Re: [PATCH RFC] eeprom: at24: extend driver to plug into the NVMEM framework

From	Andrew Lunn <andrew@lunn.ch>
Newsgroups	linux.kernel
Subject	Re: [PATCH RFC] eeprom: at24: extend driver to plug into the NVMEM framework
Date	2015-08-20 18:50 +0200
Message-ID	<pZBcn-290-13@gated-at.bofh.it> (permalink)
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> It's true that this is something that we might have overlooked. Is it
> expected to maintain that compatibility when moving a driver from one
> framework to another (and this is a real question, not a troll)?

Yes. There will be user space applications reading from the eeprom
file in /sys. In fact, until the NVMEM framework arrived, it was not
easy to access the eeprom from kernel space, meaning the majority of
users must of been user space...
 
> If so, we might provide a compatibility layer to add the former file
> too, protected by a kconfig option maybe ?

There is one other detail you might of missed. Both AT24 and AT25 do
have an in kernel API. In the at24_platform_data you can have a
callback function "setup" which gets called when the device is
probed. setup() is called with a struct memory_accessor which contains
function pointers for reading and writing to the EEPROM. A few
platforms use these for getting the MAC address out of the EEPROM.
And these platforms are old style, not DT.

    Andrew
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Thread

Re: [PATCH RFC] eeprom: at24: extend driver to plug into the NVMEM  framework Maxime Ripard <maxime.ripard@free-electrons.com> - 2015-08-20 18:00 +0200
  Re: [PATCH RFC] eeprom: at24: extend driver to plug into the NVMEM  framework Andrew Lunn <andrew@lunn.ch> - 2015-08-20 18:50 +0200
    Re: [PATCH RFC] eeprom: at24: extend driver to plug into the NVMEM  framework Maxime Ripard <maxime.ripard@free-electrons.com> - 2015-08-21 00:00 +0200

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