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