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

Jean-Francois Moine moinejf at free.fr
Wed Jan 22 11:19:53 CET 2014

On Wed, 22 Jan 2014 11:20:32 +0200
Jyri Sarha <jsarha at 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 at 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

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

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