3 files changed, 681 insertions, 71 deletions

diff --git a/embassy-stm32/src/i2c/config.rs b/embassy-stm32/src/i2c/config.rs
new file mode 100644
index 000000000..eba14f6e0
--- /dev/null
+++ b/embassy-stm32/src/i2c/config.rs
@@ -0,0 +1,149 @@
+use stm32_metapac::i2c::vals::Oamsk;
+
+use crate::gpio::Pull;
+
+#[repr(u8)]
+#[derive(Copy, Clone)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum AddrMask {
+    NOMASK,
+    MASK1,
+    MASK2,
+    MASK3,
+    MASK4,
+    MASK5,
+    MASK6,
+    MASK7,
+}
+impl From<AddrMask> for Oamsk {
+    fn from(value: AddrMask) -> Self {
+        match value {
+            AddrMask::NOMASK => Oamsk::NOMASK,
+            AddrMask::MASK1 => Oamsk::MASK1,
+            AddrMask::MASK2 => Oamsk::MASK2,
+            AddrMask::MASK3 => Oamsk::MASK3,
+            AddrMask::MASK4 => Oamsk::MASK4,
+            AddrMask::MASK5 => Oamsk::MASK5,
+            AddrMask::MASK6 => Oamsk::MASK6,
+            AddrMask::MASK7 => Oamsk::MASK7,
+        }
+    }
+}
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum Address {
+    SevenBit(u8),
+    TenBit(u16),
+}
+impl From<u8> for Address {
+    fn from(value: u8) -> Self {
+        Address::SevenBit(value)
+    }
+}
+impl From<u16> for Address {
+    fn from(value: u16) -> Self {
+        assert!(value < 0x400, "Ten bit address must be less than 0x400");
+        Address::TenBit(value)
+    }
+}
+impl Address {
+    pub(super) fn add_mode(&self) -> stm32_metapac::i2c::vals::Addmode {
+        match self {
+            Address::SevenBit(_) => stm32_metapac::i2c::vals::Addmode::BIT7,
+            Address::TenBit(_) => stm32_metapac::i2c::vals::Addmode::BIT10,
+        }
+    }
+    pub fn addr(&self) -> u16 {
+        match self {
+            Address::SevenBit(addr) => *addr as u16,
+            Address::TenBit(addr) => *addr,
+        }
+    }
+}
+
+#[derive(Copy, Clone)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct OA2 {
+    pub addr: u8,
+    pub mask: AddrMask,
+}
+
+#[derive(Copy, Clone)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum OwnAddresses {
+    OA1(Address),
+    OA2(OA2),
+    Both { oa1: Address, oa2: OA2 },
+}
+
+/// Slave Configuration
+#[derive(Copy, Clone)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct SlaveAddrConfig {
+    /// Target Address(es)
+    pub addr: OwnAddresses,
+    /// Control if the peripheral should respond to the general call address
+    pub general_call: bool,
+}
+impl SlaveAddrConfig {
+    pub fn new_oa1(addr: Address, general_call: bool) -> Self {
+        Self {
+            addr: OwnAddresses::OA1(addr),
+            general_call,
+        }
+    }
+
+    pub fn basic(addr: Address) -> Self {
+        Self {
+            addr: OwnAddresses::OA1(addr),
+            general_call: false,
+        }
+    }
+}
+
+/// I2C config
+#[non_exhaustive]
+#[derive(Copy, Clone)]
+pub struct Config {
+    /// Enable internal pullup on SDA.
+    ///
+    /// Using external pullup resistors is recommended for I2C. If you do
+    /// have external pullups you should not enable this.
+    pub sda_pullup: bool,
+    /// Enable internal pullup on SCL.
+    ///
+    /// Using external pullup resistors is recommended for I2C. If you do
+    /// have external pullups you should not enable this.
+    pub scl_pullup: bool,
+    /// Timeout.
+    #[cfg(feature = "time")]
+    pub timeout: embassy_time::Duration,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self {
+            sda_pullup: false,
+            scl_pullup: false,
+            #[cfg(feature = "time")]
+            timeout: embassy_time::Duration::from_millis(1000),
+        }
+    }
+}
+
+impl Config {
+    pub(super) fn scl_pull_mode(&self) -> Pull {
+        match self.scl_pullup {
+            true => Pull::Up,
+            false => Pull::Down,
+        }
+    }
+
+    pub(super) fn sda_pull_mode(&self) -> Pull {
+        match self.sda_pullup {
+            true => Pull::Up,
+            false => Pull::Down,
+        }
+    }
+}
diff --git a/embassy-stm32/src/i2c/mod.rs b/embassy-stm32/src/i2c/mod.rs
index 739e960b9..0457595d2 100644
--- a/embassy-stm32/src/i2c/mod.rs
+++ b/embassy-stm32/src/i2c/mod.rs
@@ -5,14 +5,18 @@
 #[cfg_attr(any(i2c_v2, i2c_v3), path = "v2.rs")]
 mod _version;
 
+mod config;
+
 use core::future::Future;
 use core::iter;
 use core::marker::PhantomData;
 
+pub use config::*;
 use embassy_hal_internal::{Peripheral, PeripheralRef};
 use embassy_sync::waitqueue::AtomicWaker;
 #[cfg(feature = "time")]
 use embassy_time::{Duration, Instant};
+use mode::{Master, MasterMode, MultiMaster};
 
 use crate::dma::ChannelAndRequest;
 #[cfg(gpio_v2)]
@@ -108,8 +112,56 @@ impl Config {
     }
 }
 
