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FMPI2c embedded-hal implementations
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@burrbull
burrbull committed Jul 29, 2024
1 parent eca5943 commit 1d4f773
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1 change: 1 addition & 0 deletions CHANGELOG.md
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Expand Up @@ -23,6 +23,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
- Use `stm32f4-staging` until `stm32f4` is released [#706]
- use GPIO pac fields instead of raw write
- RTIC2 monotonics fix: CC1 instead of CC3
- Fefactor FMPI2c `embedded-hal` implementations
- Allow different lengths of buffers in hal_1 SpiBus impl [#566]
- Clean SPI write impls
- move `ptr()` to `Ptr` trait [#773]
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288 changes: 218 additions & 70 deletions src/fmpi2c.rs
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Original file line number Diff line number Diff line change
@@ -1,17 +1,24 @@
use core::ops::Deref;

use crate::gpio;
use crate::i2c::{Error, NoAcknowledgeSource};

use crate::pac::fmpi2c1 as i2c1;
use crate::pac::{self, RCC};
use crate::rcc::{BusClock, Enable, Reset};
use fugit::{HertzU32 as Hertz, RateExtU32};

#[path = "i2c/common.rs"]
mod common;
pub use common::{Address, Error, NoAcknowledgeSource};
use common::{Hal02Operation, Hal1Operation};

// Old names
pub use I2c as FmpI2c;
pub use Mode as FmpMode;

#[path = "i2c/hal_02.rs"]
mod hal_02;
#[path = "i2c/hal_1.rs"]
mod hal_1;

pub trait Instance:
Expand Down Expand Up @@ -222,6 +229,83 @@ impl<I2C: Instance> I2c<I2C> {
Ok(())
}

/// Sends START and Address for writing
#[inline(always)]
fn prepare_write(&self, addr: Address, datalen: usize) -> Result<(), Error> {
// Set up current slave address for writing and disable autoending
self.i2c.cr2().modify(|_, w| {
match addr {
Address::Seven(addr) => {
w.add10().clear_bit();
w.sadd().set(u16::from(addr) << 1);
}
Address::Ten(addr) => {
w.add10().set_bit();
w.sadd().set(addr);
}
}
w.nbytes().set(datalen as u8);
w.rd_wrn().clear_bit();
w.autoend().clear_bit()
});

// Send a START condition
self.i2c.cr2().modify(|_, w| w.start().set_bit());

// Wait until address was sent
while {
let isr = self.i2c.isr().read();
self.check_and_clear_error_flags(&isr)
.map_err(Error::nack_addr)?;
isr.txis().bit_is_clear() && isr.tc().bit_is_clear()
} {}

Ok(())
}

/// Sends START and Address for reading
fn prepare_read(
&self,
addr: Address,
buflen: usize,
first_transaction: bool,
) -> Result<(), Error> {
// Set up current address for reading
self.i2c.cr2().modify(|_, w| {
match addr {
Address::Seven(addr) => {
w.add10().clear_bit();
w.sadd().set(u16::from(addr) << 1);
}
Address::Ten(addr) => {
w.add10().set_bit();
w.head10r().bit(!first_transaction);
w.sadd().set(addr);
}
}
w.nbytes().set(buflen as u8);
w.rd_wrn().set_bit()
});

// Send a START condition
self.i2c.cr2().modify(|_, w| w.start().set_bit());

// Send the autoend after setting the start to get a restart
self.i2c.cr2().modify(|_, w| w.autoend().set_bit());

Ok(())
}

fn write_bytes(&mut self, bytes: impl Iterator<Item = u8>) -> Result<(), Error> {
// Send bytes
for c in bytes {
self.send_byte(c)?;
}

// Fallthrough is success
Ok(())
}

fn send_byte(&self, byte: u8) -> Result<(), Error> {
// Wait until we're ready for sending
while {
Expand Down Expand Up @@ -251,72 +335,38 @@ impl<I2C: Instance> I2c<I2C> {
Ok(value)
}

pub fn read(&mut self, addr: u8, buffer: &mut [u8]) -> Result<(), Error> {
// Set up current address for reading
self.i2c.cr2().modify(|_, w| {
w.sadd().set(u16::from(addr) << 1);
w.nbytes().set(buffer.len() as u8);
w.rd_wrn().set_bit()
});

// Send a START condition
self.i2c.cr2().modify(|_, w| w.start().set_bit());

// Send the autoend after setting the start to get a restart
self.i2c.cr2().modify(|_, w| w.autoend().set_bit());

// Now read in all bytes
for c in buffer.iter_mut() {
fn read_bytes(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
// Receive bytes into buffer
for c in buffer {
*c = self.recv_byte()?;
}

self.end_transaction()
Ok(())
}

pub fn write(&mut self, addr: u8, bytes: &[u8]) -> Result<(), Error> {
// Set up current slave address for writing and enable autoending
self.i2c.cr2().modify(|_, w| {
w.sadd().set(u16::from(addr) << 1);
w.nbytes().set(bytes.len() as u8);
w.rd_wrn().clear_bit();
w.autoend().set_bit()
});

// Send a START condition
self.i2c.cr2().modify(|_, w| w.start().set_bit());

// Send out all individual bytes
for c in bytes {
self.send_byte(*c)?;
}
pub fn read(&mut self, addr: impl Into<Address>, buffer: &mut [u8]) -> Result<(), Error> {
self.prepare_read(addr.into(), buffer.len(), true)?;
self.read_bytes(buffer)?;

self.end_transaction()
}

pub fn write_read(&mut self, addr: u8, bytes: &[u8], buffer: &mut [u8]) -> Result<(), Error> {
// Set up current slave address for writing and disable autoending
self.i2c.cr2().modify(|_, w| {
w.sadd().set(u16::from(addr) << 1);
w.nbytes().set(bytes.len() as u8);
w.rd_wrn().clear_bit();
w.autoend().clear_bit()
});
pub fn write(&mut self, addr: impl Into<Address>, bytes: &[u8]) -> Result<(), Error> {
self.prepare_write(addr.into(), bytes.len())?;
self.write_bytes(bytes.iter().cloned())?;

