aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/w1/w1_io.c
blob: 02796b5a39f6d8ce8462b01a96aebe0272a427db (plain) (blame)
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
/*
 * 	w1_io.c
 *
 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
 * 
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <asm/io.h>

#include <linux/delay.h>
#include <linux/moduleparam.h>

#include "w1.h"
#include "w1_log.h"
#include "w1_io.h"

int w1_delay_parm = 1;
module_param_named(delay_coef, w1_delay_parm, int, 0);

static u8 w1_crc8_table[] = {
	0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65,
	157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220,
	35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98,
	190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255,
	70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7,
	219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154,
	101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36,
	248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185,
	140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205,
	17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80,
	175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238,
	50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115,
	202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139,
	87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22,
	233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168,
	116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53
};

void w1_delay(unsigned long tm)
{
	udelay(tm * w1_delay_parm);
}

u8 w1_touch_bit(struct w1_master *dev, int bit)
{
	if (dev->bus_master->touch_bit)
		return dev->bus_master->touch_bit(dev->bus_master->data, bit);
	else
		return w1_read_bit(dev);
}

void w1_write_bit(struct w1_master *dev, int bit)
{
	if (bit) {
		dev->bus_master->write_bit(dev->bus_master->data, 0);
		w1_delay(6);
		dev->bus_master->write_bit(dev->bus_master->data, 1);
		w1_delay(64);
	} else {
		dev->bus_master->write_bit(dev->bus_master->data, 0);
		w1_delay(60);
		dev->bus_master->write_bit(dev->bus_master->data, 1);
		w1_delay(10);
	}
}

void w1_write_8(struct w1_master *dev, u8 byte)
{
	int i;

	if (dev->bus_master->write_byte)
		dev->bus_master->write_byte(dev->bus_master->data, byte);
	else
		for (i = 0; i < 8; ++i)
			w1_write_bit(dev, (byte >> i) & 0x1);
}

u8 w1_read_bit(struct w1_master *dev)
{
	int result;

	dev->bus_master->write_bit(dev->bus_master->data, 0);
	w1_delay(6);
	dev->bus_master->write_bit(dev->bus_master->data, 1);
	w1_delay(9);

	result = dev->bus_master->read_bit(dev->bus_master->data);
	w1_delay(55);

	return result & 0x1;
}

u8 w1_read_8(struct w1_master * dev)
{
	int i;
	u8 res = 0;

	if (dev->bus_master->read_byte)
		res = dev->bus_master->read_byte(dev->bus_master->data);
	else
		for (i = 0; i < 8; ++i)
			res |= (w1_read_bit(dev) << i);

	return res;
}

void w1_write_block(struct w1_master *dev, u8 *buf, int len)
{
	int i;

	if (dev->bus_master->write_block)
		dev->bus_master->write_block(dev->bus_master->data, buf, len);
	else
		for (i = 0; i < len; ++i)
			w1_write_8(dev, buf[i]);
}

u8 w1_read_block(struct w1_master *dev, u8 *buf, int len)
{
	int i;
	u8 ret;

	if (dev->bus_master->read_block)
		ret = dev->bus_master->read_block(dev->bus_master->data, buf, len);
	else {
		for (i = 0; i < len; ++i)
			buf[i] = w1_read_8(dev);
		ret = len;
	}

	return ret;
}

int w1_reset_bus(struct w1_master *dev)
{
	int result = 0;

	if (dev->bus_master->reset_bus)
		result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1;
	else {
		dev->bus_master->write_bit(dev->bus_master->data, 0);
		w1_delay(480);
		dev->bus_master->write_bit(dev->bus_master->data, 1);
		w1_delay(70);

		result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1;
		w1_delay(410);
	}

	return result;
}

u8 w1_calc_crc8(u8 * data, int len)
{
	u8 crc = 0;

	while (len--)
		crc = w1_crc8_table[crc ^ *data++];

	return crc;
}

void w1_search_devices(struct w1_master *dev, w1_slave_found_callback cb)
{
	dev->attempts++;
	if (dev->bus_master->search)
		dev->bus_master->search(dev->bus_master->data, cb);
	else
		w1_search(dev);
}

EXPORT_SYMBOL(w1_write_bit);
EXPORT_SYMBOL(w1_write_8);
EXPORT_SYMBOL(w1_read_bit);
EXPORT_SYMBOL(w1_read_8);
EXPORT_SYMBOL(w1_reset_bus);
EXPORT_SYMBOL(w1_calc_crc8);
EXPORT_SYMBOL(w1_delay);
EXPORT_SYMBOL(w1_read_block);
EXPORT_SYMBOL(w1_write_block);
EXPORT_SYMBOL(w1_search_devices);