ASoC: bcm2835: move to use the clock framework

Since the move to the new clock framework with commit 94cb7f76caa0
("ARM: bcm2835: Switch to using the new clock driver support.")
this driver was no longer functional as it was manipulating the
clock registers locally without going true the framework.

This patch moves to use the new clock framework and also
moves away from the hardcoded address offsets for DMA getting
the dma-address directly from the device tree.

Note that the optimal bclk_ratio selection to avoid jitter
due to the use of fractional dividers, which is in the
current version has been removed, because not all devices
support these non power of 2 sized transfers, which resulted
in lots of (downstream) modules that use:
  snd_soc_dai_set_bclk_ratio(cpu_dai, sample_bits * 2);

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 64 insertions, 220 deletions

diff --git a/sound/soc/bcm/bcm2835-i2s.c b/sound/soc/bcm/bcm2835-i2s.c
index 3303d5f58082..1c1f2210387b 100644
--- a/sound/soc/bcm/bcm2835-i2s.c
+++ b/sound/soc/bcm/bcm2835-i2s.c
@@ -37,6 +37,7 @@
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/module.h>
+#include <linux/of_address.h>
 #include <linux/slab.h>
 
 #include <sound/core.h>
@@ -46,55 +47,6 @@
 #include <sound/pcm_params.h>
 #include <sound/soc.h>
 
-/* Clock registers */
-#define BCM2835_CLK_PCMCTL_REG  0x00
-#define BCM2835_CLK_PCMDIV_REG  0x04
-
-/* Clock register settings */
-#define BCM2835_CLK_PASSWD		(0x5a000000)
-#define BCM2835_CLK_PASSWD_MASK	(0xff000000)
-#define BCM2835_CLK_MASH(v)		((v) << 9)
-#define BCM2835_CLK_FLIP		BIT(8)
-#define BCM2835_CLK_BUSY		BIT(7)
-#define BCM2835_CLK_KILL		BIT(5)
-#define BCM2835_CLK_ENAB		BIT(4)
-#define BCM2835_CLK_SRC(v)		(v)
-
-#define BCM2835_CLK_SHIFT		(12)
-#define BCM2835_CLK_DIVI(v)		((v) << BCM2835_CLK_SHIFT)
-#define BCM2835_CLK_DIVF(v)		(v)
-#define BCM2835_CLK_DIVF_MASK		(0xFFF)
-
-enum {
-	BCM2835_CLK_MASH_0 = 0,
-	BCM2835_CLK_MASH_1,
-	BCM2835_CLK_MASH_2,
-	BCM2835_CLK_MASH_3,
-};
-
-enum {
-	BCM2835_CLK_SRC_GND = 0,
-	BCM2835_CLK_SRC_OSC,
-	BCM2835_CLK_SRC_DBG0,
-	BCM2835_CLK_SRC_DBG1,
-	BCM2835_CLK_SRC_PLLA,
-	BCM2835_CLK_SRC_PLLC,
-	BCM2835_CLK_SRC_PLLD,
-	BCM2835_CLK_SRC_HDMI,
-};
-
-/* Most clocks are not useable (freq = 0) */
-static const unsigned int bcm2835_clk_freq[BCM2835_CLK_SRC_HDMI+1] = {
-	[BCM2835_CLK_SRC_GND]		= 0,
-	[BCM2835_CLK_SRC_OSC]		= 19200000,
-	[BCM2835_CLK_SRC_DBG0]		= 0,
-	[BCM2835_CLK_SRC_DBG1]		= 0,
-	[BCM2835_CLK_SRC_PLLA]		= 0,
-	[BCM2835_CLK_SRC_PLLC]		= 0,
-	[BCM2835_CLK_SRC_PLLD]		= 500000000,
-	[BCM2835_CLK_SRC_HDMI]		= 0,
-};
-
 /* I2S registers */
 #define BCM2835_I2S_CS_A_REG		0x00
 #define BCM2835_I2S_FIFO_A_REG		0x04
@@ -158,10 +110,6 @@ static const unsigned int bcm2835_clk_freq[BCM2835_CLK_SRC_HDMI+1] = {
 #define BCM2835_I2S_INT_RXR		BIT(1)
 #define BCM2835_I2S_INT_TXW		BIT(0)
 
-/* I2S DMA interface */
-/* FIXME: Needs IOMMU support */
-#define BCM2835_VCMMU_SHIFT		(0x7E000000 - 0x20000000)
-
 /* General device struct */
 struct bcm2835_i2s_dev {
 	struct device				*dev;
@@ -169,21 +117,23 @@ struct bcm2835_i2s_dev {
 	unsigned int				fmt;
 	unsigned int				bclk_ratio;
 
