Re: [RFC PATCH 0/5] Add NVMEM driver for i.MX93 OTP access through ELE

[Frieder Schrempf <frieder.schrempf@kontron.de>]

Am 22.04.25 um 08:40 schrieb Arnd Bergmann:
> On Wed, Apr 16, 2025, at 16:26, Frieder Schrempf wrote:
> 
>> Therefore I implemented a simple driver that uses the ELE S400 API only, as the
>> FSB access (1) doesn't provide any benefits except for that it doesn't depend
>> on the ELE firmware being available. This is used by us downstream.
>>
>> For the upstream solution I would like to have some feedback on how to move
>> on:
>>
>> 1. switch imx-ocotp-ele.c to use ELE API exclusively
>>    -> this will create a hard dependency on the ELE firmware/driver 
>> being available
> 
> Could this cause problems for real-time Linux users? Usually going
> through a firmware driver adds more latency than doing the thing
> from Linux directly, and the firmware is usually not preemptable.
> 
> In particular, programming a one-time fuse is likely a slow
> operation in hardware, so it may still be necessary to support
> both methods if there are users that need to update the fuses
> on real-time systems.

Hm, interesting thought. I can't really tell if that could end up being
a real problem, but it might just be another good argument for
supporting both methods, yes.