[alsa-devel] [PATCH] ASoC: max98090: add shutdown callback for max98090

[Caesar Wang]

在 2015年04月16日 05:14, Anish Kumar 写道:
> 在 04/10/2015 03:38 AM, Anish Kumar 写道:
>>> To fix pop noise when shutdown,the pop noise during shutdown
>>> is the pmic cutoff power of codec without any notice.
>> Is the power turned off without any intimation to the codec driver?
>> Or is it physically removed? Can you describe the probelm
>> better?
>> When device is shutdown with playing music, the origin driver does nothing for shutdown operation,
>> as a result, pmic will cut off the power of codec IC, thus cause a pop noise from speaker and headphone.
>> So the patch added a shutdown callback for driver, enable volume smoothing and disable zero cross,
>> this is referenced from mic_input which does the samething before mic switch.
>> I'm very happy if some suggestion from maximintegrate . :-)
> Please let me know if the patch worked for you.

Yes, the patch can work for me.
We had tested on chromiumos.

>> +static void max98090_i2c_shutdown(struct i2c_client *i2c)
>> +{
>> +       struct max98090_priv *max98090 = dev_get_drvdata(&i2c->dev);
>> +
>> +       dev_info(&i2c->dev, "shut down device\n");
>> +
>> +       /* Enable volume smoothing, disable zero cross.  This will cause
>> +        * a quick 40ms ramp to mute on shutdown.
>> +        */
>> +       regmap_write(max98090->regmap,
>> +               M98090_REG_LEVEL_CONTROL, M98090_VSENN_MASK);
>> +       regmap_write(max98090->regmap,
>> +               M98090_REG_DEVICE_SHUTDOWN, 0x00);
>> +       msleep(40);
>> +}
>> +
>>
>>
>
>
>
>

-- 
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王晓腾    Caesar Wang
Product R&D Dept.III
Fuzhou Rockchip Electronics Co.Ltd
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