drivers/w1/slaves/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/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
  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 *, struct bin_attribute *,
  46                                  char *, loff_t, size_t);
  47
  48 static struct bin_attribute w1_therm_bin_attr = {
  49         .attr = {
  50                 .name = "w1_slave",
  51                 .mode = S_IRUGO,
  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 /* The return value is millidegrees Centigrade. */
  96 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
  97 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
  98
  99 static struct w1_therm_family_converter w1_therm_families[] = {
 100         {
 101                 .f              = &w1_therm_family_DS18S20,
 102                 .convert        = w1_DS18S20_convert_temp
 103         },
 104         {
 105                 .f              = &w1_therm_family_DS1822,
 106                 .convert        = w1_DS18B20_convert_temp
 107         },
 108         {
 109                 .f              = &w1_therm_family_DS18B20,
 110                 .convert        = w1_DS18B20_convert_temp
 111         },
 112 };
 113
 114 static inline int w1_DS18B20_convert_temp(u8 rom[9])
 115 {
 116         s16 t = (rom[1] << 8) | rom[0];
 117         t = t*1000/16;
 118         return t;
 119 }
 120
 121 static inline int w1_DS18S20_convert_temp(u8 rom[9])
 122 {
 123         int t, h;
 124
 125         if (!rom[7])
 126                 return 0;
 127
 128         if (rom[1] == 0)
 129                 t = ((s32)rom[0] >> 1)*1000;
 130         else
 131                 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
 132
 133         t -= 250;
 134         h = 1000*((s32)rom[7] - (s32)rom[6]);
 135         h /= (s32)rom[7];
 136         t += h;
 137
 138         return t;
 139 }
 140
 141 static inline int w1_convert_temp(u8 rom[9], u8 fid)
 142 {
 143         int i;
 144
 145         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
 146                 if (w1_therm_families[i].f->fid == fid)
 147                         return w1_therm_families[i].convert(rom);
 148
 149         return 0;
 150 }
 151
 152 static int w1_therm_check_rom(u8 rom[9])
 153 {
 154         int i;
 155
 156         for (i=0; i<sizeof(bad_roms)/9; ++i)
 157                 if (!memcmp(bad_roms[i], rom, 9))
 158                         return 1;
 159
 160         return 0;
 161 }
 162
 163 static ssize_t w1_therm_read_bin(struct kobject *kobj,
 164                                  struct bin_attribute *bin_attr,
 165                                  char *buf, loff_t off, size_t count)
 166 {
 167         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 168         struct w1_master *dev = sl->master;
 169         u8 rom[9], crc, verdict;
 170         int i, max_trying = 10;
 171
 172         mutex_lock(&sl->master->mutex);
 173
 174         if (off > W1_SLAVE_DATA_SIZE) {
 175                 count = 0;
 176                 goto out;
 177         }
 178         if (off + count > W1_SLAVE_DATA_SIZE) {
 179                 count = 0;
 180                 goto out;
 181         }
 182
 183         memset(buf, 0, count);
 184         memset(rom, 0, sizeof(rom));
 185
 186         count = 0;
 187         verdict = 0;
 188         crc = 0;
 189
 190         while (max_trying--) {
 191                 if (!w1_reset_select_slave(sl)) {
 192                         int count = 0;
 193                         unsigned int tm = 750;
 194
 195                         w1_write_8(dev, W1_CONVERT_TEMP);
 196
 197                         msleep(tm);
 198
 199                         if (!w1_reset_select_slave(sl)) {
 200
 201                                 w1_write_8(dev, W1_READ_SCRATCHPAD);
 202                                 if ((count = w1_read_block(dev, rom, 9)) != 9) {
 203                                         dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
 204                                 }
 205
 206                                 crc = w1_calc_crc8(rom, 8);
 207
 208                                 if (rom[8] == crc)
 209                                         verdict = 1;
 210                         }
 211                 }
 212
 213                 if (!w1_therm_check_rom(rom))
 214                         break;
 215         }
 216
 217         for (i = 0; i < 9; ++i)
 218                 count += sprintf(buf + count, "%02x ", rom[i]);
 219         count += sprintf(buf + count, ": crc=%02x %s\n",
 220                            crc, (verdict) ? "YES" : "NO");
 221         if (verdict)
 222                 memcpy(sl->rom, rom, sizeof(sl->rom));
 223         else
 224                 dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n");
 225
 226         for (i = 0; i < 9; ++i)
 227                 count += sprintf(buf + count, "%02x ", sl->rom[i]);
 228
 229         count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom, sl->family->fid));
 230 out:
 231         mutex_unlock(&dev->mutex);
 232
 233         return count;
 234 }
 235
 236 static int __init w1_therm_init(void)
 237 {
 238         int err, i;
 239
 240         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
 241                 err = w1_register_family(w1_therm_families[i].f);
 242                 if (err)
 243                         w1_therm_families[i].broken = 1;
 244         }
 245
 246         return 0;
 247 }
 248
 249 static void __exit w1_therm_fini(void)
 250 {
 251         int i;
 252
 253         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
 254                 if (!w1_therm_families[i].broken)
 255                         w1_unregister_family(w1_therm_families[i].f);
 256 }
 257
 258 module_init(w1_therm_init);
 259 module_exit(w1_therm_fini);