LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Mark Brown <broonie@kernel.org>
To: Jean-Francois Moine <moinejf@free.fr>
Cc: Lars-Peter Clausen <lars@metafoo.de>,
	Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
	devicetree@vger.kernel.org, alsa-devel@alsa-project.org,
	Russell King - ARM Linux <linux@arm.linux.org.uk>,
	linux-kernel@vger.kernel.org, Jyri Sarha <jsarha@ti.com>
Subject: Re: [alsa-devel] [PATCH v2 3/3] ASoC: add generic dt-card support
Date: Tue, 3 Feb 2015 16:47:48 +0000	[thread overview]
Message-ID: <20150203164748.GR21293@sirena.org.uk> (raw)
In-Reply-To: <20150124083027.3b3a018f@armhf>

[-- Attachment #1: Type: text/plain, Size: 2380 bytes --]

On Sat, Jan 24, 2015 at 08:30:27AM +0100, Jean-Francois Moine wrote:
> Mark Brown <broonie@kernel.org> wrote:
> > On Fri, Jan 23, 2015 at 07:34:56PM +0100, Jean-Francois Moine wrote:

> > > The simple card builder, 'dt-card' (maybe a better name would have been
> > > 'graph-card'), acts just like the simple-card except that it does not
> > > appear in the DT. Its creation is done by an audio controller.

> > Which audio controller?  There may be several CPU side audio interfaces
> > in the same card.  For example people often want to have both low
> > latency and high latency audio paths from the CPU into the hardware (low
> > latency tends to increase power burn).  SoC centric system designs do
> > sometimes also have PDM I/O, expecting to be directly connected to DMICs
> > and so on, which results in a relatively large number of CPU interfaces.

> The audio controller which creates the card depends on the complexity
> of the card. When there are many controllers, it is up to the designer
> to define either a master audio controller or to instantiate a 'card'
> device via the DT for doing the job.

So how does the simple controller interact with a more complex one given
that it's somehow picking some controller node to start from?

> > > Well, forget about this. I never clearly understood why some widgets
> > > and routes had to be defined at card level.

> > Please do try to understand the idea of representing simple components
> > on the board and analogue interconects between devices - it's really
> > important and not something that can be neglected.

> The problem is that this understanding would stay abstract: I have no
> such a hardware. Anyway, if the representation can be done with the
> simple-card, it may also be done with a graph of ports.

If you have a device with any sort of speaker or microphone, or any sort
of external connector for interfacing with an external device like a
headphone jack, then you have something that could be a widget.

> > That DT binding was done entirely in the context of video applications
> > IIRC, this is the first time it's been discussed in this context.

> http://mailman.alsa-project.org/pipermail/alsa-devel/2014-January/070622.html
> http://mailman.alsa-project.org/pipermail/alsa-devel/2015-January/086273.html

So there's been some in passing mentions, not really serious discussion
though...

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 473 bytes --]

  reply	other threads:[~2015-02-03 16:48 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-21 19:27 [PATCH v2 0/3] ASoC: add audio card creation from graph of ports in DT Jean-Francois Moine
2015-01-20 18:47 ` [PATCH v2 1/3] ASoC: core: export snd_soc_get_dai_name Jean-Francois Moine
2015-01-20 19:16 ` [PATCH v2 3/3] ASoC: add generic dt-card support Jean-Francois Moine
2015-01-21 20:14   ` [alsa-devel] " Lars-Peter Clausen
2015-01-22  8:07     ` Jean-Francois Moine
2015-01-22 19:00       ` Mark Brown
2015-01-22 19:25       ` Lars-Peter Clausen
2015-01-23 12:15         ` Jean-Francois Moine
2015-01-23 13:56           ` Lars-Peter Clausen
2015-01-23 17:40             ` Mark Brown
2015-01-23 18:34             ` Jean-Francois Moine
2015-01-23 19:13               ` Mark Brown
2015-01-24  7:30                 ` Jean-Francois Moine
2015-02-03 16:47                   ` Mark Brown [this message]
2015-02-03 19:31                     ` Jean-Francois Moine
2015-02-07  8:33                       ` Mark Brown
2015-01-24 11:27               ` Lars-Peter Clausen
2015-01-24 13:18                 ` Jean-Francois Moine
2015-01-26 11:53                   ` Lars-Peter Clausen
2015-01-26 18:22                     ` Jean-Francois Moine
2015-01-21 19:10 ` [PATCH v2 2/3] Documentation: of: Document audio graph bindings Jean-Francois Moine

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20150203164748.GR21293@sirena.org.uk \
    --to=broonie@kernel.org \
    --cc=alsa-devel@alsa-project.org \
    --cc=devicetree@vger.kernel.org \
    --cc=jsarha@ti.com \
    --cc=kuninori.morimoto.gx@renesas.com \
    --cc=lars@metafoo.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@arm.linux.org.uk \
    --cc=moinejf@free.fr \
    --subject='Re: [alsa-devel] [PATCH v2 3/3] ASoC: add generic dt-card support' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).