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 static u8 bad_roms[][9] = { 49 {0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87}, 50 {} 51 }; 52 53 static ssize_t w1_therm_read(struct device *device, 54 struct device_attribute *attr, char *buf); 55 56 static struct device_attribute w1_therm_attr = 57 __ATTR(w1_slave, S_IRUGO, w1_therm_read, NULL); 58 59 static int w1_therm_add_slave(struct w1_slave *sl) 60 { 61 return device_create_file(&sl->dev, &w1_therm_attr); 62 } 63 64 static void w1_therm_remove_slave(struct w1_slave *sl) 65 { 66 device_remove_file(&sl->dev, &w1_therm_attr); 67 } 68 69 static struct w1_family_ops w1_therm_fops = { 70 .add_slave = w1_therm_add_slave, 71 .remove_slave = w1_therm_remove_slave, 72 }; 73 74 static struct w1_family w1_therm_family_DS18S20 = { 75 .fid = W1_THERM_DS18S20, 76 .fops = &w1_therm_fops, 77 }; 78 79 static struct w1_family w1_therm_family_DS18B20 = { 80 .fid = W1_THERM_DS18B20, 81 .fops = &w1_therm_fops, 82 }; 83 84 static struct w1_family w1_therm_family_DS1822 = { 85 .fid = W1_THERM_DS1822, 86 .fops = &w1_therm_fops, 87 }; 88 89 static struct w1_family w1_therm_family_DS28EA00 = { 90 .fid = W1_THERM_DS28EA00, 91 .fops = &w1_therm_fops, 92 }; 93 94 struct w1_therm_family_converter 95 { 96 u8 broken; 97 u16 reserved; 98 struct w1_family *f; 99 int (*convert)(u8 rom[9]); 100 }; 101 102 /* The return value is millidegrees Centigrade. */ 103 static inline int w1_DS18B20_convert_temp(u8 rom[9]); 104 static inline int w1_DS18S20_convert_temp(u8 rom[9]); 105 106 static struct w1_therm_family_converter w1_therm_families[] = { 107 { 108 .f = &w1_therm_family_DS18S20, 109 .convert = w1_DS18S20_convert_temp 110 }, 111 { 112 .f = &w1_therm_family_DS1822, 113 .convert = w1_DS18B20_convert_temp 114 }, 115 { 116 .f = &w1_therm_family_DS18B20, 117 .convert = w1_DS18B20_convert_temp 118 }, 119 { 120 .f = &w1_therm_family_DS28EA00, 121 .convert = w1_DS18B20_convert_temp 122 }, 123 }; 124 125 static inline int w1_DS18B20_convert_temp(u8 rom[9]) 126 { 127 s16 t = le16_to_cpup((__le16 *)rom); 128 return t*1000/16; 129 } 130 131 static inline int w1_DS18S20_convert_temp(u8 rom[9]) 132 { 133 int t, h; 134 135 if (!rom[7]) 136 return 0; 137 138 if (rom[1] == 0) 139 t = ((s32)rom[0] >> 1)*1000; 140 else 141 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1); 142 143 t -= 250; 144 h = 1000*((s32)rom[7] - (s32)rom[6]); 145 h /= (s32)rom[7]; 146 t += h; 147 148 return t; 149 } 150 151 static inline int w1_convert_temp(u8 rom[9], u8 fid) 152 { 153 int i; 154 155 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) 156 if (w1_therm_families[i].f->fid == fid) 157 return w1_therm_families[i].convert(rom); 158 159 return 0; 160 } 161 162 static int w1_therm_check_rom(u8 rom[9]) 163 { 164 int i; 165 166 for (i=0; i<sizeof(bad_roms)/9; ++i) 167 if (!memcmp(bad_roms[i], rom, 9)) 168 return 1; 169 170 return 0; 171 } 172 173 static ssize_t w1_therm_read(struct device *device, 174 struct device_attribute *attr, char *buf) 175 { 176 struct w1_slave *sl = dev_to_w1_slave(device); 177 struct w1_master *dev = sl->master; 178 u8 rom[9], crc, verdict, external_power; 179 int i, max_trying = 10; 180 ssize_t c = PAGE_SIZE; 181 182 i = mutex_lock_interruptible(&dev->mutex); 183 if (i != 0) 184 return i; 185 186 memset(rom, 0, sizeof(rom)); 187 188 verdict = 0; 189 crc = 0; 190 191 while (max_trying--) { 192 if (!w1_reset_select_slave(sl)) { 193 int count = 0; 194 unsigned int tm = 750; 195 unsigned long sleep_rem; 196 197 w1_write_8(dev, W1_READ_PSUPPLY); 198 external_power = w1_read_8(dev); 199 200 if (w1_reset_select_slave(sl)) 201 continue; 202 203 /* 750ms strong pullup (or delay) after the convert */ 204 if (!external_power && w1_strong_pullup) 205 w1_next_pullup(dev, tm); 206 207 w1_write_8(dev, W1_CONVERT_TEMP); 208 209 if (external_power) { 210 mutex_unlock(&dev->mutex); 211 212 sleep_rem = msleep_interruptible(tm); 213 if (sleep_rem != 0) 214 return -EINTR; 215 216 i = mutex_lock_interruptible(&dev->mutex); 217 if (i != 0) 218 return i; 219 } else if (!w1_strong_pullup) { 220 sleep_rem = msleep_interruptible(tm); 221 if (sleep_rem != 0) { 222 mutex_unlock(&dev->mutex); 223 return -EINTR; 224 } 225 } 226 227 if (!w1_reset_select_slave(sl)) { 228 229 w1_write_8(dev, W1_READ_SCRATCHPAD); 230 if ((count = w1_read_block(dev, rom, 9)) != 9) { 231 dev_warn(device, "w1_read_block() " 232 "returned %u instead of 9.\n", 233 count); 234 } 235 236 crc = w1_calc_crc8(rom, 8); 237 238 if (rom[8] == crc) 239 verdict = 1; 240 } 241 } 242 243 if (!w1_therm_check_rom(rom)) 244 break; 245 } 246 247 for (i = 0; i < 9; ++i) 248 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", rom[i]); 249 c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n", 250 crc, (verdict) ? "YES" : "NO"); 251 if (verdict) 252 memcpy(sl->rom, rom, sizeof(sl->rom)); 253 else 254 dev_warn(device, "18S20 doesn't respond to CONVERT_TEMP.\n"); 255 256 for (i = 0; i < 9; ++i) 257 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", sl->rom[i]); 258 259 c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n", 260 w1_convert_temp(rom, sl->family->fid)); 261 mutex_unlock(&dev->mutex); 262 263 return PAGE_SIZE - c; 264 } 265 266 static int __init w1_therm_init(void) 267 { 268 int err, i; 269 270 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) { 271 err = w1_register_family(w1_therm_families[i].f); 272 if (err) 273 w1_therm_families[i].broken = 1; 274 } 275 276 return 0; 277 } 278 279 static void __exit w1_therm_fini(void) 280 { 281 int i; 282 283 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) 284 if (!w1_therm_families[i].broken) 285 w1_unregister_family(w1_therm_families[i].f); 286 } 287 288 module_init(w1_therm_init); 289 module_exit(w1_therm_fini); 290