Re: [PATCH] ASoC: fsl-asoc-card: add wm8960 support

[Nicolin Chen <nicoleotsuka@gmail.com>]

Hi Shawn,

   Sorry for my late reply.

On Sun, Sep 06, 2015 at 07:33:44PM +0800, Shawn Guo wrote:
> On Fri, Aug 14, 2015 at 02:22:53AM -0700, Nicolin Chen wrote:
> > I have to add Shawn for help :)
> > 
> > On Fri, Aug 14, 2015 at 03:38:16PM +0800, Zidan Wang wrote:
> > 
> > > ccm ----->1------------------>2<------------>3
> > > 	  |                   |
> > >     	  |                   |		
> > > 	  4 SAIx MCLK1        5 SAIx MCLK2
> > > 
> > > If this bit is set, the clock route is ccm->1->2->3, 2 to 5 is disconnect.
> > > If this bit is clear, the clock route is 3->2->5, 1 to 2 is disconnect.
> > 
> > @Shawn
> > 
> > Suppose 1 and 2 are clock MUXs that we can't specifically touch
> > via registers. And 3 is an IO PAD that can either output a clock
> > from CCM or input a clock from an external source outside SoC.
> > Both 4 and 5 are two clock sources for one single SAI, SAI2 for
> > example.
> > 
> > There is a bit in the GPR register to control above routes. And
> > my question is where should be the best place to put this bit.
> 
> If this route selection is a decision of board design, it should fit
> device tree quite well.  As the platform maintainer, I surely hope we
> can handle this in audio driver.  But if there is really no place better
> than platform code to handle it, I can accept it.

I understand your concern. This route decides the source of mclk2,

955                         sai1: sai@021d4000 {
956                                 compatible = "fsl,imx6sx-sai";
957                                 reg = <0x021d4000 0x4000>;
958                                 interrupts = <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>;
959                                 clocks = <&clks IMX6SX_CLK_SAI1_IPG>,
960                                          <&clks IMX6SX_CLK_SAI1>,
961                                          <&clks 0>, <&clks 0>;
962                                 clock-names = "bus", "mclk1", "mclk2", "mclk3";

So it doesn't make sense to me if putting it in the audio driver as
it then would be out of the clock tree.

I'm not familiar with the current platform code. Is that possible we
put it in the clock tree? Would you please give me and Zidan another
hint for the implementation?

Thanks a lot
Nicolin