+/// I2C modes
+pub mod mode {
+    trait SealedMode {}
+
+    /// Trait for I2C master operations.
+    #[allow(private_bounds)]
+    pub trait MasterMode: SealedMode {}
+
+    /// Mode allowing for I2C master operations.
+    pub struct Master;
+    /// Mode allowing for I2C master and slave operations.
+    pub struct MultiMaster;
+
+    impl SealedMode for Master {}
+    impl MasterMode for Master {}
+
+    impl SealedMode for MultiMaster {}
+    impl MasterMode for MultiMaster {}
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+/// The command kind to the slave from the master
+pub enum CommandKind {
+    /// Write to the slave
+    SlaveReceive,
+    /// Read from the slave
+    SlaveSend,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+/// The command kind to the slave from the master and the address that the slave matched
+pub struct Command {
+    pub kind: CommandKind,
+    pub address: Address,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+/// The status of the slave send operation
+pub enum SendStatus {
+    /// The slave send operation is done, all bytes have been sent and the master is not requesting more
+    Done,
+    /// The slave send operation is done, but there are leftover bytes that the master did not read
+    LeftoverBytes(usize),
+}
+
 /// I2C driver.
-pub struct I2c<'d, M: Mode> {
+pub struct I2c<'d, M: Mode, IM: MasterMode> {
     info: &'static Info,
     state: &'static State,
     kernel_clock: Hertz,
@@ -120,9 +172,10 @@ pub struct I2c<'d, M: Mode> {
     #[cfg(feature = "time")]
     timeout: Duration,
     _phantom: PhantomData<M>,
+    _phantom2: PhantomData<IM>,
 }
 
-impl<'d> I2c<'d, Async> {
+impl<'d> I2c<'d, Async, Master> {
     /// Create a new I2C driver.
     pub fn new<T: Instance>(
         peri: impl Peripheral<P = T> + 'd,
@@ -148,7 +201,7 @@ impl<'d> I2c<'d, Async> {
     }
 }
 
-impl<'d> I2c<'d, Blocking> {
+impl<'d> I2c<'d, Blocking, Master> {
     /// Create a new blocking I2C driver.
     pub fn new_blocking<T: Instance>(
         peri: impl Peripheral<P = T> + 'd,
@@ -169,7 +222,7 @@ impl<'d> I2c<'d, Blocking> {
     }
 }
 
-impl<'d, M: Mode> I2c<'d, M> {
+impl<'d, M: Mode> I2c<'d, M, Master> {
     /// Create a new I2C driver.
     fn new_inner<T: Instance>(
         _peri: impl Peripheral<P = T> + 'd,
@@ -194,8 +247,10 @@ impl<'d, M: Mode> I2c<'d, M> {
             #[cfg(feature = "time")]
             timeout: config.timeout,
             _phantom: PhantomData,
+            _phantom2: PhantomData,
         };
         this.enable_and_init(freq, config);
+
         this
     }
 
@@ -203,7 +258,9 @@ impl<'d, M: Mode> I2c<'d, M> {
         self.info.rcc.enable_and_reset();
         self.init(freq, config);
     }
+}
 
+impl<'d, M: Mode, IM: MasterMode> I2c<'d, M, IM> {
     fn timeout(&self) -> Timeout {
         Timeout {
             #[cfg(feature = "time")]
@@ -211,8 +268,28 @@ impl<'d, M: Mode> I2c<'d, M> {
         }
     }
 }
+impl<'d, M: Mode> I2c<'d, M, Master> {
+    /// Configure the I2C driver for slave operations, allowing for the driver to be used as a slave and a master (multimaster)
+    pub fn into_slave_multimaster(mut self, slave_addr_config: SlaveAddrConfig) -> I2c<'d, M, MultiMaster> {
+        let mut slave = I2c {
+            info: self.info,
+            state: self.state,
+            kernel_clock: self.kernel_clock,
+            scl: self.scl.take(),
+            sda: self.sda.take(),
+            tx_dma: self.tx_dma.take(),
+            rx_dma: self.rx_dma.take(),
+            #[cfg(feature = "time")]
+            timeout: self.timeout,
+            _phantom: PhantomData,
+            _phantom2: PhantomData,
+        };
+        slave.init_slave(slave_addr_config);
+        slave
+    }
+}
 
-impl<'d, M: Mode> Drop for I2c<'d, M> {
+impl<'d, M: Mode, IM: MasterMode> Drop for I2c<'d, M, IM> {
     fn drop(&mut self) {
         self.scl.as_ref().map(|x| x.set_as_disconnected());
         self.sda.as_ref().map(|x| x.set_as_disconnected());
@@ -329,27 +406,39 @@ foreach_peripheral!(
     };
 );
 
-impl<'d, M: Mode> embedded_hal_02::blocking::i2c::Read for I2c<'d, M> {
+impl<'d, M: Mode, IM: MasterMode, A: embedded_hal_02::blocking::i2c::AddressMode>
+    embedded_hal_02::blocking::i2c::Read<A> for I2c<'d, M, IM>
+where
+    A: Into<Address>,
+{
     type Error = Error;
 
