Hi, Alexander, On 21.08.2024 13:59, Alexander Dahl wrote: > Hei hei, > > on a custom sam9x60 based board we want to access a unique ID of the > SoC. Microchip sam-ba has a command 'readuniqueid' which returns the > content of the OTPC Product UID x Register in that case. > > (On different boards with a SAMA5D2 we use the Serial Number x Register > exposed through the atmel soc driver. Those registers are not present > in the SAM9X60 series, but only for SAMA5D2/SAMA5D4 AFAIK.) Not sure if you are talking about Chip ID, Chip ID extension registers. These are available also on SAM9X60. > > There is a driver for the OTPC of the SAMA7G5 and after comparing > register layouts it seems that one is almost identical to the one used > by SAM9X60. Currently that driver has no support for the UIDx > registers, but I suppose it would be the right place to implement it, > because the registers are within the OTPC register address offsets. > > The patch series starts with fixups for the current driver. It then > adds the necessary pieces to DT and driver to work on SAM9X60 in > general. Later support for enabling the main RC oscillator is added, > which is required on SAM9X60 for the OTPC to work. The last patch adds > an additional nvmem device for the UIDx registers. > > This v1 of the series was _not_ tested on SAMA7G5, because I don't have > such a board for testing. Actually I don't know if the main_rc_osc > clock is required on SAMA7G5 too, and if yes how to handle that with > regard to the different clock ids. If someone could test on SAMA7G5 > and/or help me sorting out the core clock id things, that would be > highly appreciated. Please add Nicolas in the loop on the next revisions of this series as this should also be tested on SAMA7G5. I don't have a SAMA7G5 with OTP memory populated. > > Also I assume some more devicetree and/or sysfs documentation is > necessary. If someone could point me what's exactly required, this > would be very helpful for me. You see I expect at least another version > v2 of the series. ;-) > > Maybe some files having that "sama7g5" should be renamed, because that > DT binding is used for more SoCs now and deserves a more generic name? Not needed, adding your compatible there is enough. > Thinking of these for example: > > - Documentation/devicetree/bindings/nvmem/microchip,sama7g5-otpc.yaml > - include/dt-bindings/nvmem/microchip,sama7g5-otpc.h > > Are there other SoCs than SAMA7G5 and SAM9X60 using the same OTPC? > > Last question: Should the UID be added to the device entropy pool with > add_device_randomness() as done in the SAMA5D2 sfr driver? > > I sent an RFC patch on this topic earlier this year, you'll find the > link below as a reference to the discussion. The patch itself was > trivial and not meant for applying as is anyways, so I decided to not > write a full changelog from RFC to v1. > > Last not least, special thanks to Christian Melki on IRC, who wrote and > tested parts of this, and was very kind and helpful in discussing the > topic several times in the past months. > > Christian, if you feel there's credit missing, just point me where to > add Co-developed-by and I'll happily do that for v2. > > Greets > Alex > > (series based on v6.11-rc4) > > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Cc: devicetree@xxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > Cc: linux-clk@xxxxxxxxxxxxxxx > Link: https://lore.kernel.org/all/20240412140802.1571935-2-ada@xxxxxxxxxxx/ > > Alexander Dahl (12): > nvmem: microchip-otpc: Avoid writing a write-only register > nvmem: microchip-otpc: Fix swapped 'sleep' and 'timeout' parameters > dt-bindings: nvmem: microchip-otpc: Add compatible for SAM9X60 > nvmem: microchip-otpc: Add SAM9X60 support > ARM: dts: microchip: sam9x60: Add OTPC node > ARM: dts: microchip: sam9x60_curiosity: Enable OTP Controller > nvmem: microchip-otpc: Add missing register definitions > nvmem: microchip-otpc: Add warnings for bad OTPC conditions on probe > clk: at91: sam9x60: Allow enabling main_rc_osc through DT > ARM: dts: microchip: sam9x60: Add clock properties to OTPC > nvmem: microchip-otpc: Enable main RC oscillator clock > nvmem: microchip-otpc: Expose UID registers as 2nd nvmem device > > .../nvmem/microchip,sama7g5-otpc.yaml | 1 + > .../dts/microchip/at91-sam9x60_curiosity.dts | 4 + > arch/arm/boot/dts/microchip/sam9x60.dtsi | 10 +++ > drivers/clk/at91/sam9x60.c | 3 +- > drivers/nvmem/microchip-otpc.c | 86 ++++++++++++++++++- > include/dt-bindings/clock/at91.h | 1 + > 6 files changed, 100 insertions(+), 5 deletions(-) > > > base-commit: 47ac09b91befbb6a235ab620c32af719f8208399
