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/device.h>
  28 #include <linux/types.h>
  29 #include <linux/delay.h>
  30
  31 #include "../w1.h"
  32 #include "../w1_int.h"
  33 #include "../w1_family.h"
  34
  35 MODULE_LICENSE("GPL");
  36 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
  37 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
  38
  39 static u8 bad_roms[][9] = {
  40                                 {0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87},
  41                                 {}
  42                         };
  43
  44 static ssize_t w1_therm_read_bin(struct kobject *, char *, loff_t, size_t);
  45
  46 static struct bin_attribute w1_therm_bin_attr = {
  47         .attr = {
  48                 .name = "w1_slave",
  49                 .mode = S_IRUGO,
  50                 .owner = THIS_MODULE,
  51         },
  52         .size = W1_SLAVE_DATA_SIZE,
  53         .read = w1_therm_read_bin,
  54 };
  55
  56 static int w1_therm_add_slave(struct w1_slave *sl)
  57 {
  58         return sysfs_create_bin_file(&sl->dev.kobj, &w1_therm_bin_attr);
  59 }
  60
  61 static void w1_therm_remove_slave(struct w1_slave *sl)
  62 {
  63         sysfs_remove_bin_file(&sl->dev.kobj, &w1_therm_bin_attr);
  64 }
  65
  66 static struct w1_family_ops w1_therm_fops = {
  67         .add_slave      = w1_therm_add_slave,
  68         .remove_slave   = w1_therm_remove_slave,
  69 };
  70
  71 static struct w1_family w1_therm_family_DS18S20 = {
  72         .fid = W1_THERM_DS18S20,
  73         .fops = &w1_therm_fops,
  74 };
  75
  76 static struct w1_family w1_therm_family_DS18B20 = {
  77         .fid = W1_THERM_DS18B20,
  78         .fops = &w1_therm_fops,
  79 };
  80
  81 static struct w1_family w1_therm_family_DS1822 = {
  82         .fid = W1_THERM_DS1822,
  83         .fops = &w1_therm_fops,
  84 };
  85
  86 struct w1_therm_family_converter
  87 {
  88         u8                      broken;
  89         u16                     reserved;
  90         struct w1_family        *f;
  91         int                     (*convert)(u8 rom[9]);
  92 };
  93
  94 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
  95 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
  96
  97 static struct w1_therm_family_converter w1_therm_families[] = {
  98         {
  99                 .f              = &w1_therm_family_DS18S20,
 100                 .convert        = w1_DS18S20_convert_temp
 101         },
 102         {
 103                 .f              = &w1_therm_family_DS1822,
 104                 .convert        = w1_DS18B20_convert_temp
 105         },
 106         {
 107                 .f              = &w1_therm_family_DS18B20,
 108                 .convert        = w1_DS18B20_convert_temp
 109         },
 110 };
 111
 112 static inline int w1_DS18B20_convert_temp(u8 rom[9])
 113 {
 114         int t = (rom[1] << 8) | rom[0];
 115         t /= 16;
 116         return t;
 117 }
 118
 119 static inline int w1_DS18S20_convert_temp(u8 rom[9])
 120 {
 121         int t, h;
 122
 123         if (!rom[7])
 124                 return 0;
 125
 126         if (rom[1] == 0)
 127                 t = ((s32)rom[0] >> 1)*1000;
 128         else
 129                 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
 130
 131         t -= 250;
 132         h = 1000*((s32)rom[7] - (s32)rom[6]);
 133         h /= (s32)rom[7];
 134         t += h;
 135
 136         return t;
 137 }
 138
 139 static inline int w1_convert_temp(u8 rom[9], u8 fid)
 140 {
 141         int i;
 142
 143         for (i=0; i<sizeof(w1_therm_families)/sizeof(w1_therm_families[0]); ++i)
 144                 if (w1_therm_families[i].f->fid == fid)
 145                         return w1_therm_families[i].convert(rom);
 146
 147         return 0;
 148 }
 149
 150 static int w1_therm_check_rom(u8 rom[9])
 151 {
 152         int i;
 153
 154         for (i=0; i<sizeof(bad_roms)/9; ++i)
 155                 if (!memcmp(bad_roms[i], rom, 9))
 156                         return 1;
 157
 158         return 0;
 159 }
 160
 161 static ssize_t w1_therm_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count)
 162 {
 163         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 164         struct w1_master *dev = sl->master;
 165         u8 rom[9], crc, verdict;
 166         int i, max_trying = 10;
 167
 168         atomic_inc(&sl->refcnt);
 169         smp_mb__after_atomic_inc();
 170         if (down_interruptible(&sl->master->mutex)) {
 171                 count = 0;
 172                 goto out_dec;
 173         }
 174
 175         if (off > W1_SLAVE_DATA_SIZE) {
 176                 count = 0;
 177                 goto out;
 178         }
 179         if (off + count > W1_SLAVE_DATA_SIZE) {
 180                 count = 0;
 181                 goto out;
 182         }
 183
 184         memset(buf, 0, count);
 185         memset(rom, 0, sizeof(rom));
 186
 187         count = 0;
 188         verdict = 0;
 189         crc = 0;
 190
 191         while (max_trying--) {
 192                 if (!w1_reset_select_slave(sl)) {
 193                         int count = 0;
 194                         unsigned int tm = 750;
 195
 196                         w1_write_8(dev, W1_CONVERT_TEMP);
 197
 198                         while (tm) {
 199                                 tm = msleep_interruptible(tm);
 200                                 if (signal_pending(current))
 201                                         flush_signals(current);
 202                         }
 203
 204                         if (!w1_reset_select_slave(sl)) {
 205
 206                                 w1_write_8(dev, W1_READ_SCRATCHPAD);
 207                                 if ((count = w1_read_block(dev, rom, 9)) != 9) {
 208                                         dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
 209                                 }
 210
 211                                 crc = w1_calc_crc8(rom, 8);
 212
 213                                 if (rom[8] == crc && rom[0])
 214                                         verdict = 1;
 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);