[PATCH] ASoC: nau8821: Add headset button detection

[SevenLee]

On 6/27/2022 8:14 PM, Mark Brown wrote:
> On Mon, Jun 27, 2022 at 11:29:59AM +0800, Seven Lee wrote:
>> This patch adds the function of headphone button detection,
>> Button detection will be enabled if the device tree
>> has a key_enable property.
> Is there any reason why we wouldn't support button detect - is this
> device unusual in requiring some external hardware to support that or
> something?

Because the size of the external resistance will affect the speed of JD
detection (insertion or extraction). When the eject detection is slow, 
the key event
may be accidentally triggered before the unplug event is issued.Causes error
detection to occur, which can cause User Space application errors. But 
the chip
design is finalized and cannot be changed. Since this is a known issue, some
client applications do not need to use key detection applications, so 
they hope to
turn off the key detection function. Since this is a known issue, some 
customer
applications do not need to use keystroke detection applications, so 
they want to
turn keystroke detection off. In this way, the application can avoid 
seeing the
occurrence of key events.