blob: 0b18178905034e788742938718041f9e1333ff13 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * w1_therm.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 therms 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/types.h>
23
24#include <linux/kernel.h>
25#include <linux/module.h>
26#include <linux/moduleparam.h>
27#include <linux/device.h>
28#include <linux/types.h>
29#include <linux/delay.h>
30
31#include "w1.h"
32#include "w1_io.h"
33#include "w1_int.h"
34#include "w1_family.h"
35
36MODULE_LICENSE("GPL");
37MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
38MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
39
40static u8 bad_roms[][9] = {
41 {0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87},
42 {}
43 };
44
45static ssize_t w1_therm_read_name(struct device *, char *);
46static ssize_t w1_therm_read_temp(struct device *, char *);
47static ssize_t w1_therm_read_bin(struct kobject *, char *, loff_t, size_t);
48
49static struct w1_family_ops w1_therm_fops = {
50 .rname = &w1_therm_read_name,
51 .rbin = &w1_therm_read_bin,
52 .rval = &w1_therm_read_temp,
53 .rvalname = "temp1_input",
54};
55
56static ssize_t w1_therm_read_name(struct device *dev, char *buf)
57{
58 struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
59
60 return sprintf(buf, "%s\n", sl->name);
61}
62
63static inline int w1_convert_temp(u8 rom[9])
64{
65 int t, h;
66
67 if (rom[1] == 0)
68 t = ((s32)rom[0] >> 1)*1000;
69 else
70 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
71
72 t -= 250;
73 h = 1000*((s32)rom[7] - (s32)rom[6]);
74 h /= (s32)rom[7];
75 t += h;
76
77 return t;
78}
79
80static ssize_t w1_therm_read_temp(struct device *dev, char *buf)
81{
82 struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
83
84 return sprintf(buf, "%d\n", w1_convert_temp(sl->rom));
85}
86
87static int w1_therm_check_rom(u8 rom[9])
88{
89 int i;
90
91 for (i=0; i<sizeof(bad_roms)/9; ++i)
92 if (!memcmp(bad_roms[i], rom, 9))
93 return 1;
94
95 return 0;
96}
97
98static ssize_t w1_therm_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count)
99{
100 struct w1_slave *sl = container_of(container_of(kobj, struct device, kobj),
101 struct w1_slave, dev);
102 struct w1_master *dev = sl->master;
103 u8 rom[9], crc, verdict;
104 int i, max_trying = 10;
105
106 atomic_inc(&sl->refcnt);
107 smp_mb__after_atomic_inc();
108 if (down_interruptible(&sl->master->mutex)) {
109 count = 0;
110 goto out_dec;
111 }
112
113 if (off > W1_SLAVE_DATA_SIZE) {
114 count = 0;
115 goto out;
116 }
117 if (off + count > W1_SLAVE_DATA_SIZE) {
118 count = 0;
119 goto out;
120 }
121
122 memset(buf, 0, count);
123 memset(rom, 0, sizeof(rom));
124
125 count = 0;
126 verdict = 0;
127 crc = 0;
128
129 while (max_trying--) {
130 if (!w1_reset_bus (dev)) {
131 int count = 0;
132 u8 match[9] = {W1_MATCH_ROM, };
133 unsigned int tm = 750;
134
135 memcpy(&match[1], (u64 *) & sl->reg_num, 8);
136
137 w1_write_block(dev, match, 9);
138
139 w1_write_8(dev, W1_CONVERT_TEMP);
140
141 while (tm) {
142 tm = msleep_interruptible(tm);
143 if (signal_pending(current))
144 flush_signals(current);
145 }
146
147 if (!w1_reset_bus (dev)) {
148 w1_write_block(dev, match, 9);
149
150 w1_write_8(dev, W1_READ_SCRATCHPAD);
151 if ((count = w1_read_block(dev, rom, 9)) != 9) {
152 dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
153 }
154
155 crc = w1_calc_crc8(rom, 8);
156
157 if (rom[8] == crc && rom[0])
158 verdict = 1;
159
160 }
161 }
162
163 if (!w1_therm_check_rom(rom))
164 break;
165 }
166
167 for (i = 0; i < 9; ++i)
168 count += sprintf(buf + count, "%02x ", rom[i]);
169 count += sprintf(buf + count, ": crc=%02x %s\n",
170 crc, (verdict) ? "YES" : "NO");
171 if (verdict)
172 memcpy(sl->rom, rom, sizeof(sl->rom));
173 else
174 dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n");
175
176 for (i = 0; i < 9; ++i)
177 count += sprintf(buf + count, "%02x ", sl->rom[i]);
178
179 count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom));
180out:
181 up(&dev->mutex);
182out_dec:
183 smp_mb__before_atomic_inc();
184 atomic_dec(&sl->refcnt);
185
186 return count;
187}
188
189static struct w1_family w1_therm_family = {
190 .fid = W1_FAMILY_THERM,
191 .fops = &w1_therm_fops,
192};
193
194static int __init w1_therm_init(void)
195{
196 return w1_register_family(&w1_therm_family);
197}
198
199static void __exit w1_therm_fini(void)
200{
201 w1_unregister_family(&w1_therm_family);
202}
203
204module_init(w1_therm_init);
205module_exit(w1_therm_fini);