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 ssize_t w1_therm_read_name(struct device *, char *);
  40 static ssize_t w1_therm_read_temp(struct device *, char *);
  41 static ssize_t w1_therm_read_bin(struct kobject *, char *, loff_t, size_t);
  42
  43 static struct w1_family_ops w1_therm_fops = {
  44         .rname = &w1_therm_read_name,
  45         .rbin = &w1_therm_read_bin,
  46         .rval = &w1_therm_read_temp,
  47         .rvalname = "temp1_input",
  48 };
  49
  50 static ssize_t w1_therm_read_name(struct device *dev, char *buf)
  51 {
  52         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  53
  54         return sprintf(buf, "%s\n", sl->name);
  55 }
  56
  57 static ssize_t w1_therm_read_temp(struct device *dev, char *buf)
  58 {
  59         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  60         s16 temp;
  61
  62         /*
  63          * Must be more precise.
  64          */
  65         temp = 0;
  66         temp <<= sl->rom[1] / 2;
  67         temp |= sl->rom[0] / 2;
  68
  69         return sprintf(buf, "%d\n", temp * 1000);
  70 }
  71
  72 static ssize_t w1_therm_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count)
  73 {
  74         struct w1_slave *sl = container_of(container_of(kobj, struct device, kobj),
  75                                                 struct w1_slave, dev);
  76         struct w1_master *dev = sl->master;
  77         u8 rom[9], crc, verdict;
  78         size_t icount;
  79         int i;
  80         u16 temp;
  81
  82         atomic_inc(&sl->refcnt);
  83         if (down_interruptible(&sl->master->mutex)) {
  84                 count = 0;
  85                 goto out_dec;
  86         }
  87
  88         if (off > W1_SLAVE_DATA_SIZE) {
  89                 count = 0;
  90                 goto out;
  91         }
  92         if (off + count > W1_SLAVE_DATA_SIZE)
  93                 count = W1_SLAVE_DATA_SIZE - off;
  94
  95         icount = count;
  96
  97         memset(buf, 0, count);
  98         memset(rom, 0, sizeof(rom));
  99
 100         count = 0;
 101         verdict = 0;
 102         crc = 0;
 103         if (!w1_reset_bus(dev)) {
 104                 u64 id = *(u64 *) & sl->reg_num;
 105                 int count = 0;
 106
 107                 w1_write_8(dev, W1_MATCH_ROM);
 108                 for (i = 0; i < 8; ++i)
 109                         w1_write_8(dev, (id >> i * 8) & 0xff);
 110
 111                 w1_write_8(dev, W1_CONVERT_TEMP);
 112
 113                 while (dev->bus_master->read_bit(dev->bus_master->data) == 0
 114                        && count < 10) {
 115                         w1_delay(1);
 116                         count++;
 117                 }
 118
 119                 if (count < 10) {
 120                         if (!w1_reset_bus(dev)) {
 121                                 w1_write_8(dev, W1_MATCH_ROM);
 122                                 for (i = 0; i < 8; ++i)
 123                                         w1_write_8(dev,
 124                                                    (id >> i * 8) & 0xff);
 125
 126                                 w1_write_8(dev, W1_READ_SCRATCHPAD);
 127                                 for (i = 0; i < 9; ++i)
 128                                         rom[i] = w1_read_8(dev);
 129
 130                                 crc = w1_calc_crc8(rom, 8);
 131
 132                                 if (rom[8] == crc && rom[0])
 133                                         verdict = 1;
 134                         }
 135                 }
 136                 else
 137                         dev_warn(&dev->dev,
 138                                   "18S20 doesn't respond to CONVERT_TEMP.\n");
 139         }
 140
 141         for (i = 0; i < 9; ++i)
 142                 count += snprintf(buf + count, icount - count, "%02x ", rom[i]);
 143         count += snprintf(buf + count, icount - count, ": crc=%02x %s\n",
 144                            crc, (verdict) ? "YES" : "NO");
 145         if (verdict)
 146                 memcpy(sl->rom, rom, sizeof(sl->rom));
 147         for (i = 0; i < 9; ++i)
 148                 count += snprintf(buf + count, icount - count, "%02x ", sl->rom[i]);
 149         temp = 0;
 150         temp <<= sl->rom[1] / 2;
 151         temp |= sl->rom[0] / 2;
 152         count += snprintf(buf + count, icount - count, "t=%u\n", temp);
 153 out:
 154         up(&dev->mutex);
 155 out_dec:
 156         atomic_dec(&sl->refcnt);
 157
 158         return count;
 159 }
 160
 161 static struct w1_family w1_therm_family = {
 162         .fid = W1_FAMILY_THERM,
 163         .fops = &w1_therm_fops,
 164 };
 165
 166 static int __init w1_therm_init(void)
 167 {
 168         return w1_register_family(&w1_therm_family);
 169 }
 170
 171 static void __exit w1_therm_fini(void)
 172 {
 173         w1_unregister_family(&w1_therm_family);
 174 }
 175
 176 module_init(w1_therm_init);
 177 module_exit(w1_therm_fini);