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/module.h>
   6 #include <linux/miscdevice.h>
   7 #include <linux/delay.h>
   8 #include <linux/proc_fs.h>
   9 #include <linux/capability.h>
  10 #include <linux/init.h>
  11 #include <linux/smp_lock.h>
  12
  13 #include <asm/hardware.h>
  14 #include <asm/mach-types.h>
  15 #include <asm/uaccess.h>
  16 #include <asm/therm.h>
  17
  18 #ifdef CONFIG_PROC_FS
  19 /* define for /proc interface */
  20 #define THERM_USE_PROC
  21 #endif
  22
  23 /* Definitions for DS1620 chip */
  24 #define THERM_START_CONVERT     0xee
  25 #define THERM_RESET             0xaf
  26 #define THERM_READ_CONFIG       0xac
  27 #define THERM_READ_TEMP         0xaa
  28 #define THERM_READ_TL           0xa2
  29 #define THERM_READ_TH           0xa1
  30 #define THERM_WRITE_CONFIG      0x0c
  31 #define THERM_WRITE_TL          0x02
  32 #define THERM_WRITE_TH          0x01
  33
  34 #define CFG_CPU                 2
  35 #define CFG_1SHOT               1
  36
  37 static const char *fan_state[] = { "off", "on", "on (hardwired)" };
  38
  39 /*
  40  * Start of NetWinder specifics
  41  *  Note!  We have to hold the gpio lock with IRQs disabled over the
  42  *  whole of our transaction to the Dallas chip, since there is a
  43  *  chance that the WaveArtist driver could touch these bits to
  44  *  enable or disable the speaker.
  45  */
  46 extern spinlock_t gpio_lock;
  47 extern unsigned int system_rev;
  48
  49 static inline void netwinder_ds1620_set_clk(int clk)
  50 {
  51         gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
  52 }
  53
  54 static inline void netwinder_ds1620_set_data(int dat)
  55 {
  56         gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
  57 }
  58
  59 static inline int netwinder_ds1620_get_data(void)
  60 {
  61         return gpio_read() & GPIO_DATA;
  62 }
  63
  64 static inline void netwinder_ds1620_set_data_dir(int dir)
  65 {
  66         gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
  67 }
  68
  69 static inline void netwinder_ds1620_reset(void)
  70 {
  71         cpld_modify(CPLD_DS_ENABLE, 0);
  72         cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
  73 }
  74
  75 static inline void netwinder_lock(unsigned long *flags)
  76 {
  77         spin_lock_irqsave(&gpio_lock, *flags);
  78 }
  79
  80 static inline void netwinder_unlock(unsigned long *flags)
  81 {
  82         spin_unlock_irqrestore(&gpio_lock, *flags);
  83 }
  84
  85 static inline void netwinder_set_fan(int i)
  86 {
  87         unsigned long flags;
  88
  89         spin_lock_irqsave(&gpio_lock, flags);
  90         gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
  91         spin_unlock_irqrestore(&gpio_lock, flags);
  92 }
  93
  94 static inline int netwinder_get_fan(void)
  95 {
  96         if ((system_rev & 0xf000) == 0x4000)
  97                 return FAN_ALWAYS_ON;
  98
  99         return (gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF;
 100 }
 101
 102 /*
 103  * End of NetWinder specifics
 104  */
 105
 106 static void ds1620_send_bits(int nr, int value)
 107 {
 108         int i;
 109
 110         for (i = 0; i < nr; i++) {
 111                 netwinder_ds1620_set_data(value & 1);
 112                 netwinder_ds1620_set_clk(0);
 113                 udelay(1);
 114                 netwinder_ds1620_set_clk(1);
 115                 udelay(1);
 116
 117                 value >>= 1;
 118         }
 119 }
 120
 121 static unsigned int ds1620_recv_bits(int nr)
 122 {
 123         unsigned int value = 0, mask = 1;
 124         int i;
 125
 126         netwinder_ds1620_set_data(0);
 127
 128         for (i = 0; i < nr; i++) {
 129                 netwinder_ds1620_set_clk(0);
 130                 udelay(1);
 131
 132                 if (netwinder_ds1620_get_data())
 133                         value |= mask;
 134
 135                 mask <<= 1;
 136
 137                 netwinder_ds1620_set_clk(1);
 138                 udelay(1);
 139         }
 140
 141         return value;
 142 }
 143
 144 static void ds1620_out(int cmd, int bits, int value)
 145 {
 146         unsigned long flags;
 147
