Merge pull request #170 from hamishmb/fix-thread-safety

[Adafruit_Blinka-hackapet.git] / src / busio.py

diff --git a/src/busio.py b/src/busio.py
index 9003bab9f257add8fef9108b88e449aebe1a398a..f71871b675be1af1cbe9148c90930e299463b8f0 100755 (executable)
--- 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
@@ -31,10 +33,12 @@ class I2C(Lockable):
                 self._i2c = _I2C(portId, mode=_I2C.MASTER, baudrate=frequency)
                 break
         else:
-            raise NotImplementedError(
-                "No Hardware I2C on (scl,sda)={}\nValid UART ports: {}".format((scl, sda), i2cPorts)
+            raise ValueError(
+                "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):
@@ -95,7 +101,7 @@ class SPI(Lockable):
                 self._pins = (portSck, portMosi, portMiso)
                 break
         else:
-            raise NotImplementedError(
+            raise ValueError(
                 "No Hardware SPI on (SCLK, MOSI, MISO)={}\nValid SPI ports:{}".
                 format((clock, MOSI, MISO), spiPorts))
 
@@ -159,6 +165,13 @@ class SPI(Lockable):
         self._spi = None
         self._pinIds = None
 
+    @property
+    def frequency(self):
+        try:
+            return self._spi.frequency
+        except AttributeError:
+            raise NotImplementedError("Frequency attribute not implemented for this platform")
+
     def write(self, buf, start=0, end=None):
         return self._spi.write(buf, start, end)
 
@@ -223,7 +236,7 @@ class UART(Lockable):
                 )
                 break
         else:
-            raise NotImplementedError(
+            raise ValueError(
                 "No Hardware UART on (tx,rx)={}\nValid UART ports: {}".format((tx, rx), uartPorts)
             )