X-Git-Url: https://defiant.homedns.org/gitweb/?a=blobdiff_plain;f=i2c.py;h=bffa9fe0c61e3b556ae534e43412dc7f07b83b16;hb=580beb73ab16024ddfab56bc26ffa261c1790906;hp=2e9a109e0fe2891175726af4e6d739958e032208;hpb=1e900f8150af092dd46c690a48b2541a36a6bca0;p=pyshared.git

diff --git a/i2c.py b/i2c.py
index 2e9a109..bffa9fe 100755
--- a/i2c.py
+++ b/i2c.py
@@ -5,14 +5,15 @@ import threading
 import inspect
 import os
 import logging
-from ctypes import *
+import struct
+import fcntl
 from time import sleep
 
 DEBUG=0
+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()
@@ -31,39 +32,49 @@ 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("/dev/i2c-2", os.O_RDWR)
+		self.dev = os.open(I2C_FILENAME, os.O_RDWR)
 		if self.dev < 0:
 			raise IOError("open")
-		err = i2c.libc.ioctl(self.dev, i2c.I2C_SLAVE, addr>>1)
-		if err < 0:
-			raise IOError("ioctl")
+		fcntl.flock(self.dev, fcntl.LOCK_EX)
+		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):
-		self.close()
+
+def i2c_write_reg(addr, reg, buf=""):
+	dev = i2c(addr)
+	s = struct.pack(">B", reg) + buf
+	dev.write(s)
+	dev.close()
+
+
+def i2c_read_reg(addr, reg, num=1):
+	i2c_write_reg(addr, reg)
+
+	dev = i2c(addr)
+	s = dev.read(num)
+	dev.close()
+	return s
+
 
 if __name__ == "__main__":
-	import struct
 	import sys
 
 	dev = i2c(0x50)