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 *buf, size_t count, loff_t *ptr)
 217 {
 218         signed int cur_temp;
 219         signed char cur_temp_degF;
 220
 221         /* Can't seek (pread) on this device */
 222         if (ptr != &file->f_pos)
 223                 return -ESPIPE;
 224
 225         cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
 226
 227         /* convert to Fahrenheit, as per wdt.c */
 228         cur_temp_degF = (cur_temp * 9) / 5 + 32;
 229
 230         if (copy_to_user(buf, &cur_temp_degF, 1))
 231                 return -EFAULT;
 232
 233         return 1;
 234 }
 235
 236 static int
 237 ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 238 {
 239         struct therm therm;
 240         int i;
 241
 242         switch(cmd) {
 243         case CMD_SET_THERMOSTATE:
 244         case CMD_SET_THERMOSTATE2:
 245                 if (!capable(CAP_SYS_ADMIN))
 246                         return -EPERM;
 247
 248                 if (cmd == CMD_SET_THERMOSTATE) {
 249                         if (get_user(therm.hi, (int *)arg))
 250                                 return -EFAULT;
 251                         therm.lo = therm.hi - 3;
 252                 } else {
 253                         if (copy_from_user(&therm, (void *)arg, sizeof(therm)))
 254                                 return -EFAULT;
 255                 }
 256
 257                 therm.lo <<= 1;
 258                 therm.hi <<= 1;
 259
 260                 ds1620_write_state(&therm);
 261                 break;
 262
 263         case CMD_GET_THERMOSTATE:
 264         case CMD_GET_THERMOSTATE2:
 265                 ds1620_read_state(&therm);
 266
 267                 therm.lo >>= 1;
 268                 therm.hi >>= 1;
 269
 270                 if (cmd == CMD_GET_THERMOSTATE) {
 271                         if (put_user(therm.hi, (int *)arg))
 272                                 return -EFAULT;
 273                 } else {
 274                         if (copy_to_user((void *)arg, &therm, sizeof(therm)))
 275                                 return -EFAULT;
 276                 }
 277                 break;
 278
 279         case CMD_GET_TEMPERATURE:
 280         case CMD_GET_TEMPERATURE2:
 281                 i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
 282
 283                 if (cmd == CMD_GET_TEMPERATURE)
 284                         i >>= 1;
 285
 286                 return put_user(i, (int *)arg) ? -EFAULT : 0;
 287
 288         case CMD_GET_STATUS:
 289                 i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
 290
 291                 return put_user(i, (int *)arg) ? -EFAULT : 0;
 292
 293         case CMD_GET_FAN:
 294                 i = netwinder_get_fan();
 295
 296                 return put_user(i, (int *)arg) ? -EFAULT : 0;
 297
 298         case CMD_SET_FAN:
 299                 if (!capable(CAP_SYS_ADMIN))
 300                         return -EPERM;
 301
 302                 if (get_user(i, (int *)arg))
 303                         return -EFAULT;
 304
 305                 netwinder_set_fan(i);
 306                 break;
 307
 308         default:
 309                 return -ENOIOCTLCMD;
 310         }
 311
 312         return 0;
 313 }
 314
 315 #ifdef THERM_USE_PROC
 316 static int
 317 proc_therm_ds1620_read(char *buf, char **start, off_t offset,
 318                        int len, int *eof, void *unused)
 319 {
 320         struct therm th;
 321         int temp;
 322
 323         ds1620_read_state(&th);
 324         temp =  cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
 325
 326         len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
 327                       "temperature: %i.%i C, fan %s\n",
 328                       th.hi >> 1, th.hi & 1 ? 5 : 0,
 329                       th.lo >> 1, th.lo & 1 ? 5 : 0,
 330                       temp  >> 1, temp  & 1 ? 5 : 0,
 331                       fan_state[netwinder_get_fan()]);
 332
 333         return len;
 334 }
 335
 336 static struct proc_dir_entry *proc_therm_ds1620;
 337 #endif
 338
 339 static struct file_operations ds1620_fops = {
 340         .owner          = THIS_MODULE,
 341         .read           = ds1620_read,
 342         .ioctl          = ds1620_ioctl,
 343 };
 344
 345 static struct miscdevice ds1620_miscdev = {
 346         TEMP_MINOR,
 347         "temp",
 348         &ds1620_fops
 349 };
 350
 351 static int __init ds1620_init(void)
 352 {
 353         int ret;
 354         struct therm th, th_start;
 355
 356         if (!machine_is_netwinder())
 357                 return -ENODEV;
 358
 359         ds1620_out(THERM_RESET, 0, 0);
 360         ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
 361         ds1620_out(THERM_START_CONVERT, 0, 0);
 362
 363         /*
 364          * Trigger the fan to start by setting
 365          * temperature high point low.  This kicks
 366          * the fan into action.
 367          */
 368         ds1620_read_state(&th);
 369         th_start.lo = 0;
 370         th_start.hi = 1;
 371         ds1620_write_state(&th_start);
 372
 373         set_current_state(TASK_INTERRUPTIBLE);
 374         schedule_timeout(2*HZ);
 375
 376         ds1620_write_state(&th);
 377
 378         ret = misc_register(&ds1620_miscdev);
 379         if (ret < 0)
 380                 return ret;
 381
 382 #ifdef THERM_USE_PROC
 383         proc_therm_ds1620 = create_proc_entry("therm", 0, 0);
 384         if (proc_therm_ds1620)
 385                 proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
 386         else
 387                 printk(KERN_ERR "therm: unable to register /proc/therm\n");
 388 #endif
 389
 390         ds1620_read_state(&th);
 391         ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
 392
 393         printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
 394                "current %i.%i C, fan %s.\n",
 395                th.hi >> 1, th.hi & 1 ? 5 : 0,
 396                th.lo >> 1, th.lo & 1 ? 5 : 0,
 397                ret   >> 1, ret   & 1 ? 5 : 0,
 398                fan_state[netwinder_get_fan()]);
 399
 400         return 0;
 401 }
 402
 403 static void __exit ds1620_exit(void)
 404 {
 405 #ifdef THERM_USE_PROC
 406         remove_proc_entry("therm", NULL);
 407 #endif
 408         misc_deregister(&ds1620_miscdev);
 409 }
 410
 411 module_init(ds1620_init);
 412 module_exit(ds1620_exit);
 413
 414 MODULE_LICENSE("GPL");