[PATCH 1/3] ASoC: DaVinci: Added two clocking possibilities to McBSP (I2S)

[PATCH 1/3] ASoC: DaVinci: Added two clocking possibilities to McBSP (I2S)

[Raffaele Recalcati]

From: Raffaele Recalcati <raffaele.recalcati@bticino.it>

    Added two clocking options for dm365 McBSP peripheral when used
    with I2S timings, that are SND_SOC_DAIFMT_CBS_CFS (the cpu generates
    clock and frame sync) and SND_SOC_DAIFMT_CBS_CFM (the cpu gets clock
    from external pin and generates frame sync).
    A slave clock management can be important when the external codec needs
    the system clock and the bit clock synchronized (tested with uda1345).
    This patch has been developed against the:
        http://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-davinci.git
    git tree and has been tested on bmx board (similar to dm365 evm, but using
    uda1345 as external audio codec).

Signed-off-by: Raffaele Recalcati <raffaele.recalcati@bticino.it>
Signed-off-by: Davide Bonfanti <davide.bonfanti@bticino.it>
---
 sound/soc/davinci/davinci-i2s.c |   92 +++++++++++++++++++++++++++++++++++----
 1 files changed, 83 insertions(+), 9 deletions(-)

diff --git a/sound/soc/davinci/davinci-i2s.c b/sound/soc/davinci/davinci-i2s.c
index adadcd3..319e8ca 100644
--- a/sound/soc/davinci/davinci-i2s.c
+++ b/sound/soc/davinci/davinci-i2s.c
@@ -68,16 +68,21 @@
 #define DAVINCI_MCBSP_RCR_RDATDLY(v)	((v) << 16)
 #define DAVINCI_MCBSP_RCR_RFIG		(1 << 18)
 #define DAVINCI_MCBSP_RCR_RWDLEN2(v)	((v) << 21)
+#define DAVINCI_MCBSP_RCR_RFRLEN2(v)	((v) << 24)
+#define DAVINCI_MCBSP_RCR_RPHASE	(1 << 31)
 
 #define DAVINCI_MCBSP_XCR_XWDLEN1(v)	((v) << 5)
 #define DAVINCI_MCBSP_XCR_XFRLEN1(v)	((v) << 8)
 #define DAVINCI_MCBSP_XCR_XDATDLY(v)	((v) << 16)
 #define DAVINCI_MCBSP_XCR_XFIG		(1 << 18)
 #define DAVINCI_MCBSP_XCR_XWDLEN2(v)	((v) << 21)
+#define DAVINCI_MCBSP_XCR_XFRLEN2(v)	((v) << 24)
+#define DAVINCI_MCBSP_XCR_XPHASE	(1 << 31)
 
 #define DAVINCI_MCBSP_SRGR_FWID(v)	((v) << 8)
 #define DAVINCI_MCBSP_SRGR_FPER(v)	((v) << 16)
 #define DAVINCI_MCBSP_SRGR_FSGM		(1 << 28)
+#define DAVINCI_MCBSP_SRGR_CLKSM	(1 << 29)
 
 #define DAVINCI_MCBSP_PCR_CLKRP		(1 << 0)
 #define DAVINCI_MCBSP_PCR_CLKXP		(1 << 1)
@@ -144,6 +149,9 @@ struct davinci_mcbsp_dev {
 	 * won't end up being swapped because of the underrun.
 	 */
 	unsigned enable_channel_combine:1;
+
+	unsigned int fmt;
+	int clk_div;
 };
 
 static inline void davinci_mcbsp_write_reg(struct davinci_mcbsp_dev *dev,
@@ -254,10 +262,12 @@ static int davinci_i2s_set_dai_fmt(struct snd_soc_dai *cpu_dai,
 	struct davinci_mcbsp_dev *dev = cpu_dai->private_data;
 	unsigned int pcr;
 	unsigned int srgr;
+	/* Attention srgr is updated by hw_params! */
 	srgr = DAVINCI_MCBSP_SRGR_FSGM |
 		DAVINCI_MCBSP_SRGR_FPER(DEFAULT_BITPERSAMPLE * 2 - 1) |
 		DAVINCI_MCBSP_SRGR_FWID(DEFAULT_BITPERSAMPLE - 1);
 
