Re: [PATCH v2 5/5] iio: light: stk3310: support the Sensortek STK36C61

[Luca Weiss]

Hi Jorijn,

On Sun Aug 30, 2026 at 10:19 PM CEST, Jorijn van der Graaf wrote:
> On Sun, Aug 30, 2026 at 12:03:29PM -0300, Marcelo Schmitt wrote:
>> Having a closer look at the data sheet I found for STK36C61, I noticed registers
>> 0x13 and 0x14 are not listed. Does the newer part has ambient light sensing
>> besides the clear channel?
>
> That looks to be the "STK36C61-A Preliminary Datasheet v0.9" hosted by
> LCSC [1], which I hadn't found before, so the cover letter's "There is
> no public datasheet" is wrong. It documents the -A variant, however,
> and gives PDT_ID as 0x93, while the part in the Fairphone 6 reports
> 0x95. It does agree with the device on the colour-engine layout: RGBC

Just to chime in, the datasheet I have access to (STK36C61-A Preliminary
Datasheet Version - 0.9.2) there are a few changes compared with the one
from LCSC but nothing too interesting:

* On the overview page LED current 228.75 changed to 218.75 mA
* ALSCTRL1 register (0x02) has different values for BIT[6:4]
  (17.92 -> 143.36; 8.96 -> 35.84; 4.48 -> 8.96)
* PDT_ID is indeed 0x95 - maybe the previous version just had wrong
  copy-pasted info?

Hope this help.

Regards
Luca

> data at 0x15-0x1C, a clear-channel gain in GAINCTRL 0x4E, and the
> shared GAIN_RGB/IT_ALS fields in ALSCTRL1.
>
> Yes, there is ambient light sensing besides the clear channel:
> 0x13/0x14 are present on this device despite their absence from the
> datasheet map. They behave exactly like the stk3310's ALS data
> registers and are what the illuminance channel reads. The ALS word
> tracks the green channel exactly, proven by the x16 gain step moving
> both from 25 to 404. The sheet's own text does describe the function:
> it defines DATA_ALS[15:0] ("16-bits ALS channel raw data"), windows it
> with the THDH/THDL_ALS thresholds at 0x0A-0x0D, and calls FLG_ALS_INT
> "the Green channel out-of-windows event", which is consistent with the
> ALS == green behaviour I measured.
>
> [1] https://www.lcsc.com/datasheet/C49230205.pdf
>
> Thanks,
> Jorijn