Pileus Git - ~andy/linux/blob - drivers/w1/slaves/w1_therm.c

   1 /*
   2  *      w1_therm.c
   3  *
   4  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
   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/sched.h>
  28 #include <linux/device.h>
  29 #include <linux/types.h>
  30 #include <linux/delay.h>
  31
  32 #include "../w1.h"
  33 #include "../w1_int.h"
  34 #include "../w1_family.h"
  35
  36 MODULE_LICENSE("GPL");
  37 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
  38 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
  39
  40 /* Allow the strong pullup to be disabled, but default to enabled.
  41  * If it was disabled a parasite powered device might not get the require
  42  * current to do a temperature conversion.  If it is enabled parasite powered
  43  * devices have a better chance of getting the current required.
  44  */
  45 static int w1_strong_pullup = 1;
  46 module_param_named(strong_pullup, w1_strong_pullup, int, 0);
  47
  48
  49 static ssize_t w1_therm_read(struct device *device,
  50         struct device_attribute *attr, char *buf);
  51
  52 static struct device_attribute w1_therm_attr =
  53         __ATTR(w1_slave, S_IRUGO, w1_therm_read, NULL);
  54
  55 static int w1_therm_add_slave(struct w1_slave *sl)
  56 {
  57         return device_create_file(&sl->dev, &w1_therm_attr);
  58 }
  59
  60 static void w1_therm_remove_slave(struct w1_slave *sl)
  61 {
  62         device_remove_file(&sl->dev, &w1_therm_attr);
  63 }
  64
  65 static struct w1_family_ops w1_therm_fops = {
  66         .add_slave      = w1_therm_add_slave,
  67         .remove_slave   = w1_therm_remove_slave,
  68 };
  69
  70 static struct w1_family w1_therm_family_DS18S20 = {
  71         .fid = W1_THERM_DS18S20,
  72         .fops = &w1_therm_fops,
  73 };
  74
  75 static struct w1_family w1_therm_family_DS18B20 = {
  76         .fid = W1_THERM_DS18B20,
  77         .fops = &w1_therm_fops,
  78 };
  79
  80 static struct w1_family w1_therm_family_DS1822 = {
  81         .fid = W1_THERM_DS1822,
  82         .fops = &w1_therm_fops,
  83 };
  84
  85 static struct w1_family w1_therm_family_DS28EA00 = {
  86         .fid = W1_THERM_DS28EA00,
  87         .fops = &w1_therm_fops,
  88 };
  89
  90 static struct w1_family w1_therm_family_DS1825 = {
  91         .fid = W1_THERM_DS1825,
  92         .fops = &w1_therm_fops,
  93 };
  94
  95 struct w1_therm_family_converter
  96 {
  97         u8                      broken;
  98         u16                     reserved;
  99         struct w1_family        *f;
 100         int                     (*convert)(u8 rom[9]);
 101 };
 102
 103 /* The return value is millidegrees Centigrade. */
 104 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
 105 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
 106
 107 static struct w1_therm_family_converter w1_therm_families[] = {
 108         {
 109                 .f              = &w1_therm_family_DS18S20,
 110                 .convert        = w1_DS18S20_convert_temp
 111         },
 112         {
 113                 .f              = &w1_therm_family_DS1822,
 114                 .convert        = w1_DS18B20_convert_temp
 115         },
 116         {
 117                 .f              = &w1_therm_family_DS18B20,
 118                 .convert        = w1_DS18B20_convert_temp
 119         },
 120         {
 121                 .f              = &w1_therm_family_DS28EA00,
 122                 .convert        = w1_DS18B20_convert_temp
 123         },
 124         {
 125                 .f              = &w1_therm_family_DS1825,
 126                 .convert        = w1_DS18B20_convert_temp
 127         }
 128 };
 129
 130 static inline int w1_DS18B20_convert_temp(u8 rom[9])
 131 {
 132         s16 t = le16_to_cpup((__le16 *)rom);
 133         return t*1000/16;
 134 }
 135
 136 static inline int w1_DS18S20_convert_temp(u8 rom[9])
 137 {
 138         int t, h;
 139
 140         if (!rom[7])
 141                 return 0;
 142
 143         if (rom[1] == 0)
 144                 t = ((s32)rom[0] >> 1)*1000;
 145         else
 146                 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
 147
 148         t -= 250;
 149         h = 1000*((s32)rom[7] - (s32)rom[6]);
 150         h /= (s32)rom[7];
 151         t += h;
 152
 153         return t;
 154 }
 155
 156 static inline int w1_convert_temp(u8 rom[9], u8 fid)
 157 {
 158         int i;
 159
 160         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
 161                 if (w1_therm_families[i].f->fid == fid)
 162                         return w1_therm_families[i].convert(rom);
 163