// Send a START condition
self.i2c.cr2().modify(|_, w| w.start().set_bit());
self.end_transaction()
}

// Wait until the transmit buffer is empty and there hasn't been any error condition
while {
let isr = self.i2c.isr().read();
self.check_and_clear_error_flags(&isr)
.map_err(Error::nack_addr)?;
isr.txis().bit_is_clear() && isr.tc().bit_is_clear()
} {}

// Send out all individual bytes
for c in bytes {
self.send_byte(*c)?;
}
pub fn write_read(
&mut self,
addr: impl Into<Address>,
bytes: &[u8],
buffer: &mut [u8],
) -> Result<(), Error> {
let addr = addr.into();
self.prepare_write(addr, bytes.len())?;
self.write_bytes(bytes.iter().cloned())?;

// Wait until data was sent
while {
Expand All @@ -326,24 +376,122 @@ impl<I2C: Instance> I2c<I2C> {
isr.tc().bit_is_clear()
} {}

// Set up current address for reading
self.i2c.cr2().modify(|_, w| {
w.sadd().set(u16::from(addr) << 1);
w.nbytes().set(buffer.len() as u8);
w.rd_wrn().set_bit()
});
self.read(addr, buffer)
}

// Send another START condition
self.i2c.cr2().modify(|_, w| w.start().set_bit());
pub fn transaction<'a>(
&mut self,
addr: impl Into<Address>,
mut ops: impl Iterator<Item = Hal1Operation<'a>>,
) -> Result<(), Error> {
let addr = addr.into();
if let Some(mut prev_op) = ops.next() {
// 1. Generate Start for operation
match &prev_op {
Hal1Operation::Read(buf) => self.prepare_read(addr, buf.len(), true)?,
Hal1Operation::Write(data) => self.prepare_write(addr, data.len())?,
};

for op in ops {
// 2. Execute previous operations.
match &mut prev_op {
Hal1Operation::Read(rb) => self.read_bytes(rb)?,
Hal1Operation::Write(wb) => self.write_bytes(wb.iter().cloned())?,
};
// 3. If operation changes type we must generate new start
match (&prev_op, &op) {
(Hal1Operation::Read(_), Hal1Operation::Write(data)) => {
self.prepare_write(addr, data.len())?
}
(Hal1Operation::Write(_), Hal1Operation::Read(buf)) => {
self.prepare_read(addr, buf.len(), false)?
}
_ => {} // No changes if operation have not changed
}

prev_op = op;
}

// Send the autoend after setting the start to get a restart
self.i2c.cr2().modify(|_, w| w.autoend().set_bit());
// 4. Now, prev_op is last command use methods variations that will generate stop
match prev_op {
Hal1Operation::Read(rb) => self.read_bytes(rb)?,
Hal1Operation::Write(wb) => self.write_bytes(wb.iter().cloned())?,
};

// Now read in all bytes
for c in buffer.iter_mut() {
*c = self.recv_byte()?;
self.end_transaction()?;
}

self.end_transaction()
// Fallthrough is success
Ok(())
}

pub fn transaction_slice(
&mut self,
addr: impl Into<Address>,
ops_slice: &mut [Hal1Operation<'_>],
) -> Result<(), Error> {
let addr = addr.into();
transaction_impl!(self, addr, ops_slice, Hal1Operation);
// Fallthrough is success
Ok(())
}

fn transaction_slice_hal_02(
&mut self,
addr: impl Into<Address>,
ops_slice: &mut [Hal02Operation<'_>],
) -> Result<(), Error> {
let addr = addr.into();
transaction_impl!(self, addr, ops_slice, Hal02Operation);
// Fallthrough is success
Ok(())
}
}

macro_rules! transaction_impl {
($self:ident, $addr:ident, $ops_slice:ident, $Operation:ident) => {
let i2c = $self;
let addr = $addr;
let mut ops = $ops_slice.iter_mut();

if let Some(mut prev_op) = ops.next() {
// 1. Generate Start for operation
match &prev_op {
$Operation::Read(buf) => i2c.prepare_read(addr, buf.len(), true)?,
$Operation::Write(data) => i2c.prepare_write(addr, data.len())?,
};

for op in ops {
// 2. Execute previous operations.
match &mut prev_op {
$Operation::Read(rb) => i2c.read_bytes(rb)?,
$Operation::Write(wb) => i2c.write_bytes(wb.iter().cloned())?,
};
// 3. If operation changes type we must generate new start
match (&prev_op, &op) {
($Operation::Read(_), $Operation::Write(data)) => {
i2c.prepare_write(addr, data.len())?
}
($Operation::Write(_), $Operation::Read(buf)) => {
i2c.prepare_read(addr, buf.len(), false)?
}
_ => {} // No changes if operation have not changed
}

prev_op = op;
}

// 4. Now, prev_op is last command use methods variations that will generate stop
match prev_op {
$Operation::Read(rb) => i2c.read_bytes(rb)?,
$Operation::Write(wb) => i2c.write_bytes(wb.iter().cloned())?,
};

i2c.end_transaction()?;
}
};
}
use transaction_impl;

// Note: implementation is from f0xx-hal
// TODO: check error handling. See https://github.com/stm32-rs/stm32f0xx-hal/pull/95/files
28 changes: 0 additions & 28 deletions src/fmpi2c/hal_02.rs
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