[alsa-devel] SAIF configuration on imx28

[George Stefan]

2012/8/23 Dong Aisheng <b29396 at freescale.com>

> On Thu, Aug 23, 2012 at 03:13:11PM +0800, George Stefan wrote:
> >    2012/8/23 Dong Aisheng <b29396 at freescale.com>
> >
> >      On Thu, Aug 23, 2012 at 02:41:30PM +0800, George Stefan wrote:
> >      ...
> >      >    /*set the saif clk mux, saif0/saif1 both use saif0 clk*/
> >      >    __raw_writel(BF_DIGCTL_CTRL_SAIF_CLKMUX_SEL(0x0),
>   \
> >      Should this be 0x2 if both saif0 and saif1 are using saif0 clk?
> >      >    IO_ADDRESS(DIGCTL_PHYS_ADDR) + HW_DIGCTL_CTRL);
> >      >    Using this configuration i am not able to receive IRQs from
> DMA and
> >      i
> >      >    think the reason
> >      >    is that SAIF is not receiving the CLK.
> >      >    What do you think?
> >      >    Thanks,
> >      >    George.
> >
> >      Regards
> >      Dong Aisheng
> >
> >    Yes, it should be 0x2 if they are using saif0 clk. but it they are
> using
> >    the CLK from an external device
> >    which is master, i think that they should use an independent clock.
> >    "In slave clocking mode, the SAIF configures the BITCLK and LRCLK
> pins as
> >    inputs, and
> >    the off-chip codec is responsible for driving both clocks to the
> >    SAIF"(imx28 reference manual)
> >    0x0 - DIRECT - SAIF0 clock pins selected for SAIF0 input clocks, and
> SAIF1
> >    clock pins selected for
> >    SAIF1 input clocks.
> >    Am i interpreting this in the wrong way?
> Your understand is right if all are working on slave mode.
> But be noted that the current driver in mainline only supports master mode,
> mainly due to playback can not work on slave mode(see spec) while capture
> can.
> If all are in slave mode, that means the playback may not work.
> You should make sure if your requirements really wants that.
> And if you want to run in slave mode, you need change the mainline driver
> to support it.
>
> Regards
> Dong Aisheng
>
> The problem in using SAIF as master, is that in slave mode the modem uses
short frame sync(SND_SOC_DAIFMT_DSP_A),
which is not supported in the current driver.