[RESEND PATCH 0/2] ASoC: stm32: i2s: add master clock provider

[RESEND PATCH 0/2] ASoC: stm32: i2s: add master clock provider

[Olivier Moysan]

Add master clock generation support in STM32 I2S driver.
Resend of patch https://lkml.org/lkml/2020/9/11/264

Olivier Moysan (2):
  ASoC: dt-bindings: add mclk provider support to stm32 i2s
  ASoC: stm32: i2s: add master clock provider

 .../bindings/sound/st,stm32-i2s.yaml          |   4 +
 sound/soc/stm/stm32_i2s.c                     | 310 +++++++++++++++---
 2 files changed, 270 insertions(+), 44 deletions(-)

-- 
2.17.1

[RESEND PATCH 1/2] ASoC: dt-bindings: add mclk provider support to stm32 i2s

[Olivier Moysan]

From: Olivier Moysan <olivier.moysan@st.com>

Add master clock provider support to STM32 I2S.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
---
 Documentation/devicetree/bindings/sound/st,stm32-i2s.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/sound/st,stm32-i2s.yaml b/Documentation/devicetree/bindings/sound/st,stm32-i2s.yaml
index f32410890589..6feb5a09c184 100644
--- a/Documentation/devicetree/bindings/sound/st,stm32-i2s.yaml
+++ b/Documentation/devicetree/bindings/sound/st,stm32-i2s.yaml
@@ -54,6 +54,10 @@ properties:
   resets:
     maxItems: 1
 
+  "#clock-cells":
+    description: Configure the I2S device as MCLK clock provider.
+    const: 0
+
 required:
   - compatible
   - "#sound-dai-cells"
-- 
2.17.1

[RESEND PATCH 2/2] ASoC: stm32: i2s: add master clock provider

[Olivier Moysan]

From: Olivier Moysan <olivier.moysan@st.com>

Add master clock generation support in STM32 I2S driver.
The master clock provided by I2S can be used to feed a codec.

Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
---
 sound/soc/stm/stm32_i2s.c | 310 ++++++++++++++++++++++++++++++++------
 1 file changed, 266 insertions(+), 44 deletions(-)

diff --git a/sound/soc/stm/stm32_i2s.c b/sound/soc/stm/stm32_i2s.c
index 7c4d63c33f15..7d1672cf78cc 100644
--- a/sound/soc/stm/stm32_i2s.c
+++ b/sound/soc/stm/stm32_i2s.c
@@ -8,6 +8,7 @@
 
 #include <linux/bitfield.h>
 #include <linux/clk.h>
+#include <linux/clk-provider.h>
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/of_irq.h>
@@ -196,6 +197,9 @@ enum i2s_datlen {
 #define STM32_I2S_IS_MASTER(x)		((x)->ms_flg == I2S_MS_MASTER)
 #define STM32_I2S_IS_SLAVE(x)		((x)->ms_flg == I2S_MS_SLAVE)
 
+#define STM32_I2S_NAME_LEN		32
+#define STM32_I2S_RATE_11K		11025
+
 /**
  * struct stm32_i2s_data - private data of I2S
  * @regmap_conf: I2S register map configuration pointer
@@ -206,6 +210,7 @@ enum i2s_datlen {
  * @dma_data_rx: dma configuration data for tx channel
  * @substream: PCM substream data pointer
  * @i2sclk: kernel clock feeding the I2S clock generator
+ * @i2smclk: master clock from I2S mclk provider
  * @pclk: peripheral clock driving bus interface
  * @x8kclk: I2S parent clock for sampling frequencies multiple of 8kHz
  * @x11kclk: I2S parent clock for sampling frequencies multiple of 11kHz
@@ -215,6 +220,9 @@ enum i2s_datlen {
  * @irq_lock: prevent race condition with IRQ
  * @mclk_rate: master clock frequency (Hz)
  * @fmt: DAI protocol
+ * @divider: prescaler division ratio
+ * @div: prescaler div field
+ * @odd: prescaler odd field
  * @refcount: keep count of opened streams on I2S
  * @ms_flg: master mode flag.
  */
@@ -227,6 +235,7 @@ struct stm32_i2s_data {
 	struct snd_dmaengine_dai_dma_data dma_data_rx;
 	struct snd_pcm_substream *substream;
 	struct clk *i2sclk;
+	struct clk *i2smclk;
 	struct clk *pclk;
 	struct clk *x8kclk;
 	struct clk *x11kclk;
@@ -236,10 +245,210 @@ struct stm32_i2s_data {
 	spinlock_t irq_lock; /* used to prevent race condition with IRQ */
 	unsigned int mclk_rate;
 	unsigned int fmt;
+	unsigned int divider;
+	unsigned int div;
+	bool odd;
 	int refcount;
 	int ms_flg;
 };
 
