Re: [PATCH 2/2] ARM: dts: sun8i-r40: Add SID node and THS calibration

[Otavio Salvador]

Hi Andre,

Thanks for the review.

Em seg., 5 de out. de 2026 às 06:02, Andre Przywara
<andre.przywara@xxxxxxx> escreveu:
>
> Hi Otavio,
>
> thanks for sending the patch!
>
> On 10/3/26 03:25, Otavio Salvador wrote:
> > Without the calibration cell, the THS driver leaves the sensor
> > calibration registers at their reset value (0x800) and the reported
> > temperatures drift from the real die temperature by a chip-dependent
> > offset.
> >
> > Add the SID node at 0x01c1b000 and wire the thermal sensor to its
> > factory calibration at eFuse offset 0x40, one 16-bit word for each of
> > the two sensors.
> >
> > The R40 user manual gives the size of the thermal sensor key (32 bits)
> > but not its offset. The vendor SDK key map names 0x48 "thermal_sensor",
> > but that word is zero on all the boards checked. On an A40i running the
> > Boardcon vendor kernel, the THS_0_1_CDATA register holds exactly the
> > eFuse word at 0x40 (0x08780875), which confirms the location.
>
> So in some U-Boot BSP sources on github I see
> arch/arm/include/asm/arch-sun8iw11p1/sid.h putting the sensor at 0x34
> (like the H3 or A64).
> Can you check the values there? I see that Tina-Linux puts them at 0x40,
> as you reported, and it's probably more reliable there than in the
> U-Boot sources, but it's worth double checking.
>
> The rest looks alright (checked the manual and how the compatible string
> is handled in the driver), so if you can confirm that it's 0x40:
>
> Reviewed-by: Andre Przywara <andre.przywara@xxxxxxx>

Yes, I checked 0x34. The BPI U-Boot sid.h for sun8iw11p1 puts the
thermal key there, but that word is zero on every A40i I dumped: three
boards on mainline with this patch, and the Boardcon board on its
vendor kernel. 0x48 is zero too. Only 0x40 holds two plausible 12-bit
values:

  board 1: 0x08780875 (vendor kernel, THS_0_1_CDATA = 0x08780875)
  board 2: 0x082d0822
  board 3: 0x083d0838

The value differs per board, and on the vendor kernel THS_0_1_CDATA
holds exactly the word at 0x40. With this patch, CDATA on boards 2 and
3 also matches their word at 0x40. So 0x40 it is, matching Tina Linux.

I also compared the MMIO window at SID + 0x200 with the register-based
readout (the H3 method) across several boots. All 64 words matched, so
the R40 doesn't seem to have the H3 readout problem.

Best regards,
Otavio

-- 
Otavio Salvador                             O.S. Systems
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