Change dimming function to non-linear

[klew]

https://forum.supla.org/viewtopic.php?p=135582#p135582

[klew]

Dimming function should be selectable. I.e. currently people may use dimmer channel to control something else than LED, which requires linear function.

[Hrumque]

And dimming "direction" should be selectable - steady 1 on gpio means 100% pwm, or stady 0 on gpio means 100% pwm

[Hrumque]

If the implementation of non-linear curves for dimming is a big problem, it can be done (even temporarily) in such a form that we limit the number of dimmer levels, e.g. to 8 or 16, and assign them pwm values (level0, level1, ... level15). So on the "input" variable the dimming remains as it is now (dim/brighten button, application, values stored in cloud etc), only in the firmware in device is made a change, even through the "case" ladder - For led lighting - I tested for 2 different light sources (led strip and led RGB) - my levels are completely smooth in 11 levels: level0 =0% pwm (off) level1 = 1% level2 = 2% level3 = 3% level4 = 5% level5 = 10% level6 = 20% level7 = 30% level8 = 45% level9 = 60% level10 = 100% between 60% pwm and 100% there is almost no brightness gain anymore. And between 1 and 3% there is a significant difference.

ADDITIONALLY - assignment of specific discrette pwm values - allows (at last) two additional possibilities:

• the ability to set the reverse direction of pwm control (in some applications - it will be useful).
• if such a ladder would be separate for each channel in RGB (W) - then the percentage set of R G and B for a given brightness would allow you to set the same color for different brightness (because as you know - this diverges with the dimming of the RGB LEDs, because each of the channels has different characteristics)

[klew]

@Hrumque it is not a big problem. It's rather easy task, however I don't have time right now to handle it, so it has to wait.

[klew]

Done in https://github.com/SUPLA/supla-device/releases/tag/v23.5