embassy-stm32: Add SimplePwmChannel #3317
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| /// This returns all four channels, including channels that | ||
| /// aren't configured with a [`PwmPin`]. | ||
| // TODO: I hate the name "split" | ||
| pub fn split(&mut self) -> SimplePwmChannels<'_, T> { |
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with this signature, the split channels still borrow from self, so you can't easily create a PWM in main then pass ownership of some channels to TaskA and others to TaskB. You'd have to put the PWM in a StaticCell to get the lifetimes right.
Instead the signature could be fn split(self) -> SimplePwmChannels<'d, T>. This way the unsplit PWM is simply gone, and the channels can live independently. It should be doable by unsafely duplicating the Timer, or making the channels contain a pointer to PAC regs.
(A split function that takes &mut self can still be useful if you want to only temporarily split, and regain access to the unsplit PWM once you drop the channels. We could have both, I've seen this "temporary split" called split_by_ref() in other crates.)
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I can't seem to unsafely clone the timer PeripheralRef, there is a missing trait bound somewhere.
Aside from that, it is a bit unfortunate that splitting the channels means that the timer will never be disabled, even if all the channels are dropped.
Ideally, the channels would be refcounted with bit flags, which could also make it easier to hand out channels without accidentally duplicating channels. That sounds pretty complex though, so I am going to leave it as a "future possibility" for now.
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yeah leaving it for future work sounds good to me.
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