[alsa-devel] [PATCH v2] ASoC: Intel: Add Cherrytrail & Braswell machine driver cht_bsw_rt5672

[Lin, Mengdong]

Hi Mark,

I've posted the v3 patch. Would you please have a review?

There are other Intel machine drivers submitted at the same time, hope they
can be integrated smoothly to avoid conflict on Kconfig and Makefile.

Thanks
Mengdong

> -----Original Message-----
> From: alsa-devel-bounces at alsa-project.org
> [mailto:alsa-devel-bounces at alsa-project.org] On Behalf Of Lin, Mengdong
> Sent: Monday, November 03, 2014 8:11 PM
> To: Mark Brown
> Cc: Koul, Vinod; alsa-devel at alsa-project.org; Prusty, Subhransu S; Girdwood,
> Liam R
> Subject: Re: [alsa-devel] [PATCH v2] ASoC: Intel: Add Cherrytrail & Braswell
> machine driver cht_bsw_rt5672
> 
> > -----Original Message-----
> > From: Mark Brown [mailto:broonie at kernel.org]
> > Sent: Friday, October 31, 2014 8:54 PM
> 
> > On Fri, Oct 31, 2014 at 12:48:26PM +0000, Lin, Mengdong wrote:
> >
> > > Now we're working with Realtek to enable runtime PM on RT5672 codec
> > driver.
> > > With help of ACPI,
> > > - the codec will be in suspended to D3 when idle , switch to its
> > > internal clock,  and BIOS will turn off the platform clock output
> > > (MCLK) to
> > save power.
> > > - And when the codec resumes to D0, BIOS will turn on the clock at
> > > first. And  hw_params will make the codec use PLL and lock to MCLK again.
> >
> > > Thus the machine driver does not need to explicitly turn on/off the
> > > platform codec by itself.
> >
> > If the machine driver has asked for the PLL to be on I'd expect the
> > CODEC driver to be respecting that...
> 
> The codec driver rt5670 defines a supply widget to control the power of PLL.
> So the PLL will be power on when there is active audio streaming and power off
> when Idle.
> The machine driver need not explicitly turn on/off the PLL, but only need to
> select PLL source to MCLK in hw_params and configure the in/out frequency.
> 
> And we've verified to enable runtime PM on the codec driver and trigger ACPI
> method to dynamically control the MCLK output from SOC to the codec:
> - When codec is active (D0), BIOS will turn on MCLK at first
> - When codec is suspended on idle (D3), codec will switch to its internal clock,
> and BIOS will turn off MCLK
> 
> I'll post V3 machine driver based on your comments on v2.
> After an internal sync, this machine driver will be moved to sound/soc/intel
> directory, with other existing Intel machines.
> 
> Thanks
> Mengdong
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