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> | |
5a0e3ad6 | 16 | #include <linux/slab.h> |
1c010ff8 | 17 | #include <linux/types.h> |
e8c76eed TH |
18 | |
19 | /* include interfaces to usb layer */ | |
20 | #include <linux/usb.h> | |
21 | ||
22 | /* include interface to i2c layer */ | |
23 | #include <linux/i2c.h> | |
24 | ||
25 | /* commands via USB, must match command ids in the firmware */ | |
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 | ||
c05d4902 JD |
35 | /* i2c bit delay, default is 10us -> 100kHz max |
36 | (in practice, due to additional delays in the i2c bitbanging | |
37 | code this results in a i2c clock of about 50kHz) */ | |
1c010ff8 JD |
38 | static unsigned short delay = 10; |
39 | module_param(delay, ushort, 0); | |
c05d4902 JD |
40 | MODULE_PARM_DESC(delay, "bit delay in microseconds " |
41 | "(default is 10us for 100kHz max)"); | |
e8c76eed TH |
42 | |
43 | static int usb_read(struct i2c_adapter *adapter, int cmd, | |
44 | int value, int index, void *data, int len); | |
45 | ||
46 | static int usb_write(struct i2c_adapter *adapter, int cmd, | |
47 | int value, int index, void *data, int len); | |
48 | ||
49 | /* ----- begin of i2c layer ---------------------------------------------- */ | |
50 | ||
51 | #define STATUS_IDLE 0 | |
52 | #define STATUS_ADDRESS_ACK 1 | |
53 | #define STATUS_ADDRESS_NAK 2 | |
54 | ||
55 | static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) | |
56 | { | |
57 | unsigned char status; | |
58 | struct i2c_msg *pmsg; | |
59 | int i; | |
60 | ||
61 | dev_dbg(&adapter->dev, "master xfer %d messages:\n", num); | |
62 | ||
63 | for (i = 0 ; i < num ; i++) { | |
64 | int cmd = CMD_I2C_IO; | |
65 | ||
66 | if (i == 0) | |
67 | cmd |= CMD_I2C_IO_BEGIN; | |
68 | ||
69 | if (i == num-1) | |
70 | cmd |= CMD_I2C_IO_END; | |
71 | ||
72 | pmsg = &msgs[i]; | |
73 | ||
74 | dev_dbg(&adapter->dev, | |
75 | " %d: %s (flags %d) %d bytes to 0x%02x\n", | |
76 | i, pmsg->flags & I2C_M_RD ? "read" : "write", | |
77 | pmsg->flags, pmsg->len, pmsg->addr); | |
78 | ||
79 | /* and directly send the message */ | |
80 | if (pmsg->flags & I2C_M_RD) { | |
81 | /* read data */ | |
82 | if (usb_read(adapter, cmd, | |
83 | pmsg->flags, pmsg->addr, | |
84 | pmsg->buf, pmsg->len) != pmsg->len) { | |
85 | dev_err(&adapter->dev, | |
86 | "failure reading data\n"); | |
87 | return -EREMOTEIO; | |
88 | } | |
89 | } else { | |
90 | /* write data */ | |
91 | if (usb_write(adapter, cmd, | |
92 | pmsg->flags, pmsg->addr, | |
93 | pmsg->buf, pmsg->len) != pmsg->len) { | |
94 | dev_err(&adapter->dev, | |
95 | "failure writing data\n"); | |
96 | return -EREMOTEIO; | |
97 | } | |
98 | } | |
99 | ||
100 | /* read status */ | |
101 | if (usb_read(adapter, CMD_GET_STATUS, 0, 0, &status, 1) != 1) { | |
102 | dev_err(&adapter->dev, "failure reading status\n"); | |
103 | return -EREMOTEIO; | |
104 | } | |
105 | ||
106 | dev_dbg(&adapter->dev, " status = %d\n", status); | |
107 | if (status == STATUS_ADDRESS_NAK) | |
108 | return -EREMOTEIO; | |
109 | } | |
110 | ||
111 | return i; | |
112 | } | |
113 | ||
114 | static u32 usb_func(struct i2c_adapter *adapter) | |
115 | { | |
1c010ff8 | 116 | __le32 func; |
