Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux...
[linux-2.6] / drivers / i2c / busses / i2c-tiny-usb.c
1 /*
2  * driver for the i2c-tiny-usb adapter - 1.0
3  * http://www.harbaum.org/till/i2c_tiny_usb
4  *
5  * Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License as
9  * published by the Free Software Foundation, version 2.
10  *
11  */
12
13 #include <linux/kernel.h>
14 #include <linux/errno.h>
15 #include <linux/module.h>
16
17 /* include interfaces to usb layer */
18 #include <linux/usb.h>
19
20 /* include interface to i2c layer */
21 #include <linux/i2c.h>
22
23 /* commands via USB, must match command ids in the firmware */
24 #define CMD_ECHO                0
25 #define CMD_GET_FUNC            1
26 #define CMD_SET_DELAY           2
27 #define CMD_GET_STATUS          3
28
29 #define CMD_I2C_IO              4
30 #define CMD_I2C_IO_BEGIN        (1<<0)
31 #define CMD_I2C_IO_END          (1<<1)
32
33 /* i2c bit delay, default is 10us -> 100kHz */
34 static int delay = 10;
35 module_param(delay, int, 0);
36 MODULE_PARM_DESC(delay, "bit delay in microseconds, "
37                  "e.g. 10 for 100kHz (default is 100kHz)");
38
39 static int usb_read(struct i2c_adapter *adapter, int cmd,
40                     int value, int index, void *data, int len);
41
42 static int usb_write(struct i2c_adapter *adapter, int cmd,
43                      int value, int index, void *data, int len);
44
45 /* ----- begin of i2c layer ---------------------------------------------- */
46
47 #define STATUS_IDLE             0
48 #define STATUS_ADDRESS_ACK      1
49 #define STATUS_ADDRESS_NAK      2
50
51 static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
52 {
53         unsigned char status;
54         struct i2c_msg *pmsg;
55         int i;
56
57         dev_dbg(&adapter->dev, "master xfer %d messages:\n", num);
58
59         for (i = 0 ; i < num ; i++) {
60                 int cmd = CMD_I2C_IO;
61
62                 if (i == 0)
63                         cmd |= CMD_I2C_IO_BEGIN;
64
65                 if (i == num-1)
66                         cmd |= CMD_I2C_IO_END;
67
68                 pmsg = &msgs[i];
69
70                 dev_dbg(&adapter->dev,
71                         "  %d: %s (flags %d) %d bytes to 0x%02x\n",
72                         i, pmsg->flags & I2C_M_RD ? "read" : "write",
73                         pmsg->flags, pmsg->len, pmsg->addr);
74
75                 /* and directly send the message */
76                 if (pmsg->flags & I2C_M_RD) {
77                         /* read data */
78                         if (usb_read(adapter, cmd,
79                                      pmsg->flags, pmsg->addr,
80                                      pmsg->buf, pmsg->len) != pmsg->len) {
81                                 dev_err(&adapter->dev,
82                                         "failure reading data\n");
83                                 return -EREMOTEIO;
84                         }
85                 } else {
86                         /* write data */
87                         if (usb_write(adapter, cmd,
88                                       pmsg->flags, pmsg->addr,
89                                       pmsg->buf, pmsg->len) != pmsg->len) {
90                                 dev_err(&adapter->dev,
91                                         "failure writing data\n");
92                                 return -EREMOTEIO;
93                         }
94                 }
95
96                 /* read status */
97                 if (usb_read(adapter, CMD_GET_STATUS, 0, 0, &status, 1) != 1) {
98                         dev_err(&adapter->dev, "failure reading status\n");
99                         return -EREMOTEIO;
100                 }
101
102                 dev_dbg(&adapter->dev, "  status = %d\n", status);
103                 if (status == STATUS_ADDRESS_NAK)
104                         return -EREMOTEIO;
105         }
106
107         return i;
108 }
109
110 static u32 usb_func(struct i2c_adapter *adapter)
111 {
112         u32 func;
113
114         /* get functionality from adapter */
115         if (usb_read(adapter, CMD_GET_FUNC, 0, 0, &func, sizeof(func)) !=
116             sizeof(func)) {
117                 dev_err(&adapter->dev, "failure reading functionality\n");
118                 return 0;
119         }
120
121         return func;
122 }
123
124 /* This is the actual algorithm we define */
125 static const struct i2c_algorithm usb_algorithm = {
126         .master_xfer    = usb_xfer,
127         .functionality  = usb_func,
128 };
129
130 /* ----- end of i2c layer ------------------------------------------------ */
131
132 /* ----- begin of usb layer ---------------------------------------------- */
133
134 /* The usb i2c interface uses a vid/pid pair donated by */
135 /* Future Technology Devices International Ltd. */
136 static struct usb_device_id i2c_tiny_usb_table [] = {
137         { USB_DEVICE(0x0403, 0xc631) },
138         { }                     /* Terminating entry */
139 };
140
141 MODULE_DEVICE_TABLE(usb, i2c_tiny_usb_table);
142
