[alsa-devel] Sharing PXA SSP ports

Daniel Mack zonque at gmail.com
Wed Jun 22 14:44:10 CEST 2011

The current API for requesting an SSP port on PXA platforms assumes
that the caller of pxa_ssp_request() is the only user of this port, so
both input and output streams must be implemented in the same driver.

In a new setup I'm working on, this is not sufficient as we connect
one codec to the input stream and another one to the output stream of
the same CPU DAI "pxa-ssp-dai.0". I'm currently using a hack that
disables the use count check in pxa_ssp_request(), but I certainly
need a cleaner solution.

What would be a good approach? Would we need a multiplexer for this
hardware bus, or can we extend the DAI driver in any clever way to
achieve that? Or is there a solution already I just don't know about?


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