w1_therm_read_bin: don't call flush_signals()
[sfrench/cifs-2.6.git] / drivers / w1 / slaves / w1_therm.c
1 /*
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/sched.h>
28 #include <linux/device.h>
29 #include <linux/types.h>
30 #include <linux/delay.h>
31
32 #include "../w1.h"
33 #include "../w1_int.h"
34 #include "../w1_family.h"
35
36 MODULE_LICENSE("GPL");
37 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
38 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
39
40 static u8 bad_roms[][9] = {
41                                 {0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87},
42                                 {}
43                         };
44
45 static ssize_t w1_therm_read_bin(struct kobject *, char *, loff_t, size_t);
46
47 static struct bin_attribute w1_therm_bin_attr = {
48         .attr = {
49                 .name = "w1_slave",
50                 .mode = S_IRUGO,
51                 .owner = THIS_MODULE,
52         },
53         .size = W1_SLAVE_DATA_SIZE,
54         .read = w1_therm_read_bin,
55 };
56
57 static int w1_therm_add_slave(struct w1_slave *sl)
58 {
59         return sysfs_create_bin_file(&sl->dev.kobj, &w1_therm_bin_attr);
60 }
61
62 static void w1_therm_remove_slave(struct w1_slave *sl)
63 {
64         sysfs_remove_bin_file(&sl->dev.kobj, &w1_therm_bin_attr);
65 }
66
67 static struct w1_family_ops w1_therm_fops = {
68         .add_slave      = w1_therm_add_slave,
69         .remove_slave   = w1_therm_remove_slave,
70 };
71
72 static struct w1_family w1_therm_family_DS18S20 = {
73         .fid = W1_THERM_DS18S20,
74         .fops = &w1_therm_fops,
75 };
76
77 static struct w1_family w1_therm_family_DS18B20 = {
78         .fid = W1_THERM_DS18B20,
79         .fops = &w1_therm_fops,
80 };
81
82 static struct w1_family w1_therm_family_DS1822 = {
83         .fid = W1_THERM_DS1822,
84         .fops = &w1_therm_fops,
85 };
86
87 struct w1_therm_family_converter
88 {
89         u8                      broken;
90         u16                     reserved;
91         struct w1_family        *f;
92         int                     (*convert)(u8 rom[9]);
93 };
94
95 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
96 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
97
98 static struct w1_therm_family_converter w1_therm_families[] = {
99         {
100                 .f              = &w1_therm_family_DS18S20,
101                 .convert        = w1_DS18S20_convert_temp
102         },
103         {
104                 .f              = &w1_therm_family_DS1822,
105                 .convert        = w1_DS18B20_convert_temp
106         },
107         {
108                 .f              = &w1_therm_family_DS18B20,
109                 .convert        = w1_DS18B20_convert_temp
110         },
111 };
112
113 static inline int w1_DS18B20_convert_temp(u8 rom[9])
114 {
115         int t = (rom[1] << 8) | rom[0];
116         t /= 16;
117         return t;
118 }
119
120 static inline int w1_DS18S20_convert_temp(u8 rom[9])
121 {
122         int t, h;
123
124         if (!rom[7])
125                 return 0;
126
127         if (rom[1] == 0)
128                 t = ((s32)rom[0] >> 1)*1000;
129         else
130                 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
131
132         t -= 250;
133         h = 1000*((s32)rom[7] - (s32)rom[6]);
134         h /= (s32)rom[7];
135         t += h;
136
137         return t;
138 }
139
140 static inline int w1_convert_temp(u8 rom[9], u8 fid)
141 {
142         int i;
143
144         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
145                 if (w1_therm_families[i].f->fid == fid)
146                         return w1_therm_families[i].convert(rom);
147
148         return 0;
149 }
150
151 static int w1_therm_check_rom(u8 rom[9])
152 {
153         int i;
154
155         for (i=0; i<sizeof(bad_roms)/9; ++i)
156                 if (!memcmp(bad_roms[i], rom, 9))
157                         return 1;
158
159         return 0;
160 }
161
162 static ssize_t w1_therm_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count)
163 {
164         struct w1_slave *sl = kobj_to_w1_slave(kobj);
165         struct w1_master *dev = sl->master;
166         u8 rom[9], crc, verdict;
167         int i, max_trying = 10;
168
169         mutex_lock(&sl->master->mutex);
170
171         if (off > W1_SLAVE_DATA_SIZE) {
172                 count = 0;
173                 goto out;
174         }
175         if (off + count > W1_SLAVE_DATA_SIZE) {
176                 count = 0;
177                 goto out;
178         }
179
180         memset(buf, 0, count);
181         memset(rom, 0, sizeof(rom));
182
183         count = 0;
184         verdict = 0;
185         crc = 0;
186
187         while (max_trying--) {
188                 if (!w1_reset_select_slave(sl)) {
189                         int count = 0;
190                         unsigned int tm = 750;
191
192                         w1_write_8(dev, W1_CONVERT_TEMP);
193
194                         msleep(tm);
195
196                         if (!w1_reset_select_slave(sl)) {
197
198                                 w1_write_8(dev, W1_READ_SCRATCHPAD);
199                                 if ((count = w1_read_block(dev, rom, 9)) != 9) {
200                                         dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
201                                 }
202
203                                 crc = w1_calc_crc8(rom, 8);
204
205                                 if (rom[8] == crc && rom[0])
206                                         verdict = 1;
207                         }
208                 }
209
210                 if (!w1_therm_check_rom(rom))
211                         break;
212         }
213
214         for (i = 0; i < 9; ++i)
215                 count += sprintf(buf + count, "%02x ", rom[i]);
216         count += sprintf(buf + count, ": crc=%02x %s\n",
217                            crc, (verdict) ? "YES" : "NO");
218         if (verdict)
219                 memcpy(sl->rom, rom, sizeof(sl->rom));
220         else
221                 dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n");
222
223         for (i = 0; i < 9; ++i)
224                 count += sprintf(buf + count, "%02x ", sl->rom[i]);
225
226         count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom, sl->family->fid));
227 out:
228         mutex_unlock(&dev->mutex);
229
230         return count;
231 }
232
233 static int __init w1_therm_init(void)
234 {
235         int err, i;
236
237         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
238                 err = w1_register_family(w1_therm_families[i].f);
239                 if (err)
240                         w1_therm_families[i].broken = 1;
241         }
242
243         return 0;
244 }
245
246 static void __exit w1_therm_fini(void)
247 {
248         int i;
249
250         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
251                 if (!w1_therm_families[i].broken)
252                         w1_unregister_family(w1_therm_families[i].f);
253 }
254
255 module_init(w1_therm_init);
256 module_exit(w1_therm_fini);