+	dev->fmt = fmt;
 	/* set master/slave audio interface */
 	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
 	case SND_SOC_DAIFMT_CBS_CFS:
@@ -372,6 +382,16 @@ static int davinci_i2s_set_dai_fmt(struct snd_soc_dai *cpu_dai,
 	return 0;
 }
 
+static int davinci_i2s_dai_set_clkdiv(struct snd_soc_dai *cpu_dai,
+				int div_id, int div)
+{
+	struct davinci_mcbsp_dev *dev = cpu_dai->private_data;
+	int srgr;
+
+	dev->clk_div = div;
+	return 0;
+}
+
 static int davinci_i2s_hw_params(struct snd_pcm_substream *substream,
 				 struct snd_pcm_hw_params *params,
 				 struct snd_soc_dai *dai)
@@ -380,8 +400,8 @@ static int davinci_i2s_hw_params(struct snd_pcm_substream *substream,
 	struct davinci_pcm_dma_params *dma_params =
 					&dev->dma_params[substream->stream];
 	struct snd_interval *i = NULL;
-	int mcbsp_word_length;
-	unsigned int rcr, xcr, srgr;
+	int mcbsp_word_length, master;
+	unsigned int rcr, xcr, srgr, clk_div, freq, framesize;
 	u32 spcr;
 	snd_pcm_format_t fmt;
 	unsigned element_cnt = 1;
@@ -396,12 +416,44 @@ static int davinci_i2s_hw_params(struct snd_pcm_substream *substream,
 		davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG, spcr);
 	}
 
-	i = hw_param_interval(params, SNDRV_PCM_HW_PARAM_SAMPLE_BITS);
-	srgr = DAVINCI_MCBSP_SRGR_FSGM;
-	srgr |= DAVINCI_MCBSP_SRGR_FWID(snd_interval_value(i) - 1);
+	master = dev->fmt & SND_SOC_DAIFMT_MASTER_MASK;
+	fmt = params_format(params);
+	mcbsp_word_length = asp_word_length[fmt];
 
-	i = hw_param_interval(params, SNDRV_PCM_HW_PARAM_FRAME_BITS);
-	srgr |= DAVINCI_MCBSP_SRGR_FPER(snd_interval_value(i) - 1);
+	switch (master) {
+	case SND_SOC_DAIFMT_CBS_CFS:
+		freq = clk_get_rate(dev->clk);
+		srgr = DAVINCI_MCBSP_SRGR_FSGM |
+		       DAVINCI_MCBSP_SRGR_CLKSM;
+		srgr |= DAVINCI_MCBSP_SRGR_FWID(mcbsp_word_length *
+						8 - 1);
+		/* symmetric waveforms */
+		clk_div = freq / (mcbsp_word_length * 16) /
+			  params->rate_num * params->rate_den;
+		srgr |= DAVINCI_MCBSP_SRGR_FPER(mcbsp_word_length *
+						16 - 1);
+		clk_div &= 0xFF;
+		srgr |= clk_div;
+		break;
+	case SND_SOC_DAIFMT_CBM_CFS:
+		srgr = DAVINCI_MCBSP_SRGR_FSGM;
+		clk_div = dev->clk_div - 1;
+		srgr |= DAVINCI_MCBSP_SRGR_FWID(mcbsp_word_length * 8 - 1);
+		srgr |= DAVINCI_MCBSP_SRGR_FPER(mcbsp_word_length * 16 - 1);
+		clk_div &= 0xFF;
+		srgr |= clk_div;
+		break;
+	default:
+		/* Clock and frame sync given from external sources */
+		i = hw_param_interval(params, SNDRV_PCM_HW_PARAM_SAMPLE_BITS);
+		srgr = DAVINCI_MCBSP_SRGR_FSGM;
+		srgr |= DAVINCI_MCBSP_SRGR_FWID(snd_interval_value(i) - 1);
+		pr_debug("%s - %d  FWID set: re-read srgr = %X\n",
+			__func__, __LINE__, snd_interval_value(i) - 1);
+
+		i = hw_param_interval(params, SNDRV_PCM_HW_PARAM_FRAME_BITS);
+		srgr |= DAVINCI_MCBSP_SRGR_FPER(snd_interval_value(i) - 1);
+	}
 	davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SRGR_REG, srgr);
 
