[alsa-devel] [PATCH] [v2] ASoC: cs4270: use the built-in register cache support
Timur Tabi
timur at freescale.com
Mon Jan 10 17:01:32 CET 2011
Update the CS4270 driver to use ASoC's internal codec register cache feature.
This change allows ASoC to perform the low-level I2C operations necessary to
read the register cache. Support is also added for initializing the register
cache with an array of known power-on default values.
The CS4270 driver was handling the register cache itself, but somwhere along
the conversion to multi-compaonent, this feature broke.
Signed-off-by: Timur Tabi <timur at freescale.com>
---
Mark, I don't have power-management support working on my hardware, so I can't
test cs4270_soc_resume(), but I have a suspicion that the call to
i2c_smbus_write_byte_data() should be replaced with codec->hw_write().
sound/soc/codecs/cs4270.c | 156 ++++++++++++++-------------------------------
1 files changed, 48 insertions(+), 108 deletions(-)
diff --git a/sound/soc/codecs/cs4270.c b/sound/soc/codecs/cs4270.c
index 3a582ca..1897d41 100644
--- a/sound/soc/codecs/cs4270.c
+++ b/sound/soc/codecs/cs4270.c
@@ -106,6 +106,21 @@
#define CS4270_MUTE_DAC_A 0x01
#define CS4270_MUTE_DAC_B 0x02
+/* Power-on default values for the registers
+ *
+ * This array contains the power-on default values of the registers, with the
+ * exception of the "CHIPID" register (01h). The lower four bits of that
+ * register contain the hardware revision, so it is treated as volatile.
+ *
+ * Also note that on the CS4270, the first readable register is 1, but ASoC
+ * assumes the first register is 0. Therfore, the array must have an entry for
+ * register 0, but we use cs4270_reg_is_readable() to tell ASoC that it can't
+ * be read.
+ */
+static const u8 cs4270_default_reg_cache[CS4270_LASTREG + 1] = {
+ 0x00, 0x00, 0x00, 0x30, 0x00, 0x60, 0x20, 0x00, 0x00
+};
+
static const char *supply_names[] = {
"va", "vd", "vlc"
};
@@ -178,6 +193,20 @@ static struct cs4270_mode_ratios cs4270_mode_ratios[] = {
/* The number of MCLK/LRCK ratios supported by the CS4270 */
#define NUM_MCLK_RATIOS ARRAY_SIZE(cs4270_mode_ratios)
+static int cs4270_reg_is_readable(unsigned int reg)
+{
+ return (reg >= CS4270_FIRSTREG) && (reg <= CS4270_LASTREG);
+}
+
+static int cs4270_reg_is_volatile(unsigned int reg)
+{
+ /* Unreadable registers are considered volatile */
+ if ((reg < CS4270_FIRSTREG) || (reg > CS4270_LASTREG))
+ return 1;
+
+ return reg == CS4270_CHIPID;
+}
+
/**
* cs4270_set_dai_sysclk - determine the CS4270 samples rates.
* @codec_dai: the codec DAI
@@ -263,97 +292,6 @@ static int cs4270_set_dai_fmt(struct snd_soc_dai *codec_dai,
}
/**
- * cs4270_fill_cache - pre-fill the CS4270 register cache.
- * @codec: the codec for this CS4270
- *
- * This function fills in the CS4270 register cache by reading the register
- * values from the hardware.
- *
- * This CS4270 registers are cached to avoid excessive I2C I/O operations.
- * After the initial read to pre-fill the cache, the CS4270 never updates
- * the register values, so we won't have a cache coherency problem.
- *
- * We use the auto-increment feature of the CS4270 to read all registers in
- * one shot.
- */
-static int cs4270_fill_cache(struct snd_soc_codec *codec)
-{
- u8 *cache = codec->reg_cache;
- struct i2c_client *i2c_client = codec->control_data;
- s32 length;
-
- length = i2c_smbus_read_i2c_block_data(i2c_client,
- CS4270_FIRSTREG | CS4270_I2C_INCR, CS4270_NUMREGS, cache);
-
- if (length != CS4270_NUMREGS) {
- dev_err(codec->dev, "i2c read failure, addr=0x%x\n",
- i2c_client->addr);
- return -EIO;
- }
-
- return 0;
-}
-
-/**
- * cs4270_read_reg_cache - read from the CS4270 register cache.
- * @codec: the codec for this CS4270
- * @reg: the register to read
- *
- * This function returns the value for a given register. It reads only from
- * the register cache, not the hardware itself.
- *
- * This CS4270 registers are cached to avoid excessive I2C I/O operations.
