ASoC: stm32: i2s: add stm32mp25 support

Merge series from Olivier Moysan <[e-mail]>:

Update STM32 I2S driver and binding to support STM32MP25 SoCs.

Documentation/devicetree/bindings/sound/st,stm32-i2s.yaml

···
   The SPI/I2S block supports I2S/PCM protocols when configured on I2S mode.
   Only some SPI instances support I2S.
 
-allOf:
-  - $ref: dai-common.yaml#
-
 properties:
   compatible:
     enum:
       - st,stm32h7-i2s
+      - st,stm32mp25-i2s
 
   "#sound-dai-cells":
     const: 0
···
       - description: clock feeding the internal clock generator.
       - description: I2S parent clock for sampling rates multiple of 8kHz.
       - description: I2S parent clock for sampling rates multiple of 11.025kHz.
+    minItems: 2
 
   clock-names:
     items:
···
       - const: i2sclk
       - const: x8k
       - const: x11k
+    minItems: 2
 
   interrupts:
     maxItems: 1
···
   - interrupts
   - dmas
   - dma-names
+
+allOf:
+  - $ref: dai-common.yaml#
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: st,stm32h7-i2s
+
+    then:
+      properties:
+        clocks:
+          minItems: 4
+
+        clock-names:
+          minItems: 4
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: st,stm32mp25-i2s
+
+    then:
+      properties:
+        clocks:
+          maxItems: 2
+
+        clock-names:
+          maxItems: 2
 
 unevaluatedProperties: false
 

sound/soc/stm/stm32_i2s.c

···
 
 #define STM32_I2S_NAME_LEN		32
 #define STM32_I2S_RATE_11K		11025
+#define STM32_I2S_MAX_SAMPLE_RATE_8K	192000
+#define STM32_I2S_MAX_SAMPLE_RATE_11K	176400
+#define STM32_I2S_CLK_RATE_TOLERANCE	1000 /* ppm */
 
 /**
  * struct stm32_i2s_data - private data of I2S
- * @regmap_conf: I2S register map configuration pointer
+ * @conf: I2S configuration pointer
  * @regmap: I2S register map pointer
  * @pdev: device data pointer
  * @dai_drv: DAI driver pointer
···
  * @divider: prescaler division ratio
  * @div: prescaler div field
  * @odd: prescaler odd field
+ * @i2s_clk_flg: flag set while exclusivity on I2S kernel clock is active
  * @refcount: keep count of opened streams on I2S
  * @ms_flg: master mode flag.
+ * @set_i2s_clk_rate: set I2S kernel clock rate
+ * @put_i2s_clk_rate: put I2S kernel clock rate
  */
 struct stm32_i2s_data {
-	const struct regmap_config *regmap_conf;
+	const struct stm32_i2s_conf *conf;
 	struct regmap *regmap;
 	struct platform_device *pdev;
 	struct snd_soc_dai_driver *dai_drv;
···
 	unsigned int divider;
 	unsigned int div;
 	bool odd;
+	bool i2s_clk_flg;
 	int refcount;
 	int ms_flg;
+	int (*set_i2s_clk_rate)(struct stm32_i2s_data *i2s, unsigned int rate);
+	void (*put_i2s_clk_rate)(struct stm32_i2s_data *i2s);
+};
+
+/**
+ * struct stm32_i2s_conf - I2S configuration
+ * @regmap_conf: regmap configuration pointer
+ * @get_i2s_clk_parent: get parent clock of I2S kernel clock
+ */
+struct stm32_i2s_conf {
+	const struct regmap_config *regmap_conf;
+	int (*get_i2s_clk_parent)(struct stm32_i2s_data *i2s);
 };
 
 struct stm32_i2smclk_data {
···
 };
 
 #define to_mclk_data(_hw) container_of(_hw, struct stm32_i2smclk_data, hw)
+
+static int stm32_i2s_get_parent_clk(struct stm32_i2s_data *i2s);
 
 static int stm32_i2s_calc_clk_div(struct stm32_i2s_data *i2s,
 				  unsigned long input_rate,
···
 				  cgfr_mask, cgfr);
 }
 