 148         netwinder_lock(&flags);
 149         netwinder_ds1620_set_clk(1);
 150         netwinder_ds1620_set_data_dir(0);
 151         netwinder_ds1620_reset();
 152
 153         udelay(1);
 154
 155         ds1620_send_bits(8, cmd);
 156         if (bits)
 157                 ds1620_send_bits(bits, value);
 158
 159         udelay(1);
 160
 161         netwinder_ds1620_reset();
 162         netwinder_unlock(&flags);
 163
 164         msleep(20);
 165 }
 166
 167 static unsigned int ds1620_in(int cmd, int bits)
 168 {
 169         unsigned long flags;
 170         unsigned int value;
 171
 172         netwinder_lock(&flags);
 173         netwinder_ds1620_set_clk(1);
 174         netwinder_ds1620_set_data_dir(0);
 175         netwinder_ds1620_reset();
 176
 177         udelay(1);
 178
 179         ds1620_send_bits(8, cmd);
 180
 181         netwinder_ds1620_set_data_dir(1);
 182         value = ds1620_recv_bits(bits);
 183
 184         netwinder_ds1620_reset();
 185         netwinder_unlock(&flags);
 186
 187         return value;
 188 }
 189
 190 static int cvt_9_to_int(unsigned int val)
 191 {
 192         if (val & 0x100)
 193                 val |= 0xfffffe00;
 194
 195         return val;
 196 }
 197
 198 static void ds1620_write_state(struct therm *therm)
 199 {
 200         ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
 201         ds1620_out(THERM_WRITE_TL, 9, therm->lo);
 202         ds1620_out(THERM_WRITE_TH, 9, therm->hi);
 203         ds1620_out(THERM_START_CONVERT, 0, 0);
 204 }
 205
 206 static void ds1620_read_state(struct therm *therm)
 207 {
 208         therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));
 209         therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
 210 }
 211
 212 static int ds1620_open(struct inode *inode, struct file *file)
 213 {
 214         cycle_kernel_lock();
 215         return nonseekable_open(inode, file);
 216 }
 217
 218 static ssize_t
 219 ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
 220 {
 221         signed int cur_temp;
 222         signed char cur_temp_degF;
 223
 224         cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
 225
 226         /* convert to Fahrenheit, as per wdt.c */
 227         cur_temp_degF = (cur_temp * 9) / 5 + 32;
 228
 229         if (copy_to_user(buf, &cur_temp_degF, 1))
 230                 return -EFAULT;
 231
 232         return 1;
 233 }
 234
 235 static int
 236 ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 237 {
 238         struct therm therm;
 239         union {
 240                 struct therm __user *therm;
 241                 int __user *i;
 242         } uarg;
 243         int i;
 244
 245         uarg.i = (int __user *)arg;
 246
 247         switch(cmd) {
 248         case CMD_SET_THERMOSTATE:
 249         case CMD_SET_THERMOSTATE2:
 250                 if (!capable(CAP_SYS_ADMIN))
 251                         return -EPERM;
 252
 253                 if (cmd == CMD_SET_THERMOSTATE) {
 254                         if (get_user(therm.hi, uarg.i))
 255                                 return -EFAULT;
 256                         therm.lo = therm.hi - 3;
 257                 } else {
 258                         if (copy_from_user(&therm, uarg.therm, sizeof(therm)))
 259                                 return -EFAULT;
 260                 }
 261
 262                 therm.lo <<= 1;
 263                 therm.hi <<= 1;
 264
 265                 ds1620_write_state(&therm);
 266                 break;
 267
 268         case CMD_GET_THERMOSTATE:
 269         case CMD_GET_THERMOSTATE2:
 270                 ds1620_read_state(&therm);
 271
 272                 therm.lo >>= 1;
 273                 therm.hi >>= 1;
 274
 275                 if (cmd == CMD_GET_THERMOSTATE) {
 276                         if (put_user(therm.hi, uarg.i))
 277                                 return -EFAULT;
 278                 } else {
 279                         if (copy_to_user(uarg.therm, &therm, sizeof(therm)))
 280                                 return -EFAULT;
 281                 }
 282                 break;
 283
 284         case CMD_GET_TEMPERATURE:
 285         case CMD_GET_TEMPERATURE2:
 286                 i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
 287
 288                 if (cmd == CMD_GET_TEMPERATURE)
 289                         i >>= 1;
 290
 291                 return put_user(i, uarg.i) ? -EFAULT : 0;
 292
 293         case CMD_GET_STATUS:
 294                 i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
 295
 296                 return put_user(i, uarg.i) ? -EFAULT : 0;
 297
 298         case CMD_GET_FAN:
 299                 i = netwinder_get_fan();
 300
 301                 return put_user(i, uarg.i) ? -EFAULT : 0;
 302
 303         case CMD_SET_FAN:
 304                 if (!capable(CAP_SYS_ADMIN))
 305                         return -EPERM;
 306
 307                 if (get_user(i, uarg.i))
 308                         return -EFAULT;
 309
 310                 netwinder_set_fan(i);
 311                 break;
 312
 313         default:
 314                 return -ENOIOCTLCMD;
 315         }
 316
 317         return 0;
 318 }
 319
 320 #ifdef THERM_USE_PROC
 321 static int
 322 proc_therm_ds1620_read(char *buf, char **start, off_t offset,
 323                        int len, int *eof, void *unused)
 324 {
 325         struct therm th;
 326         int temp;
 327
 328         ds1620_read_state(&th);
 329         temp =  cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
 330
 331         len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; "
 332                       "temperature: %i.%i C, fan %s\n",
 333                       th.hi >> 1, th.hi & 1 ? 5 : 0,
 334                       th.lo >> 1, th.lo & 1 ? 5 : 0,
 335                       temp  >> 1, temp  & 1 ? 5 : 0,
 336                       fan_state[netwinder_get_fan()]);
 337
 338         return len;
 339 }
 340
 341 static struct proc_dir_entry *proc_therm_ds1620;
 342 #endif
 343
 344 static const struct file_operations ds1620_fops = {
 345         .owner          = THIS_MODULE,
 346         .open           = ds1620_open,
 347         .read           = ds1620_read,
 348         .ioctl          = ds1620_ioctl,
 349 };
 350
 351 static struct miscdevice ds1620_miscdev = {
 352         TEMP_MINOR,
 353         "temp",
 354         &ds1620_fops
 355 };
 356
 357 static int __init ds1620_init(void)
 358 {
 359         int ret;
 360         struct therm th, th_start;
 361
 362         if (!machine_is_netwinder())
 363                 return -ENODEV;
 364
 365         ds1620_out(THERM_RESET, 0, 0);
 366         ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
 367         ds1620_out(THERM_START_CONVERT, 0, 0);
 368
 369         /*
 370          * Trigger the fan to start by setting
 371          * temperature high point low.  This kicks
 372          * the fan into action.
 373          */
 374         ds1620_read_state(&th);
 375         th_start.lo = 0;
 376         th_start.hi = 1;
 377         ds1620_write_state(&th_start);
 378
 379         msleep(2000);
 380
 381         ds1620_write_state(&th);
 382
 383         ret = misc_register(&ds1620_miscdev);
 384         if (ret < 0)
 385                 return ret;
 386
 387 #ifdef THERM_USE_PROC
 388         proc_therm_ds1620 = create_proc_entry("therm", 0, NULL);
 389         if (proc_therm_ds1620)
 390                 proc_therm_ds1620->read_proc = proc_therm_ds1620_read;
 391         else
 392                 printk(KERN_ERR "therm: unable to register /proc/therm\n");
 393 #endif
 394
 395         ds1620_read_state(&th);
 396         ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
 397
 398         printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
 399                "current %i.%i C, fan %s.\n",
 400                th.hi >> 1, th.hi & 1 ? 5 : 0,
 401                th.lo >> 1, th.lo & 1 ? 5 : 0,
 402                ret   >> 1, ret   & 1 ? 5 : 0,
 403                fan_state[netwinder_get_fan()]);
 404
 405         return 0;
 406 }
 407
 408 static void __exit ds1620_exit(void)
 409 {
 410 #ifdef THERM_USE_PROC
 411         remove_proc_entry("therm", NULL);
 412 #endif
 413         misc_deregister(&ds1620_miscdev);
 414 }
 415
 416 module_init(ds1620_init);
 417 module_exit(ds1620_exit);
 418
 419 MODULE_LICENSE("GPL");