143 /* Structure to hold all of our device specific stuff */
144 struct i2c_tiny_usb {
145         struct usb_device *usb_dev; /* the usb device for this device */
146         struct usb_interface *interface; /* the interface for this device */
147         struct i2c_adapter adapter; /* i2c related things */
148 };
149
150 static int usb_read(struct i2c_adapter *adapter, int cmd,
151                     int value, int index, void *data, int len)
152 {
153         struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;
154
155         /* do control transfer */
156         return usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0),
157                                cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |
158                                USB_DIR_IN, value, index, data, len, 2000);
159 }
160
161 static int usb_write(struct i2c_adapter *adapter, int cmd,
162                      int value, int index, void *data, int len)
163 {
164         struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;
165
166         /* do control transfer */
167         return usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0),
168                                cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
169                                value, index, data, len, 2000);
170 }
171
172 static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev)
173 {
174         usb_put_dev(dev->usb_dev);
175         kfree(dev);
176 }
177
178 static int i2c_tiny_usb_probe(struct usb_interface *interface,
179                               const struct usb_device_id *id)
180 {
181         struct i2c_tiny_usb *dev;
182         int retval = -ENOMEM;
183         u16 version;
184
185         dev_dbg(&interface->dev, "probing usb device\n");
186
187         /* allocate memory for our device state and initialize it */
188         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
189         if (dev == NULL) {
190                 dev_err(&interface->dev, "Out of memory\n");
191                 goto error;
192         }
193
194         dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
195         dev->interface = interface;
196
197         /* save our data pointer in this interface device */
198         usb_set_intfdata(interface, dev);
199
200         version = le16_to_cpu(dev->usb_dev->descriptor.bcdDevice);
201         dev_info(&interface->dev,
202                  "version %x.%02x found at bus %03d address %03d\n",
203                  version >> 8, version & 0xff,
204                  dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
205
206         /* setup i2c adapter description */
207         dev->adapter.owner = THIS_MODULE;
208         dev->adapter.class = I2C_CLASS_HWMON;
209         dev->adapter.algo = &usb_algorithm;
210         dev->adapter.algo_data = dev;
211         snprintf(dev->adapter.name, sizeof(dev->adapter.name),
212                  "i2c-tiny-usb at bus %03d device %03d",
213                  dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
214
215         if (usb_write(&dev->adapter, CMD_SET_DELAY,
216                       cpu_to_le16(delay), 0, NULL, 0) != 0) {
217                 dev_err(&dev->adapter.dev,
218                         "failure setting delay to %dus\n", delay);
219                 retval = -EIO;
220                 goto error;
221         }
222
223         dev->adapter.dev.parent = &dev->interface->dev;
224
225         /* and finally attach to i2c layer */
226         i2c_add_adapter(&dev->adapter);
227
228         /* inform user about successful attachment to i2c layer */
229         dev_info(&dev->adapter.dev, "connected i2c-tiny-usb device\n");
230
231         return 0;
232
233  error:
234         if (dev)
235                 i2c_tiny_usb_free(dev);
236
237         return retval;
238 }
239
240 static void i2c_tiny_usb_disconnect(struct usb_interface *interface)
241 {
242         struct i2c_tiny_usb *dev = usb_get_intfdata(interface);
243
244         i2c_del_adapter(&dev->adapter);
245         usb_set_intfdata(interface, NULL);
246         i2c_tiny_usb_free(dev);
247
248         dev_dbg(&interface->dev, "disconnected\n");
249 }
250
251 static struct usb_driver i2c_tiny_usb_driver = {
252         .name           = "i2c-tiny-usb",
253         .probe          = i2c_tiny_usb_probe,
254         .disconnect     = i2c_tiny_usb_disconnect,
255         .id_table       = i2c_tiny_usb_table,
256 };
257
258 static int __init usb_i2c_tiny_usb_init(void)
259 {
260         /* register this driver with the USB subsystem */
261         return usb_register(&i2c_tiny_usb_driver);
262 }
263
264 static void __exit usb_i2c_tiny_usb_exit(void)
265 {
266         /* deregister this driver with the USB subsystem */
267         usb_deregister(&i2c_tiny_usb_driver);
268 }
269
270 module_init(usb_i2c_tiny_usb_init);
271 module_exit(usb_i2c_tiny_usb_exit);
272
273 /* ----- end of usb layer ------------------------------------------------ */
274
275 MODULE_AUTHOR("Till Harbaum <Till@Harbaum.org>");
276 MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0");
277 MODULE_LICENSE("GPL");