[alsa-devel] [PATCH 4/4] ASoC: tlv320aic32x4: Support for master clock

[Markus Pargmann]

Add support for a master clock passed through DT. The master clock of
the codec is only active when the codec is in use.

Cc: Rob Herring <robh+dt at kernel.org>
Cc: Pawel Moll <pawel.moll at arm.com>
Cc: Mark Rutland <mark.rutland at arm.com>
Cc: Ian Campbell <ijc+devicetree at hellion.org.uk>
Cc: Kumar Gala <galak at codeaurora.org>
Cc: devicetree at vger.kernel.org
Signed-off-by: Markus Pargmann <mpa at pengutronix.de>
---
 .../devicetree/bindings/sound/tlv320aic32x4.txt    |  2 ++
 sound/soc/codecs/tlv320aic32x4.c                   | 23 ++++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/Documentation/devicetree/bindings/sound/tlv320aic32x4.txt b/Documentation/devicetree/bindings/sound/tlv320aic32x4.txt
index 5c8fb4a..4ed7c37 100644
--- a/Documentation/devicetree/bindings/sound/tlv320aic32x4.txt
+++ b/Documentation/devicetree/bindings/sound/tlv320aic32x4.txt
@@ -10,6 +10,8 @@ Optional properties:
  - ti,ldo-enable: Bool, has to be set when the codec is powered only through the
    LDOIN pin.
  - gpio-reset - gpio pin number used for codec reset
+ - clocks/clock-names: Clock named 'mclk' for the master clock of the codec.
+   See clock/clock-bindings.txt for information about the detailed format.
 
 
 Example:
diff --git a/sound/soc/codecs/tlv320aic32x4.c b/sound/soc/codecs/tlv320aic32x4.c
index 840f529..33ab004 100644
--- a/sound/soc/codecs/tlv320aic32x4.c
+++ b/sound/soc/codecs/tlv320aic32x4.c
@@ -33,6 +33,7 @@
 #include <linux/i2c.h>
 #include <linux/cdev.h>
 #include <linux/slab.h>
+#include <linux/clk.h>
 
 #include <sound/tlv320aic32x4.h>
 #include <sound/core.h>
@@ -67,6 +68,7 @@ struct aic32x4_priv {
 	u32 micpga_routing;
 	bool swapdacs;
 	int rstn_gpio;
+	struct clk *mclk;
 };
 
 /* 0dB min, 0.5dB steps */
@@ -487,8 +489,21 @@ static int aic32x4_mute(struct snd_soc_dai *dai, int mute)
 static int aic32x4_set_bias_level(struct snd_soc_codec *codec,
 				  enum snd_soc_bias_level level)
 {
+	struct aic32x4_priv *aic32x4 = snd_soc_codec_get_drvdata(codec);
+
 	switch (level) {
 	case SND_SOC_BIAS_ON:
+		/* Switch on master clock */
+		if (!IS_ERR(aic32x4->mclk)) {
+			int ret;
+
+			ret = clk_prepare_enable(aic32x4->mclk);
+			if (ret) {
+				dev_err(codec->dev, "Failed to enable master clock\n");
+				return ret;
+			}
+		}
+
 		/* Switch on PLL */
 		snd_soc_update_bits(codec, AIC32X4_PLLPR,
 				    AIC32X4_PLLEN, AIC32X4_PLLEN);
@@ -516,6 +531,10 @@ static int aic32x4_set_bias_level(struct snd_soc_codec *codec,
 	case SND_SOC_BIAS_PREPARE:
 		break;
 	case SND_SOC_BIAS_STANDBY:
+		/* Switch off master clock */
+		if (!IS_ERR(aic32x4->mclk))
+			clk_disable_unprepare(aic32x4->mclk);
+
 		/* Switch off PLL */
 		snd_soc_update_bits(codec, AIC32X4_PLLPR,
 				    AIC32X4_PLLEN, 0);
@@ -722,6 +741,10 @@ static int aic32x4_i2c_probe(struct i2c_client *i2c,
 		aic32x4->rstn_gpio = -1;
 	}
 
+	aic32x4->mclk = devm_clk_get(&i2c->dev, "mclk");
+	if (IS_ERR(aic32x4->mclk))
+		dev_info(&i2c->dev, "No mclk found, continuing without clock\n");
+
 	if (gpio_is_valid(aic32x4->rstn_gpio)) {
 		ret = devm_gpio_request_one(&i2c->dev, aic32x4->rstn_gpio,
 				GPIOF_OUT_INIT_LOW, "tlv320aic32x4 rstn");
-- 
1.8.5.2