ASoC: kirkwood-i2s: add support for external clock rates

This is part of a patch found in Rabeeh Khoury's git tree for the
cubox, and cleaned up by me.

Some platforms provide an external clock which can be used to allow
other sample rates to be selected.  Provide support for this.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 62 insertions, 8 deletions

diff --git a/sound/soc/kirkwood/kirkwood-i2s.c b/sound/soc/kirkwood/kirkwood-i2s.c
index 823ef1e71d1..d3629d5927e 100644
--- a/sound/soc/kirkwood/kirkwood-i2s.c
+++ b/sound/soc/kirkwood/kirkwood-i2s.c
@@ -99,6 +99,29 @@ static inline void kirkwood_set_dco(void __iomem *io, unsigned long rate)
 	} while (value == 0);
 }
 
+static void kirkwood_set_rate(struct snd_soc_dai *dai,
+	struct kirkwood_dma_data *priv, unsigned long rate)
+{
+	uint32_t clks_ctrl;
+
+	if (rate == 44100 || rate == 48000 || rate == 96000) {
+		/* use internal dco for supported rates */
+		dev_dbg(dai->dev, "%s: dco set rate = %lu\n",
+			__func__, rate);
+		kirkwood_set_dco(priv->io, rate);
+
+		clks_ctrl = KIRKWOOD_MCLK_SOURCE_DCO;
+	} else if (!IS_ERR(priv->extclk)) {
+		/* use optional external clk for other rates */
+		dev_dbg(dai->dev, "%s: extclk set rate = %lu -> %lu\n",
+			__func__, rate, 256 * rate);
+		clk_set_rate(priv->extclk, 256 * rate);
+
+		clks_ctrl = KIRKWOOD_MCLK_SOURCE_EXTCLK;
+	}
+	writel(clks_ctrl, priv->io + KIRKWOOD_CLOCKS_CTRL);
+}
+
 static int kirkwood_i2s_startup(struct snd_pcm_substream *substream,
 		struct snd_soc_dai *dai)
 {
@@ -123,8 +146,7 @@ static int kirkwood_i2s_hw_params(struct snd_pcm_substream *substream,
 		i2s_reg = KIRKWOOD_I2S_RECCTL;
 	}
 
-	/* set dco conf */
-	kirkwood_set_dco(priv->io, params_rate(params));
+	kirkwood_set_rate(dai, priv, params_rate(params));
 
 	i2s_value = readl(priv->io+i2s_reg);
 	i2s_value &= ~KIRKWOOD_I2S_CTL_SIZE_MASK;
@@ -396,21 +418,45 @@ static struct snd_soc_dai_driver kirkwood_i2s_dai = {
 		.channels_min = 1,
 		.channels_max = 2,
 		.rates = KIRKWOOD_I2S_RATES,
-		.formats = KIRKWOOD_I2S_FORMATS,},
+		.formats = KIRKWOOD_I2S_FORMATS,
+	},
 	.capture = {
 		.channels_min = 1,
 		.channels_max = 2,
 		.rates = KIRKWOOD_I2S_RATES,
-		.formats = KIRKWOOD_I2S_FORMATS,},
+		.formats = KIRKWOOD_I2S_FORMATS,
+	},
+	.ops = &kirkwood_i2s_dai_ops,
+};
+
+static struct snd_soc_dai_driver kirkwood_i2s_dai_extclk = {
+	.probe = kirkwood_i2s_probe,
+	.remove = kirkwood_i2s_remove,
+	.playback = {
+		.channels_min = 1,
+		.channels_max = 2,
+		.rates = SNDRV_PCM_RATE_8000_192000 |
+			 SNDRV_PCM_RATE_CONTINUOUS |
+			 SNDRV_PCM_RATE_KNOT,
+		.formats = KIRKWOOD_I2S_FORMATS,
+	},
+	.capture = {
+		.channels_min = 1,
+		.channels_max = 2,
+		.rates = SNDRV_PCM_RATE_8000_192000 |
+			 SNDRV_PCM_RATE_CONTINUOUS |
+			 SNDRV_PCM_RATE_KNOT,
+		.formats = KIRKWOOD_I2S_FORMATS,
+	},
 	.ops = &kirkwood_i2s_dai_ops,
 };
 
 static __devinit int kirkwood_i2s_dev_probe(struct platform_device *pdev)
 {
-	struct resource *mem;
-	struct kirkwood_asoc_platform_data *data =
-		pdev->dev.platform_data;
+	struct kirkwood_asoc_platform_data *data = pdev->dev.platform_data;
+	struct snd_soc_dai_driver *soc_dai = &kirkwood_i2s_dai;
 	struct kirkwood_dma_data *priv;
+	struct resource *mem;
 	int err;
 
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
@@ -480,11 +526,15 @@ static __devinit int kirkwood_i2s_dev_probe(struct platform_device *pdev)
 		priv->ctl_rec |= KIRKWOOD_RECCTL_BURST_128;
 	}
 
-	err = snd_soc_register_dai(&pdev->dev, &kirkwood_i2s_dai);
+	err = snd_soc_register_dai(&pdev->dev, soc_dai);
 	if (!err)
 		return 0;
 	dev_err(&pdev->dev, "snd_soc_register_dai failed\n");
 
+	if (!IS_ERR(priv->extclk)) {
+		clk_disable_unprepare(priv->extclk);
+		clk_put(priv->extclk);
+	}
 	clk_disable_unprepare(priv->clk);
 
 	return err;
@@ -496,6 +546,10 @@ static __devexit int kirkwood_i2s_dev_remove(struct platform_device *pdev)
 
 	snd_soc_unregister_dai(&pdev->dev);
 
+	if (!IS_ERR(priv->extclk)) {
+		clk_disable_unprepare(priv->extclk);
+		clk_put(priv->extclk);
+	}
 	clk_disable_unprepare(priv->clk);
 
 	return 0;