+struct stm32_i2smclk_data {
+	struct clk_hw hw;
+	unsigned long freq;
+	struct stm32_i2s_data *i2s_data;
+};
+
+#define to_mclk_data(_hw) container_of(_hw, struct stm32_i2smclk_data, hw)
+
+static int stm32_i2s_calc_clk_div(struct stm32_i2s_data *i2s,
+				  unsigned long input_rate,
+				  unsigned long output_rate)
+{
+	unsigned int ratio, div, divider = 1;
+	bool odd;
+
+	ratio = DIV_ROUND_CLOSEST(input_rate, output_rate);
+
+	/* Check the parity of the divider */
+	odd = ratio & 0x1;
+
+	/* Compute the div prescaler */
+	div = ratio >> 1;
+
+	/* If div is 0 actual divider is 1 */
+	if (div) {
+		divider = ((2 * div) + odd);
+		dev_dbg(&i2s->pdev->dev, "Divider: 2*%d(div)+%d(odd) = %d\n",
+			div, odd, divider);
+	}
+
+	/* Division by three is not allowed by I2S prescaler */
+	if ((div == 1 && odd) || div > I2S_CGFR_I2SDIV_MAX) {
+		dev_err(&i2s->pdev->dev, "Wrong divider setting\n");
+		return -EINVAL;
+	}
+
+	if (input_rate % divider)
+		dev_dbg(&i2s->pdev->dev,
+			"Rate not accurate. requested (%ld), actual (%ld)\n",
+			output_rate, input_rate / divider);
+
+	i2s->div = div;
+	i2s->odd = odd;
+	i2s->divider = divider;
+
+	return 0;
+}
+
+static int stm32_i2s_set_clk_div(struct stm32_i2s_data *i2s)
+{
+	u32 cgfr, cgfr_mask;
+
+	cgfr = I2S_CGFR_I2SDIV_SET(i2s->div) | (i2s->odd << I2S_CGFR_ODD_SHIFT);
+	cgfr_mask = I2S_CGFR_I2SDIV_MASK | I2S_CGFR_ODD;
+
+	return regmap_update_bits(i2s->regmap, STM32_I2S_CGFR_REG,
+				  cgfr_mask, cgfr);
+}
+
+static int stm32_i2s_set_parent_clock(struct stm32_i2s_data *i2s,
+				      unsigned int rate)
+{
+	struct platform_device *pdev = i2s->pdev;
+	struct clk *parent_clk;
+	int ret;
+
+	if (!(rate % STM32_I2S_RATE_11K))
+		parent_clk = i2s->x11kclk;
+	else
+		parent_clk = i2s->x8kclk;
+
+	ret = clk_set_parent(i2s->i2sclk, parent_clk);
+	if (ret)
+		dev_err(&pdev->dev,
+			"Error %d setting i2sclk parent clock\n", ret);
+
+	return ret;
+}
+
+static long stm32_i2smclk_round_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long *prate)
+{
+	struct stm32_i2smclk_data *mclk = to_mclk_data(hw);
+	struct stm32_i2s_data *i2s = mclk->i2s_data;
+	int ret;
+
+	ret = stm32_i2s_calc_clk_div(i2s, *prate, rate);
+	if (ret)
+		return ret;
+
+	mclk->freq = *prate / i2s->divider;
+
+	return mclk->freq;
+}
+
+static unsigned long stm32_i2smclk_recalc_rate(struct clk_hw *hw,
+					       unsigned long parent_rate)
+{
+	struct stm32_i2smclk_data *mclk = to_mclk_data(hw);
+
+	return mclk->freq;
+}
+
+static int stm32_i2smclk_set_rate(struct clk_hw *hw, unsigned long rate,
+				  unsigned long parent_rate)
+{
+	struct stm32_i2smclk_data *mclk = to_mclk_data(hw);
