2007-11-17 Till Straumann <strauman@slac.stanford.edu>

	* libi2c/libi2c.c, libi2c/libi2c.h, libi2c/README_libi2c:
	Added checks so that use of 'stdio' is avoided (falling
	back to 'printk') before the system is up.
	Publish driver entry points so that the libi2c driver could
	be added to the applications 'device driver table'.
	This is not fully implemented yet, though, since in addition to
	initializing libi2c the low-level i2c bus drivers as well
	as high-level i2c device drivers need to be registered
	with the library.
	Updated README_libi2c accordingly.

1 files changed, 70 insertions, 0 deletions

diff --git a/cpukit/libi2c/libi2c.h b/cpukit/libi2c/libi2c.h
index d243574333..6fa7a53981 100644
--- a/cpukit/libi2c/libi2c.h
+++ b/cpukit/libi2c/libi2c.h
@@ -60,6 +60,76 @@ extern "C" {
 /* Initialize the libary - may fail if no semaphore or no driver slot is available */
 int rtems_libi2c_initialize ();
 
+/* Alternatively to rtems_libi2c_initialize() the library can also be
+ * initialized by means of a traditional driver table entry containing
+ * the following entry points:
+ */
+rtems_status_code
+rtems_i2c_init (
+	rtems_device_major_number major,
+	rtems_device_minor_number minor,
+    void *arg);
+
+rtems_status_code
+rtems_i2c_open (
+	rtems_device_major_number major,
+	rtems_device_minor_number minor,
+    void *arg);
+
+rtems_status_code
+rtems_i2c_close (
+	rtems_device_major_number major,
+	rtems_device_minor_number minor,
+    void *arg);
+
+rtems_status_code
+rtems_i2c_read (
+	rtems_device_major_number major,
+	rtems_device_minor_number minor,
+    void *arg);
+
+rtems_status_code
+rtems_i2c_write (
+	rtems_device_major_number major,
+	rtems_device_minor_number minor,
+    void *arg);
+
+rtems_status_code
+rtems_i2c_ioctl (
+	rtems_device_major_number major,
+	rtems_device_minor_number minor,
+    void *arg);
+
+extern rtems_driver_address_table rtems_libi2c_io_ops;
+
+/* Unfortunately, if you want to add this driver to 
+ * a RTEMS configuration table then you need all the
+ * members explicitly :-( (Device_driver_table should
+ * hold pointers to rtems_driver_address_tables rather
+ * than full structs).
+ *
+ * The difficulty is that adding this driver to the
+ * configuration table is not enough; you still need
+ * to populate the framework with low-level bus-driver(s)
+ * and high-level drivers and/or device-files...
+ *
+ * Currently the preferred way is having the BSP
+ * call 'rtems_libi2c_initialize' followed by
+ * 'rtems_libi2c_register_bus' and 
+ * 'rtems_libi2c_register_drv' and/or
+ * 'mknod' (for 'raw' device nodes)
+ * from the 'pretasking_hook'.
+ */
+#define RTEMS_LIBI2C_DRIVER_TABLE_ENTRY   \
+{                                         \
+  initialization_entry:  rtems_i2c_init,  \
+  open_entry:            rtems_i2c_open,  \
+  close_entry:           rtems_i2c_close, \
+  read_entry:            rtems_i2c_read,  \
+  write_entry:           rtems_i2c_write, \
+  control_entry:         rtems_i2c_ioctl, \
+}
+
 /* Bus Driver API
  *
  * Bus drivers provide access to low-level i2c functions