linux-kernel - Re: [alsa-devel] [PATCH 2/3] ASoC: simple-card: Add support jack detection via codec

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Message-Id: <3EB722B2-2818-459C-8640-A3C2FC713F05@nh6z.net>
Date:	Fri, 22 Apr 2016 09:40:09 -0700
From:	Jeremy McDermond <nh6z@...z.net>
To:	Mark Brown <broonie@...nel.org>
Cc:	Xing Zheng <zhengxing@...k-chips.com>,
	Mark Rutland <mark.rutland@....com>,
	Andrew Lunn <andrew@...n.ch>, alsa-devel@...a-project.org,
	Mengdong Lin <mengdong.lin@...ux.intel.com>, heiko@...ech.de,
	Liam Girdwood <lgirdwood@...il.com>,
	Takashi Iwai <tiwai@...e.com>, Rob Herring <robh@...nel.org>,
	Aaro Koskinen <aaro.koskinen@....fi>,
	sugar.zhang@...k-chips.com, linux-rockchip@...ts.infradead.org,
	jay.xu@...k-chips.com, devicetree@...r.kernel.org,
	Pawel Moll <pawel.moll@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Jyri Sarha <jsarha@...com>,
	Arnaud Pouliquen <arnaud.pouliquen@...com>,
	linux-kernel@...r.kernel.org, Adam.Thomson@...semi.com,
	Kumar Gala <galak@...eaurora.org>, Jun Nie <jun.nie@...aro.org>
Subject: Re: [alsa-devel] [PATCH 2/3] ASoC: simple-card: Add support jack detection via codec

> On Apr 22, 2016, at 2:22 AM, Mark Brown <broonie@...nel.org> wrote:
> 
> On Fri, Apr 22, 2016 at 09:17:46AM +0800, Xing Zheng wrote:
> 
>> Hi Mark, the other question here, how do we make sense to use the
>> simple-card to call the "snd_soc_dai_set_pll" if the codec (like da7219)
>> requires do this?
> 
> What we should do there is move the CODEC clocking to be represented
> using the clock API and then there are common clock bindings that
> already exist for configuring clocks.

I’m a little bit curious about this.  I’m working with the clocking
on the tlv320aic32x4 driver because I’m dealing with a platform that
will be clocking it from a dynamic clock controlled by the CCF.  That
presents some problems because the aic32x4 driver has a table of clock
parameters and those rely on the mclk rate being a precise value.
The mclk might not be able to provide those exact values, so the
aic32x4 driver needs to set its PLLs and dividers accordingly.

The hardware has a couple of clock muxes, a few dividers and the
PLL.  It seems to be able to be modeled by the current CCF
components fairly well.  I’m just trying to wrap my head around
where this all would fit in.  Should the codec driver just register
a bunch of clock components in its initialization somewhere?
I’m thinking that it can’t have its own CCF driver separate from
the codec driver because you won’t have proper access to the
registers over I2C or SPI.  I don’t find a lot of examples in the
codec drivers, and there aren’t very many other drivers in the tree
that seem to register clocks with CCF that I can find.

I’m happy to work through this with the aic32x4 driver.  I just
need some guidance on how to do it so it fits in well with
everything else surrounding it.

--
Jeremy McDermond (NH6Z)
Xenotropic Systems
mcdermj@...otropic.com