[alsa-devel] [PATCH 2/3] ASoC: pxa-ssp.c, Automatically set TDM when needed

Daniel Ribeiro drwyrm at gmail.com
Sat Aug 15 13:48:17 CEST 2009


Em Sáb, 2009-08-15 às 10:51 +0100, Mark Brown escreveu:
> On Fri, Aug 14, 2009 at 01:17:41PM -0300, Daniel Ribeiro wrote:
> 
> > This should be able to deal with I2S when pxa is slave, on both pxa2xx
> > and pxa3xx, with set_tdm_slot(5, 5, 4, 16).
> 
> > Or when pxa is master, on pxa3xx only, with set_tdm_slot(3, 3, 2, 16).
> > This still violates the "DMYSTOP must be clear on network mode" rule,
> > but as all slots are active its not really network mode. And it seems to
> > work for you, so... ;)
> 
> This seems really confusing from a usability point of view - the master
> and slave configurations should look the same.  I'd expec the slave mode
> configuration you quote above to be looking for twice as many clocks as
> the master mode one.  The driver should ideally encapsulate this.

Yes, this is really confusing. The hardware is weird and behaves
different when it is driving SFRM.

On both (slave/master) modes it will use the same clk cycles, its just
that on master half the clocks are skipped by DMYSTOP.

Maybe Daniel Mack can test a setup with PXA slave of SFRM, and if it
works for him, we can drop the pxa3xx-only I2S/master mode for now. It
is a mess and I don't see an easy way to solve this. :(

-- 
Daniel Ribeiro
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