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/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 <johnpol@2ka.mipt.ru>"); 38 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family."); 39 40 static u8 bad_roms[][9] = { 41 {0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87}, 42 {} 43 }; 44 45 static ssize_t w1_therm_read_bin(struct kobject *, struct bin_attribute *, 46 char *, loff_t, size_t); 47 48 static struct bin_attribute w1_therm_bin_attr = { 49 .attr = { 50 .name = "w1_slave", 51 .mode = S_IRUGO, 52 }, 53 .size = W1_SLAVE_DATA_SIZE, 54 .read = w1_therm_read_bin, 55 }; 56 57 static int w1_therm_add_slave(struct w1_slave *sl) 58 { 59 return sysfs_create_bin_file(&sl->dev.kobj, &w1_therm_bin_attr); 60 } 61 62 static void w1_therm_remove_slave(struct w1_slave *sl) 63 { 64 sysfs_remove_bin_file(&sl->dev.kobj, &w1_therm_bin_attr); 65 } 66 67 static struct w1_family_ops w1_therm_fops = { 68 .add_slave = w1_therm_add_slave, 69 .remove_slave = w1_therm_remove_slave, 70 }; 71 72 static struct w1_family w1_therm_family_DS18S20 = { 73 .fid = W1_THERM_DS18S20, 74 .fops = &w1_therm_fops, 75 }; 76 77 static struct w1_family w1_therm_family_DS18B20 = { 78 .fid = W1_THERM_DS18B20, 79 .fops = &w1_therm_fops, 80 }; 81 82 static struct w1_family w1_therm_family_DS1822 = { 83 .fid = W1_THERM_DS1822, 84 .fops = &w1_therm_fops, 85 }; 86 87 struct w1_therm_family_converter 88 { 89 u8 broken; 90 u16 reserved; 91 struct w1_family *f; 92 int (*convert)(u8 rom[9]); 93 }; 94 95 static inline int w1_DS18B20_convert_temp(u8 rom[9]); 96 static inline int w1_DS18S20_convert_temp(u8 rom[9]); 97 98 static struct w1_therm_family_converter w1_therm_families[] = { 99 { 100 .f = &w1_therm_family_DS18S20, 101 .convert = w1_DS18S20_convert_temp 102 }, 103 { 104 .f = &w1_therm_family_DS1822, 105 .convert = w1_DS18B20_convert_temp 106 }, 107 { 108 .f = &w1_therm_family_DS18B20, 109 .convert = w1_DS18B20_convert_temp 110 }, 111 }; 112 113 static inline int w1_DS18B20_convert_temp(u8 rom[9]) 114 { 115 s16 t = (rom[1] << 8) | rom[0]; 116 t /= 16; 117 return t; 118 } 119 120 static inline int w1_DS18S20_convert_temp(u8 rom[9]) 121 { 122 int t, h; 123 124 if (!rom[7]) 125 return 0; 126 127 if (rom[1] == 0) 128 t = ((s32)rom[0] >> 1)*1000; 129 else 130 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1); 131 132 t -= 250; 133 h = 1000*((s32)rom[7] - (s32)rom[6]); 134 h /= (s32)rom[7]; 135 t += h; 136 137 return t; 138 } 139 140 static inline int w1_convert_temp(u8 rom[9], u8 fid) 141 { 142 int i; 143 144 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) 145 if (w1_therm_families[i].f->fid == fid) 146 return w1_therm_families[i].convert(rom); 147 148 return 0; 149 } 150 151 static int w1_therm_check_rom(u8 rom[9]) 152 { 153 int i; 154 155 for (i=0; i<sizeof(bad_roms)/9; ++i) 156 if (!memcmp(bad_roms[i], rom, 9)) 157 return 1; 158 159 return 0; 160 } 161 162 static ssize_t w1_therm_read_bin(struct kobject *kobj, 163 struct bin_attribute *bin_attr, 164 char *buf, loff_t off, size_t count) 165 { 166 struct w1_slave *sl = kobj_to_w1_slave(kobj); 167 struct w1_master *dev = sl->master; 168 u8 rom[9], crc, verdict; 169 int i, max_trying = 10; 170 171 mutex_lock(&sl->master->mutex); 172 173 if (off > W1_SLAVE_DATA_SIZE) { 174 count = 0; 175 goto out; 176 } 177 if (off + count > W1_SLAVE_DATA_SIZE) { 178 count = 0; 179 goto out; 180 } 181 182 memset(buf, 0, count); 183 memset(rom, 0, sizeof(rom)); 184 185 count = 0; 186 verdict = 0; 187 crc = 0; 188 189 while (max_trying--) { 190 if (!w1_reset_select_slave(sl)) { 191 int count = 0; 192 unsigned int tm = 750; 193 194 w1_write_8(dev, W1_CONVERT_TEMP); 195 196 msleep(tm); 197 198 if (!w1_reset_select_slave(sl)) { 199 200 w1_write_8(dev, W1_READ_SCRATCHPAD); 201 if ((count = w1_read_block(dev, rom, 9)) != 9) { 202 dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count); 203 } 204 205 crc = w1_calc_crc8(rom, 8); 206 207 if (rom[8] == crc) 208 verdict = 1; 209 } 210 } 211 212 if (!w1_therm_check_rom(rom)) 213 break; 214 } 215 216 for (i = 0; i < 9; ++i) 217 count += sprintf(buf + count, "%02x ", rom[i]); 218 count += sprintf(buf + count, ": crc=%02x %s\n", 219 crc, (verdict) ? "YES" : "NO"); 220 if (verdict) 221 memcpy(sl->rom, rom, sizeof(sl->rom)); 222 else 223 dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n"); 224 225 for (i = 0; i < 9; ++i) 226 count += sprintf(buf + count, "%02x ", sl->rom[i]); 227 228 count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom, sl->family->fid)); 229 out: 230 mutex_unlock(&dev->mutex); 231 232 return count; 233 } 234 235 static int __init w1_therm_init(void) 236 { 237 int err, i; 238 239 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) { 240 err = w1_register_family(w1_therm_families[i].f); 241 if (err) 242 w1_therm_families[i].broken = 1; 243 } 244 245 return 0; 246 } 247 248 static void __exit w1_therm_fini(void) 249 { 250 int i; 251 252 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) 253 if (!w1_therm_families[i].broken) 254 w1_unregister_family(w1_therm_families[i].f); 255 } 256 257 module_init(w1_therm_init); 258 module_exit(w1_therm_fini); 259