ASoC: wm8903: add regulator handling

The WM8903 has four different voltage inputs: AVDD, CPVDD, DBVDD
and DCVDD. On the Qualcomm APQ8060 Dragonboard these are all
supplied from proper regulators and thus need activating and
binding.

This is a quick-and-dirty solution just grabbing and enabling the
regulator supplies on probe() and disabling them on remove() and
the errorpath. More elaborate power management is likely possible.

I assume the nVidia designs using this codec have some hard-wired
always-on power and will be happy with using the dummy regulators
for this. But someone from the nVidia camp should probably check
whether they can bind these to proper regulators instead.

We also amend the DT binding document. A small change like this
does not warrant a separate patch for augmenting these.

Cc: devicetree@vger.kernel.org
Cc: Mark Brown <broonie@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/wm8903.txt

@@ -28,6 +28,14 @@ Optional properties:
     performed. If any entry has the value 0xffffffff, that GPIO's
     configuration will not be modified.
 
+  - AVDD-supply : Analog power supply regulator on the AVDD pin.
+
+  - CPVDD-supply : Charge pump supply regulator on the CPVDD pin.
+
+  - DBVDD-supply : Digital buffer supply regulator for the DBVDD pin.
+
+  - DCVDD-supply : Digital core supply regulator for the DCVDD pin.
+
 Pins on the device (for linking into audio routes):
 
   * IN1L
@@ -54,6 +62,11 @@ codec: wm8903@1a {
 	reg = <0x1a>;
 	interrupts = < 347 >;
 
+	AVDD-supply = <&fooreg_a>;
+	CPVDD-supply = <&fooreg_b>;
+	DBVDD-supply = <&fooreg_c>;
+	DCVDC-supply = <&fooreg_d>;
+
 	gpio-controller;
 	#gpio-cells = <2>;
 

sound/soc/codecs/wm8903.c

@@ -24,6 +24,7 @@
 #include <linux/pm.h>
 #include <linux/i2c.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/irq.h>
 #include <linux/mutex.h>
@@ -115,10 +116,19 @@ static const struct reg_default wm8903_reg_defaults[] = {
 	{ 172, 0x0000 },    /* R172 - Analogue Output Bias 0 */
 };
 
+#define WM8903_NUM_SUPPLIES 4
+static const char *wm8903_supply_names[WM8903_NUM_SUPPLIES] = {
+	"AVDD",
+	"CPVDD",
+	"DBVDD",
+	"DCVDD",
+};
+
 struct wm8903_priv {
 	struct wm8903_platform_data *pdata;
 	struct device *dev;
 	struct regmap *regmap;
+	struct regulator_bulk_data supplies[WM8903_NUM_SUPPLIES];
 
 	int sysclk;
 	int irq;
@@ -2030,6 +2040,23 @@ static int wm8903_i2c_probe(struct i2c_client *i2c,
 
 	pdata = wm8903->pdata;
 
+	for (i = 0; i < ARRAY_SIZE(wm8903->supplies); i++)
+		wm8903->supplies[i].supply = wm8903_supply_names[i];
+
+	ret = devm_regulator_bulk_get(&i2c->dev, ARRAY_SIZE(wm8903->supplies),
+				      wm8903->supplies);
+	if (ret != 0) {
+		dev_err(&i2c->dev, "Failed to request supplies: %d\n", ret);
+		return ret;
+	}
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(wm8903->supplies),
+				    wm8903->supplies);
+	if (ret != 0) {
+		dev_err(&i2c->dev, "Failed to enable supplies: %d\n", ret);
+		return ret;
+	}
+
 	ret = regmap_read(wm8903->regmap, WM8903_SW_RESET_AND_ID, &val);
 	if (ret != 0) {
 		dev_err(&i2c->dev, "Failed to read chip ID: %d\n", ret);
@@ -2160,6 +2187,8 @@ static int wm8903_i2c_probe(struct i2c_client *i2c,
 
 	return 0;
 err:
+	regulator_bulk_disable(ARRAY_SIZE(wm8903->supplies),
+			       wm8903->supplies);
 	return ret;
 }
 
@@ -2167,6 +2196,8 @@ static int wm8903_i2c_remove(struct i2c_client *client)
 {
 	struct wm8903_priv *wm8903 = i2c_get_clientdata(client);
 
+	regulator_bulk_disable(ARRAY_SIZE(wm8903->supplies),
+			       wm8903->supplies);
 	if (client->irq)
 		free_irq(client->irq, wm8903);
 	wm8903_free_gpio(wm8903);