summaryrefslogtreecommitdiff
path: root/drivers/w1/slaves/w1_therm.c
blob: 112f4ec59035424bc36b7251fcb6367c9bca7f77 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
/*
 *	w1_therm.c
 *
 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the therms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <asm/types.h>

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/delay.h>

#include "../w1.h"
#include "../w1_int.h"
#include "../w1_family.h"

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");

static u8 bad_roms[][9] = {
				{0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87},
				{}
			};

static ssize_t w1_therm_read_bin(struct kobject *, struct bin_attribute *,
				 char *, loff_t, size_t);

static struct bin_attribute w1_therm_bin_attr = {
	.attr = {
		.name = "w1_slave",
		.mode = S_IRUGO,
	},
	.size = W1_SLAVE_DATA_SIZE,
	.read = w1_therm_read_bin,
};

static int w1_therm_add_slave(struct w1_slave *sl)
{
	return sysfs_create_bin_file(&sl->dev.kobj, &w1_therm_bin_attr);
}

static void w1_therm_remove_slave(struct w1_slave *sl)
{
	sysfs_remove_bin_file(&sl->dev.kobj, &w1_therm_bin_attr);
}

static struct w1_family_ops w1_therm_fops = {
	.add_slave	= w1_therm_add_slave,
	.remove_slave	= w1_therm_remove_slave,
};

static struct w1_family w1_therm_family_DS18S20 = {
	.fid = W1_THERM_DS18S20,
	.fops = &w1_therm_fops,
};

static struct w1_family w1_therm_family_DS18B20 = {
	.fid = W1_THERM_DS18B20,
	.fops = &w1_therm_fops,
};

static struct w1_family w1_therm_family_DS1822 = {
	.fid = W1_THERM_DS1822,
	.fops = &w1_therm_fops,
};

struct w1_therm_family_converter
{
	u8			broken;
	u16			reserved;
	struct w1_family	*f;
	int			(*convert)(u8 rom[9]);
};

static inline int w1_DS18B20_convert_temp(u8 rom[9]);
static inline int w1_DS18S20_convert_temp(u8 rom[9]);

static struct w1_therm_family_converter w1_therm_families[] = {
	{
		.f		= &w1_therm_family_DS18S20,
		.convert 	= w1_DS18S20_convert_temp
	},
	{
		.f		= &w1_therm_family_DS1822,
		.convert 	= w1_DS18B20_convert_temp
	},
	{
		.f		= &w1_therm_family_DS18B20,
		.convert 	= w1_DS18B20_convert_temp
	},
};

static inline int w1_DS18B20_convert_temp(u8 rom[9])
{
	s16 t = (rom[1] << 8) | rom[0];
	t /= 16;
	return t;
}

static inline int w1_DS18S20_convert_temp(u8 rom[9])
{
	int t, h;

	if (!rom[7])
		return 0;

	if (rom[1] == 0)
		t = ((s32)rom[0] >> 1)*1000;
	else
		t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);

	t -= 250;
	h = 1000*((s32)rom[7] - (s32)rom[6]);
	h /= (s32)rom[7];
	t += h;

	return t;
}

static inline int w1_convert_temp(u8 rom[9], u8 fid)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
		if (w1_therm_families[i].f->fid == fid)
			return w1_therm_families[i].convert(rom);

	return 0;
}

static int w1_therm_check_rom(u8 rom[9])
{
	int i;

	for (i=0; i<sizeof(bad_roms)/9; ++i)
		if (!memcmp(bad_roms[i], rom, 9))
			return 1;

	return 0;
}

static ssize_t w1_therm_read_bin(struct kobject *kobj,
				 struct bin_attribute *bin_attr,
				 char *buf, loff_t off, size_t count)
{
	struct w1_slave *sl = kobj_to_w1_slave(kobj);
	struct w1_master *dev = sl->master;
	u8 rom[9], crc, verdict;
	int i, max_trying = 10;

	mutex_lock(&sl->master->mutex);

	if (off > W1_SLAVE_DATA_SIZE) {
		count = 0;
		goto out;
	}
	if (off + count > W1_SLAVE_DATA_SIZE) {
		count = 0;
		goto out;
	}

	memset(buf, 0, count);
	memset(rom, 0, sizeof(rom));

	count = 0;
	verdict = 0;
	crc = 0;

	while (max_trying--) {
		if (!w1_reset_select_slave(sl)) {
			int count = 0;
			unsigned int tm = 750;

			w1_write_8(dev, W1_CONVERT_TEMP);

			msleep(tm);

			if (!w1_reset_select_slave(sl)) {

				w1_write_8(dev, W1_READ_SCRATCHPAD);
				if ((count = w1_read_block(dev, rom, 9)) != 9) {
					dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
				}

				crc = w1_calc_crc8(rom, 8);

				if (rom[8] == crc)
					verdict = 1;
			}
		}

		if (!w1_therm_check_rom(rom))
			break;
	}

	for (i = 0; i < 9; ++i)
		count += sprintf(buf + count, "%02x ", rom[i]);
	count += sprintf(buf + count, ": crc=%02x %s\n",
			   crc, (verdict) ? "YES" : "NO");
	if (verdict)
		memcpy(sl->rom, rom, sizeof(sl->rom));
	else
		dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n");

	for (i = 0; i < 9; ++i)
		count += sprintf(buf + count, "%02x ", sl->rom[i]);

	count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom, sl->family->fid));
out:
	mutex_unlock(&dev->mutex);

	return count;
}

static int __init w1_therm_init(void)
{
	int err, i;

	for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
		err = w1_register_family(w1_therm_families[i].f);
		if (err)
			w1_therm_families[i].broken = 1;
	}

	return 0;
}

static void __exit w1_therm_fini(void)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
		if (!w1_therm_families[i].broken)
			w1_unregister_family(w1_therm_families[i].f);
}

module_init(w1_therm_init);
module_exit(w1_therm_fini);