drivers/w1/w1_therm.c

   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/device.h>
  28 #include <linux/types.h>
  29 #include <linux/delay.h>
  30
  31 #include "w1.h"
  32 #include "w1_io.h"
  33 #include "w1_int.h"
  34 #include "w1_family.h"
  35
  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.");
  39
  40 static u8 bad_roms[][9] = {
  41                                 {0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87},
  42                                 {}
  43                         };
  44
  45 static ssize_t w1_therm_read_name(struct device *, struct device_attribute *attr, char *);
  46 static ssize_t w1_therm_read_bin(struct kobject *, char *, loff_t, size_t);
  47
  48 static struct w1_family_ops w1_therm_fops = {
  49         .rname = &w1_therm_read_name,
  50         .rbin = &w1_therm_read_bin,
  51 };
  52
  53 static struct w1_family w1_therm_family_DS18S20 = {
  54         .fid = W1_THERM_DS18S20,
  55         .fops = &w1_therm_fops,
  56 };
  57
  58 static struct w1_family w1_therm_family_DS18B20 = {
  59         .fid = W1_THERM_DS18B20,
  60         .fops = &w1_therm_fops,
  61 };
  62 static struct w1_family w1_therm_family_DS1822 = {
  63         .fid = W1_THERM_DS1822,
  64         .fops = &w1_therm_fops,
  65 };
  66
  67 struct w1_therm_family_converter
  68 {
  69         u8                      fid;
  70         u8                      broken;
  71         u16                     reserved;
  72         struct w1_family        *f;
  73         int                     (*convert)(u8 rom[9]);
  74 };
  75
  76 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
  77 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
  78
  79 static struct w1_therm_family_converter w1_therm_families[] = {
  80         {
  81                 .fid            = W1_THERM_DS18S20,
  82                 .f              = &w1_therm_family_DS18S20,
  83                 .convert        = w1_DS18S20_convert_temp
  84         },
  85         {
  86                 .fid            = W1_THERM_DS1822,
  87                 .f              = &w1_therm_family_DS1822,
  88                 .convert        = w1_DS18B20_convert_temp
  89         },
  90         {
  91                 .fid            = W1_THERM_DS18B20,
  92                 .f              = &w1_therm_family_DS18B20,
  93                 .convert        = w1_DS18B20_convert_temp
  94         },
  95 };
  96
  97 static ssize_t w1_therm_read_name(struct device *dev, struct device_attribute *attr, char *buf)
  98 {
  99         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
 100
 101         return sprintf(buf, "%s\n", sl->name);
 102 }
 103
 104 static inline int w1_DS18B20_convert_temp(u8 rom[9])
 105 {
 106         int t = (rom[1] << 8) | rom[0];
 107         t /= 16;
 108         return t;
 109 }
 110
 111 static inline int w1_DS18S20_convert_temp(u8 rom[9])
 112 {
 113         int t, h;
 114
 115         if (!rom[7])
 116                 return 0;
 117
 118         if (rom[1] == 0)
 119                 t = ((s32)rom[0] >> 1)*1000;
 120         else
 121                 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
 122
 123         t -= 250;
 124         h = 1000*((s32)rom[7] - (s32)rom[6]);
 125         h /= (s32)rom[7];
 126         t += h;
 127
 128         return t;
 129 }
 130
 131 static inline int w1_convert_temp(u8 rom[9], u8 fid)
 132 {
 133         int i;
 134
 135         for (i=0; i<sizeof(w1_therm_families)/sizeof(w1_therm_families[0]); ++i)
 136                 if (w1_therm_families[i].fid == fid)
 137                         return w1_therm_families[i].convert(rom);
 138
 139         return 0;
 140 }
 141
 142 static int w1_therm_check_rom(u8 rom[9])
 143 {
 144         int i;
 145
 146         for (i=0; i<sizeof(bad_roms)/9; ++i)
 147                 if (!memcmp(bad_roms[i], rom, 9))
 148                         return 1;
 149
 150         return 0;
 151 }
 152
 153 static ssize_t w1_therm_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count)
