ADD I2C driver framework and I2C gpio driver

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@2128 bbd45198-f89e-11dd-88c7-29a3b14d5316

components/drivers/i2c/SConscript

@@ -0,0 +1,18 @@
+Import('RTT_ROOT')
+from building import *
+
+cwd = GetCurrentDir()
+src = Split("""
+i2c_core.c
+i2c_dev.c
+""")
+
+if GetDepend('RT_USING_I2C_BITOPS'):
+    src = src + ['i2c-bit-ops.c']
+
+# The set of source files associated with this SConscript file.
+path = [cwd]
+
+group = DefineGroup('DeviceDrivers', src, depend = ['RT_USING_I2C'], CPPPATH = path)
+
+Return('group')