[ALSA] ASoC: Add support for BCLK based on (Rate * Chn * Word Size)

This patch adds support for the DAI BCLK to be generated by multiplying
Rate * Channels * Word Size (RCW).
This now gives 3 options for BCLK clocking and synchronisation :-
 1. BCLK = Rate * x
 2. BCLK = MCLK / x
 3. BCLK = Rate * Chn * Word Size.  (New)
Changes:-
 o Add support for RCW generation of BCLK
 o Update Documentation to include RCW.
 o Update DAI documentation for label = value DAI modes.
 o Add RCW support to wm8731, wm8750 and pxa2xx-i2s drivers.
Signed-off-by: Liam Girdwood <lg@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

Documentation/sound/alsa/soc/clocking.txt

@@ -26,9 +26,9 @@ between the codec and CPU.
 
 The DAI also has a frame clock to signal the start of each audio frame. This
 clock is sometimes referred to as LRC (left right clock) or FRAME. This clock
-runs at exactly the sample rate.
+runs at exactly the sample rate (LRC = Rate).
 
-Bit Clock is usually always a ratio of MCLK or a multiple of LRC. i.e.
+Bit Clock can be generated as follows:-
 
 BCLK = MCLK / x
 
@@ -36,9 +36,14 @@ BCLK = MCLK / x
 
 BCLK = LRC * x
 
+ or
+
+BCLK = LRC * Channels * Word Size
+
 This relationship depends on the codec or SoC CPU in particular. ASoC can quite
-easily match a codec that generates BCLK by division (FSBD) with a CPU that
-generates BCLK by multiplication (FSB).
+easily match BCLK generated by division (SND_SOC_DAI_BFS_DIV) with BCLK by
+multiplication (SND_SOC_DAI_BFS_RATE) or BCLK generated  by
+Rate * Channels * Word size (RCW or SND_SOC_DAI_BFS_RCW).
 
 
 ASoC Clocking

include/sound/soc.h

@@ -21,7 +21,7 @@
 #include <sound/control.h>
 #include <sound/ac97_codec.h>
 
-#define SND_SOC_VERSION "0.11.8"
+#define SND_SOC_VERSION "0.12"
 
 /*
  * Convenience kcontrol builders
@@ -141,19 +141,24 @@
 /* bit clock dividers */
 #define SND_SOC_FSBD(x)			(1 << (x - 1))	/* ratio mclk:bclk */
 #define SND_SOC_FSBD_REAL(x)	(ffs(x))
-#define SND_SOC_FSBD_ALL		0xffff /* all bit clock dividers supported */
 
-/* bit clock ratio to sample rate */
-#define SND_SOC_FSB(x)			(1 << ((x - 16) / 16))
-#define SND_SOC_FSB_REAL(x)		(((ffs(x) - 1) * 16) + 16)
+/* bit clock ratio to (sample rate * channels * word size) */
+#define SND_SOC_FSBW(x)			(1 << (x - 1))
+#define SND_SOC_FSBW_REAL(x)		(ffs(x))
 /* all bclk ratios supported */
-#define SND_SOC_FSB_ALL			SND_SOC_FSBD_ALL
+#define SND_SOC_FSB_ALL			~0ULL
 
 /*
  * DAI hardware flags
  */
-/* use bfs mclk divider mode, else sample rate ratio */
+/* use bfs mclk divider mode (BCLK = MCLK / x) */
 #define SND_SOC_DAI_BFS_DIV		0x1
+/* use bfs rate mulitplier  (BCLK = RATE * x)*/
+#define SND_SOC_DAI_BFS_RATE	0x2
+/* use bfs rcw multiplier (BCLK = RATE * CHN * WORD SIZE) */
+#define SND_SOC_DAI_BFS_RCW		0x4
+/* capture and playback can use different clocks */
+#define SND_SOC_DAI_ASYNC		0x8
 
