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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * driver for the i2c-tiny-usb adapter - 1.0
4 * http://www.harbaum.org/till/i2c_tiny_usb
5 *
6 * Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)
7 */
8
9#include <linux/kernel.h>
10#include <linux/errno.h>
11#include <linux/module.h>
12#include <linux/slab.h>
13#include <linux/types.h>
14
15/* include interfaces to usb layer */
16#include <linux/usb.h>
17
18/* include interface to i2c layer */
19#include <linux/i2c.h>
20
21/* commands via USB, must match command ids in the firmware */
22#define CMD_ECHO 0
23#define CMD_GET_FUNC 1
24#define CMD_SET_DELAY 2
25#define CMD_GET_STATUS 3
26
27#define CMD_I2C_IO 4
28#define CMD_I2C_IO_BEGIN (1<<0)
29#define CMD_I2C_IO_END (1<<1)
30
31/* i2c bit delay, default is 10us -> 100kHz max
32 (in practice, due to additional delays in the i2c bitbanging
33 code this results in a i2c clock of about 50kHz) */
34static unsigned short delay = 10;
35module_param(delay, ushort, 0);
36MODULE_PARM_DESC(delay, "bit delay in microseconds "
37 "(default is 10us for 100kHz max)");
38
39static int usb_read(struct i2c_adapter *adapter, int cmd,
40 int value, int index, void *data, int len);
41
42static 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
51static int usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
52{
53 unsigned char *pstatus;
54 struct i2c_msg *pmsg;
55 int i, ret;
56
57 pstatus = kmalloc(sizeof(*pstatus), GFP_KERNEL);
58 if (!pstatus)
59 return -ENOMEM;
60
61 for (i = 0 ; i < num ; i++) {
62 int cmd = CMD_I2C_IO;
63
64 if (i == 0)
65 cmd |= CMD_I2C_IO_BEGIN;
66
67 if (i == num-1)
68 cmd |= CMD_I2C_IO_END;
69
70 pmsg = &msgs[i];
71
72 dev_dbg(&adapter->dev,
73 " %d: %s (flags %d) %d bytes to 0x%02x\n",
74 i, pmsg->flags & I2C_M_RD ? "read" : "write",
75 pmsg->flags, pmsg->len, pmsg->addr);
76
77 /* and directly send the message */
78 if (pmsg->flags & I2C_M_RD) {
79 /* read data */
80 if (usb_read(adapter, cmd,
81 pmsg->flags, pmsg->addr,
82 pmsg->buf, pmsg->len) != pmsg->len) {
83 dev_err(&adapter->dev,
84 "failure reading data\n");
85 ret = -EIO;
86 goto out;
87 }
88 } else {
89 /* write data */
90 if (usb_write(adapter, cmd,
91 pmsg->flags, pmsg->addr,
92 pmsg->buf, pmsg->len) != pmsg->len) {
93 dev_err(&adapter->dev,
94 "failure writing data\n");
95 ret = -EIO;
96 goto out;
97 }
98 }
99
100 /* read status */
101 if (usb_read(adapter, CMD_GET_STATUS, 0, 0, pstatus, 1) != 1) {
102 dev_err(&adapter->dev, "failure reading status\n");
103 ret = -EIO;
104 goto out;
105 }
106
107 dev_dbg(&adapter->dev, " status = %d\n", *pstatus);
108 if (*pstatus == STATUS_ADDRESS_NAK) {
109 ret = -ENXIO;
110 goto out;
111 }
112 }
113
114 ret = i;
115out:
116 kfree(pstatus);
117 return ret;
118}
119
120static u32 usb_func(struct i2c_adapter *adapter)
121{
122 __le32 *pfunc;
123 u32 ret;
124
125 pfunc = kmalloc(sizeof(*pfunc), GFP_KERNEL);
126
127 /* get functionality from adapter */
128 if (!pfunc || usb_read(adapter, CMD_GET_FUNC, 0, 0, pfunc,
129 sizeof(*pfunc)) != sizeof(*pfunc)) {
130 dev_err(&adapter->dev, "failure reading functionality\n");
131 ret = 0;
132 goto out;
133 }
134
135 ret = le32_to_cpup(pfunc);
136out:
137 kfree(pfunc);
138 return ret;
139}
140
141/* This is the actual algorithm we define */
142static const struct i2c_algorithm usb_algorithm = {
143 .xfer = usb_xfer,
144 .functionality = usb_func,
145};
146
147/* ----- end of i2c layer ------------------------------------------------ */
148
149/* ----- begin of usb layer ---------------------------------------------- */
150
151/*
152 * Initially the usb i2c interface uses a vid/pid pair donated by
153 * Future Technology Devices International Ltd., later a pair was
154 * bought from EZPrototypes
155 */
156static const struct usb_device_id i2c_tiny_usb_table[] = {
157 { USB_DEVICE(0x0403, 0xc631) }, /* FTDI */
158 { USB_DEVICE(0x1c40, 0x0534) }, /* EZPrototypes */
159 { } /* Terminating entry */
160};
161
162MODULE_DEVICE_TABLE(usb, i2c_tiny_usb_table);
163
164/* Structure to hold all of our device specific stuff */
165struct i2c_tiny_usb {
166 struct usb_device *usb_dev; /* the usb device for this device */
167 struct usb_interface *interface; /* the interface for this device */
168 struct i2c_adapter adapter; /* i2c related things */
169};
170
171static int usb_read(struct i2c_adapter *adapter, int cmd,
172 int value, int index, void *data, int len)
173{
174 struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;
175 void *dmadata = kmalloc(len, GFP_KERNEL);
176 int ret;
177
178 if (!dmadata)
179 return -ENOMEM;
180
181 /* do control transfer */
182 ret = usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0),
183 cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE |
184 USB_DIR_IN, value, index, dmadata, len, 2000);
185
186 memcpy(data, dmadata, len);
187 kfree(dmadata);
188 return ret;
189}
190
191static int usb_write(struct i2c_adapter *adapter, int cmd,
192 int value, int index, void *data, int len)
193{
194 struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data;
195 void *dmadata = kmemdup(data, len, GFP_KERNEL);
196 int ret;
197
198 if (!dmadata)
199 return -ENOMEM;
200
201 /* do control transfer */
202 ret = usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0),
