Cloneable timer

[jannic]

Make Timer a cloneable type:

We don't support de-initializing a Timer anyways. And once it's initialized, all operations on it are either read-only, or already wrapped in the separate alarm structures.

Therefore, we can safely allow for Timer to be cloned, and implement the delay functions directly on it. That makes the API more ergonomic.

Co-authored-by: Wilfried Chauveau wilfried.chauveau@ithinuel.me

[ithinuel]

I really find this convoluted for a loop that's only present when we're implementing support for u64.
I think it would be more readable and less error-prone to have this in its own impl block.

[jannic]

Fair. It's one thing that the optimizer removes the loop, but that doesn't help readability. I'll implement the u64 version separately.

[jannic]

Or should we skip the u64 implementation entirely? A blocking delay of more than an hour is usually just wrong. And if someone really needs it for some reason, it's not difficult to implement it locally:

 use embedded_hal::blocking::delay::DelayUs;                                                                                                                                                                     
                                                                                                                                                                                                                 
 pub struct DelayU64<T>(T);                                                                                                                                                                                      
                                                                                                                                                                                                                 
 impl<T> DelayU64<T> {                                                                                                                                                                                           
     pub fn new(delay: T) -> Self {                                                                                                                                                                              
         Self(delay)                                                                                                                                                                                             
     }                                                                                                                                                                                                           
 }                                                                                                                                                 
                                                                                                                                                                                                                 
 impl<T> DelayUs<u64> for DelayU64<T>                                                                                                                                                                            
 where                                                                                                                                                                                                           
     T: DelayUs<u32>,                                                                                                                                                                                            
 {                                                                                                                                                                                                               
     fn delay_us(&mut self, mut us: u64) {                                                                                                                                                                 
         while us > u32::MAX as u64 {                                                                                                                                                                
             self.0.delay_us(u32::MAX);                                                                                                                                                                          
             us -= u32::MAX as u64;                                                                                             
         }                                                                                                                      
         self.0.delay_us(us as u32);                                                                                            
     }                                                                                                                          
 } 

And in case anyone really misses these functions, we can always add them later.