Gripper does not move on command.

[sbstorz]

To reproduce

1. Start the hardware with scene_bringup, using real hardware.
2. Activate the gripper controller, the gripper hardware should be started automatically.
3. Send a new target position.

The controller manager output is nominal:

[ros2_control_node-1] [INFO] [1765536957.802142531] [controller_manager]: Activating controllers: [ gripper_controller ]
[ros2_control_node-1] [INFO] [1765536957.802480787] [controller_manager]: Switch controller timeout is set to 0, using default 1s!
[ros2_control_node-1] [INFO] [1765536957.802627267] [controller_manager]: Requested controller switch from non-realtime loop
[ros2_control_node-1] [INFO] [1765536957.868845155] [controller_manager]: Activated controllers: [ gripper_controller ]
[ros2_control_node-1] [INFO] [1765536957.869011246] [controller_manager]: Successfully switched controllers!
[ros2_control_node-1] [INFO] [1765536975.401446662] [gripper_controller]: Received & accepted new action goal

but the gripper does not move.

[sbstorz]

This could be caused by a not enabled PWM. Technically the RPI_PWM::start() should return a failure if the PWM fails to enable, however I am not certain this can be trusted. 82764f9 tried to fix it, but still relies on the correct error reporting back.

[sbstorz]

Still an issue.

Hardware component is active:

ros2 control list_hardware_components 

gives:

Hardware Component 1
        name: bioscara_gripper_128
        type: system
        plugin name: bioscara_hardware_interfaces/BioscaraGripperHardwareInterface
        state: id=3 label=active
        read/write rate: 50 Hz
        is_async: False
        command interfaces
                gripper/position [available] [claimed]

but PWM is NOT enabled:

cat /sys/class/pwm/pwmchip0/pwm0/enable

returns 0

Potential Fix
In RPI_PWM::start()
repeat until /sys/class/pwm/pwmchip0/pwm0/enable is 1