[ALSA] soc - neo1973_wm8753.c add suspend and shutdown hooks for lm4857 chip

Patch taken from the openmoko bugtracker
http://bugzilla.openmoko.org/cgi-bin/bugzilla/show_bug.cgi?id=781

This patch adds Suspend/Resume and Shutdown support for the lm4857 to
the driver.
Signed-off-by: Graeme Gregory <graeme@openmoko.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/soc/s3c24xx/neo1973_wm8753.c

@@ -616,6 +616,35 @@ static int lm4857_i2c_attach(struct i2c_adapter *adap)
 	return i2c_probe(adap, &addr_data, lm4857_amp_probe);
 }
 
+static u8 lm4857_state;
+
+static int lm4857_suspend(struct i2c_client *dev, pm_message_t state)
+{
+	dev_dbg(&dev->dev, "lm4857_suspend\n");
+	lm4857_state = lm4857_regs[LM4857_CTRL] & 0xf;
+	if (lm4857_state) {
+		lm4857_regs[LM4857_CTRL] &= 0xf0;
+		lm4857_write_regs();
+	}
+	return 0;
+}
+
+static int lm4857_resume(struct i2c_client *dev)
+{
+	if (lm4857_state) {
+		lm4857_regs[LM4857_CTRL] |= (lm4857_state & 0x0f);
+		lm4857_write_regs();
+	}
+	return 0;
+}
+
+static void lm4857_shutdown(struct i2c_client *dev)
+{
+	dev_dbg(&dev->dev, "lm4857_shutdown\n");
+	lm4857_regs[LM4857_CTRL] &= 0xf0;
+	lm4857_write_regs();
+}
+
 /* corgi i2c codec control layer */
 static struct i2c_driver lm4857_i2c_driver = {
 	.driver = {
@@ -623,6 +652,9 @@ static struct i2c_driver lm4857_i2c_driver = {
 		.owner = THIS_MODULE,
 	},
 	.id =             I2C_DRIVERID_LM4857,
+	.suspend =        lm4857_suspend,
+	.resume	=         lm4857_resume,
+	.shutdown =       lm4857_shutdown,
 	.attach_adapter = lm4857_i2c_attach,
 	.detach_client =  lm4857_i2c_detach,
 	.command =        NULL,