On Tue, Nov 22, 2011 at 07:47:10PM +0900, Tomoya MORINAGA wrote:

2011/11/21 Mark Brown broonie@opensource.wolfsonmicro.com wrote:

BTW, What's TLV ? Let me know the full spell of this "TLV".

Tag/Length/Value.

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+static const struct snd_kcontrol_new ml26124_dsp_controls[] = {

• SOC_SINGLE("Play Limitter ON/OFF", ML26124_FILTER_EN, 0, 1, 0),

Do you mean SOC_SINGLE("Play Limitter Switch", ML26124_FILTER_EN, 0, 1, 0) ?

Yes.

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• SOC_SINGLE("Set ALC position", ML26124_FILTER_EN, 5, 1, 0),

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What does this actually do?  From the name it *really* doesn't look like a mixer input.

The above means where connects the ALC. So, this doesn't relate to mixer input.

If this control is not a mixer input it should not be a mixer input in the driver. Though with your explanation I still don't understand what it does so presumably the naming also needs to be improved.

However I couldn't understand the meaning of the widgets. So I didn't write anything.

See Documentation/sound/alsa/soc/dapm.txt.

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+static int snd_card_codec_reg_read(struct ml26124_priv *priv,

• unsigned char reg, unsigned char *val)

+{

• unsigned char data;
• struct i2c_client *i2c;

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Use the standard register access code, don't open code things in your driver unless there's a good reason to.  Current best practice for most I2C or SPI devices is to use regmap, see any recently added driver for examples.

What's "regmap" mean ? or do you mean drivers/mfd/* ? Could you tell me this ?

drivers/base/regmap and also grep in sound/soc/codecs/*.c

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Use snd_soc_update_bits() and the other standard register access functions.

Using snd_soc_update_bits(), need to register ".read" method.

Or use a cache.

Is the same as the above snd_card_codec_reg_read ?

I don't understand this question.