Allow configuring default pull mode for inputs

Rahix · Jan 29, 2024 · 3948972 · 3948972
1 parent 756aabf
commit 3948972
Showing 1 changed file with 71 additions and 8 deletions.
diff --git a/src/dev/pi4ioe5v6408.rs b/src/dev/pi4ioe5v6408.rs
@@ -13,8 +13,9 @@ where
     /// # Arguments
     /// - `i2c` - The I2C bus the device is connected to
     /// - `addr` - The address of the device. The address is 0x43 if `addr` is `false` and 0x44 if `addr` is `true`
-    pub fn new(i2c: I2C, addr: bool) -> Result<Self, I2C::BusError> {
-        Self::with_mutex(i2c, addr)
+    /// - `default_pull_mode` - The default pull mode for all pins (The pins are configured as inputs on reset)
+    pub fn new(i2c: I2C, addr: bool, default_pull_mode: PullMode) -> Result<Self, I2C::BusError> {
+        Self::with_mutex(i2c, addr, default_pull_mode)
     }
 }
 
@@ -29,8 +30,17 @@ where
     /// # Arguments
     /// - `i2c` - The I2C bus the device is connected to
     /// - `addr` - The address of the device. The address is 0x43 if `addr` is `false` and 0x44 if `addr` is `true`
-    pub fn with_mutex(i2c: I2C, addr: bool) -> Result<Self, I2C::BusError> {
-        Ok(Self(shared_bus::BusMutex::create(Driver::new(i2c, addr)?)))
+    /// - `default_pull_mode` - The default pull mode for all pins (The pins are configured as inputs on reset)
+    pub fn with_mutex(
+        i2c: I2C,
+        addr: bool,
+        default_pull_mode: PullMode,
+    ) -> Result<Self, I2C::BusError> {
+        Ok(Self(shared_bus::BusMutex::create(Driver::new(
+            i2c,
+            addr,
+            default_pull_mode,
+        )?)))
     }
 
     pub fn split<'a>(&'a mut self) -> Parts<'a, I2C, M> {
@@ -83,14 +93,28 @@ impl From<Regs> for u8 {
     }
 }
 
+/// The pull mode for an input pin
+pub enum PullMode {
+    /// Pull the pin up
+    PullUp,
+    /// Pull the pin down
+    PullDown,
+    /// Don't activate pull-up or pull-down resistors and leave the pin floating
+    Floating,
+}
+
 pub struct Driver<I2C> {
     i2c: I2C,
     addr: u8,
     out: u8,
 }
 
 impl<I2C: crate::I2cBus> Driver<I2C> {
-    pub fn new(mut i2c: I2C, addr: bool) -> Result<Self, I2C::BusError> {
+    pub fn new(
+        mut i2c: I2C,
+        addr: bool,
+        default_pull_mode: PullMode,
+    ) -> Result<Self, I2C::BusError> {
         let addr = if addr { 0x44 } else { 0x43 };
 
         let device_id = i2c.read_reg(addr, Regs::DeviceIdControl)?; // Reset the "(Power on) Reset Interrupt" bit (and validate the device ID)
@@ -113,9 +137,18 @@ impl<I2C: crate::I2cBus> Driver<I2C> {
 
         // Change reset values we don't want
         i2c.write_reg(addr, Regs::OutputHighImpedance, 0)?; // Disable high impedance mode on all outputs
-        i2c.write_reg(addr, Regs::PullUpPullDownSelection, 0xff)?; // Enable Pull-Ups on all inputs
         i2c.write_reg(addr, Regs::InterruptMaskRegister, 0xff)?; // Disable interrupts on all inputs
 
+        match default_pull_mode {
+            PullMode::PullUp => {
+                i2c.write_reg(addr, Regs::PullUpPullDownSelection, 0xff)?; // Pull-Ups on all inputs
+            }
+            PullMode::PullDown => {} // Nothing to do, as this is the default
+            PullMode::Floating => {
+                i2c.write_reg(addr, Regs::PullUpPullDownEnable, 0)?; // Disable pull-up/pull-down on all inputs
+            }
+        }
+
         Ok(Self { i2c, addr, out: 0 })
     }
 }
@@ -173,6 +206,7 @@ impl<I2C: crate::I2cBus> crate::PortDriverTotemPole for Driver<I2C> {
 
 #[cfg(test)]
 mod tests {
+    use super::PullMode;
     use embedded_hal_mock::i2c as mock_i2c;
 
     #[test]
@@ -181,7 +215,6 @@ mod tests {
             // driver setup
             mock_i2c::Transaction::write_read(0x43, vec![0x01], vec![0xa2]),
             mock_i2c::Transaction::write(0x43, vec![0x07, 0]),
-            mock_i2c::Transaction::write(0x43, vec![0x0d, 0xff]),
             mock_i2c::Transaction::write(0x43, vec![0x11, 0xff]),
             // pin setup io0
             mock_i2c::Transaction::write_read(0x43, vec![0x03], vec![0]),
@@ -203,7 +236,7 @@ mod tests {
         ];
         let mut bus = mock_i2c::Mock::new(&expectations);
 
-        let mut pca = super::Pi4ioe5v6408::new(bus.clone(), false).unwrap();
+        let mut pca = super::Pi4ioe5v6408::new(bus.clone(), false, PullMode::PullDown).unwrap();
         let pca_pins = pca.split();
 
         let io0 = pca_pins.io0.into_output().unwrap();
@@ -220,4 +253,34 @@ mod tests {
 
         bus.done();
     }
+
+    #[test]
+    fn pi4ioe5v6408_setup_pullup() {
+        let expectations = [
+            // driver setup
+            mock_i2c::Transaction::write_read(0x43, vec![0x01], vec![0xa2]),
+            mock_i2c::Transaction::write(0x43, vec![0x07, 0]),
+            mock_i2c::Transaction::write(0x43, vec![0x11, 0xff]),
+            mock_i2c::Transaction::write(0x43, vec![0x0d, 0xff]),
+        ];
+        let mut bus = mock_i2c::Mock::new(&expectations);
+
+        let _pca = super::Pi4ioe5v6408::new(bus.clone(), false, PullMode::PullUp).unwrap();
+        bus.done();
+    }
+
+    #[test]
+    fn pi4ioe5v6408_setup_floating() {
+        let expectations = [
+            // driver setup
+            mock_i2c::Transaction::write_read(0x44, vec![0x01], vec![0xa2]),
+            mock_i2c::Transaction::write(0x44, vec![0x07, 0]),
+            mock_i2c::Transaction::write(0x44, vec![0x11, 0xff]),
+            mock_i2c::Transaction::write(0x44, vec![0x0b, 0]),
+        ];
+        let mut bus = mock_i2c::Mock::new(&expectations);
+
+        let _pca = super::Pi4ioe5v6408::new(bus.clone(), true, PullMode::Floating).unwrap();
+        bus.done();
+    }
 }