-    fn read(&mut self, address: u8, buffer: &mut [u8]) -> Result<(), Self::Error> {
-        self.blocking_read(address, buffer)
+    fn read(&mut self, address: A, buffer: &mut [u8]) -> Result<(), Self::Error> {
+        self.blocking_read(address.into(), buffer)
     }
 }
 
-impl<'d, M: Mode> embedded_hal_02::blocking::i2c::Write for I2c<'d, M> {
+impl<'d, M: Mode, IM: MasterMode, A: embedded_hal_02::blocking::i2c::AddressMode>
+    embedded_hal_02::blocking::i2c::Write<A> for I2c<'d, M, IM>
+where
+    A: Into<Address>,
+{
     type Error = Error;
 
-    fn write(&mut self, address: u8, write: &[u8]) -> Result<(), Self::Error> {
-        self.blocking_write(address, write)
+    fn write(&mut self, address: A, write: &[u8]) -> Result<(), Self::Error> {
+        self.blocking_write(address.into(), write)
     }
 }
 
-impl<'d, M: Mode> embedded_hal_02::blocking::i2c::WriteRead for I2c<'d, M> {
+impl<'d, M: Mode, IM: MasterMode, A: embedded_hal_02::blocking::i2c::AddressMode>
+    embedded_hal_02::blocking::i2c::WriteRead<A> for I2c<'d, M, IM>
+where
+    A: Into<Address>,
+{
     type Error = Error;
 
-    fn write_read(&mut self, address: u8, write: &[u8], read: &mut [u8]) -> Result<(), Self::Error> {
-        self.blocking_write_read(address, write, read)
+    fn write_read(&mut self, address: A, write: &[u8], read: &mut [u8]) -> Result<(), Self::Error> {
+        self.blocking_write_read(address.into(), write, read)
     }
 }
 
@@ -369,51 +458,57 @@ impl embedded_hal_1::i2c::Error for Error {
     }
 }
 
-impl<'d, M: Mode> embedded_hal_1::i2c::ErrorType for I2c<'d, M> {
+impl<'d, M: Mode, IM: MasterMode> embedded_hal_1::i2c::ErrorType for I2c<'d, M, IM> {
     type Error = Error;
 }
 
-impl<'d, M: Mode> embedded_hal_1::i2c::I2c for I2c<'d, M> {
-    fn read(&mut self, address: u8, read: &mut [u8]) -> Result<(), Self::Error> {
-        self.blocking_read(address, read)
+impl<'d, M: Mode, IM: MasterMode, A: embedded_hal_1::i2c::AddressMode> embedded_hal_1::i2c::I2c<A> for I2c<'d, M, IM>
+where
+    Address: From<A>,
+{
+    fn read(&mut self, address: A, read: &mut [u8]) -> Result<(), Self::Error> {
+        self.blocking_read(address.into(), read)
     }
 
-    fn write(&mut self, address: u8, write: &[u8]) -> Result<(), Self::Error> {
-        self.blocking_write(address, write)
+    fn write(&mut self, address: A, write: &[u8]) -> Result<(), Self::Error> {
+        self.blocking_write(address.into(), write)
     }
 
-    fn write_read(&mut self, address: u8, write: &[u8], read: &mut [u8]) -> Result<(), Self::Error> {
-        self.blocking_write_read(address, write, read)
+    fn write_read(&mut self, address: A, write: &[u8], read: &mut [u8]) -> Result<(), Self::Error> {
+        self.blocking_write_read(address.into(), write, read)
     }
 
     fn transaction(
         &mut self,
-        address: u8,
+        address: A,
         operations: &mut [embedded_hal_1::i2c::Operation<'_>],
     ) -> Result<(), Self::Error> {
-        self.blocking_transaction(address, operations)
+        self.blocking_transaction(address.into(), operations)
     }
 }
 
-impl<'d> embedded_hal_async::i2c::I2c for I2c<'d, Async> {
-    async fn read(&mut self, address: u8, read: &mut [u8]) -> Result<(), Self::Error> {
-        self.read(address, read).await
+impl<'d, IM: MasterMode, A: embedded_hal_async::i2c::AddressMode> embedded_hal_async::i2c::I2c<A> for I2c<'d, Async, IM>
+where
+    Address: From<A>,
+{
+    async fn read(&mut self, address: A, read: &mut [u8]) -> Result<(), Self::Error> {
+        self.read(address.into(), read).await
     }
 
-    async fn write(&mut self, address: u8, write: &[u8]) -> Result<(), Self::Error> {
-        self.write(address, write).await
+    async fn write(&mut self, address: A, write: &[u8]) -> Result<(), Self::Error> {
+        self.write(address.into(), write).await
     }
 
-    async fn write_read(&mut self, address: u8, write: &[u8], read: &mut [u8]) -> Result<(), Self::Error> {
-        self.write_read(address, write, read).await
+    async fn write_read(&mut self, address: A, write: &[u8], read: &mut [u8]) -> Result<(), Self::Error> {
+        self.write_read(address.into(), write, read).await
     }
 
     async fn transaction(
         &mut self,
-        address: u8,
+        address: A,
         operations: &mut [embedded_hal_1::i2c::Operation<'_>],
     ) -> Result<(), Self::Error> {
-        self.transaction(address, operations).await
+        self.transaction(address.into(), operations).await
     }
 }
 
diff --git a/embassy-stm32/src/i2c/v2.rs b/embassy-stm32/src/i2c/v2.rs
index 8c8df79dd..c2560d819 100644
--- a/embassy-stm32/src/i2c/v2.rs
+++ b/embassy-stm32/src/i2c/v2.rs
@@ -2,9 +2,12 @@ use core::cmp;
 use core::future::poll_fn;
 use core::task::Poll;
 
