Can I detect insertion and removal of headset using alsa API ? Which API should I use ? My kernel is 3.0 Linux running on ARM.
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Can I detect insertion and removal of headset using alsa API ? Which API should I use ? My kernel is 3.0 Linux running on ARM.
Having wanted precisely this functionality for a embedded project, I did some investigations and came to the conclusion (about 6 months ago) that there isn’t any generic support in ALSA for jack insertion detection.
Interestingly, I did find headphone (and microphone) detection support in the codec driver I was using (tlv310aic3xxx), but is didn’t seem to be plumbed into any upper layers. I suspect that the reason this exists is is Android.
There are essentially two ways of adding this support:
Add support to the codec driver – probably exposing a
sysfsnode that something in user-space can then block on.Force access to the I2C bus on which the codec is hung (the codec driver usually ‘owns’ the device) and programme the relevant registers from user-space.
You may face an additional architectural problem in that whilst the codec can detect insertion events, it needs some way of interrupting the CPU. The tlv310aic3xxx devices have programmable GPIO pins, which can be connecting to a interrupt line on the main CPU (if on an embedded platform, this will be another GPIO line). Without this, you’ll need to poll it.