 	rcr = DAVINCI_MCBSP_RCR_RFIG;
@@ -426,12 +478,29 @@ static int davinci_i2s_hw_params(struct snd_pcm_substream *substream,
 			element_cnt = 1;
 			fmt = double_fmt[fmt];
 		}
+		if (master == SND_SOC_DAIFMT_CBS_CFS ||
+				master == SND_SOC_DAIFMT_CBS_CFM) {
+			rcr |= DAVINCI_MCBSP_RCR_RFRLEN2(0);
+			xcr |= DAVINCI_MCBSP_XCR_XFRLEN2(0);
+			rcr |= DAVINCI_MCBSP_RCR_RPHASE;
+			xcr |= DAVINCI_MCBSP_XCR_XPHASE;
+		} else {
+			rcr |= DAVINCI_MCBSP_RCR_RFRLEN2(element_cnt - 1);
+			xcr |= DAVINCI_MCBSP_XCR_XFRLEN2(element_cnt - 1);
+		}
 	}
 	dma_params->acnt = dma_params->data_type = data_type[fmt];
 	dma_params->fifo_level = 0;
 	mcbsp_word_length = asp_word_length[fmt];
-	rcr |= DAVINCI_MCBSP_RCR_RFRLEN1(element_cnt - 1);
-	xcr |= DAVINCI_MCBSP_XCR_XFRLEN1(element_cnt - 1);
+
+	if (master == SND_SOC_DAIFMT_CBS_CFS ||
+			master == SND_SOC_DAIFMT_CBS_CFM) {
+		rcr |= DAVINCI_MCBSP_RCR_RFRLEN1(0);
+		xcr |= DAVINCI_MCBSP_XCR_XFRLEN1(0);
+	} else {
+		rcr |= DAVINCI_MCBSP_RCR_RFRLEN1(element_cnt - 1);
+		xcr |= DAVINCI_MCBSP_XCR_XFRLEN1(element_cnt - 1);
+	}
 
 	rcr |= DAVINCI_MCBSP_RCR_RWDLEN1(mcbsp_word_length) |
 		DAVINCI_MCBSP_RCR_RWDLEN2(mcbsp_word_length);
@@ -442,6 +511,10 @@ static int davinci_i2s_hw_params(struct snd_pcm_substream *substream,
 		davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_XCR_REG, xcr);
 	else
 		davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_RCR_REG, rcr);
+
+	pr_debug("%s - %d  srgr=%X\n", __func__, __LINE__, srgr);
+	pr_debug("%s - %d  xcr=%X\n", __func__, __LINE__, xcr);
+	pr_debug("%s - %d  rcr=%X\n", __func__, __LINE__, rcr);
 	return 0;
 }
 
@@ -500,6 +573,7 @@ static struct snd_soc_dai_ops davinci_i2s_dai_ops = {
 	.trigger	= davinci_i2s_trigger,
 	.hw_params	= davinci_i2s_hw_params,
 	.set_fmt	= davinci_i2s_set_dai_fmt,
+	.set_clkdiv	= davinci_i2s_dai_set_clkdiv,
 
 };
 
-- 
1.7.0.4

Re: [PATCH 1/3] ASoC: DaVinci: Added two clocking possibilities to McBSP (I2S)

[Mark Brown]

On Wed, Jun 30, 2010 at 03:47:56PM +0200, Raffaele Recalcati wrote:

> +static int davinci_i2s_dai_set_clkdiv(struct snd_soc_dai *cpu_dai,
> +				int div_id, int div)
> +{
> +	struct davinci_mcbsp_dev *dev = cpu_dai->private_data;
> +	int srgr;
> +
> +	dev->clk_div = div;
> +	return 0;
> +}

As previously mentioned this should check the div_id argument.

> +	switch (master) {
> +	case SND_SOC_DAIFMT_CBS_CFS:

...

> +	case SND_SOC_DAIFMT_CBM_CFS:

...

> +	default:
> +		/* Clock and frame sync given from external sources */

The two remaining options (_CBM_CFM and _CBS_CFM) are different, your
description matches _CBM_CFM.

> +		if (master == SND_SOC_DAIFMT_CBS_CFS ||
> +				master == SND_SOC_DAIFMT_CBS_CFM) {

Switch statement again.