-	struct regmap *i2s_regmap;
-	struct regmap *clk_regmap;
+	struct regmap				*i2s_regmap;
+	struct clk				*clk;
+	bool					clk_prepared;
 };
 
 static void bcm2835_i2s_start_clock(struct bcm2835_i2s_dev *dev)
 {
-	/* Start the clock if in master mode */
 	unsigned int master = dev->fmt & SND_SOC_DAIFMT_MASTER_MASK;
 
+	if (dev->clk_prepared)
+		return;
+
 	switch (master) {
 	case SND_SOC_DAIFMT_CBS_CFS:
 	case SND_SOC_DAIFMT_CBS_CFM:
-		regmap_update_bits(dev->clk_regmap, BCM2835_CLK_PCMCTL_REG,
-			BCM2835_CLK_PASSWD_MASK | BCM2835_CLK_ENAB,
-			BCM2835_CLK_PASSWD | BCM2835_CLK_ENAB);
+		clk_prepare_enable(dev->clk);
+		dev->clk_prepared = true;
 		break;
 	default:
 		break;
@@ -192,28 +142,9 @@ static void bcm2835_i2s_start_clock(struct bcm2835_i2s_dev *dev)
 
 static void bcm2835_i2s_stop_clock(struct bcm2835_i2s_dev *dev)
 {
-	uint32_t clkreg;
-	int timeout = 1000;
-
-	/* Stop clock */
-	regmap_update_bits(dev->clk_regmap, BCM2835_CLK_PCMCTL_REG,
-			BCM2835_CLK_PASSWD_MASK | BCM2835_CLK_ENAB,
-			BCM2835_CLK_PASSWD);
-
-	/* Wait for the BUSY flag going down */
-	while (--timeout) {
-		regmap_read(dev->clk_regmap, BCM2835_CLK_PCMCTL_REG, &clkreg);
-		if (!(clkreg & BCM2835_CLK_BUSY))
-			break;
-	}
-
-	if (!timeout) {
-		/* KILL the clock */
-		dev_err(dev->dev, "I2S clock didn't stop. Kill the clock!\n");
-		regmap_update_bits(dev->clk_regmap, BCM2835_CLK_PCMCTL_REG,
-			BCM2835_CLK_KILL | BCM2835_CLK_PASSWD_MASK,
-			BCM2835_CLK_KILL | BCM2835_CLK_PASSWD);
-	}
+	if (dev->clk_prepared)
+		clk_disable_unprepare(dev->clk);
+	dev->clk_prepared = false;
 }
 
 static void bcm2835_i2s_clear_fifos(struct bcm2835_i2s_dev *dev,
@@ -223,8 +154,7 @@ static void bcm2835_i2s_clear_fifos(struct bcm2835_i2s_dev *dev,
 	uint32_t syncval;
 	uint32_t csreg;
 	uint32_t i2s_active_state;
-	uint32_t clkreg;
-	uint32_t clk_active_state;
+	bool clk_was_prepared;
 	uint32_t off;
 	uint32_t clr;
 
@@ -238,15 +168,10 @@ static void bcm2835_i2s_clear_fifos(struct bcm2835_i2s_dev *dev,
 	regmap_read(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, &csreg);
 	i2s_active_state = csreg & (BCM2835_I2S_RXON | BCM2835_I2S_TXON);
 
-	regmap_read(dev->clk_regmap, BCM2835_CLK_PCMCTL_REG, &clkreg);
-	clk_active_state = clkreg & BCM2835_CLK_ENAB;
-
 	/* Start clock if not running */
-	if (!clk_active_state) {
-		regmap_update_bits(dev->clk_regmap, BCM2835_CLK_PCMCTL_REG,
-			BCM2835_CLK_PASSWD_MASK | BCM2835_CLK_ENAB,
-			BCM2835_CLK_PASSWD | BCM2835_CLK_ENAB);
-	}
+	clk_was_prepared = dev->clk_prepared;
+	if (!clk_was_prepared)
+		bcm2835_i2s_start_clock(dev);
 
 	/* Stop I2S module */
 	regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, off, 0);
@@ -280,7 +205,7 @@ static void bcm2835_i2s_clear_fifos(struct bcm2835_i2s_dev *dev,
 		dev_err(dev->dev, "I2S SYNC error!\n");
 
 	/* Stop clock if it was not running before */
-	if (!clk_active_state)
+	if (!clk_was_prepared)
 		bcm2835_i2s_stop_clock(dev);
 
