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/slab.h>
  31 #include <linux/delay.h>
  32
  33 #include "../w1.h"
  34 #include "../w1_int.h"
  35 #include "../w1_family.h"
  36
  37 MODULE_LICENSE("GPL");
  38 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>");
  39 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
  40 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18S20));
  41 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1822));
  42 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18B20));
  43 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1825));
  44 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS28EA00));
  45
  46 /* Allow the strong pullup to be disabled, but default to enabled.
  47  * If it was disabled a parasite powered device might not get the require
  48  * current to do a temperature conversion.  If it is enabled parasite powered
  49  * devices have a better chance of getting the current required.
  50  * In case the parasite power-detection is not working (seems to be the case
  51  * for some DS18S20) the strong pullup can also be forced, regardless of the
  52  * power state of the devices.
  53  *
  54  * Summary of options:
  55  * - strong_pullup = 0  Disable strong pullup completely
  56  * - strong_pullup = 1  Enable automatic strong pullup detection
  57  * - strong_pullup = 2  Force strong pullup
  58  */
  59 static int w1_strong_pullup = 1;
  60 module_param_named(strong_pullup, w1_strong_pullup, int, 0);
  61
  62 static int w1_therm_add_slave(struct w1_slave *sl)
  63 {
  64         sl->family_data = kzalloc(9, GFP_KERNEL);
  65         if (!sl->family_data)
  66                 return -ENOMEM;
  67         return 0;
  68 }
  69
  70 static void w1_therm_remove_slave(struct w1_slave *sl)
  71 {
  72         kfree(sl->family_data);
  73         sl->family_data = NULL;
  74 }
  75
  76 static ssize_t w1_slave_show(struct device *device,
  77         struct device_attribute *attr, char *buf);
  78
  79 static DEVICE_ATTR_RO(w1_slave);
  80
  81 static struct attribute *w1_therm_attrs[] = {
  82         &dev_attr_w1_slave.attr,
  83         NULL,
  84 };
  85 ATTRIBUTE_GROUPS(w1_therm);
  86
  87 static struct w1_family_ops w1_therm_fops = {
  88         .add_slave      = w1_therm_add_slave,
  89         .remove_slave   = w1_therm_remove_slave,
  90         .groups         = w1_therm_groups,
  91 };
  92
  93 static struct w1_family w1_therm_family_DS18S20 = {
  94         .fid = W1_THERM_DS18S20,
  95         .fops = &w1_therm_fops,
  96 };
  97
  98 static struct w1_family w1_therm_family_DS18B20 = {
  99         .fid = W1_THERM_DS18B20,
 100         .fops = &w1_therm_fops,
 101 };
 102
 103 static struct w1_family w1_therm_family_DS1822 = {
 104         .fid = W1_THERM_DS1822,
 105         .fops = &w1_therm_fops,
 106 };
 107
 108 static struct w1_family w1_therm_family_DS28EA00 = {
 109         .fid = W1_THERM_DS28EA00,
 110         .fops = &w1_therm_fops,
 111 };
 112
 113 static struct w1_family w1_therm_family_DS1825 = {
 114         .fid = W1_THERM_DS1825,
 115         .fops = &w1_therm_fops,
 116 };
 117
 118 struct w1_therm_family_converter
 119 {
 120         u8                      broken;
 121         u16                     reserved;
 122         struct w1_family        *f;
 123         int                     (*convert)(u8 rom[9]);
 124 };
 125
 126 /* The return value is millidegrees Centigrade. */
 127 static inline int w1_DS18B20_convert_temp(u8 rom[9]);
 128 static inline int w1_DS18S20_convert_temp(u8 rom[9]);
 129
 130 static struct w1_therm_family_converter w1_therm_families[] = {
 131         {
 132                 .f              = &w1_therm_family_DS18S20,
 133                 .convert        = w1_DS18S20_convert_temp
 134         },
 135         {
 136                 .f              = &w1_therm_family_DS1822,
 137                 .convert        = w1_DS18B20_convert_temp
 138         },
 139         {
 140                 .f              = &w1_therm_family_DS18B20,
 141                 .convert        = w1_DS18B20_convert_temp
 142         },
 143         {
 144                 .f              = &w1_therm_family_DS28EA00,
 145                 .convert        = w1_DS18B20_convert_temp
 146         },
 147         {
 148                 .f              = &w1_therm_family_DS1825,
 149                 .convert        = w1_DS18B20_convert_temp
 150         }
 151 };
 152
 153 static inline int w1_DS18B20_convert_temp(u8 rom[9])
 154 {
 155         s16 t = le16_to_cpup((__le16 *)rom);
 156         return t*1000/16;
 157 }
 158
 159 static inline int w1_DS18S20_convert_temp(u8 rom[9])
 160 {
 161         int t, h;
 162
 163         if (!rom[7])
 164                 return 0;
 165
 166         if (rom[1] == 0)
 167                 t = ((s32)rom[0] >> 1)*1000;
 168         else
 169                 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
 170
 171         t -= 250;
 172         h = 1000*((s32)rom[7] - (s32)rom[6]);
 173         h /= (s32)rom[7];
 174         t += h;
 175
 176         return t;
 177 }
