ASoC: twl6040: Custom caching for sensitive DL1/2 path registers

Introduce a small register cache for registers which needs special caching
to reduce pop noise:
TWL6040_REG_HSLCTL, TWL6040_REG_HSRCTL, TWL6040_REG_EARCTL, TWL6040_REG_HFLCTL
and TWL6040_REG_HFRCTL.
Switch over and use the new small cache for these registers instead of the
main reg_cache.
This is in preparation to remove the local ASoC reg_cache from the driver.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 49 insertions, 2 deletions

diff --git a/sound/soc/codecs/twl6040.c b/sound/soc/codecs/twl6040.c
index ef13a501a7b4..fb8c65bd6e5d 100644
--- a/sound/soc/codecs/twl6040.c
+++ b/sound/soc/codecs/twl6040.c
@@ -72,6 +72,7 @@ struct twl6040_data {
         int hs_power_mode_locked;
         bool dl1_unmuted;
         bool dl2_unmuted;
+        u8 dl12_cache[TWL6040_REG_HFRCTL - TWL6040_REG_HSLCTL + 1];
         unsigned int clk_in;
         unsigned int sysclk;
         struct twl6040_jack_data hs_jack;
@@ -174,18 +175,62 @@ static struct snd_pcm_hw_constraint_list sysclk_constraints[] = {
         { .count = ARRAY_SIZE(hp_rates), .list = hp_rates, },
 };
 
+static inline int twl6040_read_dl12_cache(struct snd_soc_codec *codec,
+                                           u8 reg, u8 *value)
+{
+        struct twl6040_data *priv = snd_soc_codec_get_drvdata(codec);
+        int ret = 0;
+
+        switch (reg) {
+        case TWL6040_REG_HSLCTL:
+        case TWL6040_REG_HSRCTL:
+        case TWL6040_REG_EARCTL:
+        case TWL6040_REG_HFLCTL:
+        case TWL6040_REG_HFRCTL:
+                *value = priv->dl12_cache[reg - TWL6040_REG_HSLCTL];
+                break;
+        default:
+                ret = -EINVAL;
+                break;
+        }
+
+        return ret;
+}
+
 /*
  * read twl6040 register cache
  */
 static inline unsigned int twl6040_read_reg_cache(struct snd_soc_codec *codec,
-                                                unsigned int reg)
+                                                  unsigned int reg)
 {
         u8 *cache = codec->reg_cache;
+        u8 value;
 
         if (reg >= TWL6040_CACHEREGNUM)
                 return -EIO;
 
-        return cache[reg];
+        if (twl6040_read_dl12_cache(codec, reg, &value))
+                value = cache[reg];
+
+        return value;
+}
+
+static inline void twl6040_update_dl12_cache(struct snd_soc_codec *codec,
+                                             u8 reg, u8 value)
+{
+        struct twl6040_data *priv = snd_soc_codec_get_drvdata(codec);
+
+        switch (reg) {
+        case TWL6040_REG_HSLCTL:
+        case TWL6040_REG_HSRCTL:
+        case TWL6040_REG_EARCTL:
+        case TWL6040_REG_HFLCTL:
+        case TWL6040_REG_HFRCTL:
+                priv->dl12_cache[reg - TWL6040_REG_HSLCTL] = value;
+                break;
+        default:
+                break;
+        }
 }
 
 /*
@@ -199,6 +244,8 @@ static inline void twl6040_write_reg_cache(struct snd_soc_codec *codec,
         if (reg >= TWL6040_CACHEREGNUM)
                 return;
         cache[reg] = value;
+
+        twl6040_update_dl12_cache(codec, reg, value);
 }
 
 /*