linux-kernel - Re: [PATCH v5 char-misc-next] misc: microchip: pci1xxxx: Add OTP/EEPROM driver for the pci1xxxx switch

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Message-ID: <Y/NBJ5xzUoNHEOm2@kroah.com>
Date:   Mon, 20 Feb 2023 10:45:11 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Kumaravel.Thiagarajan@...rochip.com
Cc:     arnd@...db.de, linux-gpio@...r.kernel.org, michael@...le.cc,
        srinivas.kandagatla@...aro.org, linux-kernel@...r.kernel.org,
        UNGLinuxDriver@...rochip.com, Tharunkumar.Pasumarthi@...rochip.com
Subject: Re: [PATCH v5 char-misc-next] misc: microchip: pci1xxxx: Add
 OTP/EEPROM driver for the pci1xxxx switch

On Mon, Feb 20, 2023 at 09:31:45AM +0000, Kumaravel.Thiagarajan@...rochip.com wrote:
> > I do not recommend using a block interface for this at all.  Why not
> > the
> > "normal" EEPROM interface that the kernel has today (i.e. a binary
> > sysfs
> > file)?  That way you can mmap it and edit locations how ever you
> > want.
> Greg, I have one question about the sysfs interface. If OTP and EEPROM
> are enumerated as two sysfs files of 8KB each, will that start
> occupying the RAM permamently or is the swapping in and out of the RAM
> handled automatically by the kernel based on the user trying to access
> it.

It depends on exactly what you are doing here with the binary sysfs
file.  Try it yourself and see how it works.

thanks,

greg k-h