134 lines
3.8 KiB
Python
134 lines
3.8 KiB
Python
import fcntl
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import io
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import logging
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import pigpio
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import struct
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import time
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logger = logging.getLogger(__name__)
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actions = {
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"getnodeid": [0x90, 0xE0],
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"getserial": [0x90, 0xE1],
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"getdatatype": [0xA4, 0x00],
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"getdatalog": [0xA4, 0x01],
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}
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class I2CRaw:
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def __init__(self, address, bus):
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I2C_SLAVE = 0x0703
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self.fr = io.open(f"/dev/i2c-{bus}", "rb", buffering=0)
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self.fw = io.open(f"/dev/i2c-{bus}", "wb", buffering=0)
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fcntl.ioctl(self.fr, I2C_SLAVE, address)
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fcntl.ioctl(self.fw, I2C_SLAVE, address)
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def write_i2c_block_data(self, data):
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if type(data) is not list:
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return -1
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data = bytearray(data)
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self.fw.write(data)
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return 0
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def read_i2c_block_data(self, n_bytes):
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data_raw = self.fr.read(n_bytes)
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unpack_format = "B" * n_bytes
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return list(struct.unpack(unpack_format, data_raw))
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def close(self):
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self.fr.close()
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self.fw.close()
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class I2CMaster:
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def __init__(self, address, bus, queue):
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self.i = I2CRaw(address=address, bus=bus)
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self.queue = queue
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def compose_request(self, action):
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# 0x80 = source, 0x04 = msg_type, 0x00 = length
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request = [0x80] + actions[action] + [0x04, 0x00]
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request.append(self.calculate_checksum(request))
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return request
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def calculate_checksum(self, request):
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s = 0x82
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for i in request:
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s += i
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checksum = 256 - (s % 256)
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if checksum == 256:
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checksum = 0
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return checksum
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def execute_action(self, action):
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request = self.compose_request(action)
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result = None
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for i in range(0, 20):
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logger.debug(f"Executing action: {action}")
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self.i.write_i2c_block_data(request)
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time.sleep(0.21)
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logger.debug("Queue size: {}".format(self.queue.qsize()))
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if self.queue.qsize() > 0:
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result = self.queue.get()
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break
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if result is None:
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logger.error("No valid result in 20 requests")
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return result
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def close(self):
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self.i.close()
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class I2CSlave:
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def __init__(self, address, queue):
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self.address = address
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self.queue = queue
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self.pi = pigpio.pi()
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if not self.pi.connected:
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logger.error("not pi.connected")
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return
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def set_callback(self):
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logger.debug("set_callback()")
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self.event_callback = self.pi.event_callback(pigpio.EVENT_BSC, self.callback)
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self.pi.bsc_i2c(self.address)
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def callback(self, id, tick):
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logger.debug(f"callback({id}, {tick})")
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s, b, d = self.pi.bsc_i2c(self.address)
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result = None
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if b:
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logger.debug(f"Received {b} bytes! Status {s}")
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result = [hex(c) for c in d]
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logger.debug(f"Callback Response: {result}")
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if self.is_checksum_valid(result) and self.is_length_valid(result):
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self.queue.put(result)
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else:
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logger.debug(f"Received number of bytes was {b}")
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def is_checksum_valid(self, b):
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s = 0x80
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for i in b[:-1]:
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s += int(i, 0)
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checksum = 256 - (s % 256)
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if checksum == 256:
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checksum = 0
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if checksum != int(b[-1], 0):
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logger.debug(f"Checksum invalid (0x{checksum:02x} != {b[-1]})")
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return False
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return True
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def is_length_valid(self, b):
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length_in_msg = int(b[4], 0)
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actual_length = len(b) - 6
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if length_in_msg != actual_length:
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logger.debug(f"Length invalid ({length_in_msg} != {actual_length})")
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return False
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return True
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def close(self):
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self.event_callback.cancel()
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self.pi.bsc_i2c(0)
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self.pi.stop()
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