Re: [alsa-devel] [PATCH RFC v2 REPOST 3/8] ASoC: davinci-evm: HDMI audio support for TDA998x trough McASP I2S bus - Jean-Francois Moine

From: Jean-Francois Moine <moinejf@free.fr>
To: Jyri Sarha <jsarha@ti.com>
Cc: devicetree@vger.kernel.org, alsa-devel@alsa-project.org,
	dri-devel@lists.freedesktop.org, "Ujfalusi,
	Peter" <peter.ujfalusi@ti.com>, Mark Brown <broonie@kernel.org>,
	bcousson@baylibre.com, linux-omap@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [alsa-devel] [PATCH RFC v2 REPOST 3/8] ASoC: davinci-evm: HDMI audio support for TDA998x trough McASP I2S bus
Date: Wed, 22 Jan 2014 11:19:53 +0100	[thread overview]
Message-ID: <20140122111953.238349a5@armhf> (raw)
In-Reply-To: <52DF8D60.9020505@ti.com>

On Wed, 22 Jan 2014 11:20:32 +0200
Jyri Sarha <jsarha@ti.com> wrote:

> On 01/15/2014 05:51 PM, Jean-Francois Moine wrote:
> > On Wed, 15 Jan 2014 13:27:21 +0200
> > Jyri Sarha <jsarha@ti.com> wrote:
> >
> >>   From driver/gpu/drm/i2c/tda998x_drv.c. The driver configures CTS_N
> >> register statically to a value that works only with 4 byte samples.
> >> According to my tests it is possible to support 3 and 2 byte samples too
> >> by changing the CTS_N register value, but I am not sure if the
> >> configuration can be changed on the fly. My data sheet of the nxp chip
> >> is very vague about the register definitions, but I suppose the register
> >> configures some clock divider on the chip. HDMI supports only upto 24bit
> >> audio and the data sheet states that any extraneous least significant
> >> bits are ignored.
> >
> > In the tda998x driver, the CTS_N is automatic (AIP_CNTRL_0_ACR_MAN is
> > not set).
> >
> > Then, in my Cubox (Marvell A510 + tda19988), the 16, 24 and 32 bits
> > formats are working well with I2S input at any rate.
> >
> 
> Could you refer the kernel version (main line?) and the involved ASoC 
> drivers so could take I a look if there is something I could do differently?

Both drivers are in the kernel main line.

The ASoC is in sound/soc/kirkwood/. kirkwood-i2s.c defines the DAIs I2S
and S/PDIF outputs.

As both I2S and S/PDIF may be used for HDMI output in the Cubox,
I wrote a tda998x CODEC which gets the audio ports from the DT and
dynamically sets these ports and the audio type (i2s / spdif) on audio
streaming start. I have not submitted yet this codec and the associated
changes in tda998x, because I am waiting for a first patch series on the
tda998x to be applied
(http://lists.freedesktop.org/archives/dri-devel/2014-January/051552.html).

-- 
Ken ar c'hentañ	|	      ** Breizh ha Linux atav! **
Jef		|		http://moinejf.free.fr/
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