coredevice: add I2C, PCA9548, TCA6424A drivers

artiq/coredevice/i2c.py

@@ -0,0 +1,75 @@
+from artiq.language.core import syscall, kernel
+from artiq.language.types import TBool, TInt8, TInt32, TNone
+from artiq.coredevice.exceptions import I2CError
+
+
+@syscall
+def i2c_init(busno: TInt32) -> TNone:
+    raise NotImplementedError("syscall not simulated")
+
+
+@syscall
+def i2c_start(busno: TInt32) -> TNone:
+    raise NotImplementedError("syscall not simulated")
+
+
+@syscall
+def i2c_stop(busno: TInt32) -> TNone:
+    raise NotImplementedError("syscall not simulated")
+
+
+@syscall
+def i2c_write(busno: TInt32, b: TInt32) -> TBool:
+    raise NotImplementedError("syscall not simulated")
+
+
+@syscall
+def i2c_read(busno: TInt32, ack: TBool) -> TInt32:
+    raise NotImplementedError("syscall not simulated")
+
+
+class PCA9548:
+    def __init__(self, dmgr, busno=0, address=0x74):
+        self.core = dmgr.get("core")
+        self.busno = busno
+        self.address = address
+
+    @kernel
+    def set(self, channel):
+        i2c_init(self.busno)
+        i2c_start(self.busno)
+        try:
+            if not i2c_write(self.busno, self.address):
+                raise I2CError("PCA9548 failed to ack address")
+            if not i2c_write(self.busno, 1 << channel):
+                raise I2CError("PCA9548 failed to ack control word")
+        finally:
+            i2c_stop(self.busno)
+
+
+class TCA6424A:
+    def __init__(self, dmgr, busno=0, address=0x44):
+        self.core = dmgr.get("core")
+        self.busno = busno
+        self.address = address
+
+    @kernel
+    def _write24(self, command, value):
+        i2c_init(self.busno)
+        i2c_start(self.busno)
+        try:
+            if not i2c_write(self.busno, self.address):
+                raise I2CError("TCA6424A failed to ack address")
+            if not i2c_write(self.busno, command):
+                raise I2CError("TCA6424A failed to ack command")
+            for i in range(3):
+                if not i2c_write(self.busno, value >> 16):
+                    raise I2CError("TCA6424A failed to ack command")
+                value <<= 8
+        finally:
+            i2c_stop(self.busno)
+
+    @kernel
+    def set(self, outputs):
+        self._write24(0x8c, 0)  # set all directions to output
+        self._write24(0x84, output)  # set levels