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                      broken;
  70         u16                     reserved;
  71         struct w1_family        *f;
  72         int                     (*convert)(u8 rom[9]);
  73 };
  74
  75 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
  76 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
  77
  78 static struct w1_therm_family_converter w1_therm_families[] = {
  79         {
  80                 .f              = &w1_therm_family_DS18S20,
  81                 .convert        = w1_DS18S20_convert_temp
  82         },
  83         {
  84                 .f              = &w1_therm_family_DS1822,
  85                 .convert        = w1_DS18B20_convert_temp
  86         },
  87         {
  88                 .f              = &w1_therm_family_DS18B20,
  89                 .convert        = w1_DS18B20_convert_temp
  90         },
  91 };
  92
  93 static ssize_t w1_therm_read_name(struct device *dev, struct device_attribute *attr, char *buf)
  94 {
  95         struct w1_slave *sl = dev_to_w1_slave(dev);
  96         return sprintf(buf, "%s\n", sl->name);
  97 }
  98
  99 static inline int w1_DS18B20_convert_temp(u8 rom[9])
 100 {
 101         int t = (rom[1] << 8) | rom[0];
 102         t /= 16;
 103         return t;
 104 }
 105
 106 static inline int w1_DS18S20_convert_temp(u8 rom[9])
 107 {
 108         int t, h;
 109
 110         if (!rom[7])
 111                 return 0;
 112
 113         if (rom[1] == 0)
 114                 t = ((s32)rom[0] >> 1)*1000;
 115         else
 116                 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
 117
 118         t -= 250;
 119         h = 1000*((s32)rom[7] - (s32)rom[6]);
 120         h /= (s32)rom[7];
 121         t += h;
 122
 123         return t;
 124 }
 125
 126 static inline int w1_convert_temp(u8 rom[9], u8 fid)
 127 {
 128         int i;
 129
 130         for (i=0; i<sizeof(w1_therm_families)/sizeof(w1_therm_families[0]); ++i)
 131                 if (w1_therm_families[i].f->fid == fid)
 132                         return w1_therm_families[i].convert(rom);
 133
 134         return 0;
 135 }
 136
 137 static int w1_therm_check_rom(u8 rom[9])
 138 {
 139         int i;
 140
 141         for (i=0; i<sizeof(bad_roms)/9; ++i)
 142                 if (!memcmp(bad_roms[i], rom, 9))
 143                         return 1;
 144
 145         return 0;
 146 }
 147
 148 static ssize_t w1_therm_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count)
 149 {
 150         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 151         struct w1_master *dev = sl->master;
 152         u8 rom[9], crc, verdict;
 153         int i, max_trying = 10;
 154
 155         atomic_inc(&sl->refcnt);
 156         smp_mb__after_atomic_inc();
 157         if (down_interruptible(&sl->master->mutex)) {
 158                 count = 0;
 159                 goto out_dec;
 160         }
 161
 162         if (off > W1_SLAVE_DATA_SIZE) {
 163                 count = 0;
 164                 goto out;
 165         }
 166         if (off + count > W1_SLAVE_DATA_SIZE) {
 167                 count = 0;
 168                 goto out;
 169         }
 170
 171         memset(buf, 0, count);
 172         memset(rom, 0, sizeof(rom));
 173
 174         count = 0;
 175         verdict = 0;
 176         crc = 0;
 177
 178         while (max_trying--) {
 179                 if (!w1_reset_select_slave(sl)) {
 180                         int count = 0;
 181                         unsigned int tm = 750;
 182
 183                         w1_write_8(dev, W1_CONVERT_TEMP);
 184
 185                         while (tm) {
 186                                 tm = msleep_interruptible(tm);
 187                                 if (signal_pending(current))
 188                                         flush_signals(current);
 189                         }
 190
 191                         if (!w1_reset_select_slave(sl)) {
 192
 193                                 w1_write_8(dev, W1_READ_SCRATCHPAD);
 194                                 if ((count = w1_read_block(dev, rom, 9)) != 9) {
 195                                         dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
 196                                 }
 197
 198                                 crc = w1_calc_crc8(rom, 8);
 199
 200                                 if (rom[8] == crc && rom[0])
 201                                         verdict = 1;
 202                         }
 203                 }
 204
 205                 if (!w1_therm_check_rom(rom))
 206                         break;
 207         }
 208
 209         for (i = 0; i < 9; ++i)
 210                 count += sprintf(buf + count, "%02x ", rom[i]);
 211         count += sprintf(buf + count, ": crc=%02x %s\n",
 212                            crc, (verdict) ? "YES" : "NO");
 213         if (verdict)
 214                 memcpy(sl->rom, rom, sizeof(sl->rom));
 215         else
 216                 dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n");
 217
 218         for (i = 0; i < 9; ++i)
 219                 count += sprintf(buf + count, "%02x ", sl->rom[i]);
 220
 221         count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom, sl->family->fid));
 222 out:
 223         up(&dev->mutex);
 224 out_dec:
 225         smp_mb__before_atomic_inc();
 226         atomic_dec(&sl->refcnt);
 227
 228         return count;
 229 }
 230
 231 static int __init w1_therm_init(void)
 232 {
 233         int err, i;
 234
 235         for (i=0; i<sizeof(w1_therm_families)/sizeof(w1_therm_families[0]); ++i) {
 236                 err = w1_register_family(w1_therm_families[i].f);
 237                 if (err)
 238                         w1_therm_families[i].broken = 1;
 239         }
 240
 241         return 0;
 242 }
 243
 244 static void __exit w1_therm_fini(void)
 245 {
 246         int i;
 247
 248         for (i=0; i<sizeof(w1_therm_families)/sizeof(w1_therm_families[0]); ++i)
 249                 if (!w1_therm_families[i].broken)
 250                         w1_unregister_family(w1_therm_families[i].f);
 251 }
 252
 253 module_init(w1_therm_init);
 254 module_exit(w1_therm_fini);