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
|
/*
* w1_ds2405.c
*
* Copyright (c) 2017 Maciej S. Szmigiero <mail@maciej.szmigiero.name>
* Based on w1_therm.c copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
*
*
* This program is free software; you can redistribute it and/or modify
* it under the therms 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.
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/mutex.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/w1.h>
#define W1_FAMILY_DS2405 0x05
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Maciej S. Szmigiero <mail@maciej.szmigiero.name>");
MODULE_DESCRIPTION("Driver for 1-wire Dallas DS2405 PIO.");
MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2405));
static int w1_ds2405_select(struct w1_slave *sl, bool only_active)
{
struct w1_master *dev = sl->master;
u64 dev_addr = le64_to_cpu(*(u64 *)&sl->reg_num);
unsigned int bit_ctr;
if (w1_reset_bus(dev) != 0)
return 0;
/*
* We cannot use a normal Match ROM command
* since doing so would toggle PIO state
*/
w1_write_8(dev, only_active ? W1_ALARM_SEARCH : W1_SEARCH);
for (bit_ctr = 0; bit_ctr < 64; bit_ctr++) {
int bit2send = !!(dev_addr & BIT(bit_ctr));
u8 ret;
ret = w1_triplet(dev, bit2send);
if ((ret & (BIT(0) | BIT(1))) ==
(BIT(0) | BIT(1))) /* no devices found */
return 0;
if (!!(ret & BIT(2)) != bit2send)
/* wrong direction taken - no such device */
return 0;
}
return 1;
}
static int w1_ds2405_read_pio(struct w1_slave *sl)
{
if (w1_ds2405_select(sl, true))
return 0; /* "active" means PIO is low */
if (w1_ds2405_select(sl, false))
return 1;
return -ENODEV;
}
static ssize_t state_show(struct device *device,
struct device_attribute *attr, char *buf)
{
struct w1_slave *sl = dev_to_w1_slave(device);
struct w1_master *dev = sl->master;
int ret;
ssize_t f_retval;
u8 state;
ret = mutex_lock_interruptible(&dev->bus_mutex);
if (ret)
return ret;
if (!w1_ds2405_select(sl, false)) {
f_retval = -ENODEV;
goto out_unlock;
}
state = w1_read_8(dev);
if (state != 0 &&
state != 0xff) {
dev_err(device, "non-consistent state %x\n", state);
f_retval = -EIO;
goto out_unlock;
}
*buf = state ? '1' : '0';
f_retval = 1;
out_unlock:
w1_reset_bus(dev);
mutex_unlock(&dev->bus_mutex);
return f_retval;
}
static ssize_t output_show(struct device *device,
struct device_attribute *attr, char *buf)
{
struct w1_slave *sl = dev_to_w1_slave(device);
struct w1_master *dev = sl->master;
int ret;
ssize_t f_retval;
ret = mutex_lock_interruptible(&dev->bus_mutex);
if (ret)
return ret;
ret = w1_ds2405_read_pio(sl);
if (ret < 0) {
f_retval = ret;
goto out_unlock;
}
*buf = ret ? '1' : '0';
f_retval = 1;
out_unlock:
w1_reset_bus(dev);
mutex_unlock(&dev->bus_mutex);
return f_retval;
}
static ssize_t output_store(struct device *device,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct w1_slave *sl = dev_to_w1_slave(device);
struct w1_master *dev = sl->master;
int ret, current_pio;
unsigned int val;
ssize_t f_retval;
if (count < 1)
return -EINVAL;
if (sscanf(buf, " %u%n", &val, &ret) < 1)
return -EINVAL;
if (val != 0 && val != 1)
return -EINVAL;
f_retval = ret;
ret = mutex_lock_interruptible(&dev->bus_mutex);
if (ret)
return ret;
current_pio = w1_ds2405_read_pio(sl);
if (current_pio < 0) {
f_retval = current_pio;
goto out_unlock;
}
if (current_pio == val)
goto out_unlock;
if (w1_reset_bus(dev) != 0) {
f_retval = -ENODEV;
goto out_unlock;
}
/*
* can't use w1_reset_select_slave() here since it uses Skip ROM if
* there is only one device on bus
*/
do {
u64 dev_addr = le64_to_cpu(*(u64 *)&sl->reg_num);
u8 cmd[9];
cmd[0] = W1_MATCH_ROM;
memcpy(&cmd[1], &dev_addr, sizeof(dev_addr));
w1_write_block(dev, cmd, sizeof(cmd));
} while (0);
out_unlock:
w1_reset_bus(dev);
mutex_unlock(&dev->bus_mutex);
return f_retval;
}
static DEVICE_ATTR_RO(state);
static DEVICE_ATTR_RW(output);
static struct attribute *w1_ds2405_attrs[] = {
&dev_attr_state.attr,
&dev_attr_output.attr,
NULL
};
ATTRIBUTE_GROUPS(w1_ds2405);
static struct w1_family_ops w1_ds2405_fops = {
.groups = w1_ds2405_groups
};
static struct w1_family w1_family_ds2405 = {
.fid = W1_FAMILY_DS2405,
.fops = &w1_ds2405_fops
};
module_w1_family(w1_family_ds2405);
|
