[RFC 10/12] omap: mcbsp: Move sidetone clock management to mach-omap2/mcbsp.c
paul at pwsan.com
Fri Jul 1 05:23:49 EDT 2011
On Fri, 1 Jul 2011, Jarkko Nikula wrote:
> Active sidetone requires that McBSP interface clock doesn't idle and there
> is no mechanism in hwmod to turn autoidling on/off in runtime. McBSP2 and 3
> in OMAP34xx share their interface clock with McBSP sidetone module and
> that interface clock must be active when the sidetone is operating.
> Sidetone has its own autoidle bit which should keep the interface clock
> active but it is broken. Putting the McBSP core to no-idle mode when the
> sidetone is active is no good either since it results to higher power
> consumption when using the threshold based DMA transfers.
In the hwmod code/data, we've got the OCPIF_SWSUP_IDLE flag that can be
set on a struct omap_hwmod_ocp_if. I think this is probably what's needed
here. The only problem is that we haven't linked that to the clock code
to deny idle on the interface clock yet (see omap_hwmod.c:_setup()).
Adding that code in, plus adding that OCPIF_SWSUP_IDLE flag to the
McBSP2/3 data, seems like the right approach here.
I guess we also will need some basic usecounting for denying idle in the
Otherwise these direct register manipulations of clock registers, outside
the clock code, could turn into a mess :-(
At least it makes sense to move those out of the driver and into the
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