- * After the initial read to pre-fill the cache, the CS4270 never updates
- * the register values, so we won't have a cache coherency problem.
- */
-static unsigned int cs4270_read_reg_cache(struct snd_soc_codec *codec,
- unsigned int reg)
-{
- u8 *cache = codec->reg_cache;
-
- if ((reg < CS4270_FIRSTREG) || (reg > CS4270_LASTREG))
- return -EIO;
-
- return cache[reg - CS4270_FIRSTREG];
-}
-
-/**
- * cs4270_i2c_write - write to a CS4270 register via the I2C bus.
- * @codec: the codec for this CS4270
- * @reg: the register to write
- * @value: the value to write to the register
- *
- * This function writes the given value to the given CS4270 register, and
- * also updates the register cache.
- *
- * Note that we don't use the hw_write function pointer of snd_soc_codec.
- * That's because it's too clunky: the hw_write_t prototype does not match
- * i2c_smbus_write_byte_data(), and it's just another layer of overhead.
- */
-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;
-
- /* 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)) {
- dev_err(codec->dev, "i2c write failed\n");
- return -EIO;
- }
-
- /* We've written to the hardware, so update the cache */
- cache[reg - CS4270_FIRSTREG] = value;
- }
-
- return 0;
-}
-
-/**
* cs4270_hw_params - program the CS4270 with the given hardware parameters.
* @substream: the audio stream
* @params: the hardware parameters to set
@@ -554,11 +492,12 @@ static int cs4270_probe(struct snd_soc_codec *codec)
codec->control_data = cs4270->control_data;
- /* The I2C interface is set up, so pre-fill our register cache */
-
- ret = cs4270_fill_cache(codec);
+ /* Tell ASoC what kind of I/O to use to read the registers. ASoC will
+ * then do the I2C transactions itself.
+ */
+ ret = snd_soc_codec_set_cache_io(codec, 8, 8, cs4270->control_type);
if (ret < 0) {
- dev_err(codec->dev, "failed to fill register cache\n");
+ dev_err(codec->dev, "failed to set cache I/O (ret=%i)\n", ret);
return ret;
}
@@ -568,9 +507,9 @@ static int cs4270_probe(struct snd_soc_codec *codec)
* re-enabled it by using the controls.
*/
- reg = cs4270_read_reg_cache(codec, CS4270_MUTE);
+ reg = snd_soc_read(codec, CS4270_MUTE);
reg &= ~CS4270_MUTE_AUTO;
- ret = cs4270_i2c_write(codec, CS4270_MUTE, reg);
+ ret = snd_soc_write(codec, CS4270_MUTE, reg);
if (ret < 0) {
dev_err(codec->dev, "i2c write failed\n");
return ret;
@@ -582,9 +521,9 @@ static int cs4270_probe(struct snd_soc_codec *codec)
* re-enabled it by using the controls.
*/
- reg = cs4270_read_reg_cache(codec, CS4270_TRANS);
+ reg = snd_soc_read(codec, CS4270_TRANS);
reg &= ~(CS4270_TRANS_SOFT | CS4270_TRANS_ZERO);
- ret = cs4270_i2c_write(codec, CS4270_TRANS, reg);
+ ret = snd_soc_write(codec, CS4270_TRANS, reg);
if (ret < 0) {
dev_err(codec->dev, "i2c write failed\n");
return ret;
@@ -707,15 +646,16 @@ static int cs4270_soc_resume(struct snd_soc_codec *codec)
* Assign this variable to the codec_dev field of the machine driver's
* snd_soc_device structure.
*/
-static struct snd_soc_codec_driver soc_codec_device_cs4270 = {
- .probe = cs4270_probe,
- .remove = cs4270_remove,
- .suspend = cs4270_soc_suspend,
- .resume = cs4270_soc_resume,
- .read = cs4270_read_reg_cache,
- .write = cs4270_i2c_write,
- .reg_cache_size = CS4270_NUMREGS,
- .reg_word_size = sizeof(u8),
+static const struct snd_soc_codec_driver soc_codec_device_cs4270 = {
+ .probe = cs4270_probe,
+ .remove = cs4270_remove,
+ .suspend = cs4270_soc_suspend,
+ .resume = cs4270_soc_resume,
+ .volatile_register = cs4270_reg_is_volatile,
+ .readable_register = cs4270_reg_is_readable,
+ .reg_cache_size = CS4270_LASTREG,
+ .reg_word_size = sizeof(u8),
+ .reg_cache_default = cs4270_default_reg_cache,
};
/**
--
1.7.3.4
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