[PATCH 1/2] dt-bindings: microchip-otpc: document Microchip OTPC
Krzysztof Kozlowski
krzysztof.kozlowski at linaro.org
Thu May 12 08:35:56 PDT 2022
On 12/05/2022 17:31, Claudiu.Beznea at microchip.com wrote:
>>
>> Macro is a nice idea if it can be stable. I understood that length of
>> packets depends on hardware, so this part could be stable. But what
>> about number of packets, so the OTP_PKT_SAMA7G5_TEMP_CALIB_LEN below?
>
> The OTP_PKT_SAMA7G5_TEMP_CALIB_LEN here is the length of thermal
> calibration packet. This length is fixed and will not be changed.
>
> After these 2 packets (provided by Microchip) user may further flash any
> number of packets and use them as they wish.
>
> Driver is in charge of scanning the NVMEM for the available packets and
> prepare a list with their IDs and their starting offsets in NVMEM memory
> such that when it receives a read request it will be able to decode the
> packet offset based on packet identifier.
>
> In case different number of packets are available in NVMEM for different
> kind of setups (boards) these could also be referenced in board specific DT
> using OTP_PKT() macro and with proper length (which will depend on what
> user flashed).
>
>> You wrote "Boot configuration packet may vary in length", so it could be
>> changed by Microchip?
>
> Yes, between chip revisions its length could be changed.
Chip revisions like different board compatibles thus different
bindings/macro values? If not, then maybe better skip the length out of
bindings and just provide the first macro.
Best regards,
Krzysztof
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