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
36MODULE_LICENSE("GPL");
37MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
38MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
39
40static u8 bad_roms[][9] = {
41				{0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87},
42				{}
43			};
44
45static ssize_t w1_therm_read_bin(struct kobject *, char *, loff_t, size_t);
46
47static struct bin_attribute w1_therm_bin_attr = {
48	.attr = {
49		.name = "w1_slave",
50		.mode = S_IRUGO,
51		.owner = THIS_MODULE,
52	},
53	.size = W1_SLAVE_DATA_SIZE,
54	.read = w1_therm_read_bin,
55};
56
57static int w1_therm_add_slave(struct w1_slave *sl)
58{
59	return sysfs_create_bin_file(&sl->dev.kobj, &w1_therm_bin_attr);
60}
61
62static void w1_therm_remove_slave(struct w1_slave *sl)
63{
64	sysfs_remove_bin_file(&sl->dev.kobj, &w1_therm_bin_attr);
65}
66
67static struct w1_family_ops w1_therm_fops = {
68	.add_slave	= w1_therm_add_slave,
69	.remove_slave	= w1_therm_remove_slave,
70};
71
72static struct w1_family w1_therm_family_DS18S20 = {
73	.fid = W1_THERM_DS18S20,
74	.fops = &w1_therm_fops,
75};
76
77static struct w1_family w1_therm_family_DS18B20 = {
78	.fid = W1_THERM_DS18B20,
79	.fops = &w1_therm_fops,
80};
81
82static struct w1_family w1_therm_family_DS1822 = {
83	.fid = W1_THERM_DS1822,
84	.fops = &w1_therm_fops,
85};
86
87struct w1_therm_family_converter
88{
89	u8			broken;
90	u16			reserved;
91	struct w1_family	*f;
92	int			(*convert)(u8 rom[9]);
93};
94
95static inline int w1_DS18B20_convert_temp(u8 rom[9]);
96static inline int w1_DS18S20_convert_temp(u8 rom[9]);
97
98static struct w1_therm_family_converter w1_therm_families[] = {
99	{
100		.f		= &w1_therm_family_DS18S20,
101		.convert 	= w1_DS18S20_convert_temp
102	},
103	{
104		.f		= &w1_therm_family_DS1822,
105		.convert 	= w1_DS18B20_convert_temp
106	},
107	{
108		.f		= &w1_therm_family_DS18B20,
109		.convert 	= w1_DS18B20_convert_temp
110	},
111};
112
113static inline int w1_DS18B20_convert_temp(u8 rom[9])
114{
115	int t = (rom[1] << 8) | rom[0];
116	t /= 16;
117	return t;
118}
119
120static inline int w1_DS18S20_convert_temp(u8 rom[9])
121{
122	int t, h;
123
124	if (!rom[7])
125		return 0;
126
127	if (rom[1] == 0)
128		t = ((s32)rom[0] >> 1)*1000;
129	else
130		t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
131
132	t -= 250;
133	h = 1000*((s32)rom[7] - (s32)rom[6]);
134	h /= (s32)rom[7];
135	t += h;
136
137	return t;
138}
139
140static inline int w1_convert_temp(u8 rom[9], u8 fid)
141{
142	int i;
143
144	for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
145		if (w1_therm_families[i].f->fid == fid)
146			return w1_therm_families[i].convert(rom);
147
148	return 0;
149}
150
151static int w1_therm_check_rom(u8 rom[9])
152{
153	int i;
154
155	for (i=0; i<sizeof(bad_roms)/9; ++i)
156		if (!memcmp(bad_roms[i], rom, 9))
157			return 1;
158
159	return 0;
160}
161
162static ssize_t w1_therm_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count)
163{
164	struct w1_slave *sl = kobj_to_w1_slave(kobj);
165	struct w1_master *dev = sl->master;
166	u8 rom[9], crc, verdict;
167	int i, max_trying = 10;
168
169	mutex_lock(&sl->master->mutex);
170
171	if (off > W1_SLAVE_DATA_SIZE) {
172		count = 0;
173		goto out;
174	}
175	if (off + count > W1_SLAVE_DATA_SIZE) {
176		count = 0;
177		goto out;
178	}
179
180	memset(buf, 0, count);
181	memset(rom, 0, sizeof(rom));
182
183	count = 0;
184	verdict = 0;
185	crc = 0;
186
187	while (max_trying--) {
188		if (!w1_reset_select_slave(sl)) {
189			int count = 0;
190			unsigned int tm = 750;
191
192			w1_write_8(dev, W1_CONVERT_TEMP);
193
194			msleep(tm);
195
196			if (!w1_reset_select_slave(sl)) {
197
198				w1_write_8(dev, W1_READ_SCRATCHPAD);
199				if ((count = w1_read_block(dev, rom, 9)) != 9) {
200					dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
201				}
202
203				crc = w1_calc_crc8(rom, 8);
204
205				if (rom[8] == crc && rom[0])
206					verdict = 1;
207			}
208		}
209
210		if (!w1_therm_check_rom(rom))
211			break;
212	}
213
214	for (i = 0; i < 9; ++i)
215		count += sprintf(buf + count, "%02x ", rom[i]);
216	count += sprintf(buf + count, ": crc=%02x %s\n",
217			   crc, (verdict) ? "YES" : "NO");
218	if (verdict)
219		memcpy(sl->rom, rom, sizeof(sl->rom));
220	else
221		dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n");
222
223	for (i = 0; i < 9; ++i)
224		count += sprintf(buf + count, "%02x ", sl->rom[i]);
225
226	count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom, sl->family->fid));
227out:
228	mutex_unlock(&dev->mutex);
229
230	return count;
231}
232
233static int __init w1_therm_init(void)
234{
235	int err, i;
236
237	for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
238		err = w1_register_family(w1_therm_families[i].f);
239		if (err)
240			w1_therm_families[i].broken = 1;
241	}
242
243	return 0;
244}
245
246static void __exit w1_therm_fini(void)
247{
248	int i;
249
250	for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
251		if (!w1_therm_families[i].broken)
252			w1_unregister_family(w1_therm_families[i].f);
253}
254
255module_init(w1_therm_init);
256module_exit(w1_therm_fini);
257