 178
 179 static inline int w1_convert_temp(u8 rom[9], u8 fid)
 180 {
 181         int i;
 182
 183         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
 184                 if (w1_therm_families[i].f->fid == fid)
 185                         return w1_therm_families[i].convert(rom);
 186
 187         return 0;
 188 }
 189
 190
 191 static ssize_t w1_slave_show(struct device *device,
 192         struct device_attribute *attr, char *buf)
 193 {
 194         struct w1_slave *sl = dev_to_w1_slave(device);
 195         struct w1_master *dev = sl->master;
 196         u8 rom[9], crc, verdict, external_power;
 197         int i, max_trying = 10;
 198         ssize_t c = PAGE_SIZE;
 199
 200         i = mutex_lock_interruptible(&dev->bus_mutex);
 201         if (i != 0)
 202                 return i;
 203
 204         memset(rom, 0, sizeof(rom));
 205
 206         while (max_trying--) {
 207
 208                 verdict = 0;
 209                 crc = 0;
 210
 211                 if (!w1_reset_select_slave(sl)) {
 212                         int count = 0;
 213                         unsigned int tm = 750;
 214                         unsigned long sleep_rem;
 215
 216                         w1_write_8(dev, W1_READ_PSUPPLY);
 217                         external_power = w1_read_8(dev);
 218
 219                         if (w1_reset_select_slave(sl))
 220                                 continue;
 221
 222                         /* 750ms strong pullup (or delay) after the convert */
 223                         if (w1_strong_pullup == 2 ||
 224                                         (!external_power && w1_strong_pullup))
 225                                 w1_next_pullup(dev, tm);
 226
 227                         w1_write_8(dev, W1_CONVERT_TEMP);
 228
 229                         if (external_power) {
 230                                 mutex_unlock(&dev->bus_mutex);
 231
 232                                 sleep_rem = msleep_interruptible(tm);
 233                                 if (sleep_rem != 0)
 234                                         return -EINTR;
 235
 236                                 i = mutex_lock_interruptible(&dev->bus_mutex);
 237                                 if (i != 0)
 238                                         return i;
 239                         } else if (!w1_strong_pullup) {
 240                                 sleep_rem = msleep_interruptible(tm);
 241                                 if (sleep_rem != 0) {
 242                                         mutex_unlock(&dev->bus_mutex);
 243                                         return -EINTR;
 244                                 }
 245                         }
 246
 247                         if (!w1_reset_select_slave(sl)) {
 248
 249                                 w1_write_8(dev, W1_READ_SCRATCHPAD);
 250                                 if ((count = w1_read_block(dev, rom, 9)) != 9) {
 251                                         dev_warn(device, "w1_read_block() "
 252                                                 "returned %u instead of 9.\n",
 253                                                 count);
 254                                 }
 255
 256                                 crc = w1_calc_crc8(rom, 8);
 257
 258                                 if (rom[8] == crc)
 259                                         verdict = 1;
 260                         }
 261                 }
 262
 263                 if (verdict)
 264                         break;
 265         }
 266
 267         for (i = 0; i < 9; ++i)
 268                 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", rom[i]);
 269         c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n",
 270                            crc, (verdict) ? "YES" : "NO");
 271         if (verdict)
 272                 memcpy(sl->family_data, rom, sizeof(rom));
 273         else
 274                 dev_warn(device, "Read failed CRC check\n");
 275
 276         for (i = 0; i < 9; ++i)
 277                 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ",
 278                               ((u8 *)sl->family_data)[i]);
 279
 280         c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n",
 281                 w1_convert_temp(rom, sl->family->fid));
 282         mutex_unlock(&dev->bus_mutex);
 283
 284         return PAGE_SIZE - c;
 285 }
 286
 287 static int __init w1_therm_init(void)
 288 {
 289         int err, i;
 290
 291         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) {
 292                 err = w1_register_family(w1_therm_families[i].f);
 293                 if (err)
 294                         w1_therm_families[i].broken = 1;
 295         }
 296
 297         return 0;
 298 }
 299
 300 static void __exit w1_therm_fini(void)
 301 {
 302         int i;
 303
 304         for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i)
 305                 if (!w1_therm_families[i].broken)
 306                         w1_unregister_family(w1_therm_families[i].f);
 307 }
 308
 309 module_init(w1_therm_init);
 310 module_exit(w1_therm_fini);