Tracking issue for input device support

[HaoboGu]

RMK should support other input devices, like touchpad, encoder, joystick, etc.

[HaoboGu]

Related issue: #29 #69

[HaoboGu]

Since the generic task limitation(embassy-rs/embassy#2454), the only way for defining a generic input device task is to use macro. There are two options:

1. Use a proc-macro like:

#[input_device]
struct RotaryEncoder {}
impl InputDevice for RotaryEncoder {...}

which could be expanded as:

struct RotaryEncoder {}
impl InputDevice for RotaryEncoder {...}
#[embassy_executor::task]
async fn rotaryencoder_task(device: RotaryEncoder) -> ! {
  device.run().await
}

2. Use a decl macro

struct RotaryEncoder {}
impl InputDevice for RotaryEncoder {...}
impl_input_device!(RotaryEncoder, task_name);

expanded code:

struct RotaryEncoder {}
impl InputDevice for RotaryEncoder {...}
#[embassy_executor::task]
async fn task_name(device: RotaryEncoder) -> ! {
  device.run().await
}

• option 1: simple and easy to use, but it's hard to make the task name customizable; better diagnosis if users misuse it.
• option 2: the task name can be customized, but need calling impl_input_device for each device; might be hard to debug if users misuse it

Now I'm going to option 2 first, Any ideas are welcome:)

[HaoboGu]

Okay, after some testing I found neither work with generic tasks. So I have to give up embassy task. The only option seems to be join all input device's run together:

// Implement the input device for RotaryEncoder
struct RotaryEncoder {}
impl InputDevice for RotaryEncoder {...}

in user space:

let e1 = RotaryEncoder {};
let e2 = RotaryEncoder {};
join(run_rmk(), run_devices!(e1, e2)).await