4 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
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 <zbr@ioremap.net>");
38 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
39 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18S20));
40 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1822));
41 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18B20));
42 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1825));
43 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS28EA00));
45 /* Allow the strong pullup to be disabled, but default to enabled.
46 * If it was disabled a parasite powered device might not get the require
47 * current to do a temperature conversion. If it is enabled parasite powered
48 * devices have a better chance of getting the current required.
49 * In case the parasite power-detection is not working (seems to be the case
50 * for some DS18S20) the strong pullup can also be forced, regardless of the
51 * power state of the devices.
54 * - strong_pullup = 0 Disable strong pullup completely
55 * - strong_pullup = 1 Enable automatic strong pullup detection
56 * - strong_pullup = 2 Force strong pullup
58 static int w1_strong_pullup = 1;
59 module_param_named(strong_pullup, w1_strong_pullup, int, 0);
62 static ssize_t w1_therm_read(struct device *device,
63 struct device_attribute *attr, char *buf);
65 static struct device_attribute w1_therm_attr =
66 __ATTR(w1_slave, S_IRUGO, w1_therm_read, NULL);
68 static int w1_therm_add_slave(struct w1_slave *sl)
70 return device_create_file(&sl->dev, &w1_therm_attr);
73 static void w1_therm_remove_slave(struct w1_slave *sl)
75 device_remove_file(&sl->dev, &w1_therm_attr);
78 static struct w1_family_ops w1_therm_fops = {
79 .add_slave = w1_therm_add_slave,
80 .remove_slave = w1_therm_remove_slave,
83 static struct w1_family w1_therm_family_DS18S20 = {
84 .fid = W1_THERM_DS18S20,
85 .fops = &w1_therm_fops,
88 static struct w1_family w1_therm_family_DS18B20 = {
89 .fid = W1_THERM_DS18B20,
90 .fops = &w1_therm_fops,
93 static struct w1_family w1_therm_family_DS1822 = {
94 .fid = W1_THERM_DS1822,
95 .fops = &w1_therm_fops,
98 static struct w1_family w1_therm_family_DS28EA00 = {
99 .fid = W1_THERM_DS28EA00,
100 .fops = &w1_therm_fops,
103 static struct w1_family w1_therm_family_DS1825 = {
104 .fid = W1_THERM_DS1825,
105 .fops = &w1_therm_fops,
108 struct w1_therm_family_converter
113 int (*convert)(u8 rom[9]);
116 /* The return value is millidegrees Centigrade. */
117 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
118 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
120 static struct w1_therm_family_converter w1_therm_families[] = {
122 .f = &w1_therm_family_DS18S20,
123 .convert = w1_DS18S20_convert_temp
126 .f = &w1_therm_family_DS1822,
127 .convert = w1_DS18B20_convert_temp
130 .f = &w1_therm_family_DS18B20,
131 .convert = w1_DS18B20_convert_temp
134 .f = &w1_therm_family_DS28EA00,
135 .convert = w1_DS18B20_convert_temp
138 .f = &w1_therm_family_DS1825,
139 .convert = w1_DS18B20_convert_temp
143 static inline int w1_DS18B20_convert_temp(u8 rom[9])
145 s16 t = le16_to_cpup((__le16 *)rom);
149 static inline int w1_DS18S20_convert_temp(u8 rom[9])
157 t = ((s32)rom[0] >> 1)*1000;
159 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
162 h = 1000*((s32)rom[7] - (s32)rom[6]);
169 static inline int w1_convert_temp(u8 rom[9], u8 fid)
173 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
174 if (w1_therm_families[i].f->fid == fid)
175 return w1_therm_families[i].convert(rom);
181 static ssize_t w1_therm_read(struct device *device,
182 struct device_attribute *attr, char *buf)
184 struct w1_slave *sl = dev_to_w1_slave(device);
185 struct w1_master *dev = sl->master;
186 u8 rom[9], crc, verdict, external_power;
187 int i, max_trying = 10;
188 ssize_t c = PAGE_SIZE;
190 i = mutex_lock_interruptible(&dev->bus_mutex);
194 memset(rom, 0, sizeof(rom));
196 while (max_trying--) {
201 if (!w1_reset_select_slave(sl)) {
203 unsigned int tm = 750;
204 unsigned long sleep_rem;
206 w1_write_8(dev, W1_READ_PSUPPLY);
207 external_power = w1_read_8(dev);
209 if (w1_reset_select_slave(sl))
212 /* 750ms strong pullup (or delay) after the convert */
213 if (w1_strong_pullup == 2 ||
214 (!external_power && w1_strong_pullup))
215 w1_next_pullup(dev, tm);
217 w1_write_8(dev, W1_CONVERT_TEMP);
219 if (external_power) {
220 mutex_unlock(&dev->bus_mutex);
222 sleep_rem = msleep_interruptible(tm);
226 i = mutex_lock_interruptible(&dev->bus_mutex);
229 } else if (!w1_strong_pullup) {
230 sleep_rem = msleep_interruptible(tm);
231 if (sleep_rem != 0) {
232 mutex_unlock(&dev->bus_mutex);
237 if (!w1_reset_select_slave(sl)) {
239 w1_write_8(dev, W1_READ_SCRATCHPAD);
240 if ((count = w1_read_block(dev, rom, 9)) != 9) {
241 dev_warn(device, "w1_read_block() "
242 "returned %u instead of 9.\n",
246 crc = w1_calc_crc8(rom, 8);
257 for (i = 0; i < 9; ++i)
258 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", rom[i]);
259 c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
260 crc, (verdict) ? "YES" : "NO");
262 memcpy(sl->rom, rom, sizeof(sl->rom));
264 dev_warn(device, "Read failed CRC check\n");
266 for (i = 0; i < 9; ++i)
267 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", sl->rom[i]);
269 c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
270 w1_convert_temp(rom, sl->family->fid));
271 mutex_unlock(&dev->bus_mutex);
273 return PAGE_SIZE - c;
276 static int __init w1_therm_init(void)
280 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
281 err = w1_register_family(w1_therm_families[i].f);
283 w1_therm_families[i].broken = 1;
289 static void __exit w1_therm_fini(void)
293 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
294 if (!w1_therm_families[i].broken)
295 w1_unregister_family(w1_therm_families[i].f);
298 module_init(w1_therm_init);
299 module_exit(w1_therm_fini);