• Eric Anholt's avatar
    drm/vc4: Add HDMI audio support · bb7d7856
    Eric Anholt authored
    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: default avatarEric Anholt <eric@anholt.net>
    Acked-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
    Link: http://patchwork.freedesktop.org/patch/msgid/20170227202803.12855-2-eric@anholt.net
    bb7d7856
vc4_hdmi.c 36 KB