+	struct stm32_i2s_data *i2s = mclk->i2s_data;
+	int ret;
+
+	ret = stm32_i2s_calc_clk_div(i2s, parent_rate, rate);
+	if (ret)
+		return ret;
+
+	ret = stm32_i2s_set_clk_div(i2s);
+	if (ret)
+		return ret;
+
+	mclk->freq = rate;
+
+	return 0;
+}
+
+static int stm32_i2smclk_enable(struct clk_hw *hw)
+{
+	struct stm32_i2smclk_data *mclk = to_mclk_data(hw);
+	struct stm32_i2s_data *i2s = mclk->i2s_data;
+
+	dev_dbg(&i2s->pdev->dev, "Enable master clock\n");
+
+	return regmap_update_bits(i2s->regmap, STM32_I2S_CGFR_REG,
+				    I2S_CGFR_MCKOE, I2S_CGFR_MCKOE);
+}
+
+static void stm32_i2smclk_disable(struct clk_hw *hw)
+{
+	struct stm32_i2smclk_data *mclk = to_mclk_data(hw);
+	struct stm32_i2s_data *i2s = mclk->i2s_data;
+
+	dev_dbg(&i2s->pdev->dev, "Disable master clock\n");
+
+	regmap_update_bits(i2s->regmap, STM32_I2S_CGFR_REG, I2S_CGFR_MCKOE, 0);
+}
+
+static const struct clk_ops mclk_ops = {
+	.enable = stm32_i2smclk_enable,
+	.disable = stm32_i2smclk_disable,
+	.recalc_rate = stm32_i2smclk_recalc_rate,
+	.round_rate = stm32_i2smclk_round_rate,
+	.set_rate = stm32_i2smclk_set_rate,
+};
+
+static int stm32_i2s_add_mclk_provider(struct stm32_i2s_data *i2s)
+{
+	struct clk_hw *hw;
+	struct stm32_i2smclk_data *mclk;
+	struct device *dev = &i2s->pdev->dev;
+	const char *pname = __clk_get_name(i2s->i2sclk);
+	char *mclk_name, *p, *s = (char *)pname;
+	int ret, i = 0;
+
+	mclk = devm_kzalloc(dev, sizeof(*mclk), GFP_KERNEL);
+	if (!mclk)
+		return -ENOMEM;
+
+	mclk_name = devm_kcalloc(dev, sizeof(char),
+				 STM32_I2S_NAME_LEN, GFP_KERNEL);
+	if (!mclk_name)
+		return -ENOMEM;
+
+	/*
+	 * Forge mclk clock name from parent clock name and suffix.
+	 * String after "_" char is stripped in parent name.
+	 */
+	p = mclk_name;
+	while (*s && *s != '_' && (i < (STM32_I2S_NAME_LEN - 7))) {
+		*p++ = *s++;
+		i++;
+	}
+	strcat(p, "_mclk");
+
+	mclk->hw.init = CLK_HW_INIT(mclk_name, pname, &mclk_ops, 0);
+	mclk->i2s_data = i2s;
+	hw = &mclk->hw;
+
+	dev_dbg(dev, "Register master clock %s\n", mclk_name);
+	ret = devm_clk_hw_register(&i2s->pdev->dev, hw);
+	if (ret) {
+		dev_err(dev, "mclk register fails with error %d\n", ret);
+		return ret;
+	}
+	i2s->i2smclk = hw->clk;
+
+	/* register mclk provider */
+	return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, hw);
+}
+
 static irqreturn_t stm32_i2s_isr(int irq, void *devid)
 {
 	struct stm32_i2s_data *i2s = (struct stm32_i2s_data *)devid;
@@ -405,18 +614,46 @@ static int stm32_i2s_set_sysclk(struct snd_soc_dai *cpu_dai,
 				int clk_id, unsigned int freq, int dir)
 {
 	struct stm32_i2s_data *i2s = snd_soc_dai_get_drvdata(cpu_dai);
+	int ret = 0;
 
