From 182c51ce7944a214dd77a0b5c0462241e49dd418 Mon Sep 17 00:00:00 2001
From: Mark Brown <broonie@opensource.wolfsonmicro.com>
Date: Tue, 24 Jan 2012 21:07:55 +0000
Subject: [PATCH] ASoC: wm8962: Optimise power consumption for IN4 DC
 measurement usage

When the hardware is configured with one or both of the IN4 inputs used
for DC measurement (with no DC blocking capacitor connected) then we can
improve power consumption slightly in idle modes by applying a register
write sequence. Provide platform data to enable this, implemented using
a regmap patch.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
---
 include/sound/wm8962.h    |  6 ++++++
 sound/soc/codecs/wm8962.c | 18 ++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/include/sound/wm8962.h b/include/sound/wm8962.h
index 1750bed7c2f6..79e6d427b858 100644
--- a/include/sound/wm8962.h
+++ b/include/sound/wm8962.h
@@ -49,6 +49,12 @@ struct wm8962_pdata {
 	bool irq_active_low;
 
 	bool spk_mono;   /* Speaker outputs tied together as mono */
+
+	/**
+	 * This flag should be set if one or both IN4 inputs is wired
+	 * in a DC measurement configuration.
+	 */
+	bool in4_dc_measure;
 };
 
 #endif
diff --git a/sound/soc/codecs/wm8962.c b/sound/soc/codecs/wm8962.c
index cc4049e9174b..2a654fd42d12 100644
--- a/sound/soc/codecs/wm8962.c
+++ b/sound/soc/codecs/wm8962.c
@@ -3638,6 +3638,13 @@ static struct snd_soc_codec_driver soc_codec_dev_wm8962 = {
 	.volatile_register = wm8962_soc_volatile,
 };
 
+/* Improve power consumption for IN4 DC measurement mode */
+static const struct reg_default wm8962_dc_measure[] = {
+	{ 0xfd, 0x1 },
+	{ 0xcc, 0x40 },
+	{ 0xfd, 0 },
+};
+
 static const struct regmap_config wm8962_regmap = {
 	.reg_bits = 16,
 	.val_bits = 16,
@@ -3653,6 +3660,7 @@ static const struct regmap_config wm8962_regmap = {
 static __devinit int wm8962_i2c_probe(struct i2c_client *i2c,
 				      const struct i2c_device_id *id)
 {
+	struct wm8962_pdata *pdata = dev_get_platdata(&i2c->dev);
 	struct wm8962_priv *wm8962;
 	unsigned int reg;
 	int ret, i;
@@ -3731,6 +3739,16 @@ static __devinit int wm8962_i2c_probe(struct i2c_client *i2c,
 		goto err_regmap;
 	}
 
+	if (pdata && pdata->in4_dc_measure) {
+		ret = regmap_register_patch(wm8962->regmap,
+					    wm8962_dc_measure,
+					    ARRAY_SIZE(wm8962_dc_measure));
+		if (ret != 0)
+			dev_err(&i2c->dev,
+				"Failed to configure for DC mesurement: %d\n",
+				ret);
+	}
+
 	regcache_cache_only(wm8962->regmap, true);
 
 	ret = snd_soc_register_codec(&i2c->dev,