+static bool stm32_i2s_rate_accurate(struct stm32_i2s_data *i2s,
+				    unsigned int max_rate, unsigned int rate)
+{
+	struct platform_device *pdev = i2s->pdev;
+	u64 delta, dividend;
+	int ratio;
+
+	if (!rate) {
+		dev_err(&pdev->dev, "Unexpected null rate\n");
+		return false;
+	}
+
+	ratio = DIV_ROUND_CLOSEST(max_rate, rate);
+	if (!ratio)
+		return false;
+
+	dividend = mul_u32_u32(1000000, abs(max_rate - (ratio * rate)));
+	delta = div_u64(dividend, max_rate);
+
+	if (delta <= STM32_I2S_CLK_RATE_TOLERANCE)
+		return true;
+
+	dev_dbg(&pdev->dev, "Rate [%u] not accurate\n", rate);
+
+	return false;
+}
+
 static int stm32_i2s_set_parent_clock(struct stm32_i2s_data *i2s,
 				      unsigned int rate)
 {
···
 			"Error %d setting i2sclk parent clock\n", ret);
 
 	return ret;
+}
+
+static void stm32_i2s_put_parent_rate(struct stm32_i2s_data *i2s)
+{
+	if (i2s->i2s_clk_flg) {
+		i2s->i2s_clk_flg = false;
+		clk_rate_exclusive_put(i2s->i2sclk);
+	}
+}
+
+static int stm32_i2s_set_parent_rate(struct stm32_i2s_data *i2s,
+				     unsigned int rate)
+{
+	struct platform_device *pdev = i2s->pdev;
+	unsigned int i2s_clk_rate, i2s_clk_max_rate, i2s_curr_rate, i2s_new_rate;
+	int ret, div;
+
+	/*
+	 * Set maximum expected kernel clock frequency
+	 * - mclk on:
+	 *   f_i2s_ck = MCKDIV * mclk-fs * fs
+	 *   Here typical 256 ratio is assumed for mclk-fs
+	 * - mclk off:
+	 *   f_i2s_ck = MCKDIV * FRL * fs
+	 *   Where FRL=[16,32], MCKDIV=[1..256]
+	 *   f_i2s_ck = i2s_clk_max_rate * 32 / 256
+	 */
+	if (!(rate % STM32_I2S_RATE_11K))
+		i2s_clk_max_rate = STM32_I2S_MAX_SAMPLE_RATE_11K * 256;
+	else
+		i2s_clk_max_rate = STM32_I2S_MAX_SAMPLE_RATE_8K * 256;
+
+	if (!i2s->i2smclk)
+		i2s_clk_max_rate /= 8;
+
+	/* Request exclusivity, as the clock may be shared by I2S instances */
+	clk_rate_exclusive_get(i2s->i2sclk);
+	i2s->i2s_clk_flg = true;
+
+	/*
+	 * Check current kernel clock rate. If it gives the expected accuracy
+	 * return immediately.
+	 */
+	i2s_curr_rate = clk_get_rate(i2s->i2sclk);
+	if (stm32_i2s_rate_accurate(i2s, i2s_clk_max_rate, i2s_curr_rate))
+		return 0;
+
+	/*
+	 * Otherwise try to set the maximum rate and check the new actual rate.
+	 * If the new rate does not give the expected accuracy, try to set
+	 * lower rates for the kernel clock.
+	 */
+	i2s_clk_rate = i2s_clk_max_rate;
+	div = 1;
+	do {
+		/* Check new rate accuracy. Return if ok */
+		i2s_new_rate = clk_round_rate(i2s->i2sclk, i2s_clk_rate);
+		if (stm32_i2s_rate_accurate(i2s, i2s_clk_rate, i2s_new_rate)) {
+			ret = clk_set_rate(i2s->i2sclk, i2s_clk_rate);
+			if (ret) {
+				dev_err(&pdev->dev, "Error %d setting i2s_clk_rate rate. %s",
+					ret, ret == -EBUSY ?
+					"Active stream rates may be in conflict\n" : "\n");
+				goto err;
+			}
+
+			return 0;
+		}
+
+		/* Try a lower frequency */
+		div++;
+		i2s_clk_rate = i2s_clk_max_rate / div;
+	} while (i2s_clk_rate > rate);
+
+	/* no accurate rate found */
+	dev_err(&pdev->dev, "Failed to find an accurate rate");
+
+err:
+	stm32_i2s_put_parent_rate(i2s);
+
+	return -EINVAL;
 }
 
 static long stm32_i2smclk_round_rate(struct clk_hw *hw, unsigned long rate,
···
 				clk_rate_exclusive_put(i2s->i2smclk);
 				i2s->mclk_rate = 0;
 			}
+
+			if (i2s->put_i2s_clk_rate)
+				i2s->put_i2s_clk_rate(i2s);
+
 			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);
+		ret = i2s->set_i2s_clk_rate(i2s, freq);
 		if (ret)
 			return ret;
 		ret = clk_set_rate_exclusive(i2s->i2smclk, freq);
···
 	u32 cgfr;
 	int ret;
 