> +	if (master == SND_SOC_DAIFMT_CBS_CFS ||
> +			master == SND_SOC_DAIFMT_CBS_CFM) {
> +		rcr |= DAVINCI_MCBSP_RCR_RFRLEN1(0);
> +		xcr |= DAVINCI_MCBSP_XCR_XFRLEN1(0);
> +	} else {

...and another.  Please fix all these.

[PATCH 2/3] ASoC: DaVinci: Added selection of clk input pin for McBSP

[Raffaele Recalcati]

From: Raffaele Recalcati <raffaele.recalcati@bticino.it>

    When McBSP peripheral gets the clock from an external pin,
    there are three possible chooses, MCBSP_CLKX, MCBSP_CLKR
    and MCBSP_CLKS.
    evm-dm365 uses MCBSP_CLKR, instead in bmx board I have a different
    hardware connection and I use MCBSP_CLKS, so I have added
    this possibility.

    This patch has been developed against the:
        http://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-davinci.git
    git tree and has been tested on bmx board (similar to dm365 evm)

Signed-off-by: Raffaele Recalcati <raffaele.recalcati@bticino.it>
Signed-off-by: Davide Bonfanti <davide.bonfanti@bticino.it>
---
 arch/arm/mach-davinci/include/mach/asp.h |    8 ++++++++
 sound/soc/davinci/davinci-i2s.c          |   28 +++++++++++++++++++++++-----
 2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/arch/arm/mach-davinci/include/mach/asp.h b/arch/arm/mach-davinci/include/mach/asp.h
index 834725f..314570d 100644
--- a/arch/arm/mach-davinci/include/mach/asp.h
+++ b/arch/arm/mach-davinci/include/mach/asp.h
@@ -63,6 +63,9 @@ struct snd_platform_data {
 	unsigned sram_size_playback;
 	unsigned sram_size_capture;
 
+	/* To be used when cpu gets clock from external pin */
+	int clk_input_pin;
+
 	/* McASP specific fields */
 	int tdm_slots;
 	u8 op_mode;
@@ -78,6 +81,11 @@ enum {
 	MCASP_VERSION_2,	/* DA8xx/OMAPL1x */
 };
 
+enum {
+	MCBSP_CLKR = 0,		/* DM365 */
+	MCBSP_CLKS,
+};
+
 #define INACTIVE_MODE	0
 #define TX_MODE		1
 #define RX_MODE		2
diff --git a/sound/soc/davinci/davinci-i2s.c b/sound/soc/davinci/davinci-i2s.c
index 319e8ca..e478be9 100644
--- a/sound/soc/davinci/davinci-i2s.c
+++ b/sound/soc/davinci/davinci-i2s.c
@@ -152,6 +152,7 @@ struct davinci_mcbsp_dev {
 
 	unsigned int fmt;
 	int clk_div;
+	int clk_input_pin;
 };
 
 static inline void davinci_mcbsp_write_reg(struct davinci_mcbsp_dev *dev,
@@ -278,11 +279,26 @@ static int davinci_i2s_set_dai_fmt(struct snd_soc_dai *cpu_dai,
 			DAVINCI_MCBSP_PCR_CLKRM;
 		break;
 	case SND_SOC_DAIFMT_CBM_CFS:
-		/* McBSP CLKR pin is the input for the Sample Rate Generator.
-		 * McBSP FSR and FSX are driven by the Sample Rate Generator. */
-		pcr = DAVINCI_MCBSP_PCR_SCLKME |
-			DAVINCI_MCBSP_PCR_FSXM |
-			DAVINCI_MCBSP_PCR_FSRM;
+		pcr = DAVINCI_MCBSP_PCR_FSRM | DAVINCI_MCBSP_PCR_FSXM;
+		/*
+		 * Selection of the clock input pin that is the
+		 * input for the Sample Rate Generator.
+		 * McBSP FSR and FSX are driven by the Sample Rate
+		 * Generator.
+		 */
+		switch (dev->clk_input_pin) {
+		case MCBSP_CLKS:
+			pcr |= DAVINCI_MCBSP_PCR_CLKXM |
+				DAVINCI_MCBSP_PCR_CLKRM;
+			break;
+		case MCBSP_CLKR:
+			pcr |= DAVINCI_MCBSP_PCR_SCLKME;
+			break;
+		default:
+			printk(KERN_ERR "%s:bad clk_input_pin\n", __func__);
+			return -EINVAL;
+		}
+
 		break;
 	case SND_SOC_DAIFMT_CBM_CFM:
 		/* codec is master */
@@ -436,6 +452,7 @@ static int davinci_i2s_hw_params(struct snd_pcm_substream *substream,
 		srgr |= clk_div;
 		break;
 	case SND_SOC_DAIFMT_CBM_CFS:
+		/* Clock given on CLKS */
 		srgr = DAVINCI_MCBSP_SRGR_FSGM;
 		clk_div = dev->clk_div - 1;
 		srgr |= DAVINCI_MCBSP_SRGR_FWID(mcbsp_word_length * 8 - 1);
@@ -626,6 +643,7 @@ static int davinci_i2s_probe(struct platform_device *pdev)
 			pdata->sram_size_playback;
 		dev->dma_params[SNDRV_PCM_STREAM_CAPTURE].sram_size =
 			pdata->sram_size_capture;
+		dev->clk_input_pin = pdata->clk_input_pin;
 	}
 	dev->clk = clk_get(&pdev->dev, NULL);
 	if (IS_ERR(dev->clk)) {
-- 
1.7.0.4

