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13#include <linux/kernel.h>
14#include <linux/errno.h>
15#include <linux/module.h>
16#include <linux/slab.h>
17#include <linux/types.h>
18
19
20#include <linux/usb.h>
21
22
23#include <linux/i2c.h>
24
25
26#define CMD_ECHO 0
27#define CMD_GET_FUNC 1
28#define CMD_SET_DELAY 2
29#define CMD_GET_STATUS 3
30
31#define CMD_I2C_IO 4
32#define CMD_I2C_IO_BEGIN (1<<0)
33#define CMD_I2C_IO_END (1<<1)
34
35
36
37
38static unsigned short delay = 10;
39module_param(delay, ushort, 0);
40MODULE_PARM_DESC(delay, "bit delay in microseconds "
41 "(default is 10us for 100kHz max)");
42
43static int usb_read(struct i2c_adapter *adapter, int cmd,
44 int value, int index, void *data, int len);
45
46static int usb_write(struct i2c_adapter *adapter, int cmd,
47 int value, int index, void *data, int len);
48
49
50
51#define STATUS_IDLE 0
52#define STATUS_ADDRESS_ACK 1
53#define STATUS_ADDRESS_NAK 2
54
55static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
56{
57 unsigned char *pstatus;
58 struct i2c_msg *pmsg;
59 int i, ret;
60
61 dev_dbg(&adapter->dev, "master xfer %d messages:\n", num);
62
63 pstatus = kmalloc(sizeof(*pstatus), GFP_KERNEL);
64 if (!pstatus)
65 return -ENOMEM;
66
67 for (i = 0 ; i < num ; i++) {
68 int cmd = CMD_I2C_IO;
69
70 if (i == 0)
71 cmd |= CMD_I2C_IO_BEGIN;
72
73 if (i == num-1)
74 cmd |= CMD_I2C_IO_END;
75
76 pmsg = &msgs[i];
77
78 dev_dbg(&adapter->dev,
79 " %d: %s (flags %d) %d bytes to 0x%02x\n",
80 i, pmsg->flags & I2C_M_RD ? "read" : "write",
81 pmsg->flags, pmsg->len, pmsg->addr);
82
83
84 if (pmsg->flags & I2C_M_RD) {
85
86 if (usb_read(adapter, cmd,
87 pmsg->flags, pmsg->addr,
88 pmsg->buf, pmsg->len) != pmsg->len) {
89 dev_err(&adapter->dev,
90 "failure reading data\n");
91 ret = -EREMOTEIO;
92 goto out;
93 }
94 } else {
95
96 if (usb_write(adapter, cmd,
97 pmsg->flags, pmsg->addr,
98 pmsg->buf, pmsg->len) != pmsg->len) {
99 dev_err(&adapter->dev,
100 "failure writing data\n");
101 ret = -EREMOTEIO;
102 goto out;
103 }
104 }
105
106
107 if (usb_read(adapter, CMD_GET_STATUS, 0, 0, pstatus, 1) != 1) {
108 dev_err(&adapter->dev, "failure reading status\n");
109 ret = -EREMOTEIO;
110 goto out;
111 }
112
113 dev_dbg(&adapter->dev, " status = %d\n", *pstatus);
114 if (*pstatus == STATUS_ADDRESS_NAK) {
115 ret = -EREMOTEIO;
116 goto out;
117 }
118 }
119
120 ret = i;
121out:
122 kfree(pstatus);
123 return ret;
124}
125
126static u32 usb_func(struct i2c_adapter *adapter)
127{
128 __le32 *pfunc;
129 u32 ret;
130
131 pfunc = kmalloc(sizeof(*pfunc), GFP_KERNEL);
132
133
134 if (!pfunc || usb_read(adapter, CMD_GET_FUNC, 0, 0, pfunc,
135 sizeof(*pfunc)) != sizeof(*pfunc)) {
136 dev_err(&adapter->dev, "failure reading functionality\n");
137 ret = 0;
138 goto out;
139 }
140
141 ret = le32_to_cpup(pfunc);
142out:
143 kfree(pfunc);
144 return ret;
145}
146
147
148static const struct i2c_algorithm usb_algorithm = {
149 .master_xfer = usb_xfer,
150 .functionality = usb_func,
151};
152
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160
161
162static const struct usb_device_id i2c_tiny_usb_table[] = {
163 { USB_DEVICE(0x0403, 0xc631) },
164 { USB_DEVICE(0x1c40, 0x0534) },
165 { }
166};
167
168MODULE_DEVICE_TABLE(usb, i2c_tiny_usb_table);
169
170
171struct i2c_tiny_usb {
