Work around unstable I2C bus

The I2C bus the FPGA is attached to is even less stable than originally thought
Retry reads and use most commonly returned value as an interim workaround

1 files changed, 23 insertions, 18 deletions

diff --git a/pyiplledmonitor/ipl_status_led_monitor.py b/pyiplledmonitor/ipl_status_led_monitor.py
index a67186a..6e36d00 100644
--- a/pyiplledmonitor/ipl_status_led_monitor.py
+++ b/pyiplledmonitor/ipl_status_led_monitor.py
@@ -69,24 +69,29 @@ class IPLStatusLEDMonitor(DbusProperties, DbusObjectManager):
     def IPLLEDReadI2CByte(self, byte):
         retry_number = 0
         retval = 0
-        comm_fail = True;
-        while (comm_fail == True):
-            comm_fail = False;
-            try:
-                proc = subprocess.Popen(["i2cget", "-y", "12", "0x31", str(byte)], stdout=subprocess.PIPE, stderr=open(os.devnull, 'wb'), shell=False)
-                (out, err) = proc.communicate()
-                if (proc.returncode != 0):
-                    comm_fail = True
-                else:
-                    retval = int(out, 16)
-            except:
-                comm_fail = True;
-                pass
-            if (comm_fail == True):
-                retry_number += 1
-                if (retry_number > 16):
-                    break
-                time.sleep(0.1)
+        candidate_values = []
+        for read_count in range(0, 64):
+            comm_fail = True;
+            while (comm_fail == True):
+                comm_fail = False;
+                try:
+                    proc = subprocess.Popen(["i2cget", "-y", "12", "0x31", str(byte)], stdout=subprocess.PIPE, stderr=open(os.devnull, 'wb'), shell=False)
+                    (out, err) = proc.communicate()
+                    if (proc.returncode != 0):
+                        comm_fail = True
+                    else:
+                        retval = int(out, 64)
+                except:
+                    comm_fail = True;
+                    pass
+                if (comm_fail == True):
+                    retry_number += 1
+                    if (retry_number > 64):
+                        break
+                    time.sleep(0.1)
+            if (comm_fail == False):
+                candidate_values.append(retval)
+        retval = max(set(candidate_values), key=candidate_values.count)
         return retval
 
     def IPLLEDCheckSystem(self):