+use config::{Address, OwnAddresses, OA2};
 use embassy_embedded_hal::SetConfig;
 use embassy_hal_internal::drop::OnDrop;
 use embedded_hal_1::i2c::Operation;
+use mode::Master;
+use stm32_metapac::i2c::vals::Addmode;
 
 use super::*;
 use crate::pac::i2c;
@@ -13,17 +16,21 @@ pub(crate) unsafe fn on_interrupt<T: Instance>() {
     let regs = T::info().regs;
     let isr = regs.isr().read();
 
-    if isr.tcr() || isr.tc() {
+    if isr.tcr() || isr.tc() || isr.addr() || isr.stopf() {
         T::state().waker.wake();
     }
-    // The flag can only be cleared by writting to nbytes, we won't do that here, so disable
-    // the interrupt
+
     critical_section::with(|_| {
-        regs.cr1().modify(|w| w.set_tcie(false));
+        regs.cr1().modify(|w| {
+            w.set_addrie(false);
+            // The flag can only be cleared by writting to nbytes, we won't do that here, so disable
+            // the interrupt
+            w.set_tcie(false);
+        });
     });
 }
 
-impl<'d, M: Mode> I2c<'d, M> {
+impl<'d, M: Mode, IM: MasterMode> I2c<'d, M, IM> {
     pub(crate) fn init(&mut self, freq: Hertz, _config: Config) {
         self.info.regs.cr1().modify(|reg| {
             reg.set_pe(false);
@@ -51,7 +58,7 @@ impl<'d, M: Mode> I2c<'d, M> {
 
     fn master_read(
         info: &'static Info,
-        address: u8,
+        address: Address,
         length: usize,
         stop: Stop,
         reload: bool,
@@ -80,8 +87,8 @@ impl<'d, M: Mode> I2c<'d, M> {
         };
 
         info.regs.cr2().modify(|w| {
-            w.set_sadd((address << 1 | 0) as u16);
-            w.set_add10(i2c::vals::Addmode::BIT7);
+            w.set_sadd(address.addr() << 1);
+            w.set_add10(address.add_mode());
             w.set_dir(i2c::vals::Dir::READ);
             w.set_nbytes(length as u8);
             w.set_start(true);
@@ -94,7 +101,7 @@ impl<'d, M: Mode> I2c<'d, M> {
 
     fn master_write(
         info: &'static Info,
-        address: u8,
+        address: Address,
         length: usize,
         stop: Stop,
         reload: bool,
@@ -124,8 +131,8 @@ impl<'d, M: Mode> I2c<'d, M> {
         // START bit can be set even if the bus is BUSY or
         // I2C is in slave mode.
         info.regs.cr2().modify(|w| {
-            w.set_sadd((address << 1 | 0) as u16);
-            w.set_add10(i2c::vals::Addmode::BIT7);
+            w.set_sadd(address.addr() << 1);
+            w.set_add10(address.add_mode());
             w.set_dir(i2c::vals::Dir::WRITE);
             w.set_nbytes(length as u8);
             w.set_start(true);
@@ -136,14 +143,14 @@ impl<'d, M: Mode> I2c<'d, M> {
         Ok(())
     }
 
-    fn master_continue(info: &'static Info, length: usize, reload: bool, timeout: Timeout) -> Result<(), Error> {
+    fn reload(info: &'static Info, length: usize, will_reload: bool, timeout: Timeout) -> Result<(), Error> {
         assert!(length < 256 && length > 0);
 
         while !info.regs.isr().read().tcr() {
             timeout.check()?;
         }
 
-        let reload = if reload {
+        let will_reload = if will_reload {
             i2c::vals::Reload::NOTCOMPLETED
         } else {
             i2c::vals::Reload::COMPLETED
@@ -151,7 +158,7 @@ impl<'d, M: Mode> I2c<'d, M> {
 
         info.regs.cr2().modify(|w| {
             w.set_nbytes(length as u8);
-            w.set_reload(reload);
+            w.set_reload(will_reload);
         });
 
         Ok(())
@@ -229,7 +236,13 @@ impl<'d, M: Mode> I2c<'d, M> {
         }
     }
 
-    fn read_internal(&mut self, address: u8, read: &mut [u8], restart: bool, timeout: Timeout) -> Result<(), Error> {
+    fn read_internal(
+        &mut self,
+        address: Address,
+        read: &mut [u8],
+        restart: bool,
+        timeout: Timeout,
+    ) -> Result<(), Error> {
         let completed_chunks = read.len() / 255;
         let total_chunks = if completed_chunks * 255 == read.len() {
             completed_chunks
@@ -250,7 +263,7 @@ impl<'d, M: Mode> I2c<'d, M> {
 
         for (number, chunk) in read.chunks_mut(255).enumerate() {
             if number != 0 {
-                Self::master_continue(self.info, chunk.len(), number != last_chunk_idx, timeout)?;
+                Self::reload(self.info, chunk.len(), number != last_chunk_idx, timeout)?;
             }
 
             for byte in chunk {
@@ -263,7 +276,13 @@ impl<'d, M: Mode> I2c<'d, M> {
         Ok(())
     }
 