 154 {
 155         struct w1_slave *sl = container_of(container_of(kobj, struct device, kobj),
 156                                            struct w1_slave, dev);
 157         struct w1_master *dev = sl->master;
 158         u8 rom[9], crc, verdict;
 159         int i, max_trying = 10;
 160
 161         atomic_inc(&sl->refcnt);
 162         smp_mb__after_atomic_inc();
 163         if (down_interruptible(&sl->master->mutex)) {
 164                 count = 0;
 165                 goto out_dec;
 166         }
 167
 168         if (off > W1_SLAVE_DATA_SIZE) {
 169                 count = 0;
 170                 goto out;
 171         }
 172         if (off + count > W1_SLAVE_DATA_SIZE) {
 173                 count = 0;
 174                 goto out;
 175         }
 176
 177         memset(buf, 0, count);
 178         memset(rom, 0, sizeof(rom));
 179
 180         count = 0;
 181         verdict = 0;
 182         crc = 0;
 183
 184         while (max_trying--) {
 185                 if (!w1_reset_bus (dev)) {
 186                         int count = 0;
 187                         u8 match[9] = {W1_MATCH_ROM, };
 188                         unsigned int tm = 750;
 189
 190                         memcpy(&match[1], (u64 *) & sl->reg_num, 8);
 191
 192                         w1_write_block(dev, match, 9);
 193
 194                         w1_write_8(dev, W1_CONVERT_TEMP);
 195
 196                         while (tm) {
 197                                 tm = msleep_interruptible(tm);
 198                                 if (signal_pending(current))
 199                                         flush_signals(current);
 200                         }
 201
 202                         if (!w1_reset_bus (dev)) {
 203                                 w1_write_block(dev, match, 9);
 204
 205                                 w1_write_8(dev, W1_READ_SCRATCHPAD);
 206                                 if ((count = w1_read_block(dev, rom, 9)) != 9) {
 207                                         dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
 208                                 }
 209
 210                                 crc = w1_calc_crc8(rom, 8);
 211
 212                                 if (rom[8] == crc && rom[0])
 213                                         verdict = 1;
 214
 215                         }
 216                 }
 217
 218                 if (!w1_therm_check_rom(rom))
 219                         break;
 220         }
 221
 222         for (i = 0; i < 9; ++i)
 223                 count += sprintf(buf + count, "%02x ", rom[i]);
 224         count += sprintf(buf + count, ": crc=%02x %s\n",
 225                            crc, (verdict) ? "YES" : "NO");
 226         if (verdict)
 227                 memcpy(sl->rom, rom, sizeof(sl->rom));
 228         else
 229                 dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n");
 230
 231         for (i = 0; i < 9; ++i)
 232                 count += sprintf(buf + count, "%02x ", sl->rom[i]);
 233
 234         count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom, sl->family->fid));
 235 out:
 236         up(&dev->mutex);
 237 out_dec:
 238         smp_mb__before_atomic_inc();
 239         atomic_dec(&sl->refcnt);
 240
 241         return count;
 242 }
 243
 244 static int __init w1_therm_init(void)
 245 {
 246         int err, i;
 247
 248         for (i=0; i<sizeof(w1_therm_families)/sizeof(w1_therm_families[0]); ++i) {
 249                 err = w1_register_family(w1_therm_families[i].f);
 250                 if (err)
 251                         w1_therm_families[i].broken = 1;
 252         }
 253
 254         return 0;
 255 }
 256
 257 static void __exit w1_therm_fini(void)
 258 {
 259         int i;
 260
 261         for (i=0; i<sizeof(w1_therm_families)/sizeof(w1_therm_families[0]); ++i)
 262                 if (!w1_therm_families[i].broken)
 263                         w1_unregister_family(w1_therm_families[i].f);
 264 }
 265
 266 module_init(w1_therm_init);
 267 module_exit(w1_therm_fini);