Release 260111

system/sensord/sensors/i2c_sensor.py

@@ -0,0 +1,77 @@
+import time
+import smbus2
+import ctypes
+from collections.abc import Iterable
+
+from cereal import log
+
+class Sensor:
+  class SensorException(Exception):
+    pass
+
+  class DataNotReady(SensorException):
+    pass
+
+  def __init__(self, bus: int) -> None:
+    self.bus = smbus2.SMBus(bus)
+    self.source = log.SensorEventData.SensorSource.velodyne  # unknown
+    self.start_ts = 0.
+
+  def __del__(self):
+    self.bus.close()
+
+  def read(self, addr: int, length: int) -> bytes:
+    return bytes(self.bus.read_i2c_block_data(self.device_address, addr, length))
+
+  def write(self, addr: int, data: int) -> None:
+    self.bus.write_byte_data(self.device_address, addr, data)
+
+  def writes(self, writes: Iterable[tuple[int, int]]) -> None:
+    for addr, data in writes:
+      self.write(addr, data)
+
+  def verify_chip_id(self, address: int, expected_ids: list[int]) -> int:
+    chip_id = self.read(address, 1)[0]
+    assert chip_id in expected_ids
+    return chip_id
+
+  # Abstract methods that must be implemented by subclasses
+  @property
+  def device_address(self) -> int:
+    raise NotImplementedError
+
+  def reset(self) -> None:
+    # optional.
+    # not part of init due to shared registers
+    pass
+
+  def init(self) -> None:
+    raise NotImplementedError
+
+  def get_event(self, ts: int | None = None) -> log.SensorEventData:
+    raise NotImplementedError
+
+  def shutdown(self) -> None:
+    raise NotImplementedError
+
+  def is_data_valid(self) -> bool:
+    if self.start_ts == 0:
+      self.start_ts = time.monotonic()
+
+    # unclear whether we need this...
+    return (time.monotonic() - self.start_ts) > 0.5
+
+  # *** helpers ***
+  @staticmethod
+  def wait():
+    # a standard small sleep
+    time.sleep(0.005)
+
+  @staticmethod
+  def parse_16bit(lsb: int, msb: int) -> int:
+    return ctypes.c_int16((msb << 8) | lsb).value
+
+  @staticmethod
+  def parse_20bit(b2: int, b1: int, b0: int) -> int:
+    combined = ctypes.c_uint32((b0 << 16) | (b1 << 8) | b2).value
+    return ctypes.c_int32(combined).value // (1 << 4)