Merge git://bedivere.hansenpartnership.com/git/scsi-rc-fixes-2.6
[linux-2.6.git] / drivers / w1 / slaves / w1_therm.c
1 /*
2  *      w1_therm.c
3  *
4  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
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 <zbr@ioremap.net>");
38 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
39
40 /* Allow the strong pullup to be disabled, but default to enabled.
41  * If it was disabled a parasite powered device might not get the require
42  * current to do a temperature conversion.  If it is enabled parasite powered
43  * devices have a better chance of getting the current required.
44  */
45 static int w1_strong_pullup = 1;
46 module_param_named(strong_pullup, w1_strong_pullup, int, 0);
47
48 static u8 bad_roms[][9] = {
49                                 {0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87},
50                                 {}
51                         };
52
53 static ssize_t w1_therm_read(struct device *device,
54         struct device_attribute *attr, char *buf);
55
56 static struct device_attribute w1_therm_attr =
57         __ATTR(w1_slave, S_IRUGO, w1_therm_read, NULL);
58
59 static int w1_therm_add_slave(struct w1_slave *sl)
60 {
61         return device_create_file(&sl->dev, &w1_therm_attr);
62 }
63
64 static void w1_therm_remove_slave(struct w1_slave *sl)
65 {
66         device_remove_file(&sl->dev, &w1_therm_attr);
67 }
68
69 static struct w1_family_ops w1_therm_fops = {
70         .add_slave      = w1_therm_add_slave,
71         .remove_slave   = w1_therm_remove_slave,
72 };
73
74 static struct w1_family w1_therm_family_DS18S20 = {
75         .fid = W1_THERM_DS18S20,
76         .fops = &w1_therm_fops,
77 };
78
79 static struct w1_family w1_therm_family_DS18B20 = {
80         .fid = W1_THERM_DS18B20,
81         .fops = &w1_therm_fops,
82 };
83
84 static struct w1_family w1_therm_family_DS1822 = {
85         .fid = W1_THERM_DS1822,
86         .fops = &w1_therm_fops,
87 };
88
89 static struct w1_family w1_therm_family_DS28EA00 = {
90         .fid = W1_THERM_DS28EA00,
91         .fops = &w1_therm_fops,
92 };
93
94 struct w1_therm_family_converter
95 {
96         u8                      broken;
97         u16                     reserved;
98         struct w1_family        *f;
99         int                     (*convert)(u8 rom[9]);
100 };
101
102 /* The return value is millidegrees Centigrade. */
103 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
104 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
105
106 static struct w1_therm_family_converter w1_therm_families[] = {
107         {
108                 .f              = &w1_therm_family_DS18S20,
109                 .convert        = w1_DS18S20_convert_temp
110         },
111         {
112                 .f              = &w1_therm_family_DS1822,
113                 .convert        = w1_DS18B20_convert_temp
114         },
115         {
116                 .f              = &w1_therm_family_DS18B20,
117                 .convert        = w1_DS18B20_convert_temp
118         },
119         {
120                 .f              = &w1_therm_family_DS28EA00,
121                 .convert        = w1_DS18B20_convert_temp
122         },
123 };
124
125 static inline int w1_DS18B20_convert_temp(u8 rom[9])
126 {
127         s16 t = le16_to_cpup((__le16 *)rom);
128         return t*1000/16;
129 }
130
131 static inline int w1_DS18S20_convert_temp(u8 rom[9])
132 {
133         int t, h;
134
135         if (!rom[7])
136                 return 0;
137
138         if (rom[1] == 0)
139                 t = ((s32)rom[0] >> 1)*1000;
140         else
141                 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
142
143         t -= 250;
144         h = 1000*((s32)rom[7] - (s32)rom[6]);
145         h /= (s32)rom[7];
146         t += h;
147
148         return t;
149 }
150
151 static inline int w1_convert_temp(u8 rom[9], u8 fid)
152 {
153         int i;
154
155         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
156                 if (w1_therm_families[i].f->fid == fid)
157                         return w1_therm_families[i].convert(rom);
158
159         return 0;
160 }
161
162 static int w1_therm_check_rom(u8 rom[9])
163 {
164         int i;
165
166         for (i=0; i<sizeof(bad_roms)/9; ++i)
167                 if (!memcmp(bad_roms[i], rom, 9))
168                         return 1;
169
170         return 0;
171 }
172
173 static ssize_t w1_therm_read(struct device *device,
174         struct device_attribute *attr, char *buf)
175 {
176         struct w1_slave *sl = dev_to_w1_slave(device);
177         struct w1_master *dev = sl->master;
178         u8 rom[9], crc, verdict;
179         int i, max_trying = 10;
180         ssize_t c = PAGE_SIZE;
181
182         mutex_lock(&dev->mutex);
183
184         memset(rom, 0, sizeof(rom));
185
186         verdict = 0;
187         crc = 0;
188
189         while (max_trying--) {
190                 if (!w1_reset_select_slave(sl)) {
191                         int count = 0;
192                         unsigned int tm = 750;
193
194                         /* 750ms strong pullup (or delay) after the convert */
195                         if (w1_strong_pullup)
196                                 w1_next_pullup(dev, tm);
197                         w1_write_8(dev, W1_CONVERT_TEMP);
198                         if (!w1_strong_pullup)
199                                 msleep(tm);
200
201                         if (!w1_reset_select_slave(sl)) {
202
203                                 w1_write_8(dev, W1_READ_SCRATCHPAD);
204                                 if ((count = w1_read_block(dev, rom, 9)) != 9) {
205                                         dev_warn(device, "w1_read_block() "
206                                                 "returned %u instead of 9.\n",
207                                                 count);
208                                 }
209
210                                 crc = w1_calc_crc8(rom, 8);
211
212                                 if (rom[8] == crc)
213                                         verdict = 1;
214                         }
215                 }
216
217                 if (!w1_therm_check_rom(rom))
218                         break;
219         }
220
221         for (i = 0; i < 9; ++i)
222                 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", rom[i]);
223         c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
224                            crc, (verdict) ? "YES" : "NO");
225         if (verdict)
226                 memcpy(sl->rom, rom, sizeof(sl->rom));
227         else
228                 dev_warn(device, "18S20 doesn't respond to CONVERT_TEMP.\n");
229
230         for (i = 0; i < 9; ++i)
231                 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", sl->rom[i]);
232
233         c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
234                 w1_convert_temp(rom, sl->family->fid));
235         mutex_unlock(&dev->mutex);
236
237         return PAGE_SIZE - c;
238 }
239
240 static int __init w1_therm_init(void)
241 {
242         int err, i;
243
244         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
245                 err = w1_register_family(w1_therm_families[i].f);
246                 if (err)
247                         w1_therm_families[i].broken = 1;
248         }
249
250         return 0;
251 }
252
253 static void __exit w1_therm_fini(void)
254 {
255         int i;
256
257         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
258                 if (!w1_therm_families[i].broken)
259                         w1_unregister_family(w1_therm_families[i].f);
260 }
261
262 module_init(w1_therm_init);
263 module_exit(w1_therm_fini);