mfd: mc13xxx: Move SPI erratum workaround into SPI I/O function

Move the workaround for double sending AUDIO_CODEC and AUDIO_DAC writes
into the SPI core, aiding refactoring to eliminate the ASoC custom I/O
functions and avoiding the extra writes for I2C.
Signed-off-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/mc13xxx-spi.c

@@ -94,10 +94,15 @@ static int mc13xxx_spi_write(void *context, const void *data, size_t count)
 {
 	struct device *dev = context;
 	struct spi_device *spi = to_spi_device(dev);
+	const char *reg = data;
 
 	if (count != 4)
 		return -ENOTSUPP;
 
+	/* include errata fix for spi audio problems */
+	if (*reg == MC13783_AUDIO_CODEC || *reg == MC13783_AUDIO_DAC)
+		spi_write(spi, data, count);
+
 	return spi_write(spi, data, count);
 }
 

include/linux/mfd/mc13xxx.h

@@ -41,6 +41,13 @@ int mc13xxx_adc_do_conversion(struct mc13xxx *mc13xxx,
 		unsigned int mode, unsigned int channel,
 		u8 ato, bool atox, unsigned int *sample);
 
+#define MC13783_AUDIO_RX0	36
+#define MC13783_AUDIO_RX1	37
+#define MC13783_AUDIO_TX	38
+#define MC13783_SSI_NETWORK	39
+#define MC13783_AUDIO_CODEC	40
+#define MC13783_AUDIO_DAC	41
+
 #define MC13XXX_IRQ_ADCDONE	0
 #define MC13XXX_IRQ_ADCBISDONE	1
 #define MC13XXX_IRQ_TS		2

sound/soc/codecs/mc13783.c

@@ -125,10 +125,6 @@ static int mc13783_write(struct snd_soc_codec *codec,
 
 	ret = mc13xxx_reg_write(priv->mc13xxx, reg, value);
 
-	/* include errata fix for spi audio problems */
-	if (reg == MC13783_AUDIO_CODEC || reg == MC13783_AUDIO_DAC)
-		ret = mc13xxx_reg_write(priv->mc13xxx, reg, value);
-
 	mc13xxx_unlock(priv->mc13xxx);
 
 	return ret;