-	dev_dbg(cpu_dai->dev, "I2S MCLK frequency is %uHz\n", freq);
+	dev_dbg(cpu_dai->dev, "I2S MCLK frequency is %uHz. mode: %s, dir: %s\n",
+		freq, STM32_I2S_IS_MASTER(i2s) ? "master" : "slave",
+		dir ? "output" : "input");
 
-	if ((dir == SND_SOC_CLOCK_OUT) && STM32_I2S_IS_MASTER(i2s)) {
-		i2s->mclk_rate = freq;
+	/* MCLK generation is available only in master mode */
+	if (dir == SND_SOC_CLOCK_OUT && STM32_I2S_IS_MASTER(i2s)) {
+		if (!i2s->i2smclk) {
+			dev_dbg(cpu_dai->dev, "No MCLK registered\n");
+			return 0;
+		}
 
-		/* Enable master clock if master mode and mclk-fs are set */
-		return regmap_update_bits(i2s->regmap, STM32_I2S_CGFR_REG,
-					  I2S_CGFR_MCKOE, I2S_CGFR_MCKOE);
+		/* Assume shutdown if requested frequency is 0Hz */
+		if (!freq) {
+			/* Release mclk rate only if rate was actually set */
+			if (i2s->mclk_rate) {
+				clk_rate_exclusive_put(i2s->i2smclk);
+				i2s->mclk_rate = 0;
+			}
+			return regmap_update_bits(i2s->regmap,
+						  STM32_I2S_CGFR_REG,
+						  I2S_CGFR_MCKOE, 0);
+		}
+		/* If master clock is used, set parent clock now */
+		ret = stm32_i2s_set_parent_clock(i2s, freq);
+		if (ret)
+			return ret;
+		ret = clk_set_rate_exclusive(i2s->i2smclk, freq);
+		if (ret) {
+			dev_err(cpu_dai->dev, "Could not set mclk rate\n");
+			return ret;
+		}
+		ret = regmap_update_bits(i2s->regmap, STM32_I2S_CGFR_REG,
+					 I2S_CGFR_MCKOE, I2S_CGFR_MCKOE);
+		if (!ret)
+			i2s->mclk_rate = freq;
 	}
 
-	return 0;
+	return ret;
 }
 
 static int stm32_i2s_configure_clock(struct snd_soc_dai *cpu_dai,
@@ -424,11 +661,10 @@ static int stm32_i2s_configure_clock(struct snd_soc_dai *cpu_dai,
 {
 	struct stm32_i2s_data *i2s = snd_soc_dai_get_drvdata(cpu_dai);
 	unsigned long i2s_clock_rate;
-	unsigned int tmp, div, real_div, nb_bits, frame_len;
+	unsigned int nb_bits, frame_len;
 	unsigned int rate = params_rate(params);
+	u32 cgfr;
 	int ret;
-	u32 cgfr, cgfr_mask;
-	bool odd;
 
 	if (!(rate % 11025))
 		clk_set_parent(i2s->i2sclk, i2s->x11kclk);
@@ -449,7 +685,10 @@ static int stm32_i2s_configure_clock(struct snd_soc_dai *cpu_dai,
 	 *   dsp mode : div = i2s_clk / (nb_bits x ws)
 	 */
 	if (i2s->mclk_rate) {
-		tmp = DIV_ROUND_CLOSEST(i2s_clock_rate, i2s->mclk_rate);
+		ret = stm32_i2s_calc_clk_div(i2s, i2s_clock_rate,
+					     i2s->mclk_rate);
+		if (ret)
+			return ret;
 	} else {
 		frame_len = 32;
 		if ((i2s->fmt & SND_SOC_DAIFMT_FORMAT_MASK) ==
@@ -462,34 +701,13 @@ static int stm32_i2s_configure_clock(struct snd_soc_dai *cpu_dai,
 			return ret;
 
