[alsa-devel] [PATCH 4/4] ASoC: Flag the i.MX SSI driver as using symmetric rates

Sascha Hauer s.hauer at pengutronix.de
Mon Jan 11 13:14:19 CET 2010

On Mon, Jan 11, 2010 at 11:36:31AM +0000, Mark Brown wrote:
> On Mon, Jan 11, 2010 at 12:20:47PM +0100, Sascha Hauer wrote:
> > Why this limitation? I can successfully record with 16000Hz while
> > playing at 48000Hz on my PCM037 board. What is missing in the driver to
> > 'officially' support asymmetric rates?
> At least some of the driver was unconditionally setting both TX and RX
> configuration simultaneously, though looking again hw_params() is OK.

You probably mean imx_ssi_set_dai_fmt(), imx_ssi_set_dai_tdm_slot()
and imx_ssi_set_dai_sysclk(). We do not have the playback/record
information available in these functions. Should we pass a struct
snd_pcm_substream * to the functions?

> I'll drop the patch.  Like I say, I've never actually seen the driver
> working - even when configured as the master it doesn't seem to do any
> DMA (well, FIQs).

Unfortunately I do not have a mx31ads available, so I can't provide a
driver for this board. I never used master mode, but if I understand the
datasheet correctly the SSI unit has two clock inputs, one for the
register accesses which gets enabled by clk_enable and one for the baud
rate which doesn't get touched by the driver atm. Have you checked that
the baud clock is configured correctly?
If you have by chance a mx27ads or a mx35 3stack board I could see that
I make the driver work on one of these boards.


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