1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
|
/*
* I2C_ALGO_USB.C
* i2c algorithm for USB-I2C Bridges
*
* Copyright (c) 1999-2005 Joerg Heckenbach <joerg@heckenbach-aw.de>
* Dwaine Garden <dwainegarden@rogers.com>
*
* This module is part of usbvision driver project.
* Updates to driver completed by Dwaine P. Garden
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/version.h>
#include <linux/utsname.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/usb.h>
#include <linux/i2c.h>
#include "usbvision-i2c.h"
static int debug_i2c_usb = 0;
#if defined(module_param) // Showing parameters under SYSFS
module_param (debug_i2c_usb, int, 0444); // debug_i2c_usb mode of the device driver
#else
MODULE_PARM(debug_i2c_usb, "i"); // debug_i2c_usb mode of the device driver
#endif
static inline int try_write_address(struct i2c_adapter *i2c_adap,
unsigned char addr, int retries)
{
struct i2c_algo_usb_data *adap = i2c_adap->algo_data;
void *data;
int i, ret = -1;
char buf[4];
data = i2c_get_adapdata(i2c_adap);
buf[0] = 0x00;
for (i = 0; i <= retries; i++) {
ret = (adap->outb(data, addr, buf, 1));
if (ret == 1)
break; /* success! */
udelay(5 /*adap->udelay */ );
if (i == retries) /* no success */
break;
udelay(adap->udelay);
}
if (debug_i2c_usb) {
if (i) {
info("%s: Needed %d retries for address %#2x", __FUNCTION__, i, addr);
info("%s: Maybe there's no device at this address", __FUNCTION__);
}
}
return ret;
}
static inline int try_read_address(struct i2c_adapter *i2c_adap,
unsigned char addr, int retries)
{
struct i2c_algo_usb_data *adap = i2c_adap->algo_data;
void *data;
int i, ret = -1;
char buf[4];
data = i2c_get_adapdata(i2c_adap);
for (i = 0; i <= retries; i++) {
ret = (adap->inb(data, addr, buf, 1));
if (ret == 1)
break; /* success! */
udelay(5 /*adap->udelay */ );
if (i == retries) /* no success */
break;
udelay(adap->udelay);
}
if (debug_i2c_usb) {
if (i) {
info("%s: Needed %d retries for address %#2x", __FUNCTION__, i, addr);
info("%s: Maybe there's no device at this address", __FUNCTION__);
}
}
return ret;
}
static inline int usb_find_address(struct i2c_adapter *i2c_adap,
struct i2c_msg *msg, int retries,
unsigned char *add)
{
unsigned short flags = msg->flags;
unsigned char addr;
int ret;
if ((flags & I2C_M_TEN)) {
/* a ten bit address */
addr = 0xf0 | ((msg->addr >> 7) & 0x03);
/* try extended address code... */
ret = try_write_address(i2c_adap, addr, retries);
if (ret != 1) {
err("died at extended address code, while writing");
return -EREMOTEIO;
}
add[0] = addr;
if (flags & I2C_M_RD) {
/* okay, now switch into reading mode */
addr |= 0x01;
ret = try_read_address(i2c_adap, addr, retries);
if (ret != 1) {
err("died at extended address code, while reading");
return -EREMOTEIO;
}
}
} else { /* normal 7bit address */
addr = (msg->addr << 1);
if (flags & I2C_M_RD)
addr |= 1;
if (flags & I2C_M_REV_DIR_ADDR)
addr ^= 1;
add[0] = addr;
if (flags & I2C_M_RD)
ret = try_read_address(i2c_adap, addr, retries);
else
ret = try_write_address(i2c_adap, addr, retries);
if (ret != 1) {
return -EREMOTEIO;
}
}
return 0;
}
static int
usb_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num)
{
struct i2c_msg *pmsg;
struct i2c_algo_usb_data *adap = i2c_adap->algo_data;
void *data;
int i, ret;
unsigned char addr;
data = i2c_get_adapdata(i2c_adap);
for (i = 0; i < num; i++) {
pmsg = &msgs[i];
ret = usb_find_address(i2c_adap, pmsg, i2c_adap->retries, &addr);
if (ret != 0) {
if (debug_i2c_usb) {
info("%s: got NAK from device, message #%d\n", __FUNCTION__, i);
}
return (ret < 0) ? ret : -EREMOTEIO;
}
if (pmsg->flags & I2C_M_RD) {
/* read bytes into buffer */
ret = (adap->inb(data, addr, pmsg->buf, pmsg->len));
if (ret < pmsg->len) {
return (ret < 0) ? ret : -EREMOTEIO;
}
} else {
/* write bytes from buffer */
ret = (adap->outb(data, addr, pmsg->buf, pmsg->len));
if (ret < pmsg->len) {
return (ret < 0) ? ret : -EREMOTEIO;
}
}
}
return num;
}
static int algo_control(struct i2c_adapter *adapter, unsigned int cmd, unsigned long arg)
{
return 0;
}
static u32 usb_func(struct i2c_adapter *adap)
{
return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
}
/* -----exported algorithm data: ------------------------------------- */
static struct i2c_algorithm i2c_usb_algo = {
.master_xfer = usb_xfer,
.smbus_xfer = NULL,
.slave_send = NULL,
.slave_recv = NULL,
.algo_control = algo_control,
.functionality = usb_func,
};
/*
* registering functions to load algorithms at runtime
*/
int usbvision_i2c_usb_add_bus(struct i2c_adapter *adap)
{
/* register new adapter to i2c module... */
adap->algo = &i2c_usb_algo;
adap->timeout = 100; /* default values, should */
adap->retries = 3; /* be replaced by defines */
#ifdef MODULE
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 4, 21)
MOD_INC_USE_COUNT;
#endif
#endif
i2c_add_adapter(adap);
if (debug_i2c_usb) {
info("i2c bus for %s registered", adap->name);
}
return 0;
}
int usbvision_i2c_usb_del_bus(struct i2c_adapter *adap)
{
i2c_del_adapter(adap);
if (debug_i2c_usb) {
info("i2c bus for %s unregistered", adap->name);
}
#ifdef MODULE
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 4, 21)
MOD_DEC_USE_COUNT;
#endif
#endif
return 0;
}
EXPORT_SYMBOL(usbvision_i2c_usb_add_bus);
EXPORT_SYMBOL(usbvision_i2c_usb_del_bus);
|
