Re: Adding OTP-only device to MTD or CHAR subsystem?

From: Arnd Bergmann
Date: Mon Dec 28 2015 - 18:39:34 EST


On Monday 28 December 2015 15:21:08 Scott Branden wrote:
> Greg/Brian/Arnd,
>
> We have OTP device drivers for accessing OTP memory in our SoCs.
>
> I looking for the right place and model to place such OTP device drivers.
>
> 1) Should we follow the bfin-otp model in drivers/char? This doesn't
> seem like the right place to put it although following the bfin example
> is quite simple to implement. We actually had a custom set of Ioctl's
> that I changed to use the standard file access model used by the bfin
> driver. But a custom util is still needed to issue an OTPLOCK command.
> I'm guess mtd-utils has such abilities (or should).
>
> 2) Instead, should we start adding OTP-only drivers into the MTD
> subsystem? Onenand and CFI based MTD devices already have OTP
> programmable regions. If we created a new OTP device type in the MTD
> subsystem this looks like a good thing to do. mtd-utils could/should be
> used to access the OTP device then along with standard fileio operations.
>
> 3) Or some other suggestion of where to place OTP device drivers?

I think drivers/nvmem is now the right place for this.

Arnd
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