Re: [PATCH 2/3] ASoC: DaVinci: Added selection of clk input pin for McBSP

[Mark Brown]

On Wed, Jun 30, 2010 at 03:47:57PM +0200, Raffaele Recalcati wrote:

> +	/* To be used when cpu gets clock from external pin */
> +	int clk_input_pin;
> +

As previously indicated please say how to use this.

> +		default:
> +			printk(KERN_ERR "%s:bad clk_input_pin\n", __func__);

Use dev_err().

[PATCH 3/3] ASoC: DaVinci: Added fast clock timing for McBSP (I2S)

[Raffaele Recalcati]

From: Raffaele Recalcati <raffaele.recalcati@bticino.it>

    i2s_fast_clock switch can be used to have a better approximate
    frequency.
    The waveform will be not symmetric.

    This patch has been developed against the
        http://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-davinci.git
    git tree and has been tested on bmx board (similar to dm365 evm, but using
    uda1345 as external audio codec).

Signed-off-by: Raffaele Recalcati <raffaele.recalcati@bticino.it>
Signed-off-by: Davide Bonfanti <davide.bonfanti@bticino.it>
---
 arch/arm/mach-davinci/include/mach/asp.h |    7 +++++++
 sound/soc/davinci/davinci-i2s.c          |   24 +++++++++++++++++++-----
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/arch/arm/mach-davinci/include/mach/asp.h b/arch/arm/mach-davinci/include/mach/asp.h
index 314570d..2d8f8af 100644
--- a/arch/arm/mach-davinci/include/mach/asp.h
+++ b/arch/arm/mach-davinci/include/mach/asp.h
@@ -63,6 +63,13 @@ struct snd_platform_data {
 	unsigned sram_size_playback;
 	unsigned sram_size_capture;
 
+	/*
+	 * This define works when both clock and FS are output for the cpu
+	 * and makes clock very fast (FS is not symmetrical, but sampling
+	 * frequency is better approximated
+	 */
+	bool i2s_fast_clock;
+
 	/* To be used when cpu gets clock from external pin */
 	int clk_input_pin;
 
diff --git a/sound/soc/davinci/davinci-i2s.c b/sound/soc/davinci/davinci-i2s.c
index e478be9..0af5bae 100644
--- a/sound/soc/davinci/davinci-i2s.c
+++ b/sound/soc/davinci/davinci-i2s.c
@@ -150,6 +150,7 @@ struct davinci_mcbsp_dev {
 	 */
 	unsigned enable_channel_combine:1;
 