-    fn write_internal(&mut self, address: u8, write: &[u8], send_stop: bool, timeout: Timeout) -> Result<(), Error> {
+    fn write_internal(
+        &mut self,
+        address: Address,
+        write: &[u8],
+        send_stop: bool,
+        timeout: Timeout,
+    ) -> Result<(), Error> {
         let completed_chunks = write.len() / 255;
         let total_chunks = if completed_chunks * 255 == write.len() {
             completed_chunks
@@ -291,7 +310,7 @@ impl<'d, M: Mode> I2c<'d, M> {
 
         for (number, chunk) in write.chunks(255).enumerate() {
             if number != 0 {
-                Self::master_continue(self.info, chunk.len(), number != last_chunk_idx, timeout)?;
+                Self::reload(self.info, chunk.len(), number != last_chunk_idx, timeout)?;
             }
 
             for byte in chunk {
@@ -320,18 +339,18 @@ impl<'d, M: Mode> I2c<'d, M> {
     //  Blocking public API
 
     /// Blocking read.
-    pub fn blocking_read(&mut self, address: u8, read: &mut [u8]) -> Result<(), Error> {
+    pub fn blocking_read(&mut self, address: Address, read: &mut [u8]) -> Result<(), Error> {
         self.read_internal(address, read, false, self.timeout())
         // Automatic Stop
     }
 
     /// Blocking write.
-    pub fn blocking_write(&mut self, address: u8, write: &[u8]) -> Result<(), Error> {
+    pub fn blocking_write(&mut self, address: Address, write: &[u8]) -> Result<(), Error> {
         self.write_internal(address, write, true, self.timeout())
     }
 
     /// Blocking write, restart, read.
-    pub fn blocking_write_read(&mut self, address: u8, write: &[u8], read: &mut [u8]) -> Result<(), Error> {
+    pub fn blocking_write_read(&mut self, address: Address, write: &[u8], read: &mut [u8]) -> Result<(), Error> {
         let timeout = self.timeout();
         self.write_internal(address, write, false, timeout)?;
         self.read_internal(address, read, true, timeout)
@@ -343,7 +362,7 @@ impl<'d, M: Mode> I2c<'d, M> {
     /// Consecutive operations of same type are merged. See [transaction contract] for details.
     ///
     /// [transaction contract]: embedded_hal_1::i2c::I2c::transaction
-    pub fn blocking_transaction(&mut self, addr: u8, operations: &mut [Operation<'_>]) -> Result<(), Error> {
+    pub fn blocking_transaction(&mut self, addr: Address, operations: &mut [Operation<'_>]) -> Result<(), Error> {
         let _ = addr;
         let _ = operations;
         todo!()
@@ -352,7 +371,7 @@ impl<'d, M: Mode> I2c<'d, M> {
     /// Blocking write multiple buffers.
     ///
     /// The buffers are concatenated in a single write transaction.
-    pub fn blocking_write_vectored(&mut self, address: u8, write: &[&[u8]]) -> Result<(), Error> {
+    pub fn blocking_write_vectored(&mut self, address: Address, write: &[&[u8]]) -> Result<(), Error> {
         if write.is_empty() {
             return Err(Error::ZeroLengthTransfer);
         }
@@ -385,7 +404,7 @@ impl<'d, M: Mode> I2c<'d, M> {
             let last_chunk_idx = total_chunks.saturating_sub(1);
 
             if idx != 0 {
-                if let Err(err) = Self::master_continue(
+                if let Err(err) = Self::reload(
                     self.info,
                     slice_len.min(255),
                     (idx != last_slice_index) || (slice_len > 255),
@@ -398,7 +417,7 @@ impl<'d, M: Mode> I2c<'d, M> {
 
             for (number, chunk) in slice.chunks(255).enumerate() {
                 if number != 0 {
-                    if let Err(err) = Self::master_continue(
+                    if let Err(err) = Self::reload(
                         self.info,
                         chunk.len(),
                         (number != last_chunk_idx) || (idx != last_slice_index),
@@ -431,10 +450,10 @@ impl<'d, M: Mode> I2c<'d, M> {
     }
 }
 
-impl<'d> I2c<'d, Async> {
+impl<'d, IM: MasterMode> I2c<'d, Async, IM> {
     async fn write_dma_internal(
         &mut self,
-        address: u8,
+        address: Address,
         write: &[u8],
         first_slice: bool,
         last_slice: bool,
@@ -482,7 +501,7 @@ impl<'d> I2c<'d, Async> {
                         timeout,
                     )?;
                 } else {
-                    Self::master_continue(self.info, total_len.min(255), (total_len > 255) || !last_slice, timeout)?;
+                    Self::reload(self.info, total_len.min(255), (total_len > 255) || !last_slice, timeout)?;
                     self.info.regs.cr1().modify(|w| w.set_tcie(true));
                 }
             } else if !(isr.tcr() || isr.tc()) {
@@ -493,7 +512,7 @@ impl<'d> I2c<'d, Async> {
             } else {
                 let last_piece = (remaining_len <= 255) && last_slice;
 
-                if let Err(e) = Self::master_continue(self.info, remaining_len.min(255), !last_piece, timeout) {
+                if let Err(e) = Self::reload(self.info, remaining_len.min(255), !last_piece, timeout) {
                     return Poll::Ready(Err(e));
                 }
                 self.info.regs.cr1().modify(|w| w.set_tcie(true));
@@ -519,7 +538,7 @@ impl<'d> I2c<'d, Async> {
 
     async fn read_dma_internal(
         &mut self,
-        address: u8,
+        address: Address,
         buffer: &mut [u8],
         restart: bool,
         timeout: Timeout,
@@ -569,7 +588,7 @@ impl<'d> I2c<'d, Async> {
             } else {
                 let last_piece = remaining_len <= 255;
 
