[alsa-devel] [PATCH 4/4] ASoC: tegra: i2s: Add support for more than 2 channels

[Jorge Sanjuan]

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>
Signed-off-by: Jorge Sanjuan <jorge.sanjuan at codethink.co.uk>
---
 sound/soc/tegra/tegra30_i2s.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/sound/soc/tegra/tegra30_i2s.c b/sound/soc/tegra/tegra30_i2s.c
index e26c19ef7439..0f240d7989d0 100644
--- a/sound/soc/tegra/tegra30_i2s.c
+++ b/sound/soc/tegra/tegra30_i2s.c
@@ -138,16 +138,17 @@ 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;
+	int ret, sample_size, srate, i2sclock, bitcnt, audio_bits, channels;
 	struct tegra30_ahub_cif_conf cif_conf;
 
-	if (params_channels(params) != 2)
+	if (params_channels(params) > 8)
 		return -EINVAL;
 
 	mask = TEGRA30_I2S_CTRL_BIT_SIZE_MASK;
 	switch (params_format(params)) {
 	case SNDRV_PCM_FORMAT_S16_LE:
 		val = TEGRA30_I2S_CTRL_BIT_SIZE_16;
+		audio_bits = TEGRA30_AUDIOCIF_BITS_16;
 		sample_size = 16;
 		break;
 	case SNDRV_PCM_FORMAT_S24_LE:
@@ -157,6 +158,7 @@ static int tegra30_i2s_hw_params(struct snd_pcm_substream *substream,
 		break;
 	case SNDRV_PCM_FORMAT_S32_LE:
 		val = TEGRA30_I2S_CTRL_BIT_SIZE_32;
+		audio_bits = TEGRA30_AUDIOCIF_BITS_32;
 		sample_size = 32;
 		break;
 	default:
@@ -166,9 +168,10 @@ static int tegra30_i2s_hw_params(struct snd_pcm_substream *substream,
 	regmap_update_bits(i2s->regmap, TEGRA30_I2S_CTRL, mask, val);
 
 	srate = params_rate(params);
+	channels = params_channels(params);
 
 	/* Final "* 2" required by Tegra hardware */
-	i2sclock = srate * params_channels(params) * sample_size * 2;
+	i2sclock = srate * channels * sample_size * 2;
 
 	bitcnt = (i2sclock / (2 * srate)) - 1;
 	if (bitcnt < 0 || bitcnt > TEGRA30_I2S_TIMING_CHANNEL_BIT_COUNT_MASK_US)
@@ -188,10 +191,10 @@ static int tegra30_i2s_hw_params(struct snd_pcm_substream *substream,
 	regmap_write(i2s->regmap, TEGRA30_I2S_TIMING, val);
 
 	cif_conf.threshold = 0;
-	cif_conf.audio_channels = 2;
-	cif_conf.client_channels = 2;
-	cif_conf.audio_bits = TEGRA30_AUDIOCIF_BITS_16;
-	cif_conf.client_bits = TEGRA30_AUDIOCIF_BITS_16;
+	cif_conf.audio_channels = channels;
+	cif_conf.client_channels = channels;
+	cif_conf.audio_bits = audio_bits;
+	cif_conf.client_bits = audio_bits;
 	cif_conf.expand = 0;
 	cif_conf.stereo_conv = 0;
 	cif_conf.replicate = 0;
@@ -329,7 +332,7 @@ static const struct snd_soc_dai_driver tegra30_i2s_dai_template = {
 	.playback = {
 		.stream_name = "Playback",
 		.channels_min = 2,
-		.channels_max = 2,
+		.channels_max = 8,
 		.rates = SNDRV_PCM_RATE_8000_96000,
 		.formats = SNDRV_PCM_FMTBIT_S32_LE |
 			   SNDRV_PCM_FMTBIT_S24_LE |
@@ -338,7 +341,7 @@ static const struct snd_soc_dai_driver tegra30_i2s_dai_template = {
 	.capture = {
 		.stream_name = "Capture",
 		.channels_min = 2,
-		.channels_max = 2,
+		.channels_max = 8,
 		.rates = SNDRV_PCM_RATE_8000_96000,
 		.formats = SNDRV_PCM_FMTBIT_S32_LE |
 			   SNDRV_PCM_FMTBIT_S24_LE |
-- 
2.11.0