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/smp_lock.h>
   8 #include <linux/delay.h>
   9 #include <linux/proc_fs.h>
  10 #include <linux/capability.h>
  11 #include <linux/init.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 ssize_t
 213 ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr)
 214 {
 215         signed int cur_temp;
 216         signed char cur_temp_degF;
 217
 218         cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1;
 219
 220         /* convert to Fahrenheit, as per wdt.c */
 221         cur_temp_degF = (cur_temp * 9) / 5 + 32;
 222
 223         if (copy_to_user(buf, &cur_temp_degF, 1))
 224                 return -EFAULT;
 225
 226         return 1;
 227 }
 228
 229 static int
 230 ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 231 {
 232         struct therm therm;
 233         union {
 234                 struct therm __user *therm;
 235                 int __user *i;
 236         } uarg;
 237         int i;
 238
 239         uarg.i = (int __user *)arg;
 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, uarg.i))
 249                                 return -EFAULT;
 250                         therm.lo = therm.hi - 3;
 251                 } else {
 252                         if (copy_from_user(&therm, uarg.therm, 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, uarg.i))
 271                                 return -EFAULT;
 272                 } else {
 273                         if (copy_to_user(uarg.therm, &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, uarg.i) ? -EFAULT : 0;
 286
 287         case CMD_GET_STATUS:
 288                 i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3;
 289
 290                 return put_user(i, uarg.i) ? -EFAULT : 0;
 291
 292         case CMD_GET_FAN:
 293                 i = netwinder_get_fan();
 294
 295                 return put_user(i, uarg.i) ? -EFAULT : 0;
 296
 297         case CMD_SET_FAN:
 298                 if (!capable(CAP_SYS_ADMIN))
 299                         return -EPERM;
 300
 301                 if (get_user(i, uarg.i))
 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 const struct file_operations ds1620_fops = {
 339         .owner          = THIS_MODULE,
 340         .open           = nonseekable_open,
 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         msleep(2000);
 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, NULL);
 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 static 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);
 412
 413 MODULE_LICENSE("GPL");