e8c76eed TH |
117 | |
118 | /* get functionality from adapter */ | |
119 | if (usb_read(adapter, CMD_GET_FUNC, 0, 0, &func, sizeof(func)) != | |
120 | sizeof(func)) { | |
121 | dev_err(&adapter->dev, "failure reading functionality\n"); | |
122 | return 0; | |
123 | } | |
124 | ||
1c010ff8 | 125 | return le32_to_cpu(func); |
e8c76eed TH |
126 | } |
127 | ||
128 | /* This is the actual algorithm we define */ | |
129 | static const struct i2c_algorithm usb_algorithm = { | |
130 | .master_xfer = usb_xfer, | |
131 | .functionality = usb_func, | |
132 | }; | |
133 | ||
134 | /* ----- end of i2c layer ------------------------------------------------ */ | |
135 | ||
136 | /* ----- begin of usb layer ---------------------------------------------- */ | |
137 | ||
fa16eefd TH |
138 | /* |
139 | * Initially the usb i2c interface uses a vid/pid pair donated by | |
140 | * Future Technology Devices International Ltd., later a pair was | |
141 | * bought from EZPrototypes | |
142 | */ | |
4111ecd2 | 143 | static const struct usb_device_id i2c_tiny_usb_table[] = { |
fa16eefd TH |
144 | { USB_DEVICE(0x0403, 0xc631) }, /* FTDI */ |
145 | { USB_DEVICE(0x1c40, 0x0534) }, /* EZPrototypes */ | |
146 | { } /* Terminating entry */ | |
e8c76eed TH |
147 | }; |
148 | ||
149 | MODULE_DEVICE_TABLE(usb, i2c_tiny_usb_table); | |
150 | ||
151 | /* Structure to hold all of our device specific stuff */ | |
152 | struct i2c_tiny_usb { | |
153 | struct usb_device *usb_dev; /* the usb device for this device */ | |
154 | struct usb_interface *interface; /* the interface for this device */ | |
155 | struct i2c_adapter adapter; /* i2c related things */ | |
156 | }; | |
157 | ||
158 | static int usb_read(struct i2c_adapter *adapter, int cmd, | |
159 | int value, int index, void *data, int len) | |
160 | { | |
161 | struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data; | |
162 | ||
163 | /* do control transfer */ | |
164 | return usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0), | |
165 | cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE | | |
166 | USB_DIR_IN, value, index, data, len, 2000); | |
167 | } | |
168 | ||
169 | static int usb_write(struct i2c_adapter *adapter, int cmd, | |
170 | int value, int index, void *data, int len) | |
171 | { | |
172 | struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data; | |
173 | ||
174 | /* do control transfer */ | |
175 | return usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0), | |
176 | cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE, | |
177 | value, index, data, len, 2000); | |
178 | } | |
179 | ||
180 | static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev) | |
181 | { | |
182 | usb_put_dev(dev->usb_dev); | |
183 | kfree(dev); | |
184 | } | |
185 | ||
186 | static int i2c_tiny_usb_probe(struct usb_interface *interface, | |
187 | const struct usb_device_id *id) | |
188 | { | |
189 | struct i2c_tiny_usb *dev; | |
190 | int retval = -ENOMEM; | |
191 | u16 version; | |
192 | ||
193 | dev_dbg(&interface->dev, "probing usb device\n"); | |
194 | ||
195 | /* allocate memory for our device state and initialize it */ | |
196 | dev = kzalloc(sizeof(*dev), GFP_KERNEL); | |
