From fc64706b655a99c64ed12409a66382746864ccc7 Mon Sep 17 00:00:00 2001
From: root <you@example.com>
Date: Fri, 28 Jan 2022 18:09:02 +0000
Subject: [PATCH] Add locking in spi

---
 compLib/Spi.py | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/compLib/Spi.py b/compLib/Spi.py
index d585365..a370b20 100644
--- a/compLib/Spi.py
+++ b/compLib/Spi.py
@@ -1,5 +1,6 @@
 import importlib
-from threading import Thread, Lock
+from threading import Thread
+import multiprocessing
 from enum import IntEnum
 import time
 import sys
@@ -8,13 +9,14 @@ from compLib.LogstashLogging import Logging
 
 SPI_BUS = 1
 SPI_DEVICE = 2
-SPI_SPEED = 1000000
+SPI_SPEED = 4000000
 SPI_BUFFER_SIZE = 32
 SPI_HEALTH = True
 
 # For development purposes
 spi_found = importlib.util.find_spec("spidev") is not None
 spi =  None
+spi_lock = multiprocessing.Lock()
 if spi_found:
     import spidev
     spi = spidev.SpiDev()
@@ -23,8 +25,6 @@ if spi_found:
     spi.mode = 0
     spi.bits_per_word = 8
 
-    spi_mutex = Lock()
-
 class Register(IntEnum):
     IDENTIFICATION_MODEL_ID = 1,
     IDENTIFICATION_MODEL_REV_MAJOR = 2,
@@ -115,13 +115,16 @@ class Spi(object):
             return [] * SPI_BUFFER_SIZE
         
         write_reg = tx_buffer[1]
+        tx_buffer_copy = tx_buffer.copy()
 
-        spi.xfer(tx_buffer)
-        rx_buffer = spi.xfer([0] * SPI_BUFFER_SIZE)
-        
-        if rx_buffer[1] != write_reg:
-            Logging.get_logger().error(f"SPI error during read/write of register {write_reg}!")
-            return [0] * SPI_BUFFER_SIZE
+        with spi_lock:
+            spi.xfer(tx_buffer)
+            rx_buffer = spi.xfer([0] * SPI_BUFFER_SIZE)
+            
+            if rx_buffer[1] != write_reg:
+                Logging.get_logger().error(f"SPI error during read/write of register {write_reg}! Retrying automatically")
+                time.sleep(0.01)
+                return Spi.transfer(tx_buffer_copy)
 
         return rx_buffer
 
@@ -202,7 +205,7 @@ class Spi(object):
     def health_check_loop():
         while SPI_HEALTH:
             Spi.health_check()
-            time.sleep(0.5)
+            time.sleep(5)
 
     @staticmethod
     def get_version():