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

[Andre Przywara]

On Mon, 5 Oct 2026 12:49:57 -0300
Otavio Salvador <otavio.salvador@xxxxxxxxxxxxxxxx> wrote:

Hi Otavio,

> 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:

Yes, I found my BananaPi-M2 Berry, and can confirm that 0x34 holds 0,
and 0x40 reads 0x085a0857.

So all fine, 0x40 it is.

Thanks for checking, and my tag of course stands.

> 
>   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.

Yes, we have never seen this issue again, it seems to have been a
one-off bug.

Cheers,
Andre