[alsa-devel] SAIF configuration on imx28

[Dong Aisheng]

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