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
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* w1_ds2423.c
*
* Copyright (c) 2010 Mika Laitio <lamikr@pilppa.org>
*
* This driver will read and write the value of 4 counters to w1_slave file in
* sys filesystem.
* Inspired by the w1_therm and w1_ds2431 drivers.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/crc16.h>
#include <linux/w1.h>
#define W1_COUNTER_DS2423 0x1D
#define CRC16_VALID 0xb001
#define CRC16_INIT 0
#define COUNTER_COUNT 4
#define READ_BYTE_COUNT 42
static ssize_t w1_slave_show(struct device *device,
struct device_attribute *attr, char *out_buf)
{
struct w1_slave *sl = dev_to_w1_slave(device);
struct w1_master *dev = sl->master;
u8 rbuf[COUNTER_COUNT * READ_BYTE_COUNT];
u8 wrbuf[3];
int rom_addr;
int read_byte_count;
int result;
ssize_t c;
int ii;
int p;
int crc;
c = PAGE_SIZE;
rom_addr = (12 << 5) + 31;
wrbuf[0] = 0xA5;
wrbuf[1] = rom_addr & 0xFF;
wrbuf[2] = rom_addr >> 8;
mutex_lock(&dev->bus_mutex);
if (!w1_reset_select_slave(sl)) {
w1_write_block(dev, wrbuf, 3);
read_byte_count = 0;
for (p = 0; p < 4; p++) {
/*
* 1 byte for first bytes in ram page read
* 4 bytes for counter
* 4 bytes for zero bits
* 2 bytes for crc
* 31 remaining bytes from the ram page
*/
read_byte_count += w1_read_block(dev,
rbuf + (p * READ_BYTE_COUNT), READ_BYTE_COUNT);
for (ii = 0; ii < READ_BYTE_COUNT; ++ii)
c -= snprintf(out_buf + PAGE_SIZE - c,
c, "%02x ",
rbuf[(p * READ_BYTE_COUNT) + ii]);
if (read_byte_count != (p + 1) * READ_BYTE_COUNT) {
dev_warn(device,
"w1_counter_read() returned %u bytes "
"instead of %d bytes wanted.\n",
read_byte_count,
READ_BYTE_COUNT);
c -= snprintf(out_buf + PAGE_SIZE - c,
c, "crc=NO\n");
} else {
if (p == 0) {
crc = crc16(CRC16_INIT, wrbuf, 3);
crc = crc16(crc, rbuf, 11);
} else {
/*
* DS2423 calculates crc from all bytes
* read after the previous crc bytes.
*/
crc = crc16(CRC16_INIT,
(rbuf + 11) +
((p - 1) * READ_BYTE_COUNT),
READ_BYTE_COUNT);
}
if (crc == CRC16_VALID) {
result = 0;
for (ii = 4; ii > 0; ii--) {
result <<= 8;
result |= rbuf[(p *
READ_BYTE_COUNT) + ii];
}
c -= snprintf(out_buf + PAGE_SIZE - c,
c, "crc=YES c=%d\n", result);
} else {
c -= snprintf(out_buf + PAGE_SIZE - c,
c, "crc=NO\n");
}
}
}
} else {
c -= snprintf(out_buf + PAGE_SIZE - c, c, "Connection error");
}
mutex_unlock(&dev->bus_mutex);
return PAGE_SIZE - c;
}
static DEVICE_ATTR_RO(w1_slave);
static struct attribute *w1_f1d_attrs[] = {
&dev_attr_w1_slave.attr,
NULL,
};
ATTRIBUTE_GROUPS(w1_f1d);
static struct w1_family_ops w1_f1d_fops = {
.groups = w1_f1d_groups,
};
static struct w1_family w1_family_1d = {
.fid = W1_COUNTER_DS2423,
.fops = &w1_f1d_fops,
};
module_w1_family(w1_family_1d);
MODULE_AUTHOR("Mika Laitio <lamikr@pilppa.org>");
MODULE_DESCRIPTION("w1 family 1d driver for DS2423, 4 counters and 4kb ram");
MODULE_LICENSE("GPL");
MODULE_ALIAS("w1-family-" __stringify(W1_COUNTER_DS2423));
|
