drivers/char/ds1620.c

   1 /*
   2  * linux/drivers/char/ds1620.c: Dallas Semiconductors DS1620
   3  *   thermometer driver (as used in the Rebel.com NetWinder)
   4  */
   5 #include <linux/config.h>
   6 #include <linux/module.h>
   7 #include <linux/sched.h>
   8 #include <linux/miscdevice.h>
   9 #include <linux/smp_lock.h>
  10 #include <linux/delay.h>
  11 #include <linux/proc_fs.h>
  12 #include <linux/capability.h>
  13 #include <linux/init.h>
  14
  15 #include <asm/hardware.h>
  16 #include <asm/mach-types.h>
  17 #include <asm/uaccess.h>
  18 #include <asm/therm.h>
  19
  20 #ifdef CONFIG_PROC_FS
  21 /* define for /proc interface */
  22 #define THERM_USE_PROC
  23 #endif
  24
  25 /* Definitions for DS1620 chip */
  26 #define THERM_START_CONVERT     0xee
  27 #define THERM_RESET             0xaf
  28 #define THERM_READ_CONFIG       0xac
  29 #define THERM_READ_TEMP         0xaa
  30 #define THERM_READ_TL           0xa2
  31 #define THERM_READ_TH           0xa1
  32 #define THERM_WRITE_CONFIG      0x0c
  33 #define THERM_WRITE_TL          0x02
  34 #define THERM_WRITE_TH          0x01
  35
  36 #define CFG_CPU                 2
  37 #define CFG_1SHOT               1
  38
  39 static const char *fan_state[] = { "off", "on", "on (hardwired)" };
  40
  41 /*
  42  * Start of NetWinder specifics
  43  *  Note!  We have to hold the gpio lock with IRQs disabled over the
  44  *  whole of our transaction to the Dallas chip, since there is a
  45  *  chance that the WaveArtist driver could touch these bits to
  46  *  enable or disable the speaker.
  47  */
  48 extern spinlock_t gpio_lock;
  49 extern unsigned int system_rev;
  50
  51 static inline void netwinder_ds1620_set_clk(int clk)
  52 {
  53         gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
  54 }
  55
  56 static inline void netwinder_ds1620_set_data(int dat)
  57 {
  58         gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
  59 }
  60
  61 static inline int netwinder_ds1620_get_data(void)
  62 {
  63         return gpio_read() & GPIO_DATA;
  64 }
  65
  66 static inline void netwinder_ds1620_set_data_dir(int dir)
  67 {
  68         gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
  69 }
  70
  71 static inline void netwinder_ds1620_reset(void)
  72 {
  73         cpld_modify(CPLD_DS_ENABLE, 0);
  74         cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
  75 }
  76
  77 static inline void netwinder_lock(unsigned long *flags)
  78 {
  79         spin_lock_irqsave(&gpio_lock, *flags);
  80 }
  81
  82 static inline void netwinder_unlock(unsigned long *flags)
  83 {
  84         spin_unlock_irqrestore(&gpio_lock, *flags);
  85 }
  86
  87 static inline void netwinder_set_fan(int i)
  88 {
  89         unsigned long flags;
  90
  91         spin_lock_irqsave(&gpio_lock, flags);
  92         gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
  93         spin_unlock_irqrestore(&gpio_lock, flags);
  94 }
  95
  96 static inline int netwinder_get_fan(void)
  97 {
  98         if ((system_rev & 0xf000) == 0x4000)
  99                 return FAN_ALWAYS_ON;
 100
 101         return (gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
 102 }
 103
 104 /*
 105  * End of NetWinder specifics
 106  */
 107
 108 static void ds1620_send_bits(int nr, int value)
 109 {
 110         int i;
 111
 112         for (i = 0; i < nr; i++) {
 113                 netwinder_ds1620_set_data(value & 1);
 114                 netwinder_ds1620_set_clk(0);
 115                 udelay(1);
 116                 netwinder_ds1620_set_clk(1);
 117                 udelay(1);
 118
 119                 value >>= 1;
 120         }
 121 }
 122
 123 static unsigned int ds1620_recv_bits(int nr)
 124 {
 125         unsigned int value = 0, mask = 1;
 126         int i;
 127
 128         netwinder_ds1620_set_data(0);
 129
 130         for (i = 0; i < nr; i++) {
 131                 netwinder_ds1620_set_clk(0);
 132                 udelay(1);
 133
 134                 if (netwinder_ds1620_get_data())
 135                         value |= mask;
 136
 137                 mask <<= 1;
 138
 139                 netwinder_ds1620_set_clk(1);
 140                 udelay(1);
 141         }
 142
