Initial commit

Signed-off-by: Thomas Klaehn <thomas.klaehn@perinet.io>

src/lib.rs

@@ -0,0 +1,72 @@
+extern crate i2cdev;
+
+use i2cdev::core::*;
+use i2cdev::linux::{LinuxI2CDevice, LinuxI2CError, LinuxI2CMessage};
+
+pub enum Channel {
+    One,
+    Two,
+    Three,
+}
+
+pub struct Ina3221 {
+    slave_addr: u16,
+    i2c_device: String,
+    shunt_resistor: f64,
+}
+
+impl Ina3221 {
+
+    pub fn new(slave_address: u16) -> Ina3221 {
+        Ina3221 {
+            slave_addr: slave_address,
+            i2c_device: format!("/dev/i2c-1"),
+            shunt_resistor: 1.0,
+        }
+    }
+
+    fn write_read_transaction(&mut self, register: u8) -> Result<u16, LinuxI2CError> {
+        let mut dev = LinuxI2CDevice::new(&self.i2c_device, self.slave_addr)?;
+
+        let binding = [register];
+        let mut read_data = [0; 2];
+        let mut msgs = [
+            LinuxI2CMessage::write(&binding),
+            LinuxI2CMessage::read(&mut read_data)
+        ];
+        dev.transfer(&mut msgs)?;
+
+        let tmp: u16 = (read_data[0] as u16) << 8 | (read_data[1] as u16);
+        Ok(tmp)
+    }
+
+    pub fn bus_voltage(&mut self, channel: Channel) -> Result<f64, LinuxI2CError> {
+        let register: u8 = match channel {
+            Channel::One => 2,
+            Channel::Two => 4,
+            Channel::Three => 6,
+        };
+        let mut tmp = self.write_read_transaction(register)?;
+        tmp = tmp >> 3;
+        let res: f64 = (tmp as f64) * 8.0 / 1000.0;
+        Ok(res)
+    }
+
+    pub fn shunt_voltage(&mut self, channel: Channel) -> Result<f64, LinuxI2CError> {
+        let register: u8 = match channel {
+            Channel::One => 1,
+            Channel::Two => 3,
+            Channel::Three => 5,
+        };
+        let mut tmp = self.write_read_transaction(register)?;
+        tmp = tmp >> 3;
+        let res: f64 = (tmp as f64) * 40.0 / 1000000.0;
+        Ok(res)
+    }
+
+    pub fn current(&mut self, channel: Channel) -> Result<f64, LinuxI2CError> {
+        let tmp: f64 = self.shunt_voltage(channel)?;
+        let res: f64 = tmp * self.shunt_resistor;
+        Ok(res)
+    }
+}