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Commit | Line | Data |
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e8c76eed TH |
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> | |
1c010ff8 | 16 | #include <linux/types.h> |
e8c76eed TH |
17 | |
18 | /* include interfaces to usb layer */ | |
19 | #include <linux/usb.h> | |
20 | ||
21 | /* include interface to i2c layer */ | |
22 | #include <linux/i2c.h> | |
23 | ||
24 | /* commands via USB, must match command ids in the firmware */ | |
25 | #define CMD_ECHO 0 | |
26 | #define CMD_GET_FUNC 1 | |
27 | #define CMD_SET_DELAY 2 | |
28 | #define CMD_GET_STATUS 3 | |
29 | ||
30 | #define CMD_I2C_IO 4 | |
31 | #define CMD_I2C_IO_BEGIN (1<<0) | |
32 | #define CMD_I2C_IO_END (1<<1) | |
33 | ||
34 | /* i2c bit delay, default is 10us -> 100kHz */ | |
1c010ff8 JD |
35 | static unsigned short delay = 10; |
36 | module_param(delay, ushort, 0); | |
e8c76eed TH |
37 | MODULE_PARM_DESC(delay, "bit delay in microseconds, " |
38 | "e.g. 10 for 100kHz (default is 100kHz)"); | |
39 | ||
40 | static int usb_read(struct i2c_adapter *adapter, int cmd, | |
41 | int value, int index, void *data, int len); | |
42 | ||
43 | static int usb_write(struct i2c_adapter *adapter, int cmd, | |
44 | int value, int index, void *data, int len); | |
45 | ||
46 | /* ----- begin of i2c layer ---------------------------------------------- */ | |
47 | ||
48 | #define STATUS_IDLE 0 | |
49 | #define STATUS_ADDRESS_ACK 1 | |
50 | #define STATUS_ADDRESS_NAK 2 | |
51 | ||
52 | static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) | |
53 | { | |
54 | unsigned char status; | |
55 | struct i2c_msg *pmsg; | |
56 | int i; | |
57 | ||
58 | dev_dbg(&adapter->dev, "master xfer %d messages:\n", num); | |
59 | ||
60 | for (i = 0 ; i < num ; i++) { | |
61 | int cmd = CMD_I2C_IO; | |
62 | ||
63 | if (i == 0) | |
64 | cmd |= CMD_I2C_IO_BEGIN; | |
65 | ||
66 | if (i == num-1) | |
67 | cmd |= CMD_I2C_IO_END; | |
68 | ||
69 | pmsg = &msgs[i]; | |
70 | ||
71 | dev_dbg(&adapter->dev, | |
72 | " %d: %s (flags %d) %d bytes to 0x%02x\n", | |
73 | i, pmsg->flags & I2C_M_RD ? "read" : "write", | |
74 | pmsg->flags, pmsg->len, pmsg->addr); | |
75 | ||
76 | /* and directly send the message */ | |
77 | if (pmsg->flags & I2C_M_RD) { | |
78 | /* read data */ | |
79 | if (usb_read(adapter, cmd, | |
80 | pmsg->flags, pmsg->addr, | |
81 | pmsg->buf, pmsg->len) != pmsg->len) { | |
82 | dev_err(&adapter->dev, | |
83 | "failure reading data\n"); | |
84 | return -EREMOTEIO; | |
85 | } | |
86 | } else { | |
87 | /* write data */ | |
88 | if (usb_write(adapter, cmd, | |
89 | pmsg->flags, pmsg->addr, | |
90 | pmsg->buf, pmsg->len) != pmsg->len) { | |
91 | dev_err(&adapter->dev, | |
92 | "failure writing data\n"); | |
93 | return -EREMOTEIO; | |
94 | } | |
95 | } | |
96 | ||
97 | /* read status */ | |
98 | if (usb_read(adapter, CMD_GET_STATUS, 0, 0, &status, 1) != 1) { | |
99 | dev_err(&adapter->dev, "failure reading status\n"); | |
100 | return -EREMOTEIO; | |
101 | } | |
102 | ||
103 | dev_dbg(&adapter->dev, " status = %d\n", status); | |
104 | if (status == STATUS_ADDRESS_NAK) | |
105 | return -EREMOTEIO; | |
106 | } | |
107 | ||
108 | return i; | |
109 | } | |
110 | ||
