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_bin(struct kobject *, char *, loff_t, size_t);
  46
  47 static 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
  57 static 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
  62 static void w1_therm_remove_slave(struct w1_slave *sl)
  63 {
  64         sysfs_remove_bin_file(&sl->dev.kobj, &w1_therm_bin_attr);
  65 }
  66
  67 static struct w1_family_ops w1_therm_fops = {
  68         .add_slave      = w1_therm_add_slave,
  69         .remove_slave   = w1_therm_remove_slave,
  70 };
  71
  72 static struct w1_family w1_therm_family_DS18S20 = {
  73         .fid = W1_THERM_DS18S20,
  74         .fops = &w1_therm_fops,
  75 };
  76
  77 static struct w1_family w1_therm_family_DS18B20 = {
  78         .fid = W1_THERM_DS18B20,
  79         .fops = &w1_therm_fops,
  80 };
  81
  82 static struct w1_family w1_therm_family_DS1822 = {
  83         .fid = W1_THERM_DS1822,
  84         .fops = &w1_therm_fops,
  85 };
  86
  87 struct w1_therm_family_converter
  88 {
  89         u8                      broken;
  90         u16                     reserved;
  91         struct w1_family        *f;
  92         int                     (*convert)(u8 rom[9]);
  93 };
  94
  95 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
  96 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
  97
  98 static 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
 113 static 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
 120 static 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
 140 static inline int w1_convert_temp(u8 rom[9], u8 fid)
 141 {
 142         int i;
 143
 144         for (i=0; i<sizeof(w1_therm_families)/sizeof(w1_therm_families[0]); ++i)
 145                 if (w1_therm_families[i].f->fid == fid)
 146                         return w1_therm_families[i].convert(rom);
 147
 148         return 0;
 149 }
 150
 151 static 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
 162 static 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         atomic_inc(&sl->refcnt);
 170         smp_mb__after_atomic_inc();
 171         if (down_interruptible(&sl->master->mutex)) {
 172                 count = 0;
 173                 goto out_dec;
 174         }
 175
 176         if (off > W1_SLAVE_DATA_SIZE) {
 177                 count = 0;
 178                 goto out;
 179         }
 180         if (off + count > W1_SLAVE_DATA_SIZE) {
 181                 count = 0;
 182                 goto out;
 183         }
 184
 185         memset(buf, 0, count);
 186         memset(rom, 0, sizeof(rom));
 187
 188         count = 0;
 189         verdict = 0;
 190         crc = 0;
 191
 192         while (max_trying--) {
 193                 if (!w1_reset_select_slave(sl)) {
 194                         int count = 0;
 195                         unsigned int tm = 750;
 196
 197                         w1_write_8(dev, W1_CONVERT_TEMP);
 198
 199                         while (tm) {
 200                                 tm = msleep_interruptible(tm);
 201                                 if (signal_pending(current))
 202                                         flush_signals(current);
 203                         }
 204
 205                         if (!w1_reset_select_slave(sl)) {
 206
 207                                 w1_write_8(dev, W1_READ_SCRATCHPAD);
 208                                 if ((count = w1_read_block(dev, rom, 9)) != 9) {
 209                                         dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
 210                                 }
 211
 212                                 crc = w1_calc_crc8(rom, 8);
 213
 214                                 if (rom[8] == crc && rom[0])
 215                                         verdict = 1;
 216                         }
 217                 }
 218
 219                 if (!w1_therm_check_rom(rom))
 220                         break;
 221         }
 222
 223         for (i = 0; i < 9; ++i)
 224                 count += sprintf(buf + count, "%02x ", rom[i]);
 225         count += sprintf(buf + count, ": crc=%02x %s\n",
 226                            crc, (verdict) ? "YES" : "NO");
 227         if (verdict)
 228                 memcpy(sl->rom, rom, sizeof(sl->rom));
 229         else
 230                 dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n");
 231
 232         for (i = 0; i < 9; ++i)
 233                 count += sprintf(buf + count, "%02x ", sl->rom[i]);
 234
 235         count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom, sl->family->fid));
 236 out:
 237         up(&dev->mutex);
 238 out_dec:
 239         smp_mb__before_atomic_inc();
 240         atomic_dec(&sl->refcnt);
 241
 242         return count;
 243 }
 244
 245 static int __init w1_therm_init(void)
 246 {
 247         int err, i;
 248
 249         for (i=0; i<sizeof(w1_therm_families)/sizeof(w1_therm_families[0]); ++i) {
 250                 err = w1_register_family(w1_therm_families[i].f);
 251                 if (err)
 252                         w1_therm_families[i].broken = 1;
 253         }
 254
 255         return 0;
 256 }
 257
 258 static void __exit w1_therm_fini(void)
 259 {
 260         int i;
 261
 262         for (i=0; i<sizeof(w1_therm_families)/sizeof(w1_therm_families[0]); ++i)
 263                 if (!w1_therm_families[i].broken)
 264                         w1_unregister_family(w1_therm_families[i].f);
 265 }
 266
 267 module_init(w1_therm_init);
 268 module_exit(w1_therm_fini);