 143         return value;
 144 }
 145
 146 static void ds1620_out(int cmd, int bits, int value)
 147 {
 148         unsigned long flags;
 149
 150         netwinder_lock(&flags);
 151         netwinder_ds1620_set_clk(1);
 152         netwinder_ds1620_set_data_dir(0);
 153         netwinder_ds1620_reset();
 154
 155         udelay(1);
 156
 157         ds1620_send_bits(8, cmd);
 158         if (bits)
 159                 ds1620_send_bits(bits, value);
 160
 161         udelay(1);
 162
 163         netwinder_ds1620_reset();
 164         netwinder_unlock(&flags);
 165
 166         set_current_state(TASK_INTERRUPTIBLE);
 167         schedule_timeout(2);
 168 }
 169
 170 static unsigned int ds1620_in(int cmd, int bits)
 171 {
 172         unsigned long flags;
 173         unsigned int value;
 174
 175         netwinder_lock(&flags);
 176         netwinder_ds1620_set_clk(1);
 177         netwinder_ds1620_set_data_dir(0);
 178         netwinder_ds1620_reset();
 179
 180         udelay(1);
 181
 182         ds1620_send_bits(8, cmd);
 183
 184         netwinder_ds1620_set_data_dir(1);
 185         value = ds1620_recv_bits(bits);
 186
 187         netwinder_ds1620_reset();
 188         netwinder_unlock(&flags);
 189
 190         return value;
 191 }
 192
 193 static int cvt_9_to_int(unsigned int val)
 194 {
 195         if (val & 0x100)
 196                 val |= 0xfffffe00;
 197
 198         return val;
 199 }
 200
 201 static void ds1620_write_state(struct therm *therm)
 202 {
 203         ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
 204         ds1620_out(THERM_WRITE_TL, 9, therm->lo);
 205         ds1620_out(THERM_WRITE_TH, 9, therm->hi);
 206         ds1620_out(THERM_START_CONVERT, 0, 0);
 207 }
 208
 209 static void ds1620_read_state(struct therm *therm)
 210 {
 211         therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));
 212         therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
 213 }
 214
 215 static ssize_t
 216 ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
 217 {
 218         signed int cur_temp;
 219         signed char cur_temp_degF;
 220
 221         cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
 222
 223         /* convert to Fahrenheit, as per wdt.c */
 224         cur_temp_degF = (cur_temp * 9) / 5 + 32;
 225
 226         if (copy_to_user(buf, &cur_temp_degF, 1))
 227                 return -EFAULT;
 228
 229         return 1;
 230 }
 231
 232 static int
 233 ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 234 {
 235         struct therm therm;
 236         union {
 237                 struct therm __user *therm;
 238                 int __user *i;
 239         } uarg;
 240         int i;
 241
 242         uarg.i = (int __user *)arg;
 243
 244         switch(cmd) {
 245         case CMD_SET_THERMOSTATE:
 246         case CMD_SET_THERMOSTATE2:
 247                 if (!capable(CAP_SYS_ADMIN))
 248                         return -EPERM;
 249
 250                 if (cmd == CMD_SET_THERMOSTATE) {
 251                         if (get_user(therm.hi, uarg.i))
 252                                 return -EFAULT;
 253                         therm.lo = therm.hi - 3;
 254                 } else {
 255                         if (copy_from_user(&therm, uarg.therm, sizeof(therm)))
 256                                 return -EFAULT;
 257                 }
 258
 259                 therm.lo <<= 1;
 260                 therm.hi <<= 1;
 261
 262                 ds1620_write_state(&therm);
 263                 break;
 264
 265         case CMD_GET_THERMOSTATE:
 266         case CMD_GET_THERMOSTATE2:
 267                 ds1620_read_state(&therm);
 268
 269                 therm.lo >>= 1;
 270                 therm.hi >>= 1;
 271
 272                 if (cmd == CMD_GET_THERMOSTATE) {
 273                         if (put_user(therm.hi, uarg.i))
 274                                 return -EFAULT;
 275                 } else {
 276                         if (copy_to_user(uarg.therm, &therm, sizeof(therm)))
 277                                 return -EFAULT;
 278                 }
 279                 break;
 280
 281         case CMD_GET_TEMPERATURE:
 282         case CMD_GET_TEMPERATURE2:
