[alsa-devel][PATCH 1/3] ASoC: fsl_sai: add sai master mode support

From: Zidan Wang
Date: Tue May 12 2015 - 03:06:14 EST

When sai works on master mode, set its bit clock and frame clock.

SAI has 4 MCLK source, bus clock, MCLK1, MCLK2 and MCLK3. fsl_sai_set_bclk
will select proper MCLK source, then calculate and set the bit clock divider.

After fsl_sai_set_bclk, enable the selected mclk in hw_params(), and add
hw_free() to disable the mclk.

Signed-off-by: Zidan Wang <zidan.wang@xxxxxxxxxxxxx>
---
sound/soc/fsl/fsl_sai.c | 117 ++++++++++++++++++++++++++++++++++++++++++++++--
sound/soc/fsl/fsl_sai.h | 9 +++-
2 files changed, 121 insertions(+), 5 deletions(-)

diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
index ee2671b..1ccc10d1 100644
--- a/sound/soc/fsl/fsl_sai.c
+++ b/sound/soc/fsl/fsl_sai.c
@@ -1,7 +1,7 @@
/*
* Freescale ALSA SoC Digital Audio Interface (SAI) driver.
*
- * Copyright 2012-2013 Freescale Semiconductor, Inc.
+ * Copyright 2012-2015 Freescale Semiconductor, Inc.
*
* This program is free software, you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
@@ -251,12 +251,14 @@ static int fsl_sai_set_dai_fmt_tr(struct snd_soc_dai *cpu_dai,
val_cr4 |= FSL_SAI_CR4_FSD_MSTR;
break;
case SND_SOC_DAIFMT_CBM_CFM:
+ sai->is_slave_mode = true;
break;
case SND_SOC_DAIFMT_CBS_CFM:
val_cr2 |= FSL_SAI_CR2_BCD_MSTR;
break;
case SND_SOC_DAIFMT_CBM_CFS:
val_cr4 |= FSL_SAI_CR4_FSD_MSTR;
+ sai->is_slave_mode = true;
break;
default:
return -EINVAL;
@@ -288,6 +290,79 @@ static int fsl_sai_set_dai_fmt(struct snd_soc_dai *cpu_dai, unsigned int fmt)
return ret;
}

+static int fsl_sai_set_bclk(struct snd_soc_dai *dai, bool tx, u32 freq)
+{
+ struct fsl_sai *sai = snd_soc_dai_get_drvdata(dai);
+ unsigned long clk_rate;
+ u32 savediv = 0, ratio, savesub = freq;
+ u32 id;
+ int ret = 0;
+
+ /* Don't apply to slave mode */
+ if (sai->is_slave_mode)
+ return 0;
+
+ for (id = 0; id < FSL_SAI_MCLK_MAX; id++) {
+ clk_rate = clk_get_rate(sai->mclk_clk[id]);
+ if (!clk_rate)
+ continue;
+
+ ratio = clk_rate / freq;
+
+ ret = clk_rate - ratio * freq;
+
+ /*
+ * Drop the source that can not be
+ * divided into the required rate.
+ */
+ if (ret != 0 && clk_rate / ret < 1000)
+ continue;
+
+ dev_dbg(dai->dev,
+ "ratio %d for freq %dHz based on clock %ldHz\n",
+ ratio, freq, clk_rate);
+
+ if (ratio % 2 == 0 && ratio >= 2 && ratio <= 512)
+ ratio /= 2;
+ else
+ continue;
+
+ if (ret < savesub) {
+ savediv = ratio;
+ sai->mclk_id[tx] = id;
+ savesub = ret;
+ }
+
+ if (ret == 0)
+ break;
+ }
+
+ if (savediv == 0) {
+ dev_err(dai->dev, "failed to derive required %cx rate: %d\n",
+ tx ? 'T' : 'R', freq);
+ return -EINVAL;
+ }
+
+ if ((tx && sai->synchronous[TX]) || (!tx && !sai->synchronous[RX])) {
+ regmap_update_bits(sai->regmap, FSL_SAI_RCR2,
+ FSL_SAI_CR2_MSEL_MASK,
+ FSL_SAI_CR2_MSEL(sai->mclk_id[tx]));
+ regmap_update_bits(sai->regmap, FSL_SAI_RCR2,
+ FSL_SAI_CR2_DIV_MASK, savediv - 1);
+ } else {
+ regmap_update_bits(sai->regmap, FSL_SAI_TCR2,
+ FSL_SAI_CR2_MSEL_MASK,
+ FSL_SAI_CR2_MSEL(sai->mclk_id[tx]));
+ regmap_update_bits(sai->regmap, FSL_SAI_TCR2,
+ FSL_SAI_CR2_DIV_MASK, savediv - 1);
+ }
+
+ dev_dbg(dai->dev, "best fit: clock id=%d, div=%d, deviation =%d\n",
+ sai->mclk_id[tx], savediv, savesub);
+
+ return 0;
+}
+
static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params,
struct snd_soc_dai *cpu_dai)
@@ -297,6 +372,24 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
unsigned int channels = params_channels(params);
u32 word_width = snd_pcm_format_width(params_format(params));
u32 val_cr4 = 0, val_cr5 = 0;
+ int ret;
+
+ if (!sai->is_slave_mode) {
+ ret = fsl_sai_set_bclk(cpu_dai, tx,
+ 2 * word_width * params_rate(params));
+ if (ret)
+ return ret;
+
+ /* Do not enable the clock if it is already enabled */
+ if (!(sai->mclk_streams & BIT(substream->stream))) {
+ ret = clk_prepare_enable(sai->mclk_clk[sai->mclk_id[tx]]);
+ if (ret)
+ return ret;
+
+ sai->mclk_streams |= BIT(substream->stream);
+ }
+
+ }

