From 5415ee164bb3f4e178910420da42d1287b74e7df Mon Sep 17 00:00:00 2001
From: Jorge Aparicio <jorge@japaric.io>
Date: Mon, 8 Jan 2018 23:45:41 +0100
Subject: [PATCH] blocking I2C traits

---
 src/blocking/i2c.rs | 86 +++++++++++++++++++++++++++++++++++++++++++++
 src/blocking/mod.rs |  1 +
 2 files changed, 87 insertions(+)
 create mode 100644 src/blocking/i2c.rs

diff --git a/src/blocking/i2c.rs b/src/blocking/i2c.rs
new file mode 100644
index 0000000..7a8ea3f
--- /dev/null
+++ b/src/blocking/i2c.rs
@@ -0,0 +1,86 @@
+//! Blocking I2C API
+
+/// Blocking read
+pub trait Read {
+    /// Error type
+    type Error;
+
+    /// Reads enough bytes from slave with `address` to fill `buffer`
+    ///
+    /// # I2C Events (contract)
+    ///
+    /// ``` text
+    /// Master: ST SAD+R        MAK    MAK ...    NMAK SP
+    /// Slave:           SAK B0     B1     ... BN
+    /// ```
+    ///
+    /// Where
+    ///
+    /// - `ST` = start condition
+    /// - `SAD+R` = slave address with 8th bit set to 1
+    /// - `SAK` = slave acknowledge
+    /// - `Bi` = ith byte of data
+    /// - `MAK` = master acknowledge
+    /// - `NMAK` = master no acknowledge
+    /// - `SP` = stop condition
+    fn read(&mut self, address: u8, buffer: &mut [u8]) -> Result<(), Self::Error>;
+}
+
+/// Blocking write
+pub trait Write {
+    /// Error type
+    type Error;
+
+    /// Sends bytes to slave with address `addr`
+    ///
+    /// # I2C Events (contract)
+    ///
+    /// ``` text
+    /// Master: ST SAD+W     B0     B1     ... BN     SP
+    /// Slave:           SAK    SAK    SAK ...    SAK
+    /// ```
+    ///
+    /// Where
+    ///
+    /// - `ST` = start condition
+    /// - `SAD+W` = slave address with 8th bit set to 0
+    /// - `SAK` = slave acknowledge
+    /// - `Bi` = ith byte of data
+    /// - `SP` = stop condition
+    fn write(&mut self, addr: u8, bytes: &[u8]) -> Result<(), Self::Error>;
+}
+
+/// Blocking write + read
+pub trait WriteRead {
+    /// Error type
+    type Error;
+
+    /// Sends bytes to slave with address `addr` and then reads enough bytes to fill `buffer` *in a
+    /// single transaction*
+    ///
+    /// # I2C Events (contract)
+    ///
+    /// ``` text
+    /// Master: ST SAD+W     O0     O1     ... OM     SR SAD+R        MAK    MAK ...    NMAK SP
+    /// Slave:           SAK    SAK    SAK ...    SAK          SAK I0     I1     ... IN
+    /// ```
+    ///
+    /// Where
+    ///
+    /// - `ST` = start condition
+    /// - `SAD+W` = slave address with 8th bit set to 0
+    /// - `SAK` = slave acknowledge
+    /// - `Oi` = ith outgoing byte of data
+    /// - `SR` = repeated start condition
+    /// - `SAD+R` = slave address with 8th bit set to 1
+    /// - `Ii` = ith incoming byte of data
+    /// - `MAK` = master acknowledge
+    /// - `NMAK` = master no acknowledge
+    /// - `SP` = stop condition
+    fn write_read(
+        &mut self,
+        address: u8,
+        bytes: &[u8],
+        buffer: &mut [u8],
+    ) -> Result<(), Self::Error>;
+}
diff --git a/src/blocking/mod.rs b/src/blocking/mod.rs
index 16d0900..dcbf6a0 100644
--- a/src/blocking/mod.rs
+++ b/src/blocking/mod.rs
@@ -1,3 +1,4 @@
 //! Blocking API
 
+pub mod i2c;
 pub mod spi;