i2c: implement EEPROM operations; add CountDown waiting indication

libboard_zynq/src/i2c/eeprom.rs

@@ -0,0 +1,84 @@
+use super::I2C;
+use crate::time::Microseconds;
+use embedded_hal::timer::CountDown;
+
+pub struct EEPROM<'a> {
+    i2c: &'a mut I2C,
+    port: u8,
+    address: u8,
+}
+
+impl<'a> EEPROM<'a> {
+    #[cfg(feature = "target_zc706")]
+    pub fn new(i2c: &'a mut I2C) -> Self {
+        EEPROM {
+            i2c: i2c,
+            port: 2,
+            address: 0b1010100,
+        }
+    }
+
+    #[cfg(feature = "target_zc706")]
+    fn select(&mut self) -> Result<(), &'static str> {
+        let mask: u16 = 1 << self.port;
+        self.i2c.pca9548_select(0b1110100, mask as u8)?;
+        Ok(())
+    }
+
+    /// Random read
+    pub fn read<'r>(&mut self, addr: u8, buf: &'r mut [u8]) -> Result<(), &'static str> {
+        self.select()?;
+
+        self.i2c.start()?;
+        self.i2c.write(self.address << 1)?;
+        self.i2c.write(addr)?;
+
+        self.i2c.restart()?;
+        self.i2c.write((self.address << 1) | 1)?;
+        let buf_len = buf.len();
+        for (i, byte) in buf.iter_mut().enumerate() {
+            *byte = self.i2c.read(i < buf_len - 1)?;
+        }
+
+        self.i2c.stop()?;
+
+        Ok(())
+    }
+
+    /// Page write
+    pub fn write(&mut self, addr: u8, buf: &[u8]) -> Result<(), &'static str> {
+        self.select()?;
+
+        self.i2c.start()?;
+        self.i2c.write(self.address << 1)?;
+        self.i2c.write(addr)?;
+        for (i, byte) in buf.iter().enumerate() {
+            self.i2c.write(*byte)?;
+        }
+
+        self.i2c.stop()?;
+        self.poll(1_000_000_000)?;
+
+        Ok(())
+    }
+
+    /// Poll
+    pub fn poll(&mut self, timeout_us: u64) -> Result<(), &'static str> {
+        self.select()?;
+
+        self.i2c.count_down.start(Microseconds(timeout_us));
+        while !self.i2c.write((self.address << 1) | 1)? {
+            if !self.i2c.count_down.waiting() {
+                return Err("I2C polling timeout")
+            }
+        }
+
+        Ok(())
+    }
+
+    pub fn read_eui48<'r>(&mut self) -> Result<[u8; 6], &'static str> {
+        let mut buffer = [0u8; 6];
+        self.read(0xFA, &mut buffer)?;
+        Ok(buffer)
+    }
+}

libboard_zynq/src/i2c/mod.rs

@@ -1,8 +1,7 @@
 //! I2C Bit-banging Controller
 
 mod regs;
-use log::{error, info, warn};
-use crate::{print, println};
+pub mod eeprom;
 use super::clocks::Clocks;
 use super::slcr;
 use super::time::Microseconds;

libboard_zynq/src/timer/global.rs

@@ -138,6 +138,15 @@ where
     }
 }
 
+impl<U: PartialOrd> CountDown<U>
+where
+    GlobalTimer: TimeSource<U>,
+{
+    pub fn waiting(&self) -> bool {
+        self.timer.now() <= self.timeout
+    }
+}
+
 /// embedded-hal sync API
 impl embedded_hal::blocking::delay::DelayMs<u64> for GlobalTimer {
     fn delay_ms(&mut self, ms: u64) {