197 | if (dev == NULL) { | |
198 | dev_err(&interface->dev, "Out of memory\n"); | |
199 | goto error; | |
200 | } | |
201 | ||
202 | dev->usb_dev = usb_get_dev(interface_to_usbdev(interface)); | |
203 | dev->interface = interface; | |
204 | ||
205 | /* save our data pointer in this interface device */ | |
206 | usb_set_intfdata(interface, dev); | |
207 | ||
208 | version = le16_to_cpu(dev->usb_dev->descriptor.bcdDevice); | |
209 | dev_info(&interface->dev, | |
210 | "version %x.%02x found at bus %03d address %03d\n", | |
211 | version >> 8, version & 0xff, | |
212 | dev->usb_dev->bus->busnum, dev->usb_dev->devnum); | |
213 | ||
214 | /* setup i2c adapter description */ | |
215 | dev->adapter.owner = THIS_MODULE; | |
216 | dev->adapter.class = I2C_CLASS_HWMON; | |
217 | dev->adapter.algo = &usb_algorithm; | |
218 | dev->adapter.algo_data = dev; | |
6a7ce82f | 219 | snprintf(dev->adapter.name, sizeof(dev->adapter.name), |
e8c76eed TH |
220 | "i2c-tiny-usb at bus %03d device %03d", |
221 | dev->usb_dev->bus->busnum, dev->usb_dev->devnum); | |
222 | ||
1c010ff8 | 223 | if (usb_write(&dev->adapter, CMD_SET_DELAY, delay, 0, NULL, 0) != 0) { |
e8c76eed TH |
224 | dev_err(&dev->adapter.dev, |
225 | "failure setting delay to %dus\n", delay); | |
226 | retval = -EIO; | |
227 | goto error; | |
228 | } | |
229 | ||
230 | dev->adapter.dev.parent = &dev->interface->dev; | |
231 | ||
232 | /* and finally attach to i2c layer */ | |
233 | i2c_add_adapter(&dev->adapter); | |
234 | ||
235 | /* inform user about successful attachment to i2c layer */ | |
236 | dev_info(&dev->adapter.dev, "connected i2c-tiny-usb device\n"); | |
237 | ||
238 | return 0; | |
239 | ||
240 | error: | |
241 | if (dev) | |
242 | i2c_tiny_usb_free(dev); | |
243 | ||
244 | return retval; | |
245 | } | |
246 | ||
247 | static void i2c_tiny_usb_disconnect(struct usb_interface *interface) | |
248 | { | |
249 | struct i2c_tiny_usb *dev = usb_get_intfdata(interface); | |
250 | ||
251 | i2c_del_adapter(&dev->adapter); | |
252 | usb_set_intfdata(interface, NULL); | |
253 | i2c_tiny_usb_free(dev); | |
254 | ||
255 | dev_dbg(&interface->dev, "disconnected\n"); | |
256 | } | |
257 | ||
258 | static struct usb_driver i2c_tiny_usb_driver = { | |
259 | .name = "i2c-tiny-usb", | |
260 | .probe = i2c_tiny_usb_probe, | |
261 | .disconnect = i2c_tiny_usb_disconnect, | |
262 | .id_table = i2c_tiny_usb_table, | |
263 | }; | |
264 | ||
265 | static int __init usb_i2c_tiny_usb_init(void) | |
266 | { | |
267 | /* register this driver with the USB subsystem */ | |
268 | return usb_register(&i2c_tiny_usb_driver); | |
269 | } | |
270 | ||
271 | static void __exit usb_i2c_tiny_usb_exit(void) | |
272 | { | |
273 | /* deregister this driver with the USB subsystem */ | |
274 | usb_deregister(&i2c_tiny_usb_driver); | |
275 | } | |
276 | ||
277 | module_init(usb_i2c_tiny_usb_init); | |
278 | module_exit(usb_i2c_tiny_usb_exit); | |
279 | ||
280 | /* ----- end of usb layer ------------------------------------------------ */ | |
281 | ||
282 | MODULE_AUTHOR("Till Harbaum <Till@Harbaum.org>"); | |
283 | MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0"); | |
284 | MODULE_LICENSE("GPL"); |