[alsa-devel] [PATCH 1/1] ASoC: TWL4030: Add support Voice DAI

[Joonyoung Shim]

On 4/14/2009 4:07 PM, Peter Ujfalusi wrote:
> On Thursday 09 April 2009 16:54:37 ext Joonyoung Shim wrote:
>> Add Voice DAI to support the PCM voice interface of the twl4030 codec.
>>
>> The PCM voice interface can be used with 8-kHz(voice narrowband) or 16-kHz
>> (voice wideband) sampling rates, and 16bits, and mono RX and mono TX or
>> stereo TX.
>>
>> If the system master clock is not 26MHz, the voice PCM interface is not
>> available.
>>
>> The PCM voice interface has two modes
>> - PCM mode1 : This uses the rising edge of the clock signal
>> - PCM mode2 : This uses the falling edge of the clock signal
>>
>> PCM mode1 and mode2 have a look of DSP_A and DSP_B, so we used DSP_A and
>> DSP_B.
> 
> Both of the PCM mode1 and mode2 is actually DSP_A, but the FS polarity is 
> inverted and also the data is shifted/sampled on the opposite edge of the 
> bitclock.

So, I will use that the PCM mode1 is SND_SOC_DAIFMT_IB_NF and PCM mode2 is
SND_SOC_DAIFMT_NB_IF. Is this right?

> 
>> +static int twl4030_voice_startup(struct snd_pcm_substream *substream,
>> +				struct snd_soc_dai *dai)
>> +{
>> +	struct snd_soc_pcm_runtime *rtd = substream->private_data;
>> +	struct snd_soc_device *socdev = rtd->socdev;
>> +	struct snd_soc_codec *codec = socdev->card->codec;
>> +	u8 infreq;
>> +
>> +	/* If the system master clock is not 26MHz, the voice PCM interface is
>> +	 * not avilable.
>> +	 */
>> +	infreq = twl4030_read_reg_cache(codec, TWL4030_REG_APLL_CTL)
>> +		& TWL4030_APLL_INFREQ;
>> +
>> +	if (infreq != TWL4030_APLL_INFREQ_26000KHZ)
>> +		return -EPERM;
> 
> Would it be feasible to add a check here against the CODEC_MODE:OPT_MODE and 
> if the codec is not in Option2 mode, than return with error?

Ok, it's good, i will add.
Thanks.

> 
>