Re: [PATCH 3/3] ASoC: omap-mcbsp: Enable/disable sidetone block auto clock gating for omap3

From: Paul Walmsley
Date: Sat Mar 19 2016 - 15:37:51 EST

On Fri, 18 Mar 2016, Peter Ujfalusi wrote:

> OMAP3's McBSP2 and McBSP3 module have integrated sidetone block with
> dedicated SYSCONFIG register. The sidetone is operating from the maain
> McBSP module's ICLK. For normal operation the sidetone clock auto idle
> support needs to be disabled when it is activated.
> Note: This is not enough to avoid choppy sidetone because this AUTOIDLE
> bit is controlling only the clock auto idle from the McBSP to the sidetone
> block. If the McBSP_ICLK is idling, the sidetone clock is going to do the
> same.
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>

Mark, please drop this patch for the time being, until the SoC integration
issues can be sorted out first. It's best to wait a little while before
applying patches like these so folks have a chance to comment on their
correctness first.

We used to handle this problem in the OMAP hwmod SoC integration layer
with a flag that forced the interface clock to stay active as long as the
underlying IP blocks were active. However I can't find that flag right
now in the current data, so maybe it got accidentally or inadvertently
removed at some point in time in the past. The right way to fix this
would be to add that flag back in, rather than messing with the SoC
integration registers from the McBSP drivers.


- Paul