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_temp(struct device *, struct device_attribute *attr, char *);
  47 static ssize_t w1_therm_read_bin(struct kobject *, char *, loff_t, size_t);
  48
  49 static struct w1_family_ops w1_therm_fops = {
  50         .rname = &w1_therm_read_name,
  51         .rbin = &w1_therm_read_bin,
  52         .rval = &w1_therm_read_temp,
  53         .rvalname = "temp1_input",
  54 };
  55
  56 static struct w1_family w1_therm_family_DS18S20 = {
  57         .fid = W1_THERM_DS18S20,
  58         .fops = &w1_therm_fops,
  59 };
  60
  61 static struct w1_family w1_therm_family_DS18B20 = {
  62         .fid = W1_THERM_DS18B20,
  63         .fops = &w1_therm_fops,
  64 };
  65 static struct w1_family w1_therm_family_DS1822 = {
  66         .fid = W1_THERM_DS1822,
  67         .fops = &w1_therm_fops,
  68 };
  69
  70 struct w1_therm_family_converter
  71 {
  72         u8                      fid;
  73         u8                      broken;
  74         u16                     reserved;
  75         struct w1_family        *f;
  76         int                     (*convert)(u8 rom[9]);
  77 };
  78
  79 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
  80 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
  81
  82 static struct w1_therm_family_converter w1_therm_families[] = {
  83         {
  84                 .fid            = W1_THERM_DS18S20,
  85                 .f              = &w1_therm_family_DS18S20,
  86                 .convert        = w1_DS18S20_convert_temp
  87         },
  88         {
  89                 .fid            = W1_THERM_DS1822,
  90                 .f              = &w1_therm_family_DS1822,
  91                 .convert        = w1_DS18B20_convert_temp
  92         },
  93         {
  94                 .fid            = W1_THERM_DS18B20,
  95                 .f              = &w1_therm_family_DS18B20,
  96                 .convert        = w1_DS18B20_convert_temp
  97         },
  98 };
  99
 100 static ssize_t w1_therm_read_name(struct device *dev, struct device_attribute *attr, char *buf)
 101 {
 102         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
 103
 104         return sprintf(buf, "%s\n", sl->name);
 105 }
 106
 107 static inline int w1_DS18B20_convert_temp(u8 rom[9])
 108 {
 109         int t = (rom[1] << 8) | rom[0];
 110         t /= 16;
 111         return t;
 112 }
 113
 114 static inline int w1_DS18S20_convert_temp(u8 rom[9])
 115 {
 116         int t, h;
 117
 118         if (!rom[7])
 119                 return 0;
 120
 121         if (rom[1] == 0)
 122                 t = ((s32)rom[0] >> 1)*1000;
 123         else
 124                 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
 125
 126         t -= 250;
 127         h = 1000*((s32)rom[7] - (s32)rom[6]);
 128         h /= (s32)rom[7];
 129         t += h;
 130
 131         return t;
 132 }
 133
 134 static inline int w1_convert_temp(u8 rom[9], u8 fid)
 135 {
 136         int i;
 137
 138         for (i=0; i<sizeof(w1_therm_families)/sizeof(w1_therm_families[0]); ++i)
 139                 if (w1_therm_families[i].fid == fid)
 140                         return w1_therm_families[i].convert(rom);
 141
 142         return 0;
 143 }
 144
 145 static ssize_t w1_therm_read_temp(struct device *dev, struct device_attribute *attr, char *buf)
 146 {
 147         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
 148
 149         return sprintf(buf, "%d\n", w1_convert_temp(sl->rom, sl->family->fid));
 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, char *buf, loff_t off, size_t count)
 164 {
 165         struct w1_slave *sl = container_of(container_of(kobj, struct device, kobj),
 166                                                 struct w1_slave, dev);
 167         struct w1_master *dev = sl->master;
 168         u8 rom[9], crc, verdict;
 169         int i, max_trying = 10;
 170
 171         atomic_inc(&sl->refcnt);
 172         smp_mb__after_atomic_inc();
 173         if (down_interruptible(&sl->master->mutex)) {
 174                 count = 0;
 175                 goto out_dec;
 176         }
 177
 178         if (off > W1_SLAVE_DATA_SIZE) {
 179                 count = 0;
 180                 goto out;
 181         }
 182         if (off + count > W1_SLAVE_DATA_SIZE) {
 183                 count = 0;
 184                 goto out;
 185         }
 186
 187         memset(buf, 0, count);
 188         memset(rom, 0, sizeof(rom));
 189
 190         count = 0;
 191         verdict = 0;
 192         crc = 0;
 193
 194         while (max_trying--) {
 195                 if (!w1_reset_bus (dev)) {
 196                         int count = 0;
 197                         u8 match[9] = {W1_MATCH_ROM, };
 198                         unsigned int tm = 750;
 199
 200                         memcpy(&match[1], (u64 *) & sl->reg_num, 8);
 201
 202                         w1_write_block(dev, match, 9);
 203
 204                         w1_write_8(dev, W1_CONVERT_TEMP);
 205
 206                         while (tm) {
 207                                 tm = msleep_interruptible(tm);
 208                                 if (signal_pending(current))
 209                                         flush_signals(current);
 210                         }
 211
 212                         if (!w1_reset_bus (dev)) {
 213                                 w1_write_block(dev, match, 9);
 214
 215                                 w1_write_8(dev, W1_READ_SCRATCHPAD);
 216                                 if ((count = w1_read_block(dev, rom, 9)) != 9) {
 217                                         dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
 218                                 }
 219
 220                                 crc = w1_calc_crc8(rom, 8);
 221
 222                                 if (rom[8] == crc && rom[0])
 223                                         verdict = 1;
 224
 225                         }
 226                 }
 227
 228                 if (!w1_therm_check_rom(rom))
 229                         break;
 230         }
 231
 232         for (i = 0; i < 9; ++i)
 233                 count += sprintf(buf + count, "%02x ", rom[i]);
 234         count += sprintf(buf + count, ": crc=%02x %s\n",
 235                            crc, (verdict) ? "YES" : "NO");
 236         if (verdict)
 237                 memcpy(sl->rom, rom, sizeof(sl->rom));
 238         else
 239                 dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n");
 240
 241         for (i = 0; i < 9; ++i)
 242                 count += sprintf(buf + count, "%02x ", sl->rom[i]);
 243
 244         count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom, sl->family->fid));
 245 out:
 246         up(&dev->mutex);
 247 out_dec:
 248         smp_mb__before_atomic_inc();
 249         atomic_dec(&sl->refcnt);
 250
 251         return count;
 252 }
 253
 254 static int __init w1_therm_init(void)
 255 {
 256         int err, i;
 257
 258         for (i=0; i<sizeof(w1_therm_families)/sizeof(w1_therm_families[0]); ++i) {
 259                 err = w1_register_family(w1_therm_families[i].f);
 260                 if (err)
 261                         w1_therm_families[i].broken = 1;
 262         }
 263
 264         return 0;
 265 }
 266
 267 static void __exit w1_therm_fini(void)
 268 {
 269         int i;
 270
 271         for (i=0; i<sizeof(w1_therm_families)/sizeof(w1_therm_families[0]); ++i)
 272                 if (!w1_therm_families[i].broken)
 273                         w1_unregister_family(w1_therm_families[i].f);
 274 }
 275
 276 module_init(w1_therm_init);
 277 module_exit(w1_therm_fini);