203 cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
204 value, index, dmadata, len, 2000);
205
206 kfree(dmadata);
207 return ret;
208}
209
210static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev)
211{
212 usb_put_dev(dev->usb_dev);
213 kfree(dev);
214}
215
216static int i2c_tiny_usb_probe(struct usb_interface *interface,
217 const struct usb_device_id *id)
218{
219 struct i2c_tiny_usb *dev;
220 int retval = -ENOMEM;
221 u16 version;
222
223 if (interface->intf_assoc &&
224 interface->intf_assoc->bFunctionClass != USB_CLASS_VENDOR_SPEC)
225 return -ENODEV;
226
227 dev_dbg(&interface->dev, "probing usb device\n");
228
229 /* allocate memory for our device state and initialize it */
230 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
231 if (!dev)
232 goto error;
233
234 dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
235 dev->interface = interface;
236
237 /* save our data pointer in this interface device */
238 usb_set_intfdata(interface, dev);
239
240 version = le16_to_cpu(dev->usb_dev->descriptor.bcdDevice);
241 dev_info(&interface->dev,
242 "version %x.%02x found at bus %03d address %03d\n",
243 version >> 8, version & 0xff,
244 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
245
246 /* setup i2c adapter description */
247 dev->adapter.owner = THIS_MODULE;
248 dev->adapter.class = I2C_CLASS_HWMON;
249 dev->adapter.algo = &usb_algorithm;
250 dev->adapter.algo_data = dev;
251 snprintf(dev->adapter.name, sizeof(dev->adapter.name),
252 "i2c-tiny-usb at bus %03d device %03d",
253 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
254
255 if (usb_write(&dev->adapter, CMD_SET_DELAY, delay, 0, NULL, 0) != 0) {
256 dev_err(&dev->adapter.dev,
257 "failure setting delay to %dus\n", delay);
258 retval = -EIO;
259 goto error;
260 }
261
262 dev->adapter.dev.parent = &dev->interface->dev;
263
264 /* and finally attach to i2c layer */
265 i2c_add_adapter(&dev->adapter);
266
267 /* inform user about successful attachment to i2c layer */
268 dev_info(&dev->adapter.dev, "connected i2c-tiny-usb device\n");
269
270 return 0;
271
272 error:
273 if (dev)
274 i2c_tiny_usb_free(dev);
275
276 return retval;
277}
278
279static void i2c_tiny_usb_disconnect(struct usb_interface *interface)
280{
281 struct i2c_tiny_usb *dev = usb_get_intfdata(interface);
282
283 i2c_del_adapter(&dev->adapter);
284 usb_set_intfdata(interface, NULL);
285 i2c_tiny_usb_free(dev);
286
287 dev_dbg(&interface->dev, "disconnected\n");
288}
289
290static struct usb_driver i2c_tiny_usb_driver = {
291 .name = "i2c-tiny-usb",
292 .probe = i2c_tiny_usb_probe,
293 .disconnect = i2c_tiny_usb_disconnect,
294 .id_table = i2c_tiny_usb_table,
295};
296
297module_usb_driver(i2c_tiny_usb_driver);
298
299/* ----- end of usb layer ------------------------------------------------ */
300
301MODULE_AUTHOR("Till Harbaum <Till@Harbaum.org>");
302MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0");
303MODULE_LICENSE("GPL");
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#include <linux/slab.h>
17#include <linux/types.h>
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
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) */
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/* ----- begin of i2c layer ---------------------------------------------- */
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 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
114static u32 usb_func(struct i2c_adapter *adapter)
115{
116 __le32 func;
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
125 return le32_to_cpu(func);
126}
127
128/* This is the actual algorithm we define */
129static 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
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 */
143static const struct usb_device_id i2c_tiny_usb_table[] = {
144 { USB_DEVICE(0x0403, 0xc631) }, /* FTDI */
145 { USB_DEVICE(0x1c40, 0x0534) }, /* EZPrototypes */
146 { } /* Terminating entry */
147};
148
149MODULE_DEVICE_TABLE(usb, i2c_tiny_usb_table);
150
151/* Structure to hold all of our device specific stuff */
152struct 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
158static 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
169static 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
180static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev)
181{
182 usb_put_dev(dev->usb_dev);
183 kfree(dev);
184}
185
186static 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;
219 snprintf(dev->adapter.name, sizeof(dev->adapter.name),
220 "i2c-tiny-usb at bus %03d device %03d",
221 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
222
223 if (usb_write(&dev->adapter, CMD_SET_DELAY, delay, 0, NULL, 0) != 0) {
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
247static 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
258static 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
265static 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
271static 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
277module_init(usb_i2c_tiny_usb_init);
278module_exit(usb_i2c_tiny_usb_exit);
279
280/* ----- end of usb layer ------------------------------------------------ */
281
282MODULE_AUTHOR("Till Harbaum <Till@Harbaum.org>");
283MODULE_DESCRIPTION("i2c-tiny-usb driver v1.0");
284MODULE_LICENSE("GPL");