 	/* Restore I2S state */
@@ -309,19 +234,9 @@ static int bcm2835_i2s_hw_params(struct snd_pcm_substream *substream,
 				 struct snd_soc_dai *dai)
 {
 	struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
-
 	unsigned int sampling_rate = params_rate(params);
 	unsigned int data_length, data_delay, bclk_ratio;
 	unsigned int ch1pos, ch2pos, mode, format;
-	unsigned int mash = BCM2835_CLK_MASH_1;
-	unsigned int divi, divf, target_frequency;
-	int clk_src = -1;
-	unsigned int master = dev->fmt & SND_SOC_DAIFMT_MASTER_MASK;
-	bool bit_master =	(master == SND_SOC_DAIFMT_CBS_CFS
-					|| master == SND_SOC_DAIFMT_CBS_CFM);
-
-	bool frame_master =	(master == SND_SOC_DAIFMT_CBS_CFS
-					|| master == SND_SOC_DAIFMT_CBM_CFS);
 	uint32_t csreg;
 
 	/*
@@ -343,11 +258,9 @@ static int bcm2835_i2s_hw_params(struct snd_pcm_substream *substream,
 	switch (params_format(params)) {
 	case SNDRV_PCM_FORMAT_S16_LE:
 		data_length = 16;
-		bclk_ratio = 40;
 		break;
 	case SNDRV_PCM_FORMAT_S32_LE:
 		data_length = 32;
-		bclk_ratio = 80;
 		break;
 	default:
 		return -EINVAL;
@@ -356,69 +269,12 @@ static int bcm2835_i2s_hw_params(struct snd_pcm_substream *substream,
 	/* If bclk_ratio already set, use that one. */
 	if (dev->bclk_ratio)
 		bclk_ratio = dev->bclk_ratio;
+	else
+		/* otherwise calculate a fitting block ratio */
+		bclk_ratio = 2 * data_length;
 
-	/*
-	 * Clock Settings
-	 *
-	 * The target frequency of the bit clock is
-	 *	sampling rate * frame length
-	 *
-	 * Integer mode:
-	 * Sampling rates that are multiples of 8000 kHz
-	 * can be driven by the oscillator of 19.2 MHz
-	 * with an integer divider as long as the frame length
-	 * is an integer divider of 19200000/8000=2400 as set up above.
-	 * This is no longer possible if the sampling rate
-	 * is too high (e.g. 192 kHz), because the oscillator is too slow.
-	 *
-	 * MASH mode:
-	 * For all other sampling rates, it is not possible to
-	 * have an integer divider. Approximate the clock
-	 * with the MASH module that induces a slight frequency
-	 * variance. To minimize that it is best to have the fastest
-	 * clock here. That is PLLD with 500 MHz.
-	 */
-	target_frequency = sampling_rate * bclk_ratio;
-	clk_src = BCM2835_CLK_SRC_OSC;
-	mash = BCM2835_CLK_MASH_0;
-
-	if (bcm2835_clk_freq[clk_src] % target_frequency == 0
-			&& bit_master && frame_master) {
-		divi = bcm2835_clk_freq[clk_src] / target_frequency;
-		divf = 0;
-	} else {
-		uint64_t dividend;
-
-		if (!dev->bclk_ratio) {
-			/*
-			 * Overwrite bclk_ratio, because the
-			 * above trick is not needed or can
-			 * not be used.
-			 */
-			bclk_ratio = 2 * data_length;
-		}
-
-		target_frequency = sampling_rate * bclk_ratio;
-
-		clk_src = BCM2835_CLK_SRC_PLLD;
-		mash = BCM2835_CLK_MASH_1;
-
-		dividend = bcm2835_clk_freq[clk_src];
-		dividend <<= BCM2835_CLK_SHIFT;
-		do_div(dividend, target_frequency);
-		divi = dividend >> BCM2835_CLK_SHIFT;
-		divf = dividend & BCM2835_CLK_DIVF_MASK;
-	}
-
-	/* Set clock divider */
-	regmap_write(dev->clk_regmap, BCM2835_CLK_PCMDIV_REG, BCM2835_CLK_PASSWD
-			| BCM2835_CLK_DIVI(divi)
-			| BCM2835_CLK_DIVF(divf));
-
-	/* Setup clock, but don't start it yet */
-	regmap_write(dev->clk_regmap, BCM2835_CLK_PCMCTL_REG, BCM2835_CLK_PASSWD
-			| BCM2835_CLK_MASH(mash)
-			| BCM2835_CLK_SRC(clk_src));
+	/* set target clock rate*/
+	clk_set_rate(dev->clk, sampling_rate * bclk_ratio);
 
 	/* Setup the frame format */
 	format = BCM2835_I2S_CHEN;
@@ -692,7 +548,7 @@ static const struct snd_soc_dai_ops bcm2835_i2s_dai_ops = {
 	.trigger	= bcm2835_i2s_trigger,
 	.hw_params	= bcm2835_i2s_hw_params,
 	.set_fmt	= bcm2835_i2s_set_dai_fmt,
-	.set_bclk_ratio	= bcm2835_i2s_set_dai_bclk_ratio
+	.set_bclk_ratio	= bcm2835_i2s_set_dai_bclk_ratio,
 };
 
 static int bcm2835_i2s_dai_probe(struct snd_soc_dai *dai)
@@ -750,34 +606,14 @@ static bool bcm2835_i2s_precious_reg(struct device *dev, unsigned int reg)
 	};
 }
 