111 | static u32 usb_func(struct i2c_adapter *adapter) | |
112 | { | |
1c010ff8 | 113 | __le32 func; |
e8c76eed TH |
114 | |
115 | /* get functionality from adapter */ | |
116 | if (usb_read(adapter, CMD_GET_FUNC, 0, 0, &func, sizeof(func)) != | |
117 | sizeof(func)) { | |
118 | dev_err(&adapter->dev, "failure reading functionality\n"); | |
119 | return 0; | |
120 | } | |
121 | ||
1c010ff8 | 122 | return le32_to_cpu(func); |
e8c76eed TH |
123 | } |
124 | ||
125 | /* This is the actual algorithm we define */ | |
126 | static const struct i2c_algorithm usb_algorithm = { | |
127 | .master_xfer = usb_xfer, | |
128 | .functionality = usb_func, | |
129 | }; | |
130 | ||
131 | /* ----- end of i2c layer ------------------------------------------------ */ | |
132 | ||
133 | /* ----- begin of usb layer ---------------------------------------------- */ | |
134 | ||
fa16eefd TH |
135 | /* |
136 | * Initially the usb i2c interface uses a vid/pid pair donated by | |
137 | * Future Technology Devices International Ltd., later a pair was | |
138 | * bought from EZPrototypes | |
139 | */ | |
e8c76eed | 140 | static struct usb_device_id i2c_tiny_usb_table [] = { |
fa16eefd TH |
141 | { USB_DEVICE(0x0403, 0xc631) }, /* FTDI */ |
142 | { USB_DEVICE(0x1c40, 0x0534) }, /* EZPrototypes */ | |
143 | { } /* Terminating entry */ | |
e8c76eed TH |
144 | }; |
145 | ||
146 | MODULE_DEVICE_TABLE(usb, i2c_tiny_usb_table); | |
147 | ||
148 | /* Structure to hold all of our device specific stuff */ | |
149 | struct i2c_tiny_usb { | |
150 | struct usb_device *usb_dev; /* the usb device for this device */ | |
151 | struct usb_interface *interface; /* the interface for this device */ | |
152 | struct i2c_adapter adapter; /* i2c related things */ | |
153 | }; | |
154 | ||
155 | static int usb_read(struct i2c_adapter *adapter, int cmd, | |
156 | int value, int index, void *data, int len) | |
157 | { | |
158 | struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data; | |
159 | ||
160 | /* do control transfer */ | |
161 | return usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0), | |
162 | cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE | | |
163 | USB_DIR_IN, value, index, data, len, 2000); | |
164 | } | |
165 | ||
166 | static int usb_write(struct i2c_adapter *adapter, int cmd, | |
167 | int value, int index, void *data, int len) | |
168 | { | |
169 | struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data; | |
170 | ||
171 | /* do control transfer */ | |
172 | return usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0), | |
173 | cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE, | |
174 | value, index, data, len, 2000); | |
175 | } | |
176 | ||
177 | static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev) | |
178 | { | |
179 | usb_put_dev(dev->usb_dev); | |
180 | kfree(dev); | |
181 | } | |
182 | ||
183 | static int i2c_tiny_usb_probe(struct usb_interface *interface, | |
184 | const struct usb_device_id *id) | |
185 | { | |
186 | struct i2c_tiny_usb *dev; | |
187 | int retval = -ENOMEM; | |
188 | u16 version; | |
189 | ||
190 | dev_dbg(&interface->dev, "probing usb device\n"); | |
191 | ||
192 | /* allocate memory for our device state and initialize it */ | |
