From: Erik Andresen <erik@vontaene.de>
Date: Wed, 28 Dec 2016 13:52:24 +0000 (+0100)
Subject: i2c: use python low level api instead ob c calls
X-Git-Url: https://defiant.homedns.org/gitweb/?a=commitdiff_plain;h=f23971240165455313729886360541bee726b42c;p=pyshared.git

i2c: use python low level api instead ob c calls
---

diff --git a/i2c.py b/i2c.py
index 2bb9f94..60d825d 100755
--- a/i2c.py
+++ b/i2c.py
@@ -7,7 +7,6 @@ import os
 import logging
 import struct
 import fcntl
-from ctypes import *
 from time import sleep
 
 DEBUG=0
@@ -15,7 +14,6 @@ I2C_FILENAME = "/dev/i2c-2"
 logger = logging.getLogger(__name__)
 
 class i2c:
-	libc = CDLL("libc.so.6")
 	I2C_SLAVE = 0x0703  # Use this slave address
 	__single = None
 	__lock = threading.Lock()
@@ -34,33 +32,29 @@ class i2c:
 					logger.warning("Error: (%s) I2C blocked %fs by %s!", parent, count*0.001, parent_owner)
 				i2c.__parent_owner = inspect.stack()[1]
 			i2c.__single = True
-		self.dev = i2c.libc.open(I2C_FILENAME, os.O_RDWR)
+		self.dev = os.open(I2C_FILENAME, os.O_RDWR)
 		if self.dev < 0:
 			raise IOError("open")
 		fcntl.flock(self.dev, fcntl.LOCK_EX)
-		err = i2c.libc.ioctl(self.dev, i2c.I2C_SLAVE, addr>>1)
-		if err < 0:
-			raise IOError("ioctl")
+		fcntl.ioctl(self.dev, i2c.I2C_SLAVE, addr>>1)
 
 	def write(self, s):
-		num_write = i2c.libc.write(self.dev, s, len(s))
+		num_write = os.write(self.dev, s)
 		if num_write != len(s):
 			self.close()
 			raise IOError("write: %d" % (num_write))
 	
 	def read(self, num):
-		buf = create_string_buffer(num)
-		num_read = i2c.libc.read(self.dev, buf, num)
-		if num_read != num:
+		buf = os.read(self.dev, num)
+		if len(buf) != num:
 			self.close()
-			raise IOError("read: %d" % (num_read))
-		return buf.raw
+			raise IOError("read: %d" % (len(buf)))
+		return buf
 
 	def close(self):
 		if self.dev:
-			i2c.libc.close(self.dev)
+			os.close(self.dev)
 			self.dev = None
-			#i2c.__parent_owner = None
 			i2c.__single = None
 
 	def __del__(self):
@@ -84,7 +78,6 @@ def i2c_read_reg(addr, reg, num=1):
 
 
 if __name__ == "__main__":
-	import struct
 	import sys
 
 	dev = i2c(0x50)