1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Driver for RobotFuzz OSIF
4 *
5 * Copyright (c) 2013 Andrew Lunn <andrew@lunn.ch>
6 * Copyright (c) 2007 Barry Carter <Barry.Carter@robotfuzz.com>
7 *
8 * Based on the i2c-tiny-usb by
9 *
10 * Copyright (C) 2006 Til Harbaum (Till@Harbaum.org)
11 */
12
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/errno.h>
16 #include <linux/i2c.h>
17 #include <linux/slab.h>
18 #include <linux/usb.h>
19
20 #define OSIFI2C_READ 20
21 #define OSIFI2C_WRITE 21
22 #define OSIFI2C_STOP 22
23 #define OSIFI2C_STATUS 23
24 #define OSIFI2C_SET_BIT_RATE 24
25
26 #define STATUS_ADDRESS_ACK 0
27 #define STATUS_ADDRESS_NAK 2
28
29 struct osif_priv {
30 struct usb_device *usb_dev;
31 struct usb_interface *interface;
32 struct i2c_adapter adapter;
33 unsigned char status;
34 };
35
osif_usb_read(struct i2c_adapter * adapter,int cmd,int value,int index,void * data,int len)36 static int osif_usb_read(struct i2c_adapter *adapter, int cmd,
37 int value, int index, void *data, int len)
38 {
39 struct osif_priv *priv = adapter->algo_data;
40
41 return usb_control_msg(priv->usb_dev, usb_rcvctrlpipe(priv->usb_dev, 0),
42 cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |
43 USB_DIR_IN, value, index, data, len, 2000);
44 }
45
osif_usb_write(struct i2c_adapter * adapter,int cmd,int value,int index,void * data,int len)46 static int osif_usb_write(struct i2c_adapter *adapter, int cmd,
47 int value, int index, void *data, int len)
48 {
49
50 struct osif_priv *priv = adapter->algo_data;
51
52 return usb_control_msg(priv->usb_dev, usb_sndctrlpipe(priv->usb_dev, 0),
53 cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
54 value, index, data, len, 2000);
55 }
56
osif_xfer(struct i2c_adapter * adapter,struct i2c_msg * msgs,int num)57 static int osif_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
58 int num)
59 {
60 struct osif_priv *priv = adapter->algo_data;
61 struct i2c_msg *pmsg;
62 int ret;
63 int i;
64
65 for (i = 0; i < num; i++) {
66 pmsg = &msgs[i];
67
68 if (pmsg->flags & I2C_M_RD) {
69 ret = osif_usb_read(adapter, OSIFI2C_READ,
70 pmsg->flags, pmsg->addr,
71 pmsg->buf, pmsg->len);
72 if (ret != pmsg->len) {
73 dev_err(&adapter->dev, "failure reading data\n");
74 return -EREMOTEIO;
75 }
76 } else {
77 ret = osif_usb_write(adapter, OSIFI2C_WRITE,
78 pmsg->flags, pmsg->addr,
79 pmsg->buf, pmsg->len);
80 if (ret != pmsg->len) {
81 dev_err(&adapter->dev, "failure writing data\n");
82 return -EREMOTEIO;
83 }
84 }
85
86 ret = osif_usb_write(adapter, OSIFI2C_STOP, 0, 0, NULL, 0);
87 if (ret) {
88 dev_err(&adapter->dev, "failure sending STOP\n");
89 return -EREMOTEIO;
90 }
91
92 /* read status */
93 ret = osif_usb_read(adapter, OSIFI2C_STATUS, 0, 0,
94 &priv->status, 1);
95 if (ret != 1) {
96 dev_err(&adapter->dev, "failure reading status\n");
97 return -EREMOTEIO;
98 }
99
100 if (priv->status != STATUS_ADDRESS_ACK) {
101 dev_dbg(&adapter->dev, "status = %d\n", priv->status);
102 return -EREMOTEIO;
103 }
104 }
105
106 return i;
107 }
108
osif_func(struct i2c_adapter * adapter)109 static u32 osif_func(struct i2c_adapter *adapter)
110 {
111 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
112 }
113
114 /* prevent invalid 0-length usb_control_msg */
115 static const struct i2c_adapter_quirks osif_quirks = {
116 .flags = I2C_AQ_NO_ZERO_LEN_READ,
117 };
118
119 static const struct i2c_algorithm osif_algorithm = {
120 .xfer = osif_xfer,
121 .functionality = osif_func,
122 };
123
124 #define USB_OSIF_VENDOR_ID 0x1964
125 #define USB_OSIF_PRODUCT_ID 0x0001
126
127 static const struct usb_device_id osif_table[] = {
128 { USB_DEVICE(USB_OSIF_VENDOR_ID, USB_OSIF_PRODUCT_ID) },
129 { }
130 };
131 MODULE_DEVICE_TABLE(usb, osif_table);
132
osif_probe(struct usb_interface * interface,const struct usb_device_id * id)133 static int osif_probe(struct usb_interface *interface,
134 const struct usb_device_id *id)
135 {
136 int ret;
137 struct osif_priv *priv;
138 u16 version;
139
140 priv = devm_kzalloc(&interface->dev, sizeof(*priv), GFP_KERNEL);
141 if (!priv)
142 return -ENOMEM;
143
144 priv->usb_dev = usb_get_dev(interface_to_usbdev(interface));
145 priv->interface = interface;
146
147 usb_set_intfdata(interface, priv);
148
149 priv->adapter.owner = THIS_MODULE;
150 priv->adapter.class = I2C_CLASS_HWMON;
151 priv->adapter.quirks = &osif_quirks;
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_write(&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
osif_disconnect(struct usb_interface * interface)181 static 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
190 static 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
197 module_usb_driver(osif_driver);
198
199 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
200 MODULE_AUTHOR("Barry Carter <barry.carter@robotfuzz.com>");
201 MODULE_DESCRIPTION("RobotFuzz OSIF driver");
202 MODULE_LICENSE("GPL v2");
203