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

[Ben Dooks]

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)
 		return -EINVAL;
 
 	mask = TEGRA30_I2S_CTRL_BIT_SIZE_MASK;
@@ -157,9 +163,8 @@ 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);
-
 	/* 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)
@@ -179,8 +184,8 @@ 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_channels = channels;
+	cif_conf.client_channels = channels;
 	cif_conf.audio_bits = audio_bits;
 	cif_conf.client_bits = audio_bits;
 	cif_conf.expand = 0;
@@ -319,7 +324,7 @@ 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 |
@@ -328,7 +333,7 @@ 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 |
diff --git a/sound/soc/tegra/tegra30_i2s.h b/sound/soc/tegra/tegra30_i2s.h
index 0b1f3125a7c0..ae30e3c96337 100644
--- a/sound/soc/tegra/tegra30_i2s.h
+++ b/sound/soc/tegra/tegra30_i2s.h
@@ -224,6 +224,7 @@ struct tegra30_i2s {
 	const struct tegra30_i2s_soc_data *soc_data;
 	struct snd_soc_dai_driver dai;
 	int cif_id;
+	bool is_tdm;
 	struct clk *clk_i2s;
 	enum tegra30_ahub_txcif capture_i2s_cif;
 	enum tegra30_ahub_rxcif capture_fifo_cif;
-- 
2.23.0