ASoC: max98088: Add master clock handling

If master clock is provided through device tree, then update
the master clock frequency during set_sysclk.

Cc: Tushar Behera <tushar.behera@linaro.org>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Acked-by: Tushar Behera <trblinux@gmail.com>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
[m.felsch@pengutronix.de: move mclk request to i2c_probe]
[m.felsch@pengutronix.de: make use of snd_soc_component_get_bias_level()]
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/max98088.c

@@ -16,6 +16,7 @@
 #include <linux/pm.h>
 #include <linux/i2c.h>
 #include <linux/regmap.h>
+#include <linux/clk.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
@@ -42,6 +43,7 @@ struct max98088_priv {
 	struct regmap *regmap;
 	enum max98088_type devtype;
 	struct max98088_pdata *pdata;
+	struct clk *mclk;
 	unsigned int sysclk;
 	struct max98088_cdata dai[2];
 	int eq_textcnt;
@@ -1103,6 +1105,11 @@ static int max98088_dai_set_sysclk(struct snd_soc_dai *dai,
        if (freq == max98088->sysclk)
                return 0;
 
+	if (!IS_ERR(max98088->mclk)) {
+		freq = clk_round_rate(max98088->mclk, freq);
+		clk_set_rate(max98088->mclk, freq);
+	}
+
        /* Setup clocks for slave mode, and using the PLL
         * PSCLK = 0x01 (when master clk is 10MHz to 20MHz)
         *         0x02 (when master clk is 20MHz to 30MHz)..
@@ -1310,6 +1317,20 @@ static int max98088_set_bias_level(struct snd_soc_component *component,
 		break;
 
 	case SND_SOC_BIAS_PREPARE:
+		/*
+		 * SND_SOC_BIAS_PREPARE is called while preparing for a
+		 * transition to ON or away from ON. If current bias_level
+		 * is SND_SOC_BIAS_ON, then it is preparing for a transition
+		 * away from ON. Disable the clock in that case, otherwise
+		 * enable it.
+		 */
+		if (!IS_ERR(max98088->mclk)) {
+			if (snd_soc_component_get_bias_level(component) ==
+			    SND_SOC_BIAS_ON)
+				clk_disable_unprepare(max98088->mclk);
+			else
+				clk_prepare_enable(max98088->mclk);
+		}
 		break;
 
 	case SND_SOC_BIAS_STANDBY:
@@ -1725,6 +1746,11 @@ static int max98088_i2c_probe(struct i2c_client *i2c,
        if (IS_ERR(max98088->regmap))
 	       return PTR_ERR(max98088->regmap);
 
+	max98088->mclk = devm_clk_get(&i2c->dev, "mclk");
+	if (IS_ERR(max98088->mclk))
+		if (PTR_ERR(max98088->mclk) == -EPROBE_DEFER)
+			return PTR_ERR(max98088->mclk);
+
        max98088->devtype = id->driver_data;
 
        i2c_set_clientdata(i2c, max98088);