193 | dev = kzalloc(sizeof(*dev), GFP_KERNEL); | |
194 | if (dev == NULL) { | |
195 | dev_err(&interface->dev, "Out of memory\n"); | |
196 | goto error; | |
197 | } | |
198 | ||
199 | dev->usb_dev = usb_get_dev(interface_to_usbdev(interface)); | |
200 | dev->interface = interface; | |
201 | ||
202 | /* save our data pointer in this interface device */ | |
203 | usb_set_intfdata(interface, dev); | |
204 | ||
205 | version = le16_to_cpu(dev->usb_dev->descriptor.bcdDevice); | |
206 | dev_info(&interface->dev, | |
207 | "version %x.%02x found at bus %03d address %03d\n", | |
208 | version >> 8, version & 0xff, | |
209 | dev->usb_dev->bus->busnum, dev->usb_dev->devnum); | |
210 | ||
211 | /* setup i2c adapter description */ | |
212 | dev->adapter.owner = THIS_MODULE; | |
213 | dev->adapter.class = I2C_CLASS_HWMON; | |
214 | dev->adapter.algo = &usb_algorithm; | |
215 | dev->adapter.algo_data = dev; | |
6a7ce82f | 216 | snprintf(dev->adapter.name, sizeof(dev->adapter.name), |
e8c76eed TH |
217 | "i2c-tiny-usb at bus %03d device %03d", |
218 | dev->usb_dev->bus->busnum, dev->usb_dev->devnum); | |
219 | ||
1c010ff8 | 220 | if (usb_write(&dev->adapter, CMD_SET_DELAY, delay, 0, NULL, 0) != 0) { |
e8c76eed TH |
221 | dev_err(&dev->adapter.dev, |
222 | "failure setting delay to %dus\n", delay); | |
223 | retval = -EIO; | |
224 | goto error; | |
225 | } | |
226 | ||
227 | dev->adapter.dev.parent = &dev->interface->dev; | |
228 | ||
229 | /* and finally attach to i2c layer */ | |
230 | i2c_add_adapter(&dev->adapter); | |
231 | ||
232 | /* inform user about successful attachment to i2c layer */ | |
233 | dev_info(&dev->adapter.dev, "connected i2c-tiny-usb device\n"); | |
234 | ||
235 | return 0; | |
236 | ||
237 | error: | |
238 | if (dev) | |
239 | i2c_tiny_usb_free(dev); | |
240 | ||
241 | return retval; | |
242 | } | |
243 | ||
244 | static void i2c_tiny_usb_disconnect(struct usb_interface *interface) | |
245 | { | |
246 | struct i2c_tiny_usb *dev = usb_get_intfdata(interface); | |
247 | ||
248 | i2c_del_adapter(&dev->adapter); | |
249 | usb_set_intfdata(interface, NULL); | |
250 | i2c_tiny_usb_free(dev); | |
251 | ||
252 | dev_dbg(&interface->dev, "disconnected\n"); | |
253 | } | |
254 | ||
255 | static struct usb_driver i2c_tiny_usb_driver = { | |
256 | .name = "i2c-tiny-usb", | |
257 | .probe = i2c_tiny_usb_probe, | |
258 | .disconnect = i2c_tiny_usb_disconnect, | |
259 | .id_table = i2c_tiny_usb_table, | |
260 | }; | |
261 | ||
262 | static int __init usb_i2c_tiny_usb_init(void) | |
263 | { | |
264 | /* register this driver with the USB subsystem */ | |
265 | return usb_register(&i2c_tiny_usb_driver); | |
266 | } | |
267 | ||
268 | static void __exit usb_i2c_tiny_usb_exit(void) | |
269 | { | |
270 | /* deregister this driver with the USB subsystem */ | |
271 | usb_deregister(&i2c_tiny_usb_driver); | |
272 | } | |
273 | ||
274 | module_init(usb_i2c_tiny_usb_init); | |
275 | module_exit(usb_i2c_tiny_usb_exit); | |
276 | ||
277 | /* ----- end of usb layer ------------------------------------------------ */ | |
278 | ||
279 | MODULE_AUTHOR("Till Harbaum <Till@Harbaum.org>"); | |
280 | MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0"); | |
281 | MODULE_LICENSE("GPL"); |