[alsa-devel] [PATCH 0/3] ASoC: Enable a new IC master mode: bcm2835<=>IC<=>cs42xx8

Charles Keepax ckeepax at opensource.wolfsonmicro.com
Wed Mar 22 05:34:40 PDT 2017

On Wed, Mar 22, 2017 at 11:04:34PM +1100, Matt Flax wrote:
> >Are we saying that what gets transmitted on the bus is neither valid
> >I2S or DSP mode data? But as you have your custom hardware block in
> >the middle it interprets this data correctly and converts it to a
> >regular bus format on the other side that goes to the CODEC?
> >
> >
> Yes, essentially there is translation between the two data word edge
> triggered ABP (the bcm2835's PCM block) and a Cirrus Logic TDM codec.

Hmm... I guess that is the root difficulty here. As we probably
don't want to call it DSP mode in the driver if connecting it
to something that was expecting data in that format wouldn't
work. Especially if the device actually could support DSP mode as
well, since we would then be blocking someone for implementing
legimate DSP mode in the future.

I guess really the correct thing to do would be to add some
define for the new format, but I can see that might be a tricky
road. Would perhaps some sort of BESPOKE define or something be
possible to indicate odd formats that don't fall into regular


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