ASoC: codecs: wm8904: Fix register cache incoherency

The multi-component patch(commit f0fba2ad1) moved the allocation of the
register cache from the driver to the ASoC core. Most drivers where adjusted to
this, but the wm8904 driver still uses its own register cache for its
private functions, while functions from the ASoC core use the generic cache.
Thus we end up with two from each other incoherent caches, which can lead to
undefined behaviour.
This patch fixes the issue by changing the wm8904 driver to use the
generic register cache in its private functions.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Ian Lartey <ian@opensource.wolfsonmicro.com>
Cc: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@kernel.org (for 2.6.37 only)

sound/soc/codecs/wm8904.c

@@ -50,8 +50,6 @@ static const char *wm8904_supply_names[WM8904_NUM_SUPPLIES] = {
 /* codec private data */
 struct wm8904_priv {
 
-	u16 reg_cache[WM8904_MAX_REGISTER + 1];
-
 	enum wm8904_type devtype;
 	void *control_data;
 
@@ -2094,7 +2092,7 @@ static int wm8904_digital_mute(struct snd_soc_dai *codec_dai, int mute)
 
 static void wm8904_sync_cache(struct snd_soc_codec *codec)
 {
-	struct wm8904_priv *wm8904 = snd_soc_codec_get_drvdata(codec);
+	u16 *reg_cache = codec->reg_cache;
 	int i;
 
 	if (!codec->cache_sync)
@@ -2105,14 +2103,14 @@ static void wm8904_sync_cache(struct snd_soc_codec *codec)
 	/* Sync back cached values if they're different from the
 	 * hardware default.
 	 */
-	for (i = 1; i < ARRAY_SIZE(wm8904->reg_cache); i++) {
+	for (i = 1; i < codec->driver->reg_cache_size; i++) {
 		if (!wm8904_access[i].writable)
 			continue;
 
-		if (wm8904->reg_cache[i] == wm8904_reg[i])
+		if (reg_cache[i] == wm8904_reg[i])
 			continue;
 
-		snd_soc_write(codec, i, wm8904->reg_cache[i]);
+		snd_soc_write(codec, i, reg_cache[i]);
 	}
 
 	codec->cache_sync = 0;
@@ -2371,6 +2369,7 @@ static int wm8904_probe(struct snd_soc_codec *codec)
 {
 	struct wm8904_priv *wm8904 = snd_soc_codec_get_drvdata(codec);
 	struct wm8904_pdata *pdata = wm8904->pdata;
+	u16 *reg_cache = codec->reg_cache;
 	int ret, i;
 
 	codec->cache_sync = 1;
@@ -2437,19 +2436,19 @@ static int wm8904_probe(struct snd_soc_codec *codec)
 	}
 
 	/* Change some default settings - latch VU and enable ZC */
-	wm8904->reg_cache[WM8904_ADC_DIGITAL_VOLUME_LEFT] |= WM8904_ADC_VU;
-	wm8904->reg_cache[WM8904_ADC_DIGITAL_VOLUME_RIGHT] |= WM8904_ADC_VU;
-	wm8904->reg_cache[WM8904_DAC_DIGITAL_VOLUME_LEFT] |= WM8904_DAC_VU;
-	wm8904->reg_cache[WM8904_DAC_DIGITAL_VOLUME_RIGHT] |= WM8904_DAC_VU;
-	wm8904->reg_cache[WM8904_ANALOGUE_OUT1_LEFT] |= WM8904_HPOUT_VU |
+	reg_cache[WM8904_ADC_DIGITAL_VOLUME_LEFT] |= WM8904_ADC_VU;
+	reg_cache[WM8904_ADC_DIGITAL_VOLUME_RIGHT] |= WM8904_ADC_VU;
+	reg_cache[WM8904_DAC_DIGITAL_VOLUME_LEFT] |= WM8904_DAC_VU;
+	reg_cache[WM8904_DAC_DIGITAL_VOLUME_RIGHT] |= WM8904_DAC_VU;
+	reg_cache[WM8904_ANALOGUE_OUT1_LEFT] |= WM8904_HPOUT_VU |
 		WM8904_HPOUTLZC;
-	wm8904->reg_cache[WM8904_ANALOGUE_OUT1_RIGHT] |= WM8904_HPOUT_VU |
+	reg_cache[WM8904_ANALOGUE_OUT1_RIGHT] |= WM8904_HPOUT_VU |
 		WM8904_HPOUTRZC;
-	wm8904->reg_cache[WM8904_ANALOGUE_OUT2_LEFT] |= WM8904_LINEOUT_VU |
+	reg_cache[WM8904_ANALOGUE_OUT2_LEFT] |= WM8904_LINEOUT_VU |
 		WM8904_LINEOUTLZC;
-	wm8904->reg_cache[WM8904_ANALOGUE_OUT2_RIGHT] |= WM8904_LINEOUT_VU |
+	reg_cache[WM8904_ANALOGUE_OUT2_RIGHT] |= WM8904_LINEOUT_VU |
 		WM8904_LINEOUTRZC;
-	wm8904->reg_cache[WM8904_CLOCK_RATES_0] &= ~WM8904_SR_MODE;
+	reg_cache[WM8904_CLOCK_RATES_0] &= ~WM8904_SR_MODE;
 
 	/* Apply configuration from the platform data. */
 	if (wm8904->pdata) {
@@ -2457,23 +2456,23 @@ static int wm8904_probe(struct snd_soc_codec *codec)
 			if (!pdata->gpio_cfg[i])
 				continue;
 
-			wm8904->reg_cache[WM8904_GPIO_CONTROL_1 + i]
+			reg_cache[WM8904_GPIO_CONTROL_1 + i]
 				= pdata->gpio_cfg[i] & 0xffff;
 		}
 
 		/* Zero is the default value for these anyway */
 		for (i = 0; i < WM8904_MIC_REGS; i++)
-			wm8904->reg_cache[WM8904_MIC_BIAS_CONTROL_0 + i]
+			reg_cache[WM8904_MIC_BIAS_CONTROL_0 + i]
 				= pdata->mic_cfg[i];
 	}
 
 	/* Set Class W by default - this will be managed by the Class
 	 * G widget at runtime where bypass paths are available.
 	 */
-	wm8904->reg_cache[WM8904_CLASS_W_0] |= WM8904_CP_DYN_PWR;
+	reg_cache[WM8904_CLASS_W_0] |= WM8904_CP_DYN_PWR;
 
 	/* Use normal bias source */
-	wm8904->reg_cache[WM8904_BIAS_CONTROL_0] &= ~WM8904_POBCTRL;
+	reg_cache[WM8904_BIAS_CONTROL_0] &= ~WM8904_POBCTRL;
 
 	wm8904_set_bias_level(codec, SND_SOC_BIAS_STANDBY);