ASoC: Factor out I2C 8 bit address 16 bit data I/O

As part of this refactoring the type of the CODEC hw_read operation
is changed to match the regular read operation.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

2 files changed, 72 insertions, 9 deletions

diff --git a/include/sound/soc.h b/include/sound/soc.h
index d0b29a509bdd..4a5846e72473 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -373,7 +373,7 @@ struct snd_soc_codec {
                                 size_t, unsigned int);
         int (*volatile_register)(unsigned int);
         hw_write_t hw_write;
-        hw_read_t hw_read;
+        unsigned int (*hw_read)(struct snd_soc_codec *, unsigned int);
         void *reg_cache;
         short reg_cache_size;
         short reg_cache_step;
diff --git a/sound/soc/soc-cache.c b/sound/soc/soc-cache.c
index 8b126682c843..ab058b811633 100644
--- a/sound/soc/soc-cache.c
+++ b/sound/soc/soc-cache.c
@@ -46,14 +46,82 @@ static int snd_soc_7_9_write(struct snd_soc_codec *codec, unsigned int reg,
                 return -EIO;
 }
 
+static int snd_soc_8_16_write(struct snd_soc_codec *codec, unsigned int reg,
+                              unsigned int value)
+{
+        u16 *reg_cache = codec->reg_cache;
+        u8 data[3];
+
+        data[0] = reg;
+        data[1] = (value >> 8) & 0xff;
+        data[2] = value & 0xff;
+
+        if (!snd_soc_codec_volatile_register(codec, reg))
+                reg_cache[reg] = value;
+
+        if (codec->hw_write(codec->control_data, data, 3) == 3)
+                return 0;
+        else
+                return -EIO;
+}
+
+static unsigned int snd_soc_8_16_read(struct snd_soc_codec *codec,
+                                      unsigned int reg)
+{
+        u16 *cache = codec->reg_cache;
+
+        if (reg >= codec->reg_cache_size ||
+            snd_soc_codec_volatile_register(codec, reg))
+                return codec->hw_read(codec, reg);
+        else
+                return cache[reg];
+}
+
+#if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
+static unsigned int snd_soc_8_16_read_i2c(struct snd_soc_codec *codec,
+                                          unsigned int r)
+{
+        struct i2c_msg xfer[2];
+        u8 reg = r;
+        u16 data;
+        int ret;
+        struct i2c_client *client = codec->control_data;
+
+        /* Write register */
+        xfer[0].addr = client->addr;
+        xfer[0].flags = 0;
+        xfer[0].len = 1;
+        xfer[0].buf = ®
+
+        /* Read data */
+        xfer[1].addr = client->addr;
+        xfer[1].flags = I2C_M_RD;
+        xfer[1].len = 2;
+        xfer[1].buf = (u8 *)&data;
+
+        ret = i2c_transfer(client->adapter, xfer, 2);
+        if (ret != 2) {
+                dev_err(&client->dev, "i2c_transfer() returned %d\n", ret);
+                return 0;
+        }
+
+        return (data >> 8) | ((data & 0xff) << 8);
+}
+#else
+#define snd_soc_8_16_read_i2c NULL
+#endif
 
 static struct {
         int addr_bits;
         int data_bits;
-        int (*write)(struct snd_soc_codec *, unsigned int, unsigned int);
+        int (*write)(struct snd_soc_codec *codec, unsigned int, unsigned int);
         unsigned int (*read)(struct snd_soc_codec *, unsigned int);
+        unsigned int (*i2c_read)(struct snd_soc_codec *, unsigned int);
 } io_types[] = {
         { 7, 9, snd_soc_7_9_write, snd_soc_7_9_read },
+        { 8, 16,
+          snd_soc_8_16_write, snd_soc_8_16_read,
+          snd_soc_8_16_read_i2c },
 };
 
 /**
@@ -82,13 +150,6 @@ int snd_soc_codec_set_cache_io(struct snd_soc_codec *codec,
 {
         int i;
 
-        /* We don't support volatile registers yet - refactoring of
-         * the hw_read operation will be required to do so. */
-        if (codec->volatile_register) {
-                printk(KERN_ERR "Volatile registers not yet supported\n");
-                return -EINVAL;
-        }
-
         for (i = 0; i < ARRAY_SIZE(io_types); i++)
                 if (io_types[i].addr_bits == addr_bits &&
                     io_types[i].data_bits == data_bits)
@@ -111,6 +172,8 @@ int snd_soc_codec_set_cache_io(struct snd_soc_codec *codec,
 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
                 codec->hw_write = (hw_write_t)i2c_master_send;
 #endif
+                if (io_types[i].i2c_read)
+                        codec->hw_read = io_types[i].i2c_read;
                 break;
 
         case SND_SOC_SPI: