[alsa-devel] SAIF configuration on imx28
stefan.george87 at gmail.com
Thu Aug 23 11:15:05 CEST 2012
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
> > 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
> > 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
> 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.
> 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.
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