[alsa-devel] [PATCH RFC 0/3] tda998x updates for DAI formats and bclk_ratio

[Russell King - ARM Linux admin]

This series addresses two issues with TDA998x that have been
identified:

1) Peter found that the I2S format was not being explicitly set, and
   retains its value from whatever was previously running on the
   platform.  Work around this by implementing support for setting
   the I2S format from the DAI format, rather than merely defaulting
   the register back to its power-on value.

2) Sven found that TDA998x does not work on his Freescale platform,
   which always uses a 64·fs bitclock.  The TDA998x driver was
   deriving this information from the sample width, which, while it
   works for Beagle Bone Black, does not allow the driver to be used
   with other I2S sources that may have different behaviours.

   To work around that, we implement support for
   snd_soc_dai_set_bclk_ratio() in hdmi-codec, and propagate its
   value to TDA998x and other HDMI codecs via a new member.  However,
   since snd_soc_dai_set_bclk_ratio() is never called, we need to
   avoid breaking any existing users, so we detect the lack of call
   by an impossible zero value, and subsitute a value corresponding
   with the TDA998x's old behaviour.

   It is hoped that snd_soc_dai_set_bclk_ratio() will see more
   adoption in ASoC, and the TDA998x specific defaulting can be
   removed.

 drivers/gpu/drm/i2c/tda998x_drv.c | 75 ++++++++++++++++++++++++++-------------
 include/drm/i2c/tda998x.h         | 12 +++++--
 include/sound/hdmi-codec.h        |  1 +
 sound/soc/codecs/hdmi-codec.c     | 45 +++++++++++++++++++++--
 4 files changed, 104 insertions(+), 29 deletions(-)

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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