3 releases (breaking)
0.2.0 | Oct 19, 2021 |
---|---|
0.1.0 | Oct 18, 2021 |
0.0.1 | Oct 17, 2021 |
#994 in Unix APIs
24KB
507 lines
pwmd
pwmd exposes the Linux' sysfs PWM interface to DBUS.
Why
PWM controllers are often used for LEDs. Playing around with LEDs is fun and it's also super easy to control them, thanks to a simple sysfs based API the Linux kernel exposes. Only drawback: your hacky script needs root privileges to use it.
With pwmd you can use DBUS to control LEDs without root privileges. Under the hood, pwmd uses the sysfs API - it exposes this part of sysfs to user-space via DBUS, without running the risk of scripts causing mayhem to other parts of sysfs.
Getting started
$ cargo install --git https://github.com/kevinbader/pwmd
$ sudo pwmd
pwmd then exposes its API on DBUS. For example, you could export the first PWM controller using dbus-send
:
SERVICE="com.kevinbader.pwmd"
OBJECT_PATH="/com/kevinbader/pwmd/pwm1"
INTERFACE="com.kevinbader.pwmd.pwm1"
METHOD="Export"
dbus-send --system \
--type=method_call --print-reply \
--dest=$SERVICE \
$OBJECT_PATH \
${INTERFACE}.${METHOD} uint32:0
Use busctl
to see available methods:
$ busctl --user introspect com.kevinbader.pwmd /com/kevinbader/pwmd/pwm1
NAME TYPE SIGNATURE RESULT/VALUE FLAGS
com.kevinbader.pwmd.pwm1 interface - - -
.Disable method uu (qs) -
.Enable method uu (qs) -
.Export method u (qs) -
.Quit method - (qs) -
.SetDutyCycleNs method uut (qs) -
.SetPeriodNs method uut (qs) -
.SetPolarity method uus (qs) -
.Unexport method u (qs) -
TODOs
- CONTRIBUTORS file
- GitHub Actions pipeline setup
- systemd file
- describe how to control logging output
- high-level API specifically for LEDs
Dependencies
~22–36MB
~561K SLoC