172 struct usb_device *usb_dev;
173 struct usb_interface *interface;
174 struct i2c_adapter adapter;
175};
176
177static int usb_read(struct i2c_adapter *adapter, int cmd,
178 int value, int index, void *data, int len)
179{
180 struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;
181
182
183 return usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0),
184 cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |
185 USB_DIR_IN, value, index, data, len, 2000);
186}
187
188static int usb_write(struct i2c_adapter *adapter, int cmd,
189 int value, int index, void *data, int len)
190{
191 struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;
192
193
194 return usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0),
195 cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
196 value, index, data, len, 2000);
197}
198
199static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev)
200{
201 usb_put_dev(dev->usb_dev);
202 kfree(dev);
203}
204
205static int i2c_tiny_usb_probe(struct usb_interface *interface,
206 const struct usb_device_id *id)
207{
208 struct i2c_tiny_usb *dev;
209 int retval = -ENOMEM;
210 u16 version;
211
212 dev_dbg(&interface->dev, "probing usb device\n");
213
214
215 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
216 if (dev == NULL) {
217 dev_err(&interface->dev, "Out of memory\n");
218 goto error;
219 }
220
221 dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
222 dev->interface = interface;
223
224
225 usb_set_intfdata(interface, dev);
226
227 version = le16_to_cpu(dev->usb_dev->descriptor.bcdDevice);
228 dev_info(&interface->dev,
229 "version %x.%02x found at bus %03d address %03d\n",
230 version >> 8, version & 0xff,
231 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
232
233
234 dev->adapter.owner = THIS_MODULE;
235 dev->adapter.class = I2C_CLASS_HWMON;
236 dev->adapter.algo = &usb_algorithm;
237 dev->adapter.algo_data = dev;
238 snprintf(dev->adapter.name, sizeof(dev->adapter.name),
239 "i2c-tiny-usb at bus %03d device %03d",
240 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
241
242 if (usb_write(&dev->adapter, CMD_SET_DELAY, delay, 0, NULL, 0) != 0) {
243 dev_err(&dev->adapter.dev,
244 "failure setting delay to %dus\n", delay);
245 retval = -EIO;
246 goto error;
247 }
248
249 dev->adapter.dev.parent = &dev->interface->dev;
250
251
252 i2c_add_adapter(&dev->adapter);
253
254
255 dev_info(&dev->adapter.dev, "connected i2c-tiny-usb device\n");
256
257 return 0;
258
259 error:
260 if (dev)
261 i2c_tiny_usb_free(dev);
262
263 return retval;
264}
265
266static void i2c_tiny_usb_disconnect(struct usb_interface *interface)
267{
268 struct i2c_tiny_usb *dev = usb_get_intfdata(interface);
269
270 i2c_del_adapter(&dev->adapter);
271 usb_set_intfdata(interface, NULL);
272 i2c_tiny_usb_free(dev);
273
274 dev_dbg(&interface->dev, "disconnected\n");
275}
276
277static struct usb_driver i2c_tiny_usb_driver = {
278 .name = "i2c-tiny-usb",
279 .probe = i2c_tiny_usb_probe,
280 .disconnect = i2c_tiny_usb_disconnect,
281 .id_table = i2c_tiny_usb_table,
282};
283
284module_usb_driver(i2c_tiny_usb_driver);
285
286
287
288MODULE_AUTHOR("Till Harbaum <Till@Harbaum.org>");
289MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0");
290MODULE_LICENSE("GPL");
291