4 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
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.
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.
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
22 #include <asm/types.h>
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>
33 #include "../w1_int.h"
34 #include "../w1_family.h"
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.");
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.
45 static int w1_strong_pullup = 1;
46 module_param_named(strong_pullup, w1_strong_pullup, int, 0);
48 static u8 bad_roms[][9] = {
49 {0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87},
53 static ssize_t w1_therm_read_bin(struct kobject *, struct bin_attribute *,
54 char *, loff_t, size_t);
56 static struct bin_attribute w1_therm_bin_attr = {
61 .size = W1_SLAVE_DATA_SIZE,
62 .read = w1_therm_read_bin,
65 static int w1_therm_add_slave(struct w1_slave *sl)
67 return sysfs_create_bin_file(&sl->dev.kobj, &w1_therm_bin_attr);
70 static void w1_therm_remove_slave(struct w1_slave *sl)
72 sysfs_remove_bin_file(&sl->dev.kobj, &w1_therm_bin_attr);
75 static struct w1_family_ops w1_therm_fops = {
76 .add_slave = w1_therm_add_slave,
77 .remove_slave = w1_therm_remove_slave,
80 static struct w1_family w1_therm_family_DS18S20 = {
81 .fid = W1_THERM_DS18S20,
82 .fops = &w1_therm_fops,
85 static struct w1_family w1_therm_family_DS18B20 = {
86 .fid = W1_THERM_DS18B20,
87 .fops = &w1_therm_fops,
90 static struct w1_family w1_therm_family_DS1822 = {
91 .fid = W1_THERM_DS1822,
92 .fops = &w1_therm_fops,
95 struct w1_therm_family_converter
100 int (*convert)(u8 rom[9]);
103 /* The return value is millidegrees Centigrade. */
104 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
105 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
107 static struct w1_therm_family_converter w1_therm_families[] = {
109 .f = &w1_therm_family_DS18S20,
110 .convert = w1_DS18S20_convert_temp
113 .f = &w1_therm_family_DS1822,
114 .convert = w1_DS18B20_convert_temp
117 .f = &w1_therm_family_DS18B20,
118 .convert = w1_DS18B20_convert_temp
122 static inline int w1_DS18B20_convert_temp(u8 rom[9])
124 s16 t = (rom[1] << 8) | rom[0];
129 static inline int w1_DS18S20_convert_temp(u8 rom[9])
137 t = ((s32)rom[0] >> 1)*1000;
139 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
142 h = 1000*((s32)rom[7] - (s32)rom[6]);
149 static inline int w1_convert_temp(u8 rom[9], u8 fid)
153 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
154 if (w1_therm_families[i].f->fid == fid)
155 return w1_therm_families[i].convert(rom);
160 static int w1_therm_check_rom(u8 rom[9])
164 for (i=0; i<sizeof(bad_roms)/9; ++i)
165 if (!memcmp(bad_roms[i], rom, 9))
171 static ssize_t w1_therm_read_bin(struct kobject *kobj,
172 struct bin_attribute *bin_attr,
173 char *buf, loff_t off, size_t count)
175 struct w1_slave *sl = kobj_to_w1_slave(kobj);
176 struct w1_master *dev = sl->master;
177 u8 rom[9], crc, verdict;
178 int i, max_trying = 10;
180 mutex_lock(&sl->master->mutex);
182 if (off > W1_SLAVE_DATA_SIZE) {
186 if (off + count > W1_SLAVE_DATA_SIZE) {
191 memset(buf, 0, count);
192 memset(rom, 0, sizeof(rom));
198 while (max_trying--) {
199 if (!w1_reset_select_slave(sl)) {
201 unsigned int tm = 750;
203 /* 750ms strong pullup (or delay) after the convert */
204 if (w1_strong_pullup)
205 w1_next_pullup(dev, tm);
206 w1_write_8(dev, W1_CONVERT_TEMP);
207 if (!w1_strong_pullup)
210 if (!w1_reset_select_slave(sl)) {
212 w1_write_8(dev, W1_READ_SCRATCHPAD);
213 if ((count = w1_read_block(dev, rom, 9)) != 9) {
214 dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
217 crc = w1_calc_crc8(rom, 8);
224 if (!w1_therm_check_rom(rom))
228 for (i = 0; i < 9; ++i)
229 count += sprintf(buf + count, "%02x ", rom[i]);
230 count += sprintf(buf + count, ": crc=%02x %s\n",
231 crc, (verdict) ? "YES" : "NO");
233 memcpy(sl->rom, rom, sizeof(sl->rom));
235 dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n");
237 for (i = 0; i < 9; ++i)
238 count += sprintf(buf + count, "%02x ", sl->rom[i]);
240 count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom, sl->family->fid));
242 mutex_unlock(&dev->mutex);
247 static int __init w1_therm_init(void)
251 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
252 err = w1_register_family(w1_therm_families[i].f);
254 w1_therm_families[i].broken = 1;
260 static void __exit w1_therm_fini(void)
264 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
265 if (!w1_therm_families[i].broken)
266 w1_unregister_family(w1_therm_families[i].f);
269 module_init(w1_therm_init);
270 module_exit(w1_therm_fini);