-                if let Err(e) = Self::master_continue(self.info, remaining_len.min(255), !last_piece, timeout) {
+                if let Err(e) = Self::reload(self.info, remaining_len.min(255), !last_piece, timeout) {
                     return Poll::Ready(Err(e));
                 }
                 self.info.regs.cr1().modify(|w| w.set_tcie(true));
@@ -590,12 +609,11 @@ impl<'d> I2c<'d, Async> {
 
         Ok(())
     }
-
     // =========================
     //  Async public API
 
     /// Write.
-    pub async fn write(&mut self, address: u8, write: &[u8]) -> Result<(), Error> {
+    pub async fn write(&mut self, address: Address, write: &[u8]) -> Result<(), Error> {
         let timeout = self.timeout();
         if write.is_empty() {
             self.write_internal(address, write, true, timeout)
@@ -609,7 +627,7 @@ impl<'d> I2c<'d, Async> {
     /// Write multiple buffers.
     ///
     /// The buffers are concatenated in a single write transaction.
-    pub async fn write_vectored(&mut self, address: u8, write: &[&[u8]]) -> Result<(), Error> {
+    pub async fn write_vectored(&mut self, address: Address, write: &[&[u8]]) -> Result<(), Error> {
         let timeout = self.timeout();
 
         if write.is_empty() {
@@ -632,7 +650,7 @@ impl<'d> I2c<'d, Async> {
     }
 
     /// Read.
-    pub async fn read(&mut self, address: u8, buffer: &mut [u8]) -> Result<(), Error> {
+    pub async fn read(&mut self, address: Address, buffer: &mut [u8]) -> Result<(), Error> {
         let timeout = self.timeout();
 
         if buffer.is_empty() {
@@ -644,7 +662,7 @@ impl<'d> I2c<'d, Async> {
     }
 
     /// Write, restart, read.
-    pub async fn write_read(&mut self, address: u8, write: &[u8], read: &mut [u8]) -> Result<(), Error> {
+    pub async fn write_read(&mut self, address: Address, write: &[u8], read: &mut [u8]) -> Result<(), Error> {
         let timeout = self.timeout();
 
         if write.is_empty() {
@@ -669,13 +687,343 @@ impl<'d> I2c<'d, Async> {
     /// Consecutive operations of same type are merged. See [transaction contract] for details.
     ///
     /// [transaction contract]: embedded_hal_1::i2c::I2c::transaction
-    pub async fn transaction(&mut self, addr: u8, operations: &mut [Operation<'_>]) -> Result<(), Error> {
+    pub async fn transaction(&mut self, addr: Address, operations: &mut [Operation<'_>]) -> Result<(), Error> {
         let _ = addr;
         let _ = operations;
         todo!()
     }
 }
 
