[PATCH v2 2/3] drm/vc4: Add HDMI audio support

[Boris Brezillon]

On Mon, 27 Feb 2017 12:28:02 -0800
Eric Anholt <eric at anholt.net> wrote:

> The HDMI encoder IP embeds all needed blocks to output audio, with a
> custom DAI called MAI moving audio between the two parts of the HDMI
> core.  This driver now exposes a sound card to let users stream audio
> to their display.
> 
> Using the hdmi-codec driver has been considered here, but MAI meant
> having to significantly rework hdmi-codec, and it would have left
> little shared code with the I2S mode anyway.
> 
> The encoder requires that the audio be SPDIF-formatted frames only,
> which alsalib will format-convert for us.
> 
> This patch is the combined work of Eric Anholt (initial register setup
> with a separate dmaengine driver and using simple-audio-card) and
> Boris Brezillon (moving it all into HDMI, massive debug to get it
> actually working), and which Eric has the permission to release.
> 
> v2: Drop "-audio" from sound card name, since that's already implied
>     (suggestion by Boris)
> 
> Signed-off-by: Eric Anholt <eric at anholt.net>

Acked-by: Boris Brezillon <boris.brezillon at free-electrons.com>