-static bool bcm2835_clk_volatile_reg(struct device *dev, unsigned int reg)
-{
-	switch (reg) {
-	case BCM2835_CLK_PCMCTL_REG:
-		return true;
-	default:
-		return false;
-	};
-}
-
-static const struct regmap_config bcm2835_regmap_config[] = {
-	{
-		.reg_bits = 32,
-		.reg_stride = 4,
-		.val_bits = 32,
-		.max_register = BCM2835_I2S_GRAY_REG,
-		.precious_reg = bcm2835_i2s_precious_reg,
-		.volatile_reg = bcm2835_i2s_volatile_reg,
-		.cache_type = REGCACHE_RBTREE,
-	},
-	{
-		.reg_bits = 32,
-		.reg_stride = 4,
-		.val_bits = 32,
-		.max_register = BCM2835_CLK_PCMDIV_REG,
-		.volatile_reg = bcm2835_clk_volatile_reg,
-		.cache_type = REGCACHE_RBTREE,
-	},
+static const struct regmap_config bcm2835_regmap_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+	.max_register = BCM2835_I2S_GRAY_REG,
+	.precious_reg = bcm2835_i2s_precious_reg,
+	.volatile_reg = bcm2835_i2s_volatile_reg,
+	.cache_type = REGCACHE_RBTREE,
 };
 
 static const struct snd_soc_component_driver bcm2835_i2s_component = {
@@ -787,42 +623,50 @@ static const struct snd_soc_component_driver bcm2835_i2s_component = {
 static int bcm2835_i2s_probe(struct platform_device *pdev)
 {
 	struct bcm2835_i2s_dev *dev;
-	int i;
 	int ret;
-	struct regmap *regmap[2];
-	struct resource *mem[2];
-
-	/* Request both ioareas */
-	for (i = 0; i <= 1; i++) {
-		void __iomem *base;
-
-		mem[i] = platform_get_resource(pdev, IORESOURCE_MEM, i);
-		base = devm_ioremap_resource(&pdev->dev, mem[i]);
-		if (IS_ERR(base))
-			return PTR_ERR(base);
-
-		regmap[i] = devm_regmap_init_mmio(&pdev->dev, base,
-					    &bcm2835_regmap_config[i]);
-		if (IS_ERR(regmap[i]))
-			return PTR_ERR(regmap[i]);
-	}
+	struct resource *mem;
+	void __iomem *base;
+	const __be32 *addr;
+	dma_addr_t dma_base;
 
 	dev = devm_kzalloc(&pdev->dev, sizeof(*dev),
 			   GFP_KERNEL);
 	if (!dev)
 		return -ENOMEM;
 
-	dev->i2s_regmap = regmap[0];
-	dev->clk_regmap = regmap[1];
+	/* get the clock */
+	dev->clk_prepared = false;
+	dev->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(dev->clk)) {
+		dev_err(&pdev->dev, "could not get clk: %ld\n",
+			PTR_ERR(dev->clk));
+		return PTR_ERR(dev->clk);
+	}
+
+	/* Request ioarea */
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(&pdev->dev, mem);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	dev->i2s_regmap = devm_regmap_init_mmio(&pdev->dev, base,
+				&bcm2835_regmap_config);
+	if (IS_ERR(dev->i2s_regmap))
+		return PTR_ERR(dev->i2s_regmap);
+
+	/* Set the DMA address - we have to parse DT ourselves */
+	addr = of_get_address(pdev->dev.of_node, 0, NULL, NULL);
+	if (!addr) {
+		dev_err(&pdev->dev, "could not get DMA-register address\n");
+		return -EINVAL;
+	}
+	dma_base = be32_to_cpup(addr);
 
-	/* Set the DMA address */
 	dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].addr =
-		(dma_addr_t)mem[0]->start + BCM2835_I2S_FIFO_A_REG
-					  + BCM2835_VCMMU_SHIFT;
+		dma_base + BCM2835_I2S_FIFO_A_REG;
 
 	dev->dma_data[SNDRV_PCM_STREAM_CAPTURE].addr =
-		(dma_addr_t)mem[0]->start + BCM2835_I2S_FIFO_A_REG
-					  + BCM2835_VCMMU_SHIFT;
+		dma_base + BCM2835_I2S_FIFO_A_REG;
 
 	/* Set the bus width */
 	dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].addr_width =