Add c2 port support

C2port implements a two wire serial communication protocol (bit
banging) designed to enable in-system programming, debugging, and
boundary-scan testing on low pin-count Silicon Labs devices.

Currently this code supports only flash programming through sysfs
interface but extensions shoud be easy to add.

Signed-off-by: Rodolfo Giometti <giometti@linux.it>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/c2port.h

@@ -0,0 +1,65 @@
+/*
+ *  Silicon Labs C2 port Linux support
+ *
+ *  Copyright (c) 2007 Rodolfo Giometti <giometti@linux.it>
+ *  Copyright (c) 2007 Eurotech S.p.A. <info@eurotech.it>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation
+ */
+
+#include <linux/device.h>
+
+#define C2PORT_NAME_LEN			32
+
+/*
+ * C2 port basic structs
+ */
+
+/* Main struct */
+struct c2port_ops;
+struct c2port_device {
+	unsigned int access:1;
+	unsigned int flash_access:1;
+
+	int id;
+	char name[C2PORT_NAME_LEN];
+	struct c2port_ops *ops;
+	struct mutex mutex;		/* prevent races during read/write */
+
+	struct device *dev;
+
+	void *private_data;
+};
+
+/* Basic operations */
+struct c2port_ops {
+	/* Flash layout */
+	unsigned short block_size;	/* flash block size in bytes */
+	unsigned short blocks_num;	/* flash blocks number */
+
+	/* Enable or disable the access to C2 port */
+	void (*access)(struct c2port_device *dev, int status);
+
+	/* Set C2D data line as input/output */
+	void (*c2d_dir)(struct c2port_device *dev, int dir);
+
+	/* Read/write C2D data line */
+	int (*c2d_get)(struct c2port_device *dev);
+	void (*c2d_set)(struct c2port_device *dev, int status);
+
+	/* Write C2CK clock line */
+	void (*c2ck_set)(struct c2port_device *dev, int status);
+};
+
+/*
+ * Exported functions
+ */
+
+#define to_class_dev(obj) container_of((obj), struct class_device, kobj)
+#define to_c2port_device(obj) container_of((obj), struct c2port_device, class)
+
+extern struct c2port_device *c2port_device_register(char *name,
+					struct c2port_ops *ops, void *devdata);
+extern void c2port_device_unregister(struct c2port_device *dev);