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[~shefty/rdma-dev.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 /* 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 struct w1_therm_family_converter
90 {
91         u8                      broken;
92         u16                     reserved;
93         struct w1_family        *f;
94         int                     (*convert)(u8 rom[9]);
95 };
96
97 /* The return value is millidegrees Centigrade. */
98 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
99 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
100
101 static struct w1_therm_family_converter w1_therm_families[] = {
102         {
103                 .f              = &w1_therm_family_DS18S20,
104                 .convert        = w1_DS18S20_convert_temp
105         },
106         {
107                 .f              = &w1_therm_family_DS1822,
108                 .convert        = w1_DS18B20_convert_temp
109         },
110         {
111                 .f              = &w1_therm_family_DS18B20,
112                 .convert        = w1_DS18B20_convert_temp
113         },
114 };
115
116 static inline int w1_DS18B20_convert_temp(u8 rom[9])
117 {
118         s16 t = le16_to_cpup((__le16 *)rom);
119         return t*1000/16;
120 }
121
122 static inline int w1_DS18S20_convert_temp(u8 rom[9])
123 {
124         int t, h;
125
126         if (!rom[7])
127                 return 0;
128
129         if (rom[1] == 0)
130                 t = ((s32)rom[0] >> 1)*1000;
131         else
132                 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
133
134         t -= 250;
135         h = 1000*((s32)rom[7] - (s32)rom[6]);
136         h /= (s32)rom[7];
137         t += h;
138
139         return t;
140 }
141
142 static inline int w1_convert_temp(u8 rom[9], u8 fid)
143 {
144         int i;
145
146         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
147                 if (w1_therm_families[i].f->fid == fid)
148                         return w1_therm_families[i].convert(rom);
149
150         return 0;
151 }
152
153 static int w1_therm_check_rom(u8 rom[9])
154 {
155         int i;
156
157         for (i=0; i<sizeof(bad_roms)/9; ++i)
158                 if (!memcmp(bad_roms[i], rom, 9))
159                         return 1;
160
161         return 0;
162 }
163
164 static ssize_t w1_therm_read(struct device *device,
165         struct device_attribute *attr, char *buf)
166 {
167         struct w1_slave *sl = dev_to_w1_slave(device);
168         struct w1_master *dev = sl->master;
169         u8 rom[9], crc, verdict;
170         int i, max_trying = 10;
171         ssize_t c = PAGE_SIZE;
172
173         mutex_lock(&dev->mutex);
174
175         memset(rom, 0, sizeof(rom));
176
177         verdict = 0;
178         crc = 0;
179
180         while (max_trying--) {
181                 if (!w1_reset_select_slave(sl)) {
182                         int count = 0;
183                         unsigned int tm = 750;
184
185                         /* 750ms strong pullup (or delay) after the convert */
186                         if (w1_strong_pullup)
187                                 w1_next_pullup(dev, tm);
188                         w1_write_8(dev, W1_CONVERT_TEMP);
189                         if (!w1_strong_pullup)
190                                 msleep(tm);
191
192                         if (!w1_reset_select_slave(sl)) {
193
194                                 w1_write_8(dev, W1_READ_SCRATCHPAD);
195                                 if ((count = w1_read_block(dev, rom, 9)) != 9) {
196                                         dev_warn(device, "w1_read_block() "
197                                                 "returned %u instead of 9.\n",
198                                                 count);
199                                 }
200
201                                 crc = w1_calc_crc8(rom, 8);
202
203                                 if (rom[8] == crc)
204                                         verdict = 1;
205                         }
206                 }
207
208                 if (!w1_therm_check_rom(rom))
209                         break;
210         }
211
212         for (i = 0; i < 9; ++i)
213                 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", rom[i]);
214         c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
215                            crc, (verdict) ? "YES" : "NO");
216         if (verdict)
217                 memcpy(sl->rom, rom, sizeof(sl->rom));
218         else
219                 dev_warn(device, "18S20 doesn't respond to CONVERT_TEMP.\n");
220
221         for (i = 0; i < 9; ++i)
222                 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", sl->rom[i]);
223
224         c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
225                 w1_convert_temp(rom, sl->family->fid));
226         mutex_unlock(&dev->mutex);
227
228         return PAGE_SIZE - c;
229 }
230
231 static int __init w1_therm_init(void)
232 {
233         int err, i;
234
235         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
236                 err = w1_register_family(w1_therm_families[i].f);
237                 if (err)
238                         w1_therm_families[i].broken = 1;
239         }
240
241         return 0;
242 }
243
244 static void __exit w1_therm_fini(void)
245 {
246         int i;
247
248         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
249                 if (!w1_therm_families[i].broken)
250                         w1_unregister_family(w1_therm_families[i].f);
251 }
252
253 module_init(w1_therm_init);
254 module_exit(w1_therm_fini);