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
  30 #include "w1.h"
  31 #include "w1_io.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_name(struct device *, char *);
  45 static ssize_t w1_therm_read_temp(struct device *, 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         .rval = &w1_therm_read_temp,
  52         .rvalname = "temp1_input",
  53 };
  54
  55 static ssize_t w1_therm_read_name(struct device *dev, char *buf)
  56 {
  57         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  58
  59         return sprintf(buf, "%s\n", sl->name);
  60 }
  61
  62 static ssize_t w1_therm_read_temp(struct device *dev, char *buf)
  63 {
  64         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  65         s16 temp;
  66
  67         /*
  68          * Must be more precise.
  69          */
  70         temp = 0;
  71         temp <<= sl->rom[1] / 2;
  72         temp |= sl->rom[0] / 2;
  73
  74         return sprintf(buf, "%d\n", temp * 1000);
  75 }
  76
  77 static int w1_therm_check_rom(u8 rom[9])
  78 {
  79         int i;
  80
  81         for (i=0; i<sizeof(bad_roms)/9; ++i)
  82                 if (!memcmp(bad_roms[i], rom, 9))
  83                         return 1;
  84
  85         return 0;
  86 }
  87
  88 static ssize_t w1_therm_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count)
  89 {
  90         struct w1_slave *sl = container_of(container_of(kobj, struct device, kobj),
  91                                                 struct w1_slave, dev);
  92         struct w1_master *dev = sl->master;
  93         u8 rom[9], crc, verdict;
  94         int i, max_trying = 10;
  95         u16 temp;
  96
  97         atomic_inc(&sl->refcnt);
  98         if (down_interruptible(&sl->master->mutex)) {
  99                 count = 0;
 100                 goto out_dec;
 101         }
 102
 103         if (off > W1_SLAVE_DATA_SIZE) {
 104                 count = 0;
 105                 goto out;
 106         }
 107         if (off + count > W1_SLAVE_DATA_SIZE) {
 108                 count = 0;
 109                 goto out;
 110         }
 111
 112         memset(buf, 0, count);
 113         memset(rom, 0, sizeof(rom));
 114
 115         count = 0;
 116         verdict = 0;
 117         crc = 0;
 118
 119         while (max_trying--) {
 120                 if (!w1_reset_bus (dev)) {
 121                         int count = 0;
 122                         u8 match[9] = {W1_MATCH_ROM, };
 123
 124                         memcpy(&match[1], (u64 *) & sl->reg_num, 8);
 125
 126                         w1_write_block(dev, match, 9);
 127
 128                         w1_write_8(dev, W1_CONVERT_TEMP);
 129
 130                         if (count < 10) {
 131                                 if (!w1_reset_bus(dev)) {
 132                                         w1_write_block(dev, match, 9);
 133
 134                                         w1_write_8(dev, W1_READ_SCRATCHPAD);
 135                                         if ((count = w1_read_block(dev, rom, 9)) != 9) {
 136                                                 dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
 137                                         }
 138
 139                                         crc = w1_calc_crc8(rom, 8);
 140
 141                                         if (rom[8] == crc && rom[0])
 142                                                 verdict = 1;
 143                                 }
 144                         }
 145                         else
 146                                 dev_warn(&dev->dev,
 147                                           "18S20 doesn't respond to CONVERT_TEMP.\n");
 148                 }
 149
 150                 if (!w1_therm_check_rom(rom))
 151                         break;
 152         }
 153
 154         for (i = 0; i < 9; ++i)
 155                 count += sprintf(buf + count, "%02x ", rom[i]);
 156         count += sprintf(buf + count, ": crc=%02x %s\n",
 157                            crc, (verdict) ? "YES" : "NO");
 158         if (verdict)
 159                 memcpy(sl->rom, rom, sizeof(sl->rom));
 160         for (i = 0; i < 9; ++i)
 161                 count += sprintf(buf + count, "%02x ", sl->rom[i]);
 162         temp = 0;
 163         temp <<= sl->rom[1] / 2;
 164         temp |= sl->rom[0] / 2;
 165         count += sprintf(buf + count, "t=%u\n", temp);
 166 out:
 167         up(&dev->mutex);
 168 out_dec:
 169         atomic_dec(&sl->refcnt);
 170
 171         return count;
 172 }
 173
 174 static struct w1_family w1_therm_family = {
 175         .fid = W1_FAMILY_THERM,
 176         .fops = &w1_therm_fops,
 177 };
 178
 179 static int __init w1_therm_init(void)
 180 {
 181         return w1_register_family(&w1_therm_family);
 182 }
 183
 184 static void __exit w1_therm_fini(void)
 185 {
 186         w1_unregister_family(&w1_therm_family);
 187 }
 188
 189 module_init(w1_therm_init);
 190 module_exit(w1_therm_fini);