Hello:
Okay, so after probing the various pcm lines, I think I see that the format
used for the pcm is a little bit off of what my codec likes to play nice. In
my machine/codec driver, I see that I have some lines:
/* set cpu DAI configuration */
ret = cpu_dai->dai_ops.set_fmt(cpu_dai, SND_SOC_DAIFMT_DSP_A |
SND_SOC_DAIFMT_NB_NF | SND_SOC_DAIFMT_CBS_CFS);
I believe this is where it is selecting the format. In at91-ssc.c, I see
that this format is given as:
case SND_SOC_DAIFMT_DSP_A | SND_SOC_DAIFMT_CBS_CFS:
/*
* DSP/PCM Mode A format, SSC provides BCLK and LRC clocks.
*
* The SSC transmit and receive clocks are generated from the
* MCK divider, and the BCLK signal is output on the SSC TK line.
*/
rcmr = (( ssc_p->rcmr_period << 24) & AT91_SSC_PERIOD)
| (( 1 << 16) & AT91_SSC_STTDLY)
| (( AT91_SSC_START_RISING_RF ) & AT91_SSC_START)
| (( AT91_SSC_CK_RISING ) & AT91_SSC_CKI)
| (( AT91_SSC_CKO_NONE ) & AT91_SSC_CKO)
| (( AT91_SSC_CKS_DIV ) & AT91_SSC_CKS);
rfmr = (( AT91_SSC_FSEDGE_POSITIVE ) & AT91_SSC_FSEDGE)
| (( AT91_SSC_FSOS_POSITIVE ) & AT91_SSC_FSOS)
| (( 0 << 16) & AT91_SSC_FSLEN)
| (((channels - 1) << 8) & AT91_SSC_DATNB)
| (( 1 << 7) & AT91_SSC_MSBF)
| (( 0 << 5) & AT91_SSC_LOOP)
| (((bits - 1) << 0) & AT91_SSC_DATALEN);
tcmr = (( ssc_p->tcmr_period << 24) & AT91_SSC_PERIOD)
| (( 1 << 16) & AT91_SSC_STTDLY)
| (( AT91_SSC_START_RISING_RF ) & AT91_SSC_START)
| (( AT91_SSC_CK_RISING ) & AT91_SSC_CKI)
| (( AT91_SSC_CKO_CONTINUOUS ) & AT91_SSC_CKO)
| (( AT91_SSC_CKS_DIV ) & AT91_SSC_CKS);
tfmr = (( AT91_SSC_FSEDGE_POSITIVE ) & AT91_SSC_FSEDGE)
| (( 0 << 23) & AT91_SSC_FSDEN)
| (( AT91_SSC_FSOS_POSITIVE ) & AT91_SSC_FSOS)
| (( 0 << 16) & AT91_SSC_FSLEN)
| (((channels - 1) << 8) & AT91_SSC_DATNB)
| (( 1 << 7) & AT91_SSC_MSBF)
| (( 0 << 5) & AT91_SSC_DATDEF)
| (((bits - 1) << 0) & AT91_SSC_DATALEN);
break;
I should have caught this before--I spent enough time dealing with the HW
registers. The simple ssc pcm driver I wrote sets the regs a little
differently to get the peak performance out of the codec, e.g.
In RCMR, I have STTDLY=0, AT91_SSC_CKI_FALLING, AT91_SSC_CKS_PIN.
In RFMR everything looks okay except that I have FSOS_NONE as I borrow it
from TF0
In TCMR the STTDLY=0 in mine
In TFMR I do nothing with the FSEDGE and FSDEN and I have FSLEN=7 and
DATADEF=1.
So, I left with a decision. Do I add a mode or do I modify DSP A to fit my
needs? I am not sure how much coding it would take to add a mode--I *do*
know it would take little time to modify DSP A, but I am reluctant to make a
change to something that is probably 'standard'.
Any thoughts on this?
Paul
--
***************************************
Paul David Kavan
Project Engineer
GRH Electronics, Inc.
402-734-4900
pkavan@xxxxxxxxx
***************************************
_______________________________________________
Alsa-devel mailing list
Alsa-devel@xxxxxxxxxxxxxxxx
http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
