[alsa-devel] [PATCH v4] ASoC: simple-card: add Device Tree support

Mark Rutland mark.rutland at arm.com
Mon Dec 2 17:24:38 CET 2013


On Thu, Nov 21, 2013 at 12:12:13AM +0000, Kuninori Morimoto wrote:
> 
> Hi Mark Rutland
> 
> > > --------------------
> > > So, ideally.  However we have to consider the fact that the clock API
> > > isn't reliably available makes this harder than it should be.  Even
> > > among the DT using platforms at least PowerPC still uses a custom clock
> > > API.  We could just use this as a carrot to push people to convert
> > > though.
> > > ---------------------
> > 
> > I would be happier if we could unify the common clock infrastructure, it
> > would make this kind of thing a lot lessy messy. However, I'm not
> > against the system-clock-frequency property for now.
> 
> Thank you
> 
> > > OK, sorry for my English
> > 
> > Sorry for the confusion, I'll try to be less ambiguous in future :)
> > 
> > What I was trying to get at here is that if there is neither a clock or
> > a system-clock-frequency property in the device tree, dai->sysclk will
> > not have been initialised in this path. Is this a valid case, and will
> > dai->sysclk have a well-defined, sane value?
> 
> My understanding, this "dai" itself is created by devm_kzalloc()
> So, default dai->sysclk is 0.
> And, if there is no clocks, no system-clock-frequency property,
> it try of_property_read_u32() side. but it will do nothing to dai->sysclk
> in such case. so dai->sysclk is still 0, and it is very sane on this driver.
> Is this good answer ?

That sounds fine to me. Just wanted to make sure. :)

Thanks,
Mark.


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