ASoC: twl6040: Introduce SW only shadow register

Software only shadow register to be used by the driver.
For example Earpiece path will need this shadow register.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

2 files changed, 16 insertions, 5 deletions

diff --git a/include/linux/mfd/twl6040.h b/include/linux/mfd/twl6040.h
index ec1ec794fa23..47470cadf969 100644
--- a/include/linux/mfd/twl6040.h
+++ b/include/linux/mfd/twl6040.h
@@ -68,8 +68,6 @@
 #define TWL6040_REG_ACCCTL              0x2D
 #define TWL6040_REG_STATUS              0x2E
 
-#define TWL6040_CACHEREGNUM             (TWL6040_REG_STATUS + 1)
-
 /* INTID (0x03) fields */
 
 #define TWL6040_THINT                   0x01
diff --git a/sound/soc/codecs/twl6040.c b/sound/soc/codecs/twl6040.c
index 9fbfe0ee90ff..96354660c343 100644
--- a/sound/soc/codecs/twl6040.c
+++ b/sound/soc/codecs/twl6040.c
@@ -57,6 +57,10 @@
 #define TWL6040_HF_VOL_MASK     0x1F
 #define TWL6040_HF_VOL_SHIFT    0
 
+/* Shadow register used by the driver */
+#define TWL6040_REG_SW_SHADOW   0x2F
+#define TWL6040_CACHEREGNUM     (TWL6040_REG_SW_SHADOW + 1)
+
 struct twl6040_output {
         u16 active;
         u16 left_vol;
@@ -153,6 +157,8 @@ static const u8 twl6040_reg[TWL6040_CACHEREGNUM] = {
         0x00, /* REG_HFOTRIM    0x2C    */
         0x09, /* REG_ACCCTL     0x2D    */
         0x00, /* REG_STATUS     0x2E (ro) */
+
+        0x00, /* REG_SW_SHADOW  0x2F - Shadow, non HW register */
 };
 
 /* List of registers to be restored after power up */
@@ -236,8 +242,12 @@ static int twl6040_read_reg_volatile(struct snd_soc_codec *codec,
         if (reg >= TWL6040_CACHEREGNUM)
                 return -EIO;
 
-        value = twl6040_reg_read(twl6040, reg);
-        twl6040_write_reg_cache(codec, reg, value);
+        if (likely(reg < TWL6040_REG_SW_SHADOW)) {
+                value = twl6040_reg_read(twl6040, reg);
+                twl6040_write_reg_cache(codec, reg, value);
+        } else {
+                value = twl6040_read_reg_cache(codec, reg);
+        }
 
         return value;
 }
@@ -254,7 +264,10 @@ static int twl6040_write(struct snd_soc_codec *codec,
                 return -EIO;
 
         twl6040_write_reg_cache(codec, reg, value);
-        return twl6040_reg_write(twl6040, reg, value);
+        if (likely(reg < TWL6040_REG_SW_SHADOW))
+                return twl6040_reg_write(twl6040, reg, value);
+        else
+                return 0;
 }
 
 static void twl6040_init_chip(struct snd_soc_codec *codec)