 		nb_bits = frame_len * ((cgfr & I2S_CGFR_CHLEN) + 1);
-		tmp = DIV_ROUND_CLOSEST(i2s_clock_rate, (nb_bits * rate));
-	}
-
-	/* Check the parity of the divider */
-	odd = tmp & 0x1;
-
-	/* Compute the div prescaler */
-	div = tmp >> 1;
-
-	cgfr = I2S_CGFR_I2SDIV_SET(div) | (odd << I2S_CGFR_ODD_SHIFT);
-	cgfr_mask = I2S_CGFR_I2SDIV_MASK | I2S_CGFR_ODD;
-
-	real_div = ((2 * div) + odd);
-	dev_dbg(cpu_dai->dev, "I2S clk: %ld, SCLK: %d\n",
-		i2s_clock_rate, rate);
-	dev_dbg(cpu_dai->dev, "Divider: 2*%d(div)+%d(odd) = %d\n",
-		div, odd, real_div);
-
-	if (((div == 1) && odd) || (div > I2S_CGFR_I2SDIV_MAX)) {
-		dev_err(cpu_dai->dev, "Wrong divider setting\n");
-		return -EINVAL;
+		ret = stm32_i2s_calc_clk_div(i2s, i2s_clock_rate,
+					     (nb_bits * rate));
+		if (ret)
+			return ret;
 	}
 
-	if (!div && !odd)
-		dev_warn(cpu_dai->dev, "real divider forced to 1\n");
-
-	ret = regmap_update_bits(i2s->regmap, STM32_I2S_CGFR_REG,
-				 cgfr_mask, cgfr);
+	ret = stm32_i2s_set_clk_div(i2s);
 	if (ret < 0)
 		return ret;
 
@@ -694,9 +912,6 @@ static void stm32_i2s_shutdown(struct snd_pcm_substream *substream,
 	struct stm32_i2s_data *i2s = snd_soc_dai_get_drvdata(cpu_dai);
 	unsigned long flags;
 
-	regmap_update_bits(i2s->regmap, STM32_I2S_CGFR_REG,
-			   I2S_CGFR_MCKOE, (unsigned int)~I2S_CGFR_MCKOE);
-
 	clk_disable_unprepare(i2s->i2sclk);
 
 	spin_lock_irqsave(&i2s->irq_lock, flags);
@@ -861,6 +1076,13 @@ static int stm32_i2s_parse_dt(struct platform_device *pdev,
 		return PTR_ERR(i2s->x11kclk);
 	}
 
+	/* Register mclk provider if requested */
+	if (of_find_property(np, "#clock-cells", NULL)) {
+		ret = stm32_i2s_add_mclk_provider(i2s);
+		if (ret < 0)
+			return ret;
+	}
+
 	/* Get irqs */
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
@@ -906,16 +1128,16 @@ static int stm32_i2s_probe(struct platform_device *pdev)
 	if (!i2s)
 		return -ENOMEM;
 
-	ret = stm32_i2s_parse_dt(pdev, i2s);
-	if (ret)
-		return ret;
-
 	i2s->pdev = pdev;
 	i2s->ms_flg = I2S_MS_NOT_SET;
 	spin_lock_init(&i2s->lock_fd);
 	spin_lock_init(&i2s->irq_lock);
 	platform_set_drvdata(pdev, i2s);
 
+	ret = stm32_i2s_parse_dt(pdev, i2s);
+	if (ret)
+		return ret;
+
 	ret = stm32_i2s_dais_init(pdev, i2s);
 	if (ret)
 		return ret;
-- 
2.17.1

Re: [RESEND PATCH 0/2] ASoC: stm32: i2s: add master clock provider

[Mark Brown]

On Fri, 5 Feb 2021 11:44:02 +0100, Olivier Moysan wrote:
> Add master clock generation support in STM32 I2S driver.
> Resend of patch https://lkml.org/lkml/2020/9/11/264
> 
> Olivier Moysan (2):
>   ASoC: dt-bindings: add mclk provider support to stm32 i2s
>   ASoC: stm32: i2s: add master clock provider
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/2] ASoC: dt-bindings: add mclk provider support to stm32 i2s
      commit: df91785a22e2505d2ac668f1d3e6b6e6d8ba627a
[2/2] ASoC: stm32: i2s: add master clock provider
      commit: 8a262e614ef8675cfde924c6ddf873a95db0be6a

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark