sensord: remove hardcoded irq from test (#27759)

* sensord: remove hardcoded irq from test

* fix linter

---------

Co-authored-by: Comma Device <device@comma.ai>
old-commit-hash: 08be9eed08

system/sensord/tests/test_sensord.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 import os
+import glob
 import time
 import unittest
 import numpy as np
@@ -7,7 +8,7 @@ from collections import namedtuple, defaultdict
 
 import cereal.messaging as messaging
 from cereal import log
-from system.hardware import TICI, HARDWARE
+from system.hardware import TICI
 from selfdrive.manager.process_config import managed_processes
 
 BMX = {
@@ -70,7 +71,6 @@ ALL_SENSORS = {
   }
 }
 
-LSM_IRQ = 336
 
 def get_irq_count(irq: int):
   with open(f"/sys/kernel/irq/{irq}/per_cpu_count") as f:
@@ -101,9 +101,6 @@ class TestSensord(unittest.TestCase):
     if not TICI:
       raise unittest.SkipTest
 
-    # make sure gpiochip0 is readable
-    HARDWARE.initialize_hardware()
-
     # enable LSM self test
     os.environ["LSM_SELF_TEST"] = "1"
 
@@ -114,6 +111,15 @@ class TestSensord(unittest.TestCase):
       time.sleep(3)
       cls.sample_secs = 10
       cls.events = read_sensor_events(cls.sample_secs)
+
+      # determine sensord's irq
+      cls.sensord_irq = None
+      for fn in glob.glob('/sys/kernel/irq/*/actions'):
+        with open(fn) as f:
+          if "sensord" in f.read():
+            cls.sensord_irq = int(fn.split('/')[-2])
+            break
+      assert cls.sensord_irq is not None
     finally:
       # teardown won't run if this doesn't succeed
       managed_processes["sensord"].stop()
@@ -121,8 +127,6 @@ class TestSensord(unittest.TestCase):
   @classmethod
   def tearDownClass(cls):
     managed_processes["sensord"].stop()
-    if "LSM_SELF_TEST" in os.environ:
-      del os.environ['LSM_SELF_TEST']
 
   def tearDown(self):
     managed_processes["sensord"].stop()
@@ -250,9 +254,9 @@ class TestSensord(unittest.TestCase):
     time.sleep(3)
 
     # read /proc/interrupts to verify interrupts are received
-    state_one = get_irq_count(LSM_IRQ)
+    state_one = get_irq_count(self.sensord_irq)
     time.sleep(1)
-    state_two = get_irq_count(LSM_IRQ)
+    state_two = get_irq_count(self.sensord_irq)
 
     error_msg = f"no interrupts received after sensord start!\n{state_one} {state_two}"
     assert state_one != state_two, error_msg
@@ -261,9 +265,9 @@ class TestSensord(unittest.TestCase):
     time.sleep(1)
 
     # read /proc/interrupts to verify no more interrupts are received
-    state_one = get_irq_count(LSM_IRQ)
+    state_one = get_irq_count(self.sensord_irq)
     time.sleep(1)
-    state_two = get_irq_count(LSM_IRQ)
+    state_two = get_irq_count(self.sensord_irq)
     assert state_one == state_two, "Interrupts received after sensord stop!"