 164         return 0;
 165 }
 166
 167
 168 static ssize_t w1_therm_read(struct device *device,
 169         struct device_attribute *attr, char *buf)
 170 {
 171         struct w1_slave *sl = dev_to_w1_slave(device);
 172         struct w1_master *dev = sl->master;
 173         u8 rom[9], crc, verdict, external_power;
 174         int i, max_trying = 10;
 175         ssize_t c = PAGE_SIZE;
 176
 177         i = mutex_lock_interruptible(&dev->bus_mutex);
 178         if (i != 0)
 179                 return i;
 180
 181         memset(rom, 0, sizeof(rom));
 182
 183         while (max_trying--) {
 184
 185                 verdict = 0;
 186                 crc = 0;
 187
 188                 if (!w1_reset_select_slave(sl)) {
 189                         int count = 0;
 190                         unsigned int tm = 750;
 191                         unsigned long sleep_rem;
 192
 193                         w1_write_8(dev, W1_READ_PSUPPLY);
 194                         external_power = w1_read_8(dev);
 195
 196                         if (w1_reset_select_slave(sl))
 197                                 continue;
 198
 199                         /* 750ms strong pullup (or delay) after the convert */
 200                         if (!external_power && w1_strong_pullup)
 201                                 w1_next_pullup(dev, tm);
 202
 203                         w1_write_8(dev, W1_CONVERT_TEMP);
 204
 205                         if (external_power) {
 206                                 mutex_unlock(&dev->bus_mutex);
 207
 208                                 sleep_rem = msleep_interruptible(tm);
 209                                 if (sleep_rem != 0)
 210                                         return -EINTR;
 211
 212                                 i = mutex_lock_interruptible(&dev->bus_mutex);
 213                                 if (i != 0)
 214                                         return i;
 215                         } else if (!w1_strong_pullup) {
 216                                 sleep_rem = msleep_interruptible(tm);
 217                                 if (sleep_rem != 0) {
 218                                         mutex_unlock(&dev->bus_mutex);
 219                                         return -EINTR;
 220                                 }
 221                         }
 222
 223                         if (!w1_reset_select_slave(sl)) {
 224
 225                                 w1_write_8(dev, W1_READ_SCRATCHPAD);
 226                                 if ((count = w1_read_block(dev, rom, 9)) != 9) {
 227                                         dev_warn(device, "w1_read_block() "
 228                                                 "returned %u instead of 9.\n",
 229                                                 count);
 230                                 }
 231
 232                                 crc = w1_calc_crc8(rom, 8);
 233
 234                                 if (rom[8] == crc)
 235                                         verdict = 1;
 236                         }
 237                 }
 238
 239                 if (verdict)
 240                         break;
 241         }
 242
 243         for (i = 0; i < 9; ++i)
 244                 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", rom[i]);
 245         c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
 246                            crc, (verdict) ? "YES" : "NO");
 247         if (verdict)
 248                 memcpy(sl->rom, rom, sizeof(sl->rom));
 249         else
 250                 dev_warn(device, "Read failed CRC check\n");
 251
 252         for (i = 0; i < 9; ++i)
 253                 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", sl->rom[i]);
 254
 255         c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
 256                 w1_convert_temp(rom, sl->family->fid));
 257         mutex_unlock(&dev->bus_mutex);
 258
 259         return PAGE_SIZE - c;
 260 }
 261
 262 static int __init w1_therm_init(void)
 263 {
 264         int err, i;
 265
 266         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
 267                 err = w1_register_family(w1_therm_families[i].f);
 268                 if (err)
 269                         w1_therm_families[i].broken = 1;
 270         }
 271
 272         return 0;
 273 }
 274
 275 static void __exit w1_therm_fini(void)
 276 {
 277         int i;
 278
 279         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
 280                 if (!w1_therm_families[i].broken)
 281                         w1_unregister_family(w1_therm_families[i].f);
 282 }
 283
 284 module_init(w1_therm_init);
 285 module_exit(w1_therm_fini);