-	if (!(rate % 11025))
-		clk_set_parent(i2s->i2sclk, i2s->x11kclk);
-	else
-		clk_set_parent(i2s->i2sclk, i2s->x8kclk);
+	if (!i2s->mclk_rate) {
+		ret = i2s->set_i2s_clk_rate(i2s, rate);
+		if (ret)
+			return ret;
+	}
 	i2s_clock_rate = clk_get_rate(i2s->i2sclk);
 
 	/*
···
 
 	clk_disable_unprepare(i2s->i2sclk);
 
+	/*
+	 * Release kernel clock if following conditions are fulfilled
+	 * - Master clock is not used. Kernel clock won't be released trough sysclk
+	 * - Put handler is defined. Involve that clock is managed exclusively
+	 */
+	if (!i2s->i2smclk && i2s->put_i2s_clk_rate)
+		i2s->put_i2s_clk_rate(i2s);
+
 	spin_lock_irqsave(&i2s->irq_lock, flags);
 	i2s->substream = NULL;
 	spin_unlock_irqrestore(&i2s->irq_lock, flags);
···
 	return 0;
 }
 
+static const struct stm32_i2s_conf stm32_i2s_conf_h7 = {
+	.regmap_conf = &stm32_h7_i2s_regmap_conf,
+	.get_i2s_clk_parent = stm32_i2s_get_parent_clk,
+};
+
+static const struct stm32_i2s_conf stm32_i2s_conf_mp25 = {
+	.regmap_conf = &stm32_h7_i2s_regmap_conf
+};
+
 static const struct of_device_id stm32_i2s_ids[] = {
-	{
-		.compatible = "st,stm32h7-i2s",
-		.data = &stm32_h7_i2s_regmap_conf
-	},
+	{ .compatible = "st,stm32h7-i2s", .data = &stm32_i2s_conf_h7 },
+	{ .compatible = "st,stm32mp25-i2s", .data = &stm32_i2s_conf_mp25 },
 	{},
 };
+
+static int stm32_i2s_get_parent_clk(struct stm32_i2s_data *i2s)
+{
+	struct device *dev = &i2s->pdev->dev;
+
+	i2s->x8kclk = devm_clk_get(dev, "x8k");
+	if (IS_ERR(i2s->x8kclk))
+		return dev_err_probe(dev, PTR_ERR(i2s->x8kclk), "Cannot get x8k parent clock\n");
+
+	i2s->x11kclk = devm_clk_get(dev, "x11k");
+	if (IS_ERR(i2s->x11kclk))
+		return dev_err_probe(dev, PTR_ERR(i2s->x11kclk), "Cannot get x11k parent clock\n");
+
+	return 0;
+}
 
 static int stm32_i2s_parse_dt(struct platform_device *pdev,
 			      struct stm32_i2s_data *i2s)
···
 	if (!np)
 		return -ENODEV;
 
-	i2s->regmap_conf = device_get_match_data(&pdev->dev);
-	if (!i2s->regmap_conf)
+	i2s->conf = device_get_match_data(&pdev->dev);
+	if (!i2s->conf)
 		return -EINVAL;
 
 	i2s->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
···
 		return dev_err_probe(&pdev->dev, PTR_ERR(i2s->i2sclk),
 				     "Could not get i2sclk\n");
 
-	i2s->x8kclk = devm_clk_get(&pdev->dev, "x8k");
-	if (IS_ERR(i2s->x8kclk))
-		return dev_err_probe(&pdev->dev, PTR_ERR(i2s->x8kclk),
-				     "Could not get x8k parent clock\n");
+	if (i2s->conf->get_i2s_clk_parent) {
+		i2s->set_i2s_clk_rate = stm32_i2s_set_parent_clock;
+	} else {
+		i2s->set_i2s_clk_rate = stm32_i2s_set_parent_rate;
+		i2s->put_i2s_clk_rate = stm32_i2s_put_parent_rate;
+	}
 
-	i2s->x11kclk = devm_clk_get(&pdev->dev, "x11k");
-	if (IS_ERR(i2s->x11kclk))
-		return dev_err_probe(&pdev->dev, PTR_ERR(i2s->x11kclk),
-				     "Could not get x11k parent clock\n");
+	if (i2s->conf->get_i2s_clk_parent) {
+		ret = i2s->conf->get_i2s_clk_parent(i2s);
+		if (ret)
+			return ret;
+	}
 
 	/* Register mclk provider if requested */
 	if (of_property_present(np, "#clock-cells")) {
···
 		return ret;
 
 	i2s->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "pclk",
-						i2s->base, i2s->regmap_conf);
+						i2s->base, i2s->conf->regmap_conf);
 	if (IS_ERR(i2s->regmap))
 		return dev_err_probe(&pdev->dev, PTR_ERR(i2s->regmap),
 				     "Regmap init error\n");