if (!sai->is_dsp_mode)
val_cr4 |= FSL_SAI_CR4_SYWD(word_width);
@@ -322,6 +415,22 @@ static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
return 0;
}

+static int fsl_sai_hw_free(struct snd_pcm_substream *substream,
+ struct snd_soc_dai *cpu_dai)
+{
+ struct fsl_sai *sai = snd_soc_dai_get_drvdata(cpu_dai);
+ bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
+
+ if (!sai->is_slave_mode &&
+ sai->mclk_streams & BIT(substream->stream)) {
+ clk_disable_unprepare(sai->mclk_clk[sai->mclk_id[tx]]);
+ sai->mclk_streams &= ~BIT(substream->stream);
+ }
+
+ return 0;
+}
+
+
static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd,
struct snd_soc_dai *cpu_dai)
{
@@ -428,6 +537,7 @@ static const struct snd_soc_dai_ops fsl_sai_pcm_dai_ops = {
.set_sysclk = fsl_sai_set_dai_sysclk,
.set_fmt = fsl_sai_set_dai_fmt,
.hw_params = fsl_sai_hw_params,
+ .hw_free = fsl_sai_hw_free,
.trigger = fsl_sai_trigger,
.startup = fsl_sai_startup,
.shutdown = fsl_sai_shutdown,
@@ -600,8 +710,9 @@ static int fsl_sai_probe(struct platform_device *pdev)
sai->bus_clk = NULL;
}

- for (i = 0; i < FSL_SAI_MCLK_MAX; i++) {
- sprintf(tmp, "mclk%d", i + 1);
+ sai->mclk_clk[0] = sai->bus_clk;
+ for (i = 1; i < FSL_SAI_MCLK_MAX; i++) {
+ sprintf(tmp, "mclk%d", i);
sai->mclk_clk[i] = devm_clk_get(&pdev->dev, tmp);
if (IS_ERR(sai->mclk_clk[i])) {
dev_err(&pdev->dev, "failed to get mclk%d clock: %ld\n",
diff --git a/sound/soc/fsl/fsl_sai.h b/sound/soc/fsl/fsl_sai.h
index 3466720..0662809 100644
--- a/sound/soc/fsl/fsl_sai.h
+++ b/sound/soc/fsl/fsl_sai.h
@@ -72,13 +72,15 @@

/* SAI Transmit and Recieve Configuration 2 Register */
#define FSL_SAI_CR2_SYNC BIT(30)
-#define FSL_SAI_CR2_MSEL_MASK (0xff << 26)
+#define FSL_SAI_CR2_MSEL_MASK (0x3 << 26)
#define FSL_SAI_CR2_MSEL_BUS 0
#define FSL_SAI_CR2_MSEL_MCLK1 BIT(26)
#define FSL_SAI_CR2_MSEL_MCLK2 BIT(27)
#define FSL_SAI_CR2_MSEL_MCLK3 (BIT(26) | BIT(27))
+#define FSL_SAI_CR2_MSEL(ID) ((ID) << 26)
#define FSL_SAI_CR2_BCP BIT(25)
#define FSL_SAI_CR2_BCD_MSTR BIT(24)
+#define FSL_SAI_CR2_DIV_MASK 0xff

/* SAI Transmit and Recieve Configuration 3 Register */
#define FSL_SAI_CR3_TRCE BIT(16)
@@ -120,7 +122,7 @@
#define FSL_SAI_CLK_MAST2 2
#define FSL_SAI_CLK_MAST3 3

-#define FSL_SAI_MCLK_MAX 3
+#define FSL_SAI_MCLK_MAX 4

/* SAI data transfer numbers per DMA request */
#define FSL_SAI_MAXBURST_TX 6
@@ -132,11 +134,14 @@ struct fsl_sai {
struct clk *bus_clk;
struct clk *mclk_clk[FSL_SAI_MCLK_MAX];

+ bool is_slave_mode;
bool is_lsb_first;
bool is_dsp_mode;
bool sai_on_imx;
bool synchronous[2];

+ unsigned int mclk_id[2];
+ unsigned int mclk_streams;
struct snd_dmaengine_dai_dma_data dma_params_rx;
struct snd_dmaengine_dai_dma_data dma_params_tx;
};
--
1.9.1

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