[alsa-devel] [PATCH 3/8] ASoC: tegra: i2s: Add support for more than 2 channels

[Ben Dooks]

On 2019-09-18 09:50, Jon Hunter wrote:
> On 17/09/2019 19:12, Ben Dooks wrote:
>> From: Edward Cragg <edward.cragg at codethink.co.uk>
>> 
>> The CIF configuration and clock setting is currently hard coded for 2
>> channels. Since the hardware is capable of supporting 1-8 channels add
>> support for reading the channel count from the supplied parameters to
>> allow for better TDM support. It seems the original implementation of 
>> this
>> driver was fixed at 2 channels for simplicity, and not implementing 
>> TDM.
>> 
>> Signed-off-by: Edward Cragg <edward.cragg at codethink.co.uk>
>> [ben.dooks at codethink.co.uk: added is_tdm and channel nr check]
>> ---
>>  sound/soc/tegra/tegra30_i2s.c | 21 +++++++++++++--------
>>  sound/soc/tegra/tegra30_i2s.h |  1 +
>>  2 files changed, 14 insertions(+), 8 deletions(-)
>> 
>> diff --git a/sound/soc/tegra/tegra30_i2s.c 
>> b/sound/soc/tegra/tegra30_i2s.c
>> index b5372839f672..40bcc05a9dbb 100644
>> --- a/sound/soc/tegra/tegra30_i2s.c
>> +++ b/sound/soc/tegra/tegra30_i2s.c
>> @@ -86,14 +86,17 @@ static int tegra30_i2s_set_fmt(struct snd_soc_dai 
>> *dai,
>>  		return -EINVAL;
>>  	}
>> 
>> +	i2s->is_tdm = false;
>>  	mask |= TEGRA30_I2S_CTRL_FRAME_FORMAT_MASK |
>>  		TEGRA30_I2S_CTRL_LRCK_MASK;
>>  	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
>>  	case SND_SOC_DAIFMT_DSP_A:
>> +		i2s->is_tdm = true;
>>  		val |= TEGRA30_I2S_CTRL_FRAME_FORMAT_FSYNC;
>>  		val |= TEGRA30_I2S_CTRL_LRCK_L_LOW;
>>  		break;
>>  	case SND_SOC_DAIFMT_DSP_B:
>> +		i2s->is_tdm = true;
>>  		val |= TEGRA30_I2S_CTRL_FRAME_FORMAT_FSYNC;
>>  		val |= TEGRA30_I2S_CTRL_LRCK_R_LOW;
>>  		break;
>> @@ -127,10 +130,13 @@ static int tegra30_i2s_hw_params(struct 
>> snd_pcm_substream *substream,
>>  	struct device *dev = dai->dev;
>>  	struct tegra30_i2s *i2s = snd_soc_dai_get_drvdata(dai);
>>  	unsigned int mask, val, reg;
>> -	int ret, sample_size, srate, i2sclock, bitcnt, audio_bits;
>> +	int ret, sample_size, srate, i2sclock, bitcnt, audio_bits, channels;
>>  	struct tegra30_ahub_cif_conf cif_conf;
>> 
>> -	if (params_channels(params) != 2)
>> +	channels = params_channels(params);
>> +	if (channels > 8)
>> +		return -EINVAL;
>> +	if (channels != 2 && !i2s->is_tdm)
> 
> I don't think that this additional test is really necessary. I would
> just drop this 'is_tdm' variable.

I needed it elsewhere so would prefer to leave this here.