implement pca9539 and runtime io-expander chip selection

better comments and address translation

fix spurious };

unwrap init in runtime and return err instead of panic

propagate error

del unnecessary use

Signed-off-by: SingularitySurfer <Norman_Krackow@gmx.de>

artiq/firmware/libboard_misoc/io_expander.rs

@@ -1,5 +1,14 @@
-use i2c;
 use csr;
+use i2c;
+
+// Only the bare minimum registers. Bits/IO connections equivalent between IC types.
+struct Registers {
+    // PCA9539 equivalent register names in comments
+    iodira: u8, // Configuration Port 0
+    iodirb: u8, // Configuration Port 1
+    gpioa: u8,  // Output Port 0
+    gpiob: u8,  // Output Port 1
+}
 
 pub struct IoExpander {
     busno: u8,
@@ -9,15 +18,17 @@ pub struct IoExpander {
     iodir: [u8; 2],
     out_current: [u8; 2],
     out_target: [u8; 2],
+    registers: Registers,
 }
 
 impl IoExpander {
     #[cfg(all(soc_platform = "kasli", hw_rev = "v2.0"))]
-    pub fn new(index: u8) -> Self {
+    pub fn new(index: u8) -> Result<Self, &'static str> {
         const VIRTUAL_LED_MAPPING0: [(u8, u8, u8); 2] = [(0, 0, 6), (1, 1, 6)];
         const VIRTUAL_LED_MAPPING1: [(u8, u8, u8); 2] = [(2, 0, 6), (3, 1, 6)];
+
         // Both expanders on SHARED I2C bus
-        match index {
+        let mut io_expander = match index {
             0 => IoExpander {
                 busno: 0,
                 port: 11,
@@ -26,6 +37,12 @@ impl IoExpander {
                 iodir: [0xff; 2],
                 out_current: [0; 2],
                 out_target: [0; 2],
+                registers: Registers {
+                    iodira: 0x00,
+                    iodirb: 0x01,
+                    gpioa: 0x12,
+                    gpiob: 0x13,
+                },
             },
             1 => IoExpander {
                 busno: 0,
@@ -35,9 +52,33 @@ impl IoExpander {
                 iodir: [0xff; 2],
                 out_current: [0; 2],
                 out_target: [0; 2],
+                registers: Registers {
+                    iodira: 0x00,
+                    iodirb: 0x01,
+                    gpioa: 0x12,
+                    gpiob: 0x13,
+                },
             },
-            _ => panic!("incorrect I/O expander index"),
+            _ => return Err("incorrect I/O expander index"),
+        };
+        if !io_expander.check_ack()? {
+            #[cfg(feature = "log")]
+            log::info!(
+                "MCP23017 io expander {} not found. Checking for PCA9539.",
+                index
+            );
+            io_expander.address += 0xa8; // translate to PCA9539 addresses (see schematic)
+            io_expander.registers = Registers {
+                iodira: 0x06,
+                iodirb: 0x07,
+                gpioa: 0x02,
+                gpiob: 0x03,
+            };
+            if !io_expander.check_ack()? {
+                return Err("Neither MCP23017 nor PCA9539 io expander found.");
+            };
         }
+        Ok(io_expander)
     }
 
     #[cfg(soc_platform = "kasli")]
@@ -57,9 +98,18 @@ impl IoExpander {
         Ok(())
     }
 
+    fn check_ack(&self) -> Result<bool, &'static str> {
+        // Check for ack from io expander
+        self.select()?;
+        i2c::start(self.busno)?;
+        let ack = i2c::write(self.busno, self.address)?;
+        i2c::stop(self.busno)?;
+        Ok(ack)
+    }
+
     fn update_iodir(&self) -> Result<(), &'static str> {
-        self.write(0x00, self.iodir[0])?;
-        self.write(0x01, self.iodir[1])?;
+        self.write(self.registers.iodira, self.iodir[0])?;
+        self.write(self.registers.iodirb, self.iodir[1])?;
         Ok(())
     }
 
@@ -72,9 +122,9 @@ impl IoExpander {
         self.update_iodir()?;
 
         self.out_current[0] = 0x00;
-        self.write(0x12, 0x00)?;
+        self.write(self.registers.gpioa, 0x00)?;
         self.out_current[1] = 0x00;
-        self.write(0x13, 0x00)?;
+        self.write(self.registers.gpiob, 0x00)?;
         Ok(())
     }
 
@@ -94,20 +144,18 @@ impl IoExpander {
 
     pub fn service(&mut self) -> Result<(), &'static str> {
         for (led, port, bit) in self.virtual_led_mapping.iter() {
-            let level = unsafe {
-                (csr::virtual_leds::status_read() >> led) & 1
-            };
+            let level = unsafe { (csr::virtual_leds::status_read() >> led) & 1 };
             self.set(*port, *bit, level != 0);
         }
 
         if self.out_target != self.out_current {
             self.select()?;
             if self.out_target[0] != self.out_current[0] {
-                self.write(0x12, self.out_target[0])?;
+                self.write(self.registers.gpioa, self.out_target[0])?;
                 self.out_current[0] = self.out_target[0];
             }
             if self.out_target[1] != self.out_current[1] {
-                self.write(0x13, self.out_target[1])?;
+                self.write(self.registers.gpiob, self.out_target[1])?;
                 self.out_current[1] = self.out_target[1];
             }
         }

artiq/firmware/runtime/main.rs

@@ -100,8 +100,8 @@ fn startup() {
     let (mut io_expander0, mut io_expander1);
     #[cfg(all(soc_platform = "kasli", hw_rev = "v2.0"))]
     {
-        io_expander0 = board_misoc::io_expander::IoExpander::new(0);
-        io_expander1 = board_misoc::io_expander::IoExpander::new(1);
+        io_expander0 = board_misoc::io_expander::IoExpander::new(0).unwrap();
+        io_expander1 = board_misoc::io_expander::IoExpander::new(1).unwrap();
         io_expander0.init().expect("I2C I/O expander #0 initialization failed");
         io_expander1.init().expect("I2C I/O expander #1 initialization failed");
 

artiq/firmware/satman/main.rs

@@ -486,8 +486,8 @@ pub extern fn main() -> i32 {
     let (mut io_expander0, mut io_expander1);
     #[cfg(all(soc_platform = "kasli", hw_rev = "v2.0"))]
     {
-        io_expander0 = board_misoc::io_expander::IoExpander::new(0);
-        io_expander1 = board_misoc::io_expander::IoExpander::new(1);
+        io_expander0 = board_misoc::io_expander::IoExpander::new(0).unwrap();
+        io_expander1 = board_misoc::io_expander::IoExpander::new(1).unwrap();
         io_expander0.init().expect("I2C I/O expander #0 initialization failed");
         io_expander1.init().expect("I2C I/O expander #1 initialization failed");