Re: [PATCH v8 0/2] ASoC: tda998x: add a codec to the HDMI transmitter

From: Jyri Sarha
Date: Mon Dec 29 2014 - 12:37:53 EST

On 12/29/2014 06:52 PM, Mark Brown wrote:
On Thu, Oct 23, 2014 at 10:32:49AM +0200, Jean-Francois Moine wrote:
The NXP TDA998x HDMI transmitter may transmit audio to the HDMI link
from 2 different sources, I2S and S/PDIF.

So, I'm not seeing *any* interest here from any other HDMI users. This
is a continuing theme with HDMI patches and is really very concerning,
everyone appears to be working in their own bubbles coming up with their
own things and ignoring everyone else's work - what little review I'm
seeing seems to be happening only after I explicitly prompt it. I'm
following up to Jean-Francois' patches here but this isn't specific to
them, it seems like a general thing with HDMI code.

This in turn makes me think there's some abstraction problems with
what's going on and we're going to have to go through yet more
refactorings to fix things up as we do manage to come up with better
abstractions. What I'd really like to see as a bare minimum is some
visible conversation about what we're doing and sign that people are
at least keeping in mind generic solutions when working on HDMI code.
Some commentary on the similarities and differences between hardware
and which abstractions work with which devices would also be really
helpful in working out if we're going in the right direction.

Basically at the minute I'm worried that we may be making the problems
we've got here worse not better, I've not personally had the time to sit
down and study the hardware sufficiently to form a firm impression
myself which isn't helping.

I have not seen any significant new development since v7 of these patches. My comments for v6 were mostly[1] addressed and I can live with these changes, even develop this approach further if it gets merged.

However, as a general note I see a need for a generic ASoC hdmi codec abstraction and I don't think this is generic enough. More of the audio specific implementation and HDMI standard specific things should be pushed away from the hdmi encoder driver (tda998x in this case) to the generic ASoC side hdmi codec driver (or library).

I am currently working on something that tries to be a generic solution that should be usable for different encoders and platforms, but unfortunately I have been busy with other things lately and have not been able to put anything working together yet. As soon as I have at least a bare bone API and and a proof of concept implementation working, I send RFC/POF patches out.

Best regards,

[1] I personally do not like the hdmi_get_cdev() approach. I would rather go with only a library for registering from ASoC codec component under the HDMI encoder device or a completely separate device with only a reference to the HDMI encoder.

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