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