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gerrit-public.fairphone.software / kernel / msm-5.4 / 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 / . / drivers / w1 / w1_io.c
blob: 02796b5a39f6d8ce8462b01a96aebe0272a427db [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700[diff] [blame^]1/*
2 * w1_io.c
3 *
4 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
5 *
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#include <asm/io.h>
23
24#include <linux/delay.h>
25#include <linux/moduleparam.h>
26
27#include "w1.h"
28#include "w1_log.h"
29#include "w1_io.h"
30
31int w1_delay_parm = 1;
32module_param_named(delay_coef, w1_delay_parm, int, 0);
33
34static u8 w1_crc8_table[] = {
35 0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65,
36 157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220,
37 35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98,
38 190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255,
39 70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7,
40 219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154,
41 101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36,
42 248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185,
43 140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205,
44 17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80,
45 175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238,
46 50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115,
47 202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139,
48 87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22,
49 233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168,
50 116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53
51};
52
53void w1_delay(unsigned long tm)
54{
55 udelay(tm * w1_delay_parm);
56}
57
58u8 w1_touch_bit(struct w1_master *dev, int bit)
59{
60 if (dev->bus_master->touch_bit)
61 return dev->bus_master->touch_bit(dev->bus_master->data, bit);
62 else
63 return w1_read_bit(dev);
64}
65
66void w1_write_bit(struct w1_master *dev, int bit)
67{
68 if (bit) {
69 dev->bus_master->write_bit(dev->bus_master->data, 0);
70 w1_delay(6);
71 dev->bus_master->write_bit(dev->bus_master->data, 1);
72 w1_delay(64);
73 } else {
74 dev->bus_master->write_bit(dev->bus_master->data, 0);
75 w1_delay(60);
76 dev->bus_master->write_bit(dev->bus_master->data, 1);
77 w1_delay(10);
78 }
79}
80
81void w1_write_8(struct w1_master *dev, u8 byte)
82{
83 int i;
84
85 if (dev->bus_master->write_byte)
86 dev->bus_master->write_byte(dev->bus_master->data, byte);
87 else
88 for (i = 0; i < 8; ++i)
89 w1_write_bit(dev, (byte >> i) & 0x1);
90}
91
92u8 w1_read_bit(struct w1_master *dev)
93{
94 int result;
95
96 dev->bus_master->write_bit(dev->bus_master->data, 0);
97 w1_delay(6);
98 dev->bus_master->write_bit(dev->bus_master->data, 1);
99 w1_delay(9);
100
101 result = dev->bus_master->read_bit(dev->bus_master->data);
102 w1_delay(55);
103
104 return result & 0x1;
105}
106
107u8 w1_read_8(struct w1_master * dev)
108{
109 int i;
110 u8 res = 0;
111
112 if (dev->bus_master->read_byte)
113 res = dev->bus_master->read_byte(dev->bus_master->data);
114 else
115 for (i = 0; i < 8; ++i)
116 res |= (w1_read_bit(dev) << i);
117
118 return res;
119}
120
121void w1_write_block(struct w1_master *dev, u8 *buf, int len)
122{
123 int i;
124
125 if (dev->bus_master->write_block)
126 dev->bus_master->write_block(dev->bus_master->data, buf, len);
127 else
128 for (i = 0; i < len; ++i)
129 w1_write_8(dev, buf[i]);
130}
131
132u8 w1_read_block(struct w1_master *dev, u8 *buf, int len)
133{
134 int i;
135 u8 ret;
136
137 if (dev->bus_master->read_block)
138 ret = dev->bus_master->read_block(dev->bus_master->data, buf, len);
139 else {
140 for (i = 0; i < len; ++i)
141 buf[i] = w1_read_8(dev);
142 ret = len;
143 }
144
145 return ret;
146}
147
148int w1_reset_bus(struct w1_master *dev)
149{
150 int result = 0;
151
152 if (dev->bus_master->reset_bus)
153 result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1;
154 else {
155 dev->bus_master->write_bit(dev->bus_master->data, 0);
156 w1_delay(480);
157 dev->bus_master->write_bit(dev->bus_master->data, 1);
158 w1_delay(70);
159
160 result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1;
161 w1_delay(410);
162 }
163
164 return result;
165}
166
167u8 w1_calc_crc8(u8 * data, int len)
168{
169 u8 crc = 0;
170
171 while (len--)
172 crc = w1_crc8_table[crc ^ *data++];
173
174 return crc;
175}
176
177void w1_search_devices(struct w1_master *dev, w1_slave_found_callback cb)
178{
179 dev->attempts++;
180 if (dev->bus_master->search)
181 dev->bus_master->search(dev->bus_master->data, cb);
182 else
183 w1_search(dev);
184}
185
186EXPORT_SYMBOL(w1_write_bit);
187EXPORT_SYMBOL(w1_write_8);
188EXPORT_SYMBOL(w1_read_bit);
189EXPORT_SYMBOL(w1_read_8);
190EXPORT_SYMBOL(w1_reset_bus);
191EXPORT_SYMBOL(w1_calc_crc8);
192EXPORT_SYMBOL(w1_delay);
193EXPORT_SYMBOL(w1_read_block);
194EXPORT_SYMBOL(w1_write_block);
195EXPORT_SYMBOL(w1_search_devices);