 /*
  * AC97 codec ID's bitmask
@@ -264,7 +269,7 @@ struct snd_soc_dai_mode {
 	u16 pcmdir:2;	/* SND_SOC_HWDIR_* */
 	u16 flags:8;	/* hw flags */
 	u16 fs;			/* mclk to rate divider */
-	u32 bfs;		/* mclk to bclk dividers */
+	u64 bfs;		/* mclk to bclk dividers */
 	unsigned long priv;		/* private mode data */
 };
 

sound/soc/codecs/wm8731.c

@@ -90,32 +90,36 @@ static struct snd_soc_dai_mode wm8731_modes[] = {
 		.pcmfmt = WM8731_HIFI_BITS,
 		.pcmrate = SNDRV_PCM_RATE_8000,
 		.pcmdir = WM8731_DIR,
+		.flags = SND_SOC_DAI_BFS_RATE,
 		.fs = 1536,
-		.bfs = SND_SOC_FSB(64),
+		.bfs = 64,
 	},
 	{
 		.fmt = WM8731_DAIFMT | SND_SOC_DAIFMT_CBM_CFM,
 		.pcmfmt = WM8731_HIFI_BITS,
 		.pcmrate = SNDRV_PCM_RATE_8000,
 		.pcmdir = WM8731_DIR,
+		.flags = SND_SOC_DAI_BFS_RATE,
 		.fs = 2304,
-		.bfs = SND_SOC_FSB(64),
+		.bfs = 64,
 	},
 	{
 		.fmt = WM8731_DAIFMT | SND_SOC_DAIFMT_CBM_CFM,
 		.pcmfmt = WM8731_HIFI_BITS,
 		.pcmrate = SNDRV_PCM_RATE_8000,
 		.pcmdir = WM8731_DIR,
+		.flags = SND_SOC_DAI_BFS_RATE,
 		.fs = 1408,
-		.bfs = SND_SOC_FSB(64),
+		.bfs = 64,
 	},
 	{
 		.fmt = WM8731_DAIFMT | SND_SOC_DAIFMT_CBM_CFM,
 		.pcmfmt = WM8731_HIFI_BITS,
 		.pcmrate = SNDRV_PCM_RATE_8000,
 		.pcmdir = WM8731_DIR,
+		.flags = SND_SOC_DAI_BFS_RATE,
 		.fs = 2112,
-		.bfs = SND_SOC_FSB(64),
+		.bfs = 64,
 	},
 
 	/* 32k */
@@ -124,16 +128,18 @@ static struct snd_soc_dai_mode wm8731_modes[] = {
 		.pcmfmt = WM8731_HIFI_BITS,
 		.pcmrate = SNDRV_PCM_RATE_32000,
 		.pcmdir = WM8731_DIR,
+		.flags = SND_SOC_DAI_BFS_RATE,
 		.fs = 384,
-		.bfs = SND_SOC_FSB(64),
+		.bfs = 64,
 	},
 	{
 		.fmt = WM8731_DAIFMT | SND_SOC_DAIFMT_CBM_CFM,
 		.pcmfmt = WM8731_HIFI_BITS,
 		.pcmrate = SNDRV_PCM_RATE_32000,
 		.pcmdir = WM8731_DIR,
+		.flags = SND_SOC_DAI_BFS_RATE,
 		.fs = 576,
-		.bfs = SND_SOC_FSB(64),
+		.bfs = 64,
 	},
 
 	/* 44.1k & 48k */
@@ -142,16 +148,18 @@ static struct snd_soc_dai_mode wm8731_modes[] = {
 		.pcmfmt = WM8731_HIFI_BITS,
 		.pcmrate = SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000,
 		.pcmdir = WM8731_DIR,
+		.flags = SND_SOC_DAI_BFS_RATE,
 		.fs = 256,
-		.bfs = SND_SOC_FSB(64),
+		.bfs = 64,
 	},
 	{
 		.fmt = WM8731_DAIFMT | SND_SOC_DAIFMT_CBM_CFM,
 		.pcmfmt = WM8731_HIFI_BITS,
 		.pcmrate = SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000,
 		.pcmdir = WM8731_DIR,
+		.flags = SND_SOC_DAI_BFS_RATE,
 		.fs = 384,
-		.bfs = SND_SOC_FSB(64),
+		.bfs = 64,
 	},
 
