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

[Mark Rutland <mark.rutland@arm.com>]

On Tue, Aug 19, 2014 at 08:40:51PM +0100, Jyri Sarha wrote:
> On 08/19/2014 04:16 PM, Mark Rutland wrote:
> > On Mon, Aug 18, 2014 at 10:46:41PM +0100, Jyri Sarha wrote:
> >> Add machine driver support for BeagleBone-Black HDMI audio. BBB has
> >> NXP TDA998X HDMI transmitter connected to McASP port in I2S mode. The
> >> 44100 Hz sample-rate and it's multiples can not be accurately produced
> >> on BBB. The only supported sample format is SNDRV_PCM_FORMAT_S32_LE.
> >> The 8 least significant bits are ignored.
> >>
> >> Signed-off-by: Jyri Sarha <jsarha@ti.com>
> >> ---
> >>   .../bindings/sound/davinci-evm-audio.txt           |    4 +-
> >>   sound/soc/davinci/davinci-evm.c                    |   82 +++++++++++++++++++-
> >>   2 files changed, 83 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/Documentation/devicetree/bindings/sound/davinci-evm-audio.txt b/Documentation/devicetree/bindings/sound/davinci-evm-audio.txt
> >> index 963e100..c137436 100644
> >> --- a/Documentation/devicetree/bindings/sound/davinci-evm-audio.txt
> >> +++ b/Documentation/devicetree/bindings/sound/davinci-evm-audio.txt
> >> @@ -1,7 +1,9 @@
> >>   * Texas Instruments SoC audio setups with TLV320AIC3X Codec
> >>
> >>   Required properties:
> >> -- compatible : "ti,da830-evm-audio" : forDM365/DA8xx/OMAPL1x/AM33xx
> >> +- compatible : "ti,da830-evm-audio" : for DM365/DA8xx/OMAPL1x/AM33xx
> >> +               "ti,am335x-beaglebone-black-audio" : for Beaglebone-black HDMI
> >> +                                                    audio
> >
> > To keep this legible I'd recommend reorganising this like:
> >
> > - compatible: should contain one of:
> >     * "ti,da830-evm-audio" for DM365/DA8xx/OMAPL1x/AM33xx
> >     * "ti,am335x-beaglebone-black-audio" for Beaglebone-black HDMI audio
> >
> 
> The above looks indeed better. I'll make the change. Oh, and I probably 
> should change the first line to something like:
> 
> * TI SoC audio using McASP to connect to TLV320AIC3X or HDMI endcoder
> 
> > For the BBB case, do you expect both strings or just the BBB-specific
> > string?
> >
> 
> Normally just the one. In theory a BBB with an audio-cape on top could 
> utilize another sound node with "ti,da830-evm-audio" compatible property.

Sorry, I meant in the same node. I take it we never expect:

compatible = "ti,am335x-beaglebone-black-audio", "ti,da830-evm-audio";

> > Is the 'x' in the BBB string a wildcard? If we know the particular
> > number for BBB we should use that.
> >
> 
> Yes, its a wild card. BBBs have been made at least with AM3358 and 
> AM3359 SoCs.

In general we've pushed back against wildcard strings, and used the
first implementation for the naming. We should be able to use 
"ti,am3358-beaglebone-black-audio" for AM335{8,9} assuming the block is
the same? Otherwise we might need separate strings anyway.

Thanks,
Mark.