[linux-sunxi] Re: [PATCH 1/4] brcmfmac: Add brcm, nvram_file_name dt property

[arnd@arndb.de (Arnd Bergmann)]

On Thursday, July 7, 2016 11:16:59 AM CEST Arend Van Spriel wrote:
> On 7-7-2016 10:46, Arnd Bergmann wrote:
> > On Wednesday, July 6, 2016 9:19:41 PM CEST Arend Van Spriel wrote:
> >> On 6-7-2016 15:42, Arnd Bergmann wrote:
> >>> On Wednesday, July 6, 2016 10:08:55 AM CEST Arend Van Spriel wrote:
> >>>> On Tue, Jul 5, 2016 at 3:43 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> > I'm a bit confused by the interdependencies now. You say that there are
> > board ID/rev values stored in OTP. What exactly prevents us from just
> > using those to generate a file name to look up the nvram file on disk
> > for the remaining values?
> > 
> > Do we require the firmware to be running before we can read the OTP,
> > or are there cases where the board ID in OTP is wrong or missing?
> 
> Well, both. Primarily we need firmware running to get the info. If board
> ID is missing in OTP the value from nvram file is used. If board ID in
> OTP is wrong we are screwed 

Ok.

> > If we can't rely on OTP for one of those reasons and instead add two
> > properties for boardtype/boardrev, I don't think that requires a
> > change of the compatible string, we would just document those two
> > as optional properties.
> 
> Right. I suppose the bindings update and driver update should preferably
> be in the same kernel release although bindings are supposedly OS agnostic.

It's a one-way dependency, we shouldn't add the kernel code handling
the property without having agreed on and updated the binding first.

	Arnd