+impl<'d, M: Mode> I2c<'d, M, MultiMaster> {
+    pub(crate) fn init_slave(&mut self, config: SlaveAddrConfig) {
+        self.info.regs.cr1().modify(|reg| {
+            reg.set_pe(false);
+        });
+
+        self.info.regs.cr1().modify(|reg| {
+            reg.set_nostretch(false);
+            reg.set_gcen(config.general_call);
+            reg.set_sbc(true);
+            reg.set_pe(true);
+        });
+
+        self.reconfigure_addresses(config.addr);
+    }
+
+    /// Configure the slave address.
+    pub fn reconfigure_addresses(&mut self, addresses: OwnAddresses) {
+        match addresses {
+            OwnAddresses::OA1(oa1) => self.configure_oa1(oa1),
+            OwnAddresses::OA2(oa2) => self.configure_oa2(oa2),
+            OwnAddresses::Both { oa1, oa2 } => {
+                self.configure_oa1(oa1);
+                self.configure_oa2(oa2);
+            }
+        }
+    }
+
+    fn configure_oa1(&mut self, oa1: Address) {
+        match oa1 {
+            Address::SevenBit(addr) => self.info.regs.oar1().write(|reg| {
+                reg.set_oa1en(false);
+                reg.set_oa1((addr << 1) as u16);
+                reg.set_oa1mode(Addmode::BIT7);
+                reg.set_oa1en(true);
+            }),
+            Address::TenBit(addr) => self.info.regs.oar1().write(|reg| {
+                reg.set_oa1en(false);
+                reg.set_oa1(addr);
+                reg.set_oa1mode(Addmode::BIT10);
+                reg.set_oa1en(true);
+            }),
+        }
+    }
+
+    fn configure_oa2(&mut self, oa2: OA2) {
+        self.info.regs.oar2().write(|reg| {
+            reg.set_oa2en(false);
+            reg.set_oa2msk(oa2.mask.into());
+            reg.set_oa2(oa2.addr << 1);
+            reg.set_oa2en(true);
+        });
+    }
+
+    fn determine_matched_address(&self) -> Result<Address, Error> {
+        let matched = self.info.regs.isr().read().addcode();
+
+        if matched >> 3 == 0b11110 {
+            // is 10-bit address and we need to get the other 8 bits from the rxdr
+            // we do this by doing a blocking read of 1 byte
+            let mut buffer = [0];
+            self.slave_read_internal(&mut buffer, self.timeout())?;
+            Ok(Address::TenBit((matched as u16) << 6 | buffer[0] as u16))
+        } else {
+            Ok(Address::SevenBit(matched))
+        }
+    }
+}
+
+impl<'d, M: Mode> I2c<'d, M, MultiMaster> {
+    /// # Safety
+    /// This function will clear the address flag which will stop the clock stretching.
+    /// This should only be done after the dma transfer has been set up.
+    fn slave_start(info: &'static Info, length: usize, reload: bool) {
+        assert!(length < 256);
+
+        let reload = if reload {
+            i2c::vals::Reload::NOTCOMPLETED
+        } else {
+            i2c::vals::Reload::COMPLETED
+        };
+
+        info.regs.cr2().modify(|w| {
+            w.set_nbytes(length as u8);
+            w.set_reload(reload);
+        });
+
+        // clear the address flag, will stop the clock stretching.
+        // this should only be done after the dma transfer has been set up.
+        info.regs.icr().modify(|reg| reg.set_addrcf(true));
+    }
+
+    // A blocking read operation
+    fn slave_read_internal(&self, read: &mut [u8], timeout: Timeout) -> Result<(), Error> {
+        let completed_chunks = read.len() / 255;
+        let total_chunks = if completed_chunks * 255 == read.len() {
+            completed_chunks
+        } else {
+            completed_chunks + 1
+        };
+        let last_chunk_idx = total_chunks.saturating_sub(1);
+        for (number, chunk) in read.chunks_mut(255).enumerate() {
+            if number != 0 {
+                Self::reload(self.info, chunk.len(), number != last_chunk_idx, timeout)?;
+            }
+
+            for byte in chunk {
+                // Wait until we have received something
+                self.wait_rxne(timeout)?;
+
+                *byte = self.info.regs.rxdr().read().rxdata();
+            }
+        }
+
+        Ok(())
+    }
+
+    // A blocking write operation
+    fn slave_write_internal(&mut self, write: &[u8], timeout: Timeout) -> Result<(), Error> {
+        let completed_chunks = write.len() / 255;
+        let total_chunks = if completed_chunks * 255 == write.len() {
+            completed_chunks
+        } else {
+            completed_chunks + 1
+        };
+        let last_chunk_idx = total_chunks.saturating_sub(1);
+
+        for (number, chunk) in write.chunks(255).enumerate() {
+            if number != 0 {
+                Self::reload(self.info, chunk.len(), number != last_chunk_idx, timeout)?;
+            }
+
+            for byte in chunk {
+                // Wait until we are allowed to send data
+                // (START has been ACKed or last byte when
+                // through)
+                self.wait_txe(timeout)?;
+
+                self.info.regs.txdr().write(|w| w.set_txdata(*byte));
+            }
+        }
+        Ok(())
+    }
+
+    /// Listen for incoming I2C messages.
+    ///
+    /// The listen method is an asynchronous method but it does not require DMA to be asynchronous.
+    pub async fn listen(&mut self) -> Result<Command, Error> {
+        let state = self.state;
+        self.info.regs.cr1().modify(|reg| {
+            reg.set_addrie(true);
+        });
+
+        poll_fn(|cx| {
+            state.waker.register(cx.waker());
+            let isr = self.info.regs.isr().read();
+            if !isr.addr() {
+                Poll::Pending
+            } else {
+                // we do not clear the address flag here as it will be cleared by the dma read/write
+                // if we clear it here the clock stretching will stop and the master will read in data before the slave is ready to send it
+                match isr.dir() {
+                    i2c::vals::Dir::WRITE => Poll::Ready(Ok(Command {
+                        kind: CommandKind::SlaveReceive,
+                        address: self.determine_matched_address()?,
+                    })),
+                    i2c::vals::Dir::READ => Poll::Ready(Ok(Command {
+                        kind: CommandKind::SlaveSend,
+                        address: self.determine_matched_address()?,
+                    })),
+                }
+            }
+        })
+        .await
+    }
+
+    /// Respond to a receive command.