+	bool i2s_fast_clock;
 	unsigned int fmt;
 	int clk_div;
 	int clk_input_pin;
@@ -443,11 +444,23 @@ static int davinci_i2s_hw_params(struct snd_pcm_substream *substream,
 		       DAVINCI_MCBSP_SRGR_CLKSM;
 		srgr |= DAVINCI_MCBSP_SRGR_FWID(mcbsp_word_length *
 						8 - 1);
-		/* symmetric waveforms */
-		clk_div = freq / (mcbsp_word_length * 16) /
-			  params->rate_num * params->rate_den;
-		srgr |= DAVINCI_MCBSP_SRGR_FPER(mcbsp_word_length *
-						16 - 1);
+		if (dev->i2s_fast_clock) {
+			clk_div = 256;
+			do {
+				framesize = (freq / (--clk_div)) /
+					    params->rate_num *
+					    params->rate_den;
+			} while (((framesize < 33) || (framesize > 4095)) &&
+				 (clk_div));
+			clk_div--;
+			srgr |= DAVINCI_MCBSP_SRGR_FPER(framesize - 1);
+		} else {
+			/* symmetric waveforms */
+			clk_div = freq / (mcbsp_word_length * 16) /
+				  params->rate_num * params->rate_den;
+			srgr |= DAVINCI_MCBSP_SRGR_FPER(mcbsp_word_length *
+							16 - 1);
+		}
 		clk_div &= 0xFF;
 		srgr |= clk_div;
 		break;
@@ -643,6 +656,7 @@ static int davinci_i2s_probe(struct platform_device *pdev)
 			pdata->sram_size_playback;
 		dev->dma_params[SNDRV_PCM_STREAM_CAPTURE].sram_size =
 			pdata->sram_size_capture;
+		dev->i2s_fast_clock = pdata->i2s_fast_clock;
 		dev->clk_input_pin = pdata->clk_input_pin;
 	}
 	dev->clk = clk_get(&pdev->dev, NULL);
-- 
1.7.0.4

Re: [PATCH 3/3] ASoC: DaVinci: Added fast clock timing for McBSP (I2S)

[Mark Brown]

On Wed, Jun 30, 2010 at 03:47:58PM +0200, Raffaele Recalcati wrote:

> +	/*
> +	 * This define works when both clock and FS are output for the cpu
> +	 * and makes clock very fast (FS is not symmetrical, but sampling
> +	 * frequency is better approximated
> +	 */
> +	bool i2s_fast_clock;

I'm having a hard time following the description here - which clock is
being made very fast?  The output clocks, which are the ones people can
observe, will presumably not suddenly start running very fast.

It's probably better to rename this option to reflect the actual
function (trading off between frequency accuracy and mark/space ratio)
rather than the way it's implemented internally.

> -		srgr |= DAVINCI_MCBSP_SRGR_FPER(mcbsp_word_length *
> -						16 - 1);
> +		if (dev->i2s_fast_clock) {
> +			clk_div = 256;
> +			do {
> +				framesize = (freq / (--clk_div)) /
> +					    params->rate_num *
> +					    params->rate_den;
> +			} while (((framesize < 33) || (framesize > 4095)) &&
> +				 (clk_div));
> +			clk_div--;
> +			srgr |= DAVINCI_MCBSP_SRGR_FPER(framesize - 1);
> +		} else {
> +			/* symmetric waveforms */
> +			clk_div = freq / (mcbsp_word_length * 16) /
> +				  params->rate_num * params->rate_den;
> +			srgr |= DAVINCI_MCBSP_SRGR_FPER(mcbsp_word_length *
> +							16 - 1);
> +		}

Hrm.  This doesn't really correspond to your commit message at all.
Your commit message makes it sound like you've changed something about
the clocking setup of the device, such as adding another clock source,
but what you've actually done here is change the method used to
calculate the divider.

I'm *guessing* that the actual effect of your change is that you will
normally end up selecting a very much higher bit clock than would
otherwise be the case.  It strikes me that there must be a better
algorithm for the calculation - for example, working up from the minimum
clock rate - which will give the same results as we currently have where
the driver is already generating accurate rates.

Re: [PATCH 3/3] ASoC: DaVinci: Added fast clock timing for McBSP (I2S)

[Mark Brown]

On Wed, Jun 30, 2010 at 03:47:58PM +0200, Raffaele Recalcati wrote:
> From: Raffaele Recalcati <raffaele.recalcati@bticino.it>
> 
>     i2s_fast_clock switch can be used to have a better approximate

Oh, and please look at the CC list for these posts.  You're CCing *very*
widely and at least one address (chaithrika@ti.com) actually bounces.