 283                 i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
 284
 285                 if (cmd == CMD_GET_TEMPERATURE)
 286                         i >>= 1;
 287
 288                 return put_user(i, uarg.i) ? -EFAULT : 0;
 289
 290         case CMD_GET_STATUS:
 291                 i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
 292
 293                 return put_user(i, uarg.i) ? -EFAULT : 0;
 294
 295         case CMD_GET_FAN:
 296                 i = netwinder_get_fan();
 297
 298                 return put_user(i, uarg.i) ? -EFAULT : 0;
 299
 300         case CMD_SET_FAN:
 301                 if (!capable(CAP_SYS_ADMIN))
 302                         return -EPERM;
 303
 304                 if (get_user(i, uarg.i))
 305                         return -EFAULT;
 306
 307                 netwinder_set_fan(i);
 308                 break;
 309
 310         default:
 311                 return -ENOIOCTLCMD;
 312         }
 313
 314         return 0;
 315 }
 316
 317 #ifdef THERM_USE_PROC
 318 static int
 319 proc_therm_ds1620_read(char *buf, char **start, off_t offset,
 320                        int len, int *eof, void *unused)
 321 {
 322         struct therm th;
 323         int temp;
 324
 325         ds1620_read_state(&th);
 326         temp =  cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
 327
 328         len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
 329                       "temperature: %i.%i C, fan %s\n",
 330                       th.hi >> 1, th.hi & 1 ? 5 : 0,
 331                       th.lo >> 1, th.lo & 1 ? 5 : 0,
 332                       temp  >> 1, temp  & 1 ? 5 : 0,
 333                       fan_state[netwinder_get_fan()]);
 334
 335         return len;
 336 }
 337
 338 static struct proc_dir_entry *proc_therm_ds1620;
 339 #endif
 340
 341 static struct file_operations ds1620_fops = {
 342         .owner          = THIS_MODULE,
 343         .open           = nonseekable_open,
 344         .read           = ds1620_read,
 345         .ioctl          = ds1620_ioctl,
 346 };
 347
 348 static struct miscdevice ds1620_miscdev = {
 349         TEMP_MINOR,
 350         "temp",
 351         &ds1620_fops
 352 };
 353
 354 static int __init ds1620_init(void)
 355 {
 356         int ret;
 357         struct therm th, th_start;
 358
 359         if (!machine_is_netwinder())
 360                 return -ENODEV;
 361
 362         ds1620_out(THERM_RESET, 0, 0);
 363         ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
 364         ds1620_out(THERM_START_CONVERT, 0, 0);
 365
 366         /*
 367          * Trigger the fan to start by setting
 368          * temperature high point low.  This kicks
 369          * the fan into action.
 370          */
 371         ds1620_read_state(&th);
 372         th_start.lo = 0;
 373         th_start.hi = 1;
 374         ds1620_write_state(&th_start);
 375
 376         set_current_state(TASK_INTERRUPTIBLE);
 377         schedule_timeout(2*HZ);
 378
 379         ds1620_write_state(&th);
 380
 381         ret = misc_register(&ds1620_miscdev);
 382         if (ret < 0)
 383                 return ret;
 384
 385 #ifdef THERM_USE_PROC
 386         proc_therm_ds1620 = create_proc_entry("therm", 0, NULL);
 387         if (proc_therm_ds1620)
 388                 proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
 389         else
 390                 printk(KERN_ERR "therm: unable to register /proc/therm\n");
 391 #endif
 392
 393         ds1620_read_state(&th);
 394         ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
 395
 396         printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
 397                "current %i.%i C, fan %s.\n",
 398                th.hi >> 1, th.hi & 1 ? 5 : 0,
 399                th.lo >> 1, th.lo & 1 ? 5 : 0,
 400                ret   >> 1, ret   & 1 ? 5 : 0,
 401                fan_state[netwinder_get_fan()]);
 402
 403         return 0;
 404 }
 405
 406 static void __exit ds1620_exit(void)
 407 {
 408 #ifdef THERM_USE_PROC
 409         remove_proc_entry("therm", NULL);
 410 #endif
 411         misc_deregister(&ds1620_miscdev);
 412 }
 413
 414 module_init(ds1620_init);
 415 module_exit(ds1620_exit);
 416
 417 MODULE_LICENSE("GPL");