[alsa-devel] [PATCH] ASoC: TWL4030: Add EXTMUTE to reduce pop-noise effect

[Peter Ujfalusi]

On Thursday 02 July 2009 03:17:43 ext Candelaria Villareal, Jorge wrote:
> According to TRM, an external FET controlled by a 1.8V output signal
> can be used to reduce the pop-noise heard when the audio amplifier is
> switched on. It is suggested that GPIO6 of TWL4030 be used, but any
> other gpio can be used instead. This is indicated in machine driver
> with the following twl4030_setup_data members:
>
> -hs_extmute. Set to 1 if board has support for EXTMUTE.
>
> -set_hs_extmute. Set to a callback funcion to control an external gpio
> line. Set to NULL if MUTE[GPIO6] pin is used.
>
> Codec driver takes care of enabling and disabling this output during
> the headset pop attenuation sequence.
>
> Also add a delay to let VMID settle in ramp up sequence.

I can not see any problems with this patch, but unfortunately I can not test 
it since none of my hardware supports the extmute on the headset output...

Thank you!

Acked-by: Peter Ujfalusi <peter.ujfalusi at nokia.com>