Re: [alsa-devel] atmel SSC DSP A mode
On 03.06.2019 13:19, Willem Romkes wrote:
Hi,
We are using linux-at91 and lately I have been working on adding support for a custom soundcard, a dual tlv320aic3x codec on SAMA5D3 platform. This soundcard uses DSP A mode.
We are facing audio issues: When we playback a WAV file with a sine wave, the codec outputs far from a clean sine wave. The problem I think is that the CKI settings for the TMCR register isn't set correctly. see commit 20cf2603b122bf71fb54def1de6a2ad73d5ddb0b Author: Bo Shen voice.shen@atmel.com Date: Fri Jan 30 17:38:42 2015 +0800
ASoC: atmel_ssc_dai: fix the setting for DSP mode
When SCC work in DSP A mode, the data outputs/inputs are shift out on falling edge, the frame sync are sample on the rising edge.
Reported-by: Songjun Wu songjun.wu@atmel.com Signed-off-by: Bo Shen voice.shen@atmel.com Signed-off-by: Mark Brown broonie@kernel.org
diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c index e691aab..35e44e4 100644 --- a/sound/soc/atmel/atmel_ssc_dai.c +++ b/sound/soc/atmel/atmel_ssc_dai.c @@ -502,7 +502,7 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream, rcmr = SSC_BF(RCMR_PERIOD, ssc_p->rcmr_period) | SSC_BF(RCMR_STTDLY, 1) | SSC_BF(RCMR_START, SSC_START_RISING_RF) - | SSC_BF(RCMR_CKI, SSC_CKI_RISING) + | SSC_BF(RCMR_CKI, SSC_CKI_FALLING) | SSC_BF(RCMR_CKO, SSC_CKO_NONE) | SSC_BF(RCMR_CKS, SSC_CKS_DIV);
@@ -517,7 +517,7 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream, tcmr = SSC_BF(TCMR_PERIOD, ssc_p->tcmr_period) | SSC_BF(TCMR_STTDLY, 1) | SSC_BF(TCMR_START, SSC_START_RISING_RF) - | SSC_BF(TCMR_CKI, SSC_CKI_RISING) + | SSC_BF(TCMR_CKI, SSC_CKI_FALLING) | SSC_BF(TCMR_CKO, SSC_CKO_CONTINUOUS) | SSC_BF(TCMR_CKS, SSC_CKS_DIV);
@@ -546,7 +546,7 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream, rcmr = SSC_BF(RCMR_PERIOD, 0) | SSC_BF(RCMR_STTDLY, START_DELAY) | SSC_BF(RCMR_START, SSC_START_RISING_RF) - | SSC_BF(RCMR_CKI, SSC_CKI_RISING) + | SSC_BF(RCMR_CKI, SSC_CKI_FALLING) | SSC_BF(RCMR_CKO, SSC_CKO_NONE) | SSC_BF(RCMR_CKS, ssc->clk_from_rk_pin ? SSC_CKS_PIN : SSC_CKS_CLOCK);
For both the TCMR and RCMR the CKI is set to SSC_CKI_FALLING, but I think for the TCMR the CKI should be set to SSC_CKI_RISING. See datasheet:
TCMR CKI: "1: The data outputs (Data and Frame Sync signals) are shifted out on Transmit Clock rising edge. The Frame sync signal input is sampled on Transmit clock falling edge."
RCMR CKI: "0: The data inputs (Data and Frame Sync signals) are sampled on Receive Clock falling edge. The Frame Sync signal out- put is shifted out on Receive Clock rising edge."
Setting the CKI in TCMR to SSC_CKI_RISING to fixes our issues.
Hi Willem,
It this DS of the codec you are using? http://www.ti.com/lit/ds/symlink/tlv320aic33.pdf
Are you using the DSP mode described in figure 25 DSP Serial Bus Mode Operation? If yes, then you should use the DSP_B mode...
Thanks and best regards, Codrin
Hi Codrin,
Thank you for responding.
We are using the tlv320aic3107 with the tlv320aic3x codec driver. You are correct that we could use DSP B mode. but the atmel_ssc_dai driver doesn't support DSP B mode. On the other hand, the tlv320aic3x driver does support DSP A mode where it just applies an offset of one bit.
I have continued investigating this issue and I think the whole issue is caused by our soundcard driver setting the SND_SOC_DAIFMT_IB_NF in the DAI format, which is correct if I refer to figure 25 of the tlv320aic33 datasheet and the tlv320aic3x driver. The atmel_ssc_dai driver however doesn't check on this and has the clock settings hard-coded and in the current master branch it expects you to use SND_SOC_DAIFMT_NB_NF instead. It would be a good idea to add support for the different SND_SOC_DAIFMT_xB_xF DAI formats to the atmel_ssc_dai driver.
