From 76ca3e6a3c4c2f2695d96bdb0ee2db66d3f0f32c Mon Sep 17 00:00:00 2001
From: Hamish McIntyre-Bhatty <hamishmb@live.co.uk>
Date: Thu, 31 Oct 2019 14:38:40 +0000
Subject: [PATCH] Add a lock for thread safety when the I2C class is used in a
 with statement

---
 src/busio.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/busio.py b/src/busio.py
index 9702848..73c88ef 100755
--- a/src/busio.py
+++ b/src/busio.py
@@ -7,6 +7,8 @@ See `CircuitPython:busio` in CircuitPython for more details.
 * Author(s): cefn
 """
 
+import threading
+
 from adafruit_blinka import Enum, Lockable, agnostic
 from adafruit_blinka.agnostic import board_id, detector
 import adafruit_platformdetect.board as ap_board
@@ -35,6 +37,8 @@ class I2C(Lockable):
                 "No Hardware I2C on (scl,sda)={}\nValid I2C ports: {}".format((scl, sda), i2cPorts)
             )
 
+        self._lock = threading.RLock()
+
     def deinit(self):
         try:
             del self._i2c
@@ -42,9 +46,11 @@ class I2C(Lockable):
             pass
 
     def __enter__(self):
+        self._lock.acquire()
         return self
 
     def __exit__(self, exc_type, exc_value, traceback):
+        self._lock.release()
         self.deinit()
 
     def scan(self):
-- 
2.49.0