linux-kernel - Re: multi-codec support for arizona-ldo1 was Re: System with multiple arizona (wm5102) codecs

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Message-ID: <20151013115355.GC14956@sirena.org.uk>
Date:	Tue, 13 Oct 2015 12:53:55 +0100
From:	Mark Brown <broonie@...nel.org>
To:	Pavel Machek <pavel@....cz>
Cc:	Charles Keepax <ckeepax@...nsource.wolfsonmicro.com>,
	lgirdwood@...il.com, perex@...ex.cz, tiwai@...e.de,
	patches@...nsource.wolfsonmicro.com, alsa-devel@...a-project.org,
	linux-kernel@...r.kernel.org
Subject: Re: multi-codec support for arizona-ldo1 was Re: System with
 multiple arizona (wm5102) codecs

On Mon, Oct 12, 2015 at 10:11:38PM +0200, Pavel Machek wrote:
> On Mon 2015-10-12 16:47:15, Mark Brown wrote:
> > On Mon, Oct 12, 2015 at 11:00:45AM +0200, Pavel Machek wrote:

> > >  static const struct regulator_desc arizona_ldo1_hc = {
> > > -	.name = "LDO1",

> > No, you definitely shouldn't be doing this - the regulator names should
> > reflect the names the device has in the datasheet to aid people in going
> > from software to the hardware and back again.  They shouldn't be
> > dynamically generated at runtime.  If you need to namespace by
> device

> They already are, see wm831x-ldo.c .

No, that's a different case where we actually have a repeatable IP we
can enumerate multiple instances of on a single piece of silicon which
has multiple variants available.  This is a single device with a single
regulator on it.

> > provide an interface which explicitly namespaces by device rather than
> > hacking it into another interface, the usual thing is to use the struct
> > device as the context.

> I'll need some more help here. I need to use it from ALSA, so I don't
> think I can influence that interface easily.

Sorry?  If this is going into the userspace ABI there's something
seriously wrong...

> What is currently in tree _does not work_, as there are two arizona
> chips, and two "LDO1" regulators. (Doable) suggestions how to fix that
> are welcome.

To repeat what I said above, provide an interface which namespaces by
device (as we normally do when we need to distinguish between multiple
instances of the same device).  Given that everything is part of the
same device it's very easy to discover which device so it's clearly no
problem when mapping the supplies.

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