Best regards,
--- Willem Romkes Rose Engineering Services
M 06-48013381
E willemromkes@rose-es.nl
I www.rose-es.nl
On 03-06-2019 18:05, Codrin.Ciubotariu@microchip.com wrote:
On 03.06.2019 13:19, Willem Romkes wrote:
Hi,
We are using linux-at91 and lately I have been working on adding support for a custom soundcard, a dual tlv320aic3x codec on SAMA5D3 platform. This soundcard uses DSP A mode.
We are facing audio issues: When we playback a WAV file with a sine wave, the codec outputs far from a clean sine wave. The problem I think is that the CKI settings for the TMCR register isn't set correctly. see commit 20cf2603b122bf71fb54def1de6a2ad73d5ddb0b Author: Bo Shen voice.shen@atmel.com Date: Fri Jan 30 17:38:42 2015 +0800
ASoC: atmel_ssc_dai: fix the setting for DSP mode
When SCC work in DSP A mode, the data outputs/inputs are shift out on falling edge, the frame sync are sample on the rising edge.
Reported-by: Songjun Wu songjun.wu@atmel.com Signed-off-by: Bo Shen voice.shen@atmel.com Signed-off-by: Mark Brown broonie@kernel.org
diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c index e691aab..35e44e4 100644 --- a/sound/soc/atmel/atmel_ssc_dai.c +++ b/sound/soc/atmel/atmel_ssc_dai.c @@ -502,7 +502,7 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream, rcmr = SSC_BF(RCMR_PERIOD, ssc_p->rcmr_period) | SSC_BF(RCMR_STTDLY, 1) | SSC_BF(RCMR_START, SSC_START_RISING_RF)
| SSC_BF(RCMR_CKI, SSC_CKI_RISING)
| SSC_BF(RCMR_CKI, SSC_CKI_FALLING)| SSC_BF(RCMR_CKO, SSC_CKO_NONE) | SSC_BF(RCMR_CKS, SSC_CKS_DIV);
@@ -517,7 +517,7 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream, tcmr = SSC_BF(TCMR_PERIOD, ssc_p->tcmr_period) | SSC_BF(TCMR_STTDLY, 1) | SSC_BF(TCMR_START, SSC_START_RISING_RF)
| SSC_BF(TCMR_CKI, SSC_CKI_RISING)
| SSC_BF(TCMR_CKI, SSC_CKI_FALLING)| SSC_BF(TCMR_CKO, SSC_CKO_CONTINUOUS) | SSC_BF(TCMR_CKS, SSC_CKS_DIV);
@@ -546,7 +546,7 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream, rcmr = SSC_BF(RCMR_PERIOD, 0) | SSC_BF(RCMR_STTDLY, START_DELAY) | SSC_BF(RCMR_START, SSC_START_RISING_RF)
| SSC_BF(RCMR_CKI, SSC_CKI_RISING)
| SSC_BF(RCMR_CKI, SSC_CKI_FALLING)| SSC_BF(RCMR_CKO, SSC_CKO_NONE) | SSC_BF(RCMR_CKS, ssc->clk_from_rk_pin ? SSC_CKS_PIN : SSC_CKS_CLOCK);
For both the TCMR and RCMR the CKI is set to SSC_CKI_FALLING, but I think for the TCMR the CKI should be set to SSC_CKI_RISING. See datasheet:
TCMR CKI: "1: The data outputs (Data and Frame Sync signals) are shifted out on Transmit Clock rising edge. The Frame sync signal input is sampled on Transmit clock falling edge."
RCMR CKI: "0: The data inputs (Data and Frame Sync signals) are sampled on Receive Clock falling edge. The Frame Sync signal out- put is shifted out on Receive Clock rising edge."
Setting the CKI in TCMR to SSC_CKI_RISING to fixes our issues.
Hi Willem,
It this DS of the codec you are using? http://www.ti.com/lit/ds/symlink/tlv320aic33.pd [1]
Are you using the DSP mode described in figure 25 DSP Serial Bus Mode Operation? If yes, then you should use the DSP_B mode...
Thanks and best regards, Codrin
Links: ------ [1] http://www.ti.com/lit/ds/symlink/tlv320aic33.pdf
participants (2)
-
Codrin.Ciubotariu＠microchip.com -
Willem Romkes