diff options
| -rw-r--r-- | sound/soc/codecs/cs4270.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/sound/soc/codecs/cs4270.c b/sound/soc/codecs/cs4270.c index 43d50a4d8089..5d601ad6da70 100644 --- a/sound/soc/codecs/cs4270.c +++ b/sound/soc/codecs/cs4270.c @@ -294,19 +294,24 @@ static unsigned int cs4270_read_reg_cache(struct snd_soc_codec *codec, static int cs4270_i2c_write(struct snd_soc_codec *codec, unsigned int reg, unsigned int value) { + u8 *cache = codec->reg_cache; + if ((reg < CS4270_FIRSTREG) || (reg > CS4270_LASTREG)) return -EIO; - if (i2c_smbus_write_byte_data(codec->control_data, reg, value) == 0) { + /* Only perform an I2C operation if the new value is different */ + if (cache[reg - CS4270_FIRSTREG] != value) { + struct i2c_client *client = codec->control_data; + if (i2c_smbus_write_byte_data(client, reg, value)) { + printk(KERN_ERR "cs4270: I2C write failed\n"); + return -EIO; + } + /* We've written to the hardware, so update the cache */ - u8 *cache = codec->reg_cache; cache[reg - CS4270_FIRSTREG] = value; - return 0; - } else { - printk(KERN_ERR "cs4270: I2C write of register %u failed\n", - reg); - return -EIO; } + + return 0; } /* @@ -521,7 +526,7 @@ static int cs4270_i2c_detach(struct i2c_client *client) /* A list of non-DAPM controls that the CS4270 supports */ static const struct snd_kcontrol_new cs4270_snd_controls[] = { SOC_DOUBLE_R("Master Playback Volume", - CS4270_VOLA, CS4270_VOLB, 0, 0xFF, 0) + CS4270_VOLA, CS4270_VOLB, 0, 0xFF, 1) }; static struct i2c_driver cs4270_i2c_driver = { |