FIDL in drivers

A device may implement the ddk::Messagable mixin in order to be messaged by devfs when a client tries to connect to the driver. A driver has to implement ddk::Messagable with the specific FIDL interface it would like to speak.

For example a driver implementing the fuchsia_input_report::InputDevice interface might have a class definition like the following:

class InputReportDriver;
using DriverDeviceType = ddk::Device<InputReportDriver, ddk::Unbindable,
class InputReportDriver : public DriverDeviceType{
    // Implement the class methods here.

Clients that wish to speak to this device would open the relevant device file in /dev/class/input-report/ and begin sending FIDL messages.