Re: [alsa-devel] [PATCHv2 6/6] ASoC: OMAP4: Add McPDM platform driver

[Liam Girdwood <lrg@slimlogic.co.uk>]

On Tue, 2010-01-26 at 10:27 +0200, Jarkko Nikula wrote:
> Hi
> 
> On Mon, 25 Jan 2010 15:06:44 -0600
> "Candelaria Villareal, Jorge" <jorge.candelaria@ti.com> wrote:
> 
> > > > +static int omap_mcpdm_dai_startup(struct snd_pcm_substream 
> > > *substream,
> > > > +				  struct snd_soc_dai *dai)
> > > > +{
> > > > +	struct snd_soc_pcm_runtime *rtd = substream->private_data;
> > > > +	struct snd_soc_dai *cpu_dai = rtd->dai->cpu_dai;
> > > > +	int err = 0;
> > > > +
> > > > +	if (!cpu_dai->active)
> > > > +		err = omap_mcpdm_request();
> > > 
> > > Will anything else use this hw interface other than ALSA audio ?
> > > If not, the request is probably better in the machine driver probe().
> > 
> > omap_mcpdm_request will enable the functional clock. Isn't it better
> > for the clock to be enabled only when is about to get used?
> > 
> Definitely yes if there is no any need to keep block active after the
> request. That would help the power-management if there are no active
> clocks when the streams are suspended with omap_mcpdm_stop() but the
> block remains reserved (i.e. omap_mcpdm_free is not called).


Ah ok, it seems that some other platforms have similar get_resource_x()
functions that do not additionally call their clk_enable_resource_x().
(last time I looked).

This is fine.

Liam