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//! Blocking shared SPI bus
use core::cell::RefCell;
use embassy::blocking_mutex::raw::RawMutex;
use embassy::blocking_mutex::Mutex;
use embedded_hal_1::digital::blocking::OutputPin;
use embedded_hal_1::spi;
use embedded_hal_1::spi::blocking::{SpiBusFlush, SpiDevice};
use crate::shared_bus::spi::SpiBusDeviceError;
pub struct SpiBusDevice<'a, M: RawMutex, BUS, CS> {
bus: &'a Mutex<M, RefCell<BUS>>,
cs: CS,
}
impl<'a, M: RawMutex, BUS, CS> SpiBusDevice<'a, M, BUS, CS> {
pub fn new(bus: &'a Mutex<M, RefCell<BUS>>, cs: CS) -> Self {
Self { bus, cs }
}
}
impl<'a, M: RawMutex, BUS, CS> spi::ErrorType for SpiBusDevice<'a, M, BUS, CS>
where
BUS: spi::ErrorType,
CS: OutputPin,
{
type Error = SpiBusDeviceError<BUS::Error, CS::Error>;
}
impl<BUS, M, CS> SpiDevice for SpiBusDevice<'_, M, BUS, CS>
where
M: RawMutex,
BUS: SpiBusFlush,
CS: OutputPin,
{
type Bus = BUS;
fn transaction<R>(&mut self, f: impl FnOnce(&mut Self::Bus) -> Result<R, BUS::Error>) -> Result<R, Self::Error> {
self.cs.set_low().map_err(SpiBusDeviceError::Cs)?;
let (f_res, flush_res) = self.bus.lock(|bus| {
let mut bus = bus.borrow_mut();
let f_res = f(&mut bus);
// On failure, it's important to still flush and deassert CS.
let flush_res = bus.flush();
(f_res, flush_res)
});
let cs_res = self.cs.set_high();
let f_res = f_res.map_err(SpiBusDeviceError::Spi)?;
flush_res.map_err(SpiBusDeviceError::Spi)?;
cs_res.map_err(SpiBusDeviceError::Cs)?;
Ok(f_res)
}
}
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