Hi Mark, On Tue, Jul 09, 2013 at 03:55:10PM +0100, Mark Brown wrote: > On Mon, Jul 08, 2013 at 10:25:38PM +0200, Maxime Ripard wrote: > > On Mon, Jul 08, 2013 at 09:34:26AM +0100, Mark Brown wrote: > > > > I'd really like to see more discussion of this "DT parsing code for > > > regmap" idea... I've missed almost all the context here. > > > The context was that I found we lack a way to simply express the need > > for one driver to get a value from an EEPROM-like device, for example to > > get a MAC Address, or a serial number, in a generic way, without having > > to poke directly with some custom function that would be exported by the > > EEPROM driver. > > This sort of information is often stored in places like flash partitions > too. Are we sure that regmap is a good place to be hooking in here? > The use case is sane, and being able to use regmap to do some of it > seems sensible (I've seen people use OTP in PMICs for similar purposes) > but perhaps an additional layer of abstraction on top makes sense. Ah, I didn't thought it could be stored into a partition. Ok, so using an intermediate abstraction for this makes sense (probably using regmap for all the accesses that are relevant, like i2c, spi or mmio) > > What we've been discussing so far is that: > > - To have a common framework we could base our work on, we could move > > the EEPROM drivers from drivers/misc/eeprom to MTD > > - To declare the ranges that needed to be used by a driver that was > > needing a value from one of those MTD drivers, we would use regmap > > with a MTD backend > > - And since we actually need to declare which ranges and in which > > device one driver would have to retrieve this value from, we were > > actually in need of DT bindings. > > > This is pretty much the only context involved, and we are at the early > > stage of the discussion, so any comment is very welcome :) > > If this stuff is being represented in MTD doesn't MTD already have > adequate abstractions for saying "this region in flash". But otherwise > this seems fine, it's not a generic regmap DT binding but instead rather > more specific than that. Yes, since we seem to be going to a point where regmap will be a convenience in this case, we probably won't need a generic regmap binding, but rather a generic way to define a range and offset into a referenced device. Arnd, the others, is this ok for you? Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
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