 	/* 88.2 & 96k */
@@ -160,17 +168,18 @@ static struct snd_soc_dai_mode wm8731_modes[] = {
 		.pcmfmt = WM8731_HIFI_BITS,
 		.pcmrate = SNDRV_PCM_RATE_88200 | SNDRV_PCM_RATE_96000,
 		.pcmdir = WM8731_DIR,
+		.flags = SND_SOC_DAI_BFS_RATE,
 		.fs = 128,
-		.bfs = SND_SOC_FSB(64),
-		
+		.bfs = 64,
 	},
 	{
 		.fmt = WM8731_DAIFMT | SND_SOC_DAIFMT_CBM_CFM,
 		.pcmfmt = WM8731_HIFI_BITS,
 		.pcmrate = SNDRV_PCM_RATE_88200 | SNDRV_PCM_RATE_96000,
 		.pcmdir = WM8731_DIR,
+		.flags = SND_SOC_DAI_BFS_RATE,
 		.fs = 192,
-		.bfs = SND_SOC_FSB(64),
+		.bfs = 64,
 	},
 
 	/* USB codec frame and clock master modes */
@@ -237,7 +246,7 @@ static struct snd_soc_dai_mode wm8731_modes[] = {
 		.pcmdir = WM8731_DIR,
 		.flags = SND_SOC_DAI_BFS_DIV,
 		.fs = SND_SOC_FS_ALL,
-		.bfs = SND_SOC_FSBD_ALL,
+		.bfs = SND_SOC_FSB_ALL,
 	},
 };
 

sound/soc/codecs/wm8750.c

@@ -343,7 +343,7 @@ static struct snd_soc_dai_mode wm8750_modes[] = {
 		.pcmdir = WM8750_DIR,
 		.flags = SND_SOC_DAI_BFS_DIV,
 		.fs = SND_SOC_FS_ALL,
-		.bfs = SND_SOC_FSBD_ALL,
+		.bfs = SND_SOC_FSB_ALL,
 	},
 };
 
@@ -829,6 +829,9 @@ static inline int get_coeff(int mclk, int rate)
 		if (coeff_div[i].rate == rate && coeff_div[i].mclk == mclk)
 			return i;
 	}
+
+	printk(KERN_ERR "wm8750: could not get coeff for mclk %d @ rate %d\n",
+		mclk, rate);
 	return -EINVAL;
 }
 
@@ -836,13 +839,7 @@ static inline int get_coeff(int mclk, int rate)
 static unsigned int wm8750_config_sysclk(struct snd_soc_codec_dai *dai,
 	struct snd_soc_clock_info *info, unsigned int clk)
 {
-	dai->mclk = 0;
-
-	/* check that the calculated FS and rate actually match a clock from
-	 * the machine driver */
-	if (info->fs * info->rate == clk)
 	dai->mclk = clk;
-
 	return dai->mclk;
 }
 
@@ -859,7 +856,7 @@ static int wm8750_pcm_prepare(struct snd_pcm_substream *substream)
 	if (i < 0)
 		return i;
 
-	bfs = SND_SOC_FSB_REAL(rtd->codec_dai->dai_runtime.bfs);
+	bfs = SND_SOC_FSBD_REAL(rtd->codec_dai->dai_runtime.bfs);
 
 	/* set master/slave audio interface */
 	switch (rtd->codec_dai->dai_runtime.fmt & SND_SOC_DAIFMT_CLOCK_MASK) {

sound/soc/pxa/pxa2xx-i2s.c

@@ -126,7 +126,8 @@ static struct snd_soc_dai_mode pxa2xx_i2s_modes[] = {
 		.pcmrate = PXA_I2S_RATES,
 		.pcmdir = PXA_I2S_DIR,
 		.fs = SND_SOC_FS_ALL,
-		.bfs = SND_SOC_FSB(64),
+		.flags = SND_SOC_DAI_BFS_RATE,
+		.bfs = 64,
 		.priv = 0x48,
 	},
 };