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/seq_file.h>
  10 #include <linux/capability.h>
  11 #include <linux/init.h>
  12 #include <linux/mutex.h>
  13
  14 #include <mach/hardware.h>
  15 #include <asm/mach-types.h>
  16 #include <linux/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 DEFINE_MUTEX(ds1620_mutex);
  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 unsigned int system_rev;
  49
  50 static inline void netwinder_ds1620_set_clk(int clk)
  51 {
  52         nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
  53 }
  54
  55 static inline void netwinder_ds1620_set_data(int dat)
  56 {
  57         nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
  58 }
  59
  60 static inline int netwinder_ds1620_get_data(void)
  61 {
  62         return nw_gpio_read() & GPIO_DATA;
  63 }
  64
  65 static inline void netwinder_ds1620_set_data_dir(int dir)
  66 {
  67         nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
  68 }
  69
  70 static inline void netwinder_ds1620_reset(void)
  71 {
  72         nw_cpld_modify(CPLD_DS_ENABLE, 0);
  73         nw_cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE);
  74 }
  75
  76 static inline void netwinder_lock(unsigned long *flags)
  77 {
  78         raw_spin_lock_irqsave(&nw_gpio_lock, *flags);
  79 }
  80
  81 static inline void netwinder_unlock(unsigned long *flags)
  82 {
  83         raw_spin_unlock_irqrestore(&nw_gpio_lock, *flags);
  84 }
  85
  86 static inline void netwinder_set_fan(int i)
  87 {
  88         unsigned long flags;
  89
  90         raw_spin_lock_irqsave(&nw_gpio_lock, flags);
  91         nw_gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0);
  92         raw_spin_unlock_irqrestore(&nw_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 (nw_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         msleep(20);
 166 }
 167
 168 static unsigned int ds1620_in(int cmd, int bits)
 169 {
 170         unsigned long flags;
 171         unsigned int value;
 172
 173         netwinder_lock(&flags);
 174         netwinder_ds1620_set_clk(1);
 175         netwinder_ds1620_set_data_dir(0);
 176         netwinder_ds1620_reset();
 177
 178         udelay(1);
 179
 180         ds1620_send_bits(8, cmd);
 181
 182         netwinder_ds1620_set_data_dir(1);
 183         value = ds1620_recv_bits(bits);
 184
 185         netwinder_ds1620_reset();
 186         netwinder_unlock(&flags);
 187
 188         return value;
 189 }
 190
 191 static int cvt_9_to_int(unsigned int val)
 192 {
 193         if (val & 0x100)
 194                 val |= 0xