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
|
/*
* Copyright (C) 2005 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>
*
* Simtec Generic I2C Controller
*
* 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
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
struct simtec_i2c_data {
struct resource *ioarea;
void __iomem *reg;
struct i2c_adapter adap;
struct i2c_algo_bit_data bit;
};
#define CMD_SET_SDA (1<<2)
#define CMD_SET_SCL (1<<3)
#define STATE_SDA (1<<0)
#define STATE_SCL (1<<1)
/* i2c bit-bus functions */
static void simtec_i2c_setsda(void *pw, int state)
{
struct simtec_i2c_data *pd = pw;
writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg);
}
static void simtec_i2c_setscl(void *pw, int state)
{
struct simtec_i2c_data *pd = pw;
writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg);
}
static int simtec_i2c_getsda(void *pw)
{
struct simtec_i2c_data *pd = pw;
return readb(pd->reg) & STATE_SDA ? 1 : 0;
}
static int simtec_i2c_getscl(void *pw)
{
struct simtec_i2c_data *pd = pw;
return readb(pd->reg) & STATE_SCL ? 1 : 0;
}
/* device registration */
static int simtec_i2c_probe(struct platform_device *dev)
{
struct simtec_i2c_data *pd;
struct resource *res;
int size;
int ret;
pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL);
if (pd == NULL) {
dev_err(&dev->dev, "cannot allocate private data\n");
return -ENOMEM;
}
platform_set_drvdata(dev, pd);
res = platform_get_resource(dev, IORESOURCE_MEM, 0);
if (res == NULL) {
dev_err(&dev->dev, "cannot find IO resource\n");
ret = -ENOENT;
goto err;
}
size = resource_size(res);
pd->ioarea = request_mem_region(res->start, size, dev->name);
if (pd->ioarea == NULL) {
dev_err(&dev->dev, "cannot request IO\n");
ret = -ENXIO;
goto err;
}
pd->reg = ioremap(res->start, size);
if (pd->reg == NULL) {
dev_err(&dev->dev, "cannot map IO\n");
ret = -ENXIO;
goto err_res;
}
/* setup the private data */
pd->adap.owner = THIS_MODULE;
pd->adap.algo_data = &pd->bit;
pd->adap.dev.parent = &dev->dev;
strlcpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name));
pd->bit.data = pd;
pd->bit.setsda = simtec_i2c_setsda;
pd->bit.setscl = simtec_i2c_setscl;
pd->bit.getsda = simtec_i2c_getsda;
pd->bit.getscl = simtec_i2c_getscl;
pd->bit.timeout = HZ;
pd->bit.udelay = 20;
ret = i2c_bit_add_bus(&pd->adap);
if (ret)
goto err_all;
return 0;
err_all:
iounmap(pd->reg);
err_res:
release_resource(pd->ioarea);
kfree(pd->ioarea);
err:
kfree(pd);
return ret;
}
static int simtec_i2c_remove(struct platform_device *dev)
{
struct simtec_i2c_data *pd = platform_get_drvdata(dev);
i2c_del_adapter(&pd->adap);
iounmap(pd->reg);
release_resource(pd->ioarea);
kfree(pd->ioarea);
kfree(pd);
return 0;
}
/* device driver */
static struct platform_driver simtec_i2c_driver = {
.driver = {
.name = "simtec-i2c",
.owner = THIS_MODULE,
},
.probe = simtec_i2c_probe,
.remove = simtec_i2c_remove,
};
module_platform_driver(simtec_i2c_driver);
MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:simtec-i2c");
|
