ASoC: fsl_spdif: Add core clock control for DMA access

Regmap is able to enable/disable the core clock automatically each time
it's going to access the registers. But for DMA cases during playback or
recording, it's totally beyong control of regmap. So we have to open the
clock manually.

Signed-off-by: Nicolin Chen <Guangyu.Chen@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/fsl/fsl_spdif.c

@@ -80,6 +80,7 @@ struct fsl_spdif_priv {
 	u8 rxclk_src;
 	struct clk *txclk[SPDIF_TXRATE_MAX];
 	struct clk *rxclk;
+	struct clk *coreclk;
 	struct snd_dmaengine_dai_dma_data dma_params_tx;
 	struct snd_dmaengine_dai_dma_data dma_params_rx;
 
@@ -423,10 +424,16 @@ static int fsl_spdif_startup(struct snd_pcm_substream *substream,
 
 	/* Reset module and interrupts only for first initialization */
 	if (!cpu_dai->active) {
+		ret = clk_prepare_enable(spdif_priv->coreclk);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to enable core clock\n");
+			return ret;
+		}
+
 		ret = spdif_softreset(spdif_priv);
 		if (ret) {
 			dev_err(&pdev->dev, "failed to soft reset\n");
-			return ret;
+			goto err;
 		}
 
 		/* Disable all the interrupts */
@@ -454,6 +461,11 @@ static int fsl_spdif_startup(struct snd_pcm_substream *substream,
 	regmap_update_bits(regmap, REG_SPDIF_SCR, SCR_LOW_POWER, 0);
 
 	return 0;
+
+err:
+	clk_disable_unprepare(spdif_priv->coreclk);
+
+	return ret;
 }
 
 static void fsl_spdif_shutdown(struct snd_pcm_substream *substream,
@@ -484,6 +496,7 @@ static void fsl_spdif_shutdown(struct snd_pcm_substream *substream,
 		spdif_intr_status_clear(spdif_priv);
 		regmap_update_bits(regmap, REG_SPDIF_SCR,
 				SCR_LOW_POWER, SCR_LOW_POWER);
+		clk_disable_unprepare(spdif_priv->coreclk);
 	}
 }
 
@@ -1134,6 +1147,13 @@ static int fsl_spdif_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	/* Get core clock for data register access via DMA */
+	spdif_priv->coreclk = devm_clk_get(&pdev->dev, "core");
+	if (IS_ERR(spdif_priv->coreclk)) {
+		dev_err(&pdev->dev, "no core clock in devicetree\n");
+		return PTR_ERR(spdif_priv->coreclk);
+	}
+
 	/* Select clock source for rx/tx clock */
 	spdif_priv->rxclk = devm_clk_get(&pdev->dev, "rxtx1");
 	if (IS_ERR(spdif_priv->rxclk)) {