SoC: stm32: i2s: manage clock power

Kernel clock management:
Enable/disable I2S kernel clock on audio stream startup/shutdown.

Peripheral clock management:
Manage I2S peripheral clock power through regmap services.
Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/stm/stm32_i2s.c

@@ -545,9 +545,16 @@ static int stm32_i2s_startup(struct snd_pcm_substream *substream,
 			     struct snd_soc_dai *cpu_dai)
 {
 	struct stm32_i2s_data *i2s = snd_soc_dai_get_drvdata(cpu_dai);
+	int ret;
 
 	i2s->substream = substream;
 
+	ret = clk_prepare_enable(i2s->i2sclk);
+	if (ret < 0) {
+		dev_err(cpu_dai->dev, "Failed to enable clock: %d\n", ret);
+		return ret;
+	}
+
 	spin_lock(&i2s->lock_fd);
 	i2s->refcount++;
 	spin_unlock(&i2s->lock_fd);
@@ -674,6 +681,8 @@ static void stm32_i2s_shutdown(struct snd_pcm_substream *substream,
 
 	regmap_update_bits(i2s->regmap, STM32_I2S_CGFR_REG,
 			   I2S_CGFR_MCKOE, (unsigned int)~I2S_CGFR_MCKOE);
+
+	clk_disable_unprepare(i2s->i2sclk);
 }
 
 static int stm32_i2s_dai_probe(struct snd_soc_dai *cpu_dai)
@@ -874,49 +883,26 @@ static int stm32_i2s_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	i2s->regmap = devm_regmap_init_mmio(&pdev->dev, i2s->base,
-					    i2s->regmap_conf);
+	i2s->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "pclk",
+						i2s->base, i2s->regmap_conf);
 	if (IS_ERR(i2s->regmap)) {
 		dev_err(&pdev->dev, "regmap init failed\n");
 		return PTR_ERR(i2s->regmap);
 	}
 
-	ret = clk_prepare_enable(i2s->pclk);
-	if (ret) {
-		dev_err(&pdev->dev, "Enable pclk failed: %d\n", ret);
-		return ret;
-	}
-
-	ret = clk_prepare_enable(i2s->i2sclk);
-	if (ret) {
-		dev_err(&pdev->dev, "Enable i2sclk failed: %d\n", ret);
-		goto err_pclk_disable;
-	}
-
 	ret = devm_snd_soc_register_component(&pdev->dev, &stm32_i2s_component,
 					      i2s->dai_drv, 1);
 	if (ret)
-		goto err_clocks_disable;
+		return ret;
 
 	ret = devm_snd_dmaengine_pcm_register(&pdev->dev,
 					      &stm32_i2s_pcm_config, 0);
 	if (ret)
-		goto err_clocks_disable;
+		return ret;
 
 	/* Set SPI/I2S in i2s mode */
-	ret = regmap_update_bits(i2s->regmap, STM32_I2S_CGFR_REG,
-				 I2S_CGFR_I2SMOD, I2S_CGFR_I2SMOD);
-	if (ret)
-		goto err_clocks_disable;
-
-	return ret;
-
-err_clocks_disable:
-	clk_disable_unprepare(i2s->i2sclk);
-err_pclk_disable:
-	clk_disable_unprepare(i2s->pclk);
-
-	return ret;
+	return regmap_update_bits(i2s->regmap, STM32_I2S_CGFR_REG,
+				  I2S_CGFR_I2SMOD, I2S_CGFR_I2SMOD);
 }
 
 static int stm32_i2s_remove(struct platform_device *pdev)