bbb pwm

The buzzer is of a type that needs PWM

See schematic of the cape, its connected to this pin:

P9.14 / GPIO1_18/PWMA

Probably some dts change is necessary to setup the mux / pwm.

Once it works, pwm will be accessable via sysfs:

/sys/class/pwm/

https://www.kernel.org/doc/Documentation/pwm.txt

And then we need to implement this in dbus-systemcalc or some other place. Right now dbus-systemcalc expects to write a simple 1 or 0 to a path (/etc/venus/buzzer), as the CCGX had a buzzer with integrated oscillator.

See dbus-systemcalc related code here.