1/*
2 * Driver for RobotFuzz OSIF
3 *
4 * Copyright (c) 2013 Andrew Lunn <andrew@lunn.ch>
5 * Copyright (c) 2007 Barry Carter <Barry.Carter@robotfuzz.com>
6 *
7 * Based on the i2c-tiny-usb by
8 *
9 * Copyright (C) 2006 Til Harbaum (Till@Harbaum.org)
10 *
11 *	This program is free software; you can redistribute it and/or
12 *	modify it under the terms of the GNU General Public License as
13 *	published by the Free Software Foundation, version 2.
14 */
15
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/errno.h>
19#include <linux/i2c.h>
20#include <linux/slab.h>
21#include <linux/usb.h>
22
23#define OSIFI2C_READ		20
24#define OSIFI2C_WRITE		21
25#define OSIFI2C_STOP		22
26#define OSIFI2C_STATUS		23
27#define OSIFI2C_SET_BIT_RATE	24
28
29#define STATUS_ADDRESS_ACK	0
30#define STATUS_ADDRESS_NAK	2
31
32struct osif_priv {
33	struct usb_device *usb_dev;
34	struct usb_interface *interface;
35	struct i2c_adapter adapter;
36	unsigned char status;
37};
38
39static int osif_usb_read(struct i2c_adapter *adapter, int cmd,
40			 int value, int index, void *data, int len)
41{
42	struct osif_priv *priv = adapter->algo_data;
43
44	return usb_control_msg(priv->usb_dev, usb_rcvctrlpipe(priv->usb_dev, 0),
45			       cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |
46			       USB_DIR_IN, value, index, data, len, 2000);
47}
48
49static int osif_usb_write(struct i2c_adapter *adapter, int cmd,
50			  int value, int index, void *data, int len)
51{
52
53	struct osif_priv *priv = adapter->algo_data;
54
55	return usb_control_msg(priv->usb_dev, usb_sndctrlpipe(priv->usb_dev, 0),
56			       cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
57			       value, index, data, len, 2000);
58}
59
60static int osif_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
61			 int num)
62{
63	struct osif_priv *priv = adapter->algo_data;
64	struct i2c_msg *pmsg;
65	int ret = 0;
66	int i, cmd;
67
68	for (i = 0; ret >= 0 && i < num; i++) {
69		pmsg = &msgs[i];
70
71		if (pmsg->flags & I2C_M_RD) {
72			cmd = OSIFI2C_READ;
73
74			ret = osif_usb_read(adapter, cmd, pmsg->flags,
75					    pmsg->addr, pmsg->buf,
76					    pmsg->len);
77			if (ret != pmsg->len) {
78				dev_err(&adapter->dev, "failure reading data\n");
79				return -EREMOTEIO;
80			}
81		} else {
82			cmd = OSIFI2C_WRITE;
83
84			ret = osif_usb_write(adapter, cmd, pmsg->flags,
85					     pmsg->addr, pmsg->buf, pmsg->len);
86			if (ret != pmsg->len) {
87				dev_err(&adapter->dev, "failure writing data\n");
88				return -EREMOTEIO;
89			}
90		}
91
92		ret = osif_usb_read(adapter, OSIFI2C_STOP, 0, 0, NULL, 0);
93		if (ret) {
94			dev_err(&adapter->dev, "failure sending STOP\n");
95			return -EREMOTEIO;
96		}
97
98		/* read status */
99		ret = osif_usb_read(adapter, OSIFI2C_STATUS, 0, 0,
100				    &priv->status, 1);
101		if (ret != 1) {
102			dev_err(&adapter->dev, "failure reading status\n");
103			return -EREMOTEIO;
104		}
105
106		if (priv->status != STATUS_ADDRESS_ACK) {
107			dev_dbg(&adapter->dev, "status = %d\n", priv->status);
108			return -EREMOTEIO;
109		}
110	}
111
112	return i;
113}
114
115static u32 osif_func(struct i2c_adapter *adapter)
116{
117	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
118}
119
120static struct i2c_algorithm osif_algorithm = {
121	.master_xfer	= osif_xfer,
122	.functionality	= osif_func,
123};
124
125#define USB_OSIF_VENDOR_ID	0x1964
126#define USB_OSIF_PRODUCT_ID	0x0001
127
128static struct usb_device_id osif_table[] = {
129	{ USB_DEVICE(USB_OSIF_VENDOR_ID, USB_OSIF_PRODUCT_ID) },
130	{ }
131};
132MODULE_DEVICE_TABLE(usb, osif_table);
133
134static int osif_probe(struct usb_interface *interface,
135			     const struct usb_device_id *id)
136{
137	int ret;
138	struct osif_priv *priv;
139	u16 version;
140
141	priv = devm_kzalloc(&interface->dev, sizeof(*priv), GFP_KERNEL);
142	if (!priv)
143		return -ENOMEM;
144
145	priv->usb_dev = usb_get_dev(interface_to_usbdev(interface));
146	priv->interface = interface;
147
148	usb_set_intfdata(interface, priv);
149
150	priv->adapter.owner = THIS_MODULE;
151	priv->adapter.class = I2C_CLASS_HWMON;
152	priv->adapter.algo = &osif_algorithm;
153	priv->adapter.algo_data = priv;
154	snprintf(priv->adapter.name, sizeof(priv->adapter.name),
155		 "OSIF at bus %03d device %03d",
156		 priv->usb_dev->bus->busnum, priv->usb_dev->devnum);
157
158	/*
159	 * Set bus frequency. The frequency is:
160	 * 120,000,000 / ( 16 + 2 * div * 4^prescale).
161	 * Using dev = 52, prescale = 0 give 100KHz */
162	ret = osif_usb_read(&priv->adapter, OSIFI2C_SET_BIT_RATE, 52, 0,
163			    NULL, 0);
164	if (ret) {
165		dev_err(&interface->dev, "failure sending bit rate");
166		usb_put_dev(priv->usb_dev);
167		return ret;
168	}
169
170	i2c_add_adapter(&(priv->adapter));
171
172	version = le16_to_cpu(priv->usb_dev->descriptor.bcdDevice);
173	dev_info(&interface->dev,
174		 "version %x.%02x found at bus %03d address %03d",
175		 version >> 8, version & 0xff,
176		 priv->usb_dev->bus->busnum, priv->usb_dev->devnum);
177
178	return 0;
179}
180
181static void osif_disconnect(struct usb_interface *interface)
182{
183	struct osif_priv *priv = usb_get_intfdata(interface);
184
185	i2c_del_adapter(&(priv->adapter));
186	usb_set_intfdata(interface, NULL);
187	usb_put_dev(priv->usb_dev);
188}
189
190static struct usb_driver osif_driver = {
191	.name		= "RobotFuzz Open Source InterFace, OSIF",
192	.probe		= osif_probe,
193	.disconnect	= osif_disconnect,
194	.id_table	= osif_table,
195};
196
197module_usb_driver(osif_driver);
198
199MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
200MODULE_AUTHOR("Barry Carter <barry.carter@robotfuzz.com>");
201MODULE_DESCRIPTION("RobotFuzz OSIF driver");
202MODULE_LICENSE("GPL v2");
203