Change from using (unstable) spi device numbers to spidev path.

See: doceme/py-spidev#130 for rationale and
pre-requisite changes to py-spidev.

requirements.txt

@@ -1,5 +1,8 @@
-paho-mqtt
-posix_ipc
-pyudev
-spidev
-pyserial
+# Versioning rules follow those specified in PEP 440
+# https://peps.python.org/pep-0440/
+
+# paho-mqtt
+# posix_ipc ~=0.9
+#spidev == 3.6.1.dev1 @ git+https://github.com/tim-seoss/[email protected]
+git+https://github.com/tim-seoss/[email protected]#egg=spidev
+# pyserial ~=3.4

src/scs_host/bus/spi.py

@@ -1,8 +1,14 @@
 """
 Created on 4 Jul 2016
 
-http://tightdev.net/SpiDev_Doc.pdf
-http://www.takaitra.com/posts/492
+https://github.com/doceme/py-spidev
+https://www.takaitra.com/spi-device-raspberry-pi/
+
+n.b. This is currently using an unmerged PR for py-spidev
+https://github.com/doceme/py-spidev/pull/130
+
+Until this PR is merged, this PR branch should be installed into the local
+python virtualenv.
 
 @author: Bruno Beloff ([email protected])
 
@@ -29,13 +35,12 @@ class SPI(object):
 
     # ----------------------------------------------------------------------------------------------------------------
 
-    def __init__(self, bus, device, mode, max_speed):
+    def __init__(self, dev_path, mode, max_speed):
         """
         Constructor
         """
 
-        self.__bus = bus
-        self.__device = device
+        self.__dev_path = dev_path
         self.__mode = mode
         self.__max_speed = max_speed
 
@@ -51,7 +56,7 @@ def open(self):
         self.acquire_lock()
 
         self.__connection = SpiDev()
-        self.__connection.open(self.__bus, self.__device)
+        self.__connection.open_path(self.__dev_path)
 
         self.__connection.mode = self.__mode
         self.__connection.max_speed_hz = self.__max_speed
@@ -76,10 +81,9 @@ def acquire_lock(self):
     def release_lock(self):
         Lock.release(self.__lock_name)
 
-
     @property
     def __lock_name(self):
-        return "%s-%s" % (self.__class__.__name__, self.__bus)
+        return ("%s-%s" % (self.__class__.__name__, self.__dev_path)).replace('/', '_')
 
 
     # ----------------------------------------------------------------------------------------------------------------
@@ -95,17 +99,12 @@ def read_bytes(self, count):
     # ----------------------------------------------------------------------------------------------------------------
 
     @property
-    def bus(self):
-        return self.__bus
-
-
-    @property
-    def device(self):
-        return self.__device
+    def dev_path(self):
+        return self.__dev_path
 
 
     # ----------------------------------------------------------------------------------------------------------------
 
     def __str__(self, *args, **kwargs):
-        return "SPI:{bus:%d, device:%s, mode:%d, max_speed:%d, connection:%s}" % \
-               (self.__bus, self.__device, self.__mode, self.__max_speed, self.__connection)
+        return "SPI:{dev_path:%s, mode:%d, max_speed:%d, connection:%s}" % \
+               (self.__dev_path, self.__mode, self.__max_speed, self.__connection)

src/scs_host/sys/host.py

@@ -7,8 +7,6 @@
 """
 
 import os
-import pyudev
-import re
 import socket
 
 from pathlib import Path
@@ -45,11 +43,9 @@ class Host(IoTNode, FilesystemPersistenceManager):
     # ----------------------------------------------------------------------------------------------------------------
     # devices...
 
-    __OPC_SPI_ADDR =        '48030000'                          # hard-coded memory-mapped io address
-    __OPC_SPI_DEVICE =      0                                   # hard-coded path
+    __OPC_SPI_DEV_PATH =    '/dev/spi/by-connector/H1'          # udev-managed symlink to spidev  
 
-    __NDIR_SPI_ADDR =       '481a0000'                          # hard-coded memory-mapped io address
-    __NDIR_SPI_DEVICE =     0                                   # hard-coded path
+    __NDIR_SPI_DEV_PATH =   '/dev/spi/by-connector/H3'          # udev-managed symlink to spidev  
 
     __GPS_DEVICE =          1                                   # hard-coded path
 
@@ -86,32 +82,6 @@ class Host(IoTNode, FilesystemPersistenceManager):
     __SERVER_IPV4_ADDRESS = None                                # hard-coded abs path
 
 
-    # ----------------------------------------------------------------------------------------------------------------
-
-    @staticmethod
-    def spi_bus(spi_address, spi_device):
-        context = pyudev.Context()
-
-        kernel_path = '/ocp/spi@' + spi_address + '/channel@' + str(spi_device)
-
-        for device in context.list_devices(subsystem='spidev'):
-            parent = device.parent
-
-            if type(parent) and parent['OF_FULLNAME'] == kernel_path:
-                node = device.device_node
-
-                match = re.match(r'\D+(\d+).\d+', node)              # e.g. /dev/spidev1.0
-
-                if match is None:
-                    continue
-
-                groups = match.groups()
-
-                return int(groups[0])
-
-        raise OSError("No SPI bus could be found for %s" % kernel_path)
-
-
     # ----------------------------------------------------------------------------------------------------------------
 
     @staticmethod
@@ -284,23 +254,12 @@ def __modem_list(cls):
     # SPI...
 
     @classmethod
-    def ndir_spi_bus(cls):
-        return cls.spi_bus(cls.__NDIR_SPI_ADDR, cls.__NDIR_SPI_DEVICE)
-
-
-    @classmethod
-    def ndir_spi_device(cls):
-        return cls.__NDIR_SPI_DEVICE
-
-
-    @classmethod
-    def opc_spi_bus(cls):
-        return cls.spi_bus(cls.__OPC_SPI_ADDR, cls.__OPC_SPI_DEVICE)
-
+    def ndir_spi_dev_path(cls):
+        return cls.__NDIR_SPI_DEV_PATH
 
     @classmethod
-    def opc_spi_device(cls):
-        return cls.__OPC_SPI_DEVICE
+    def opc_spi_dev_path(cls):
+        return cls.__OPC_SPI_DEV_PATH
 
 
     # ----------------------------------------------------------------------------------------------------------------