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/slab.h>
31 #include <linux/delay.h>
34 #include "../w1_int.h"
35 #include "../w1_family.h"
37 MODULE_LICENSE("GPL");
38 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
39 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
40 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18S20));
41 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1822));
42 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18B20));
43 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1825));
44 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS28EA00));
46 /* Allow the strong pullup to be disabled, but default to enabled.
47 * If it was disabled a parasite powered device might not get the require
48 * current to do a temperature conversion. If it is enabled parasite powered
49 * devices have a better chance of getting the current required.
50 * In case the parasite power-detection is not working (seems to be the case
51 * for some DS18S20) the strong pullup can also be forced, regardless of the
52 * power state of the devices.
55 * - strong_pullup = 0 Disable strong pullup completely
56 * - strong_pullup = 1 Enable automatic strong pullup detection
57 * - strong_pullup = 2 Force strong pullup
59 static int w1_strong_pullup = 1;
60 module_param_named(strong_pullup, w1_strong_pullup, int, 0);
62 struct w1_therm_family_data {
67 /* return the address of the refcnt in the family data */
68 #define THERM_REFCNT(family_data) \
69 (&((struct w1_therm_family_data*)family_data)->refcnt)
71 static int w1_therm_add_slave(struct w1_slave *sl)
73 sl->family_data = kzalloc(sizeof(struct w1_therm_family_data),
77 atomic_set(THERM_REFCNT(sl->family_data), 1);
81 static void w1_therm_remove_slave(struct w1_slave *sl)
83 int refcnt = atomic_sub_return(1, THERM_REFCNT(sl->family_data));
86 refcnt = atomic_read(THERM_REFCNT(sl->family_data));
88 kfree(sl->family_data);
89 sl->family_data = NULL;
92 static ssize_t w1_slave_show(struct device *device,
93 struct device_attribute *attr, char *buf);
95 static DEVICE_ATTR_RO(w1_slave);
97 static struct attribute *w1_therm_attrs[] = {
98 &dev_attr_w1_slave.attr,
101 ATTRIBUTE_GROUPS(w1_therm);
103 static struct w1_family_ops w1_therm_fops = {
104 .add_slave = w1_therm_add_slave,
105 .remove_slave = w1_therm_remove_slave,
106 .groups = w1_therm_groups,
109 static struct w1_family w1_therm_family_DS18S20 = {
110 .fid = W1_THERM_DS18S20,
111 .fops = &w1_therm_fops,
114 static struct w1_family w1_therm_family_DS18B20 = {
115 .fid = W1_THERM_DS18B20,
116 .fops = &w1_therm_fops,
119 static struct w1_family w1_therm_family_DS1822 = {
120 .fid = W1_THERM_DS1822,
121 .fops = &w1_therm_fops,
124 static struct w1_family w1_therm_family_DS28EA00 = {
125 .fid = W1_THERM_DS28EA00,
126 .fops = &w1_therm_fops,
129 static struct w1_family w1_therm_family_DS1825 = {
130 .fid = W1_THERM_DS1825,
131 .fops = &w1_therm_fops,
134 struct w1_therm_family_converter
139 int (*convert)(u8 rom[9]);
142 /* The return value is millidegrees Centigrade. */
143 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
144 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
146 static struct w1_therm_family_converter w1_therm_families[] = {
148 .f = &w1_therm_family_DS18S20,
149 .convert = w1_DS18S20_convert_temp
152 .f = &w1_therm_family_DS1822,
153 .convert = w1_DS18B20_convert_temp
156 .f = &w1_therm_family_DS18B20,
157 .convert = w1_DS18B20_convert_temp
160 .f = &w1_therm_family_DS28EA00,
161 .convert = w1_DS18B20_convert_temp
164 .f = &w1_therm_family_DS1825,
165 .convert = w1_DS18B20_convert_temp
169 static inline int w1_DS18B20_convert_temp(u8 rom[9])
171 s16 t = le16_to_cpup((__le16 *)rom);
175 static inline int w1_DS18S20_convert_temp(u8 rom[9])
183 t = ((s32)rom[0] >> 1)*1000;
185 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
188 h = 1000*((s32)rom[7] - (s32)rom[6]);
195 static inline int w1_convert_temp(u8 rom[9], u8 fid)
199 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
200 if (w1_therm_families[i].f->fid == fid)
201 return w1_therm_families[i].convert(rom);
207 static ssize_t w1_slave_show(struct device *device,
208 struct device_attribute *attr, char *buf)
210 struct w1_slave *sl = dev_to_w1_slave(device);
211 struct w1_master *dev = sl->master;
212 u8 rom[9], crc, verdict, external_power;
213 int i, ret, max_trying = 10;
214 ssize_t c = PAGE_SIZE;
215 u8 *family_data = sl->family_data;
217 ret = mutex_lock_interruptible(&dev->bus_mutex);
227 /* prevent the slave from going away in sleep */
228 atomic_inc(THERM_REFCNT(family_data));
229 memset(rom, 0, sizeof(rom));
231 while (max_trying--) {
236 if (!w1_reset_select_slave(sl)) {
238 unsigned int tm = 750;
239 unsigned long sleep_rem;
241 w1_write_8(dev, W1_READ_PSUPPLY);
242 external_power = w1_read_8(dev);
244 if (w1_reset_select_slave(sl))
247 /* 750ms strong pullup (or delay) after the convert */
248 if (w1_strong_pullup == 2 ||
249 (!external_power && w1_strong_pullup))
250 w1_next_pullup(dev, tm);
252 w1_write_8(dev, W1_CONVERT_TEMP);
254 if (external_power) {
255 mutex_unlock(&dev->bus_mutex);
257 sleep_rem = msleep_interruptible(tm);
258 if (sleep_rem != 0) {
263 ret = mutex_lock_interruptible(&dev->bus_mutex);
266 } else if (!w1_strong_pullup) {
267 sleep_rem = msleep_interruptible(tm);
268 if (sleep_rem != 0) {
274 if (!w1_reset_select_slave(sl)) {
276 w1_write_8(dev, W1_READ_SCRATCHPAD);
277 if ((count = w1_read_block(dev, rom, 9)) != 9) {
278 dev_warn(device, "w1_read_block() "
279 "returned %u instead of 9.\n",
283 crc = w1_calc_crc8(rom, 8);
294 for (i = 0; i < 9; ++i)
295 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", rom[i]);
296 c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
297 crc, (verdict) ? "YES" : "NO");
299 memcpy(family_data, rom, sizeof(rom));
301 dev_warn(device, "Read failed CRC check\n");
303 for (i = 0; i < 9; ++i)
304 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ",
305 ((u8 *)family_data)[i]);
307 c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
308 w1_convert_temp(rom, sl->family->fid));
312 mutex_unlock(&dev->bus_mutex);
315 atomic_dec(THERM_REFCNT(family_data));
319 static int __init w1_therm_init(void)
323 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
324 err = w1_register_family(w1_therm_families[i].f);
326 w1_therm_families[i].broken = 1;
332 static void __exit w1_therm_fini(void)
336 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
337 if (!w1_therm_families[i].broken)
338 w1_unregister_family(w1_therm_families[i].f);
341 module_init(w1_therm_init);
342 module_exit(w1_therm_fini);