Re: [alsa-devel] [PATCH] ASoC: OMAP: mcbsp: ensure that CLKX and CLKR are not used as ouput pins when they are used as input clock for the SRG.

On 01/16/2015 12:28 AM, Thomas Niederprüm wrote:

This patch fixes faulty behaviour in a setup where the input clock for the SRG is fed through the CLKR pin but the McBSP is configured to be master (SND_SOC_DAIFMT_CBS_CFS). In that case of course CLKR must not be configured as output pin. Otherwise the input clock is messed up horribly. The same reasoning applies if CLKX is configured as input for the SRG.

If CLKX/CLKR is used as input clock for McBSP then the CBS_CFS is not valid. In this case you need to use CBM_CFS.

Signed-off-by: Thomas Niederprüm niederp@physik.uni-kl.de

sound/soc/omap/omap-mcbsp.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/sound/soc/omap/omap-mcbsp.c b/sound/soc/omap/omap-mcbsp.c index bd3ef2a..c89f562 100644 --- a/sound/soc/omap/omap-mcbsp.c +++ b/sound/soc/omap/omap-mcbsp.c @@ -530,8 +530,12 @@ static int omap_mcbsp_dai_set_dai_sysclk(struct snd_soc_dai *cpu_dai,

case OMAP_MCBSP_SYSCLK_CLKX_EXT: regs->srgr2 |= CLKSM;

• regs->pcr0	|= SCLKME;
  

• regs->pcr0	&= ~CLKXM;
  

• break;
  

  case OMAP_MCBSP_SYSCLK_CLKR_EXT: regs->pcr0 |= SCLKME;

• regs->pcr0	&= ~CLKRM;
  

  break; default: err = -ENODEV;