that that long and short exposure times output by our auto exposure always maintain a fixed exposure ratio.

Once such a Fixed Exposure Ratio (let’s call it FER) value has been derived, the following changes should be made:

  1. Add these knobs to the config overrides:
    ae.wdr.DreMin = FER;
    ae.wdr.DreMax = FER;

  2. Setup DT properties for DOL sensor mode:
    min_exp_time = FER * short exposure time lower limit;
    max_exp_time = FER * short exposure time upper limit;