+    pub fn blocking_respond_to_receive(&self, read: &mut [u8]) -> Result<(), Error> {
+        let timeout = self.timeout();
+        self.slave_read_internal(read, timeout)
+    }
+
+    /// Respond to a send command.
+    pub fn blocking_respond_to_send(&mut self, write: &[u8]) -> Result<(), Error> {
+        let timeout = self.timeout();
+        self.slave_write_internal(write, timeout)
+    }
+}
+
+impl<'d> I2c<'d, Async, MultiMaster> {
+    /// Respond to a receive command.
+    pub async fn respond_to_receive(&mut self, buffer: &mut [u8]) -> Result<usize, Error> {
+        let timeout = self.timeout();
+        timeout.with(self.read_dma_internal_slave(buffer, timeout)).await
+    }
+
+    /// Respond to a send request from an I2C master.
+    pub async fn respond_to_send(&mut self, write: &[u8]) -> Result<SendStatus, Error> {
+        let timeout = self.timeout();
+        timeout.with(self.write_dma_internal_slave(write, timeout)).await
+    }
+
+    // for data reception in slave mode
+    async fn read_dma_internal_slave(&mut self, buffer: &mut [u8], timeout: Timeout) -> Result<usize, Error> {
+        let total_len = buffer.len();
+        let mut remaining_len = total_len;
+
+        let regs = self.info.regs;
+
+        let dma_transfer = unsafe {
+            regs.cr1().modify(|w| {
+                w.set_rxdmaen(true);
+                w.set_stopie(true);
+                w.set_tcie(true);
+            });
+            let src = regs.rxdr().as_ptr() as *mut u8;
+
+            self.rx_dma.as_mut().unwrap().read(src, buffer, Default::default())
+        };
+
+        let state = self.state;
+
+        let on_drop = OnDrop::new(|| {
+            regs.cr1().modify(|w| {
+                w.set_rxdmaen(false);
+                w.set_stopie(false);
+                w.set_tcie(false);
+            })
+        });
+
+        let total_received = poll_fn(|cx| {
+            state.waker.register(cx.waker());
+
+            let isr = regs.isr().read();
+
+            if remaining_len == total_len {
+                Self::slave_start(self.info, total_len.min(255), total_len > 255);
+                remaining_len = remaining_len.saturating_sub(255);
+                Poll::Pending
+            } else if isr.tcr() {
+                let is_last_slice = remaining_len <= 255;
+                if let Err(e) = Self::reload(self.info, remaining_len.min(255), !is_last_slice, timeout) {
+                    return Poll::Ready(Err(e));
+                }
+                remaining_len = remaining_len.saturating_sub(255);
+                regs.cr1().modify(|w| w.set_tcie(true));
+                Poll::Pending
+            } else if isr.stopf() {
+                regs.icr().write(|reg| reg.set_stopcf(true));
+                let poll = Poll::Ready(Ok(remaining_len));
+                poll
+            } else {
+                Poll::Pending
+            }
+        })
+        .await?;
+
+        dma_transfer.await;
+
+        drop(on_drop);
+
+        Ok(total_received)
+    }
+
+    async fn write_dma_internal_slave(&mut self, buffer: &[u8], timeout: Timeout) -> Result<SendStatus, Error> {
+        let total_len = buffer.len();
+        let mut remaining_len = total_len;
+
+        let mut dma_transfer = unsafe {
+            let regs = self.info.regs;
+            regs.cr1().modify(|w| {
+                w.set_txdmaen(true);
+                w.set_stopie(true);
+                w.set_tcie(true);
+            });
+            let dst = regs.txdr().as_ptr() as *mut u8;
+
+            self.tx_dma.as_mut().unwrap().write(buffer, dst, Default::default())
+        };
+
+        let on_drop = OnDrop::new(|| {
+            let regs = self.info.regs;
+            regs.cr1().modify(|w| {
+                w.set_txdmaen(false);
+                w.set_stopie(false);
+                w.set_tcie(false);
+            })
+        });
+
+        let state = self.state;
+
+        let size = poll_fn(|cx| {
+            state.waker.register(cx.waker());
+
+            let isr = self.info.regs.isr().read();
+
+            if remaining_len == total_len {
+                Self::slave_start(self.info, total_len.min(255), total_len > 255);
+                remaining_len = remaining_len.saturating_sub(255);
+                Poll::Pending
+            } else if isr.tcr() {
+                let is_last_slice = remaining_len <= 255;
+                if let Err(e) = Self::reload(self.info, remaining_len.min(255), !is_last_slice, timeout) {
+                    return Poll::Ready(Err(e));
+                }
+                remaining_len = remaining_len.saturating_sub(255);
+                self.info.regs.cr1().modify(|w| w.set_tcie(true));
+                Poll::Pending
+            } else if isr.stopf() {
+                self.info.regs.icr().write(|reg| reg.set_stopcf(true));
+                if remaining_len > 0 {
+                    dma_transfer.request_stop();
+                    Poll::Ready(Ok(SendStatus::LeftoverBytes(remaining_len as usize)))
+                } else {
+                    Poll::Ready(Ok(SendStatus::Done))
+                }
+            } else {
+                Poll::Pending
+            }
+        })
+        .await?;
+
+        dma_transfer.await;
+
+        drop(on_drop);
+
+        Ok(size)
+    }
+}
+
 /// I2C Stop Configuration
 ///
 /// Peripheral options for generating the STOP condition
@@ -800,7 +1148,7 @@ impl Timings {
     }
 }
 
-impl<'d, M: Mode> SetConfig for I2c<'d, M> {
+impl<'d, M: Mode> SetConfig for I2c<'d, M, Master> {
     type Config = Hertz;
     type ConfigError = ();
     fn set_config(&mut self, config: &Self::Config) -> Result<(), ()> {
@@ -816,3 +1164,21 @@ impl<'d, M: Mode> SetConfig for I2c<'d, M> {
         Ok(())
     }
 }
+
+impl<'d, M: Mode> SetConfig for I2c<'d, M, MultiMaster> {
+    type Config = (Hertz, SlaveAddrConfig);
+    type ConfigError = ();
+    fn set_config(&mut self, (config, addr_config): &Self::Config) -> Result<(), ()> {
+        let timings = Timings::new(self.kernel_clock, *config);
+        self.info.regs.timingr().write(|reg| {
+            reg.set_presc(timings.prescale);
+            reg.set_scll(timings.scll);
+            reg.set_sclh(timings.sclh);
+            reg.set_sdadel(timings.sdadel);
+            reg.set_scldel(timings.scldel);
+        });
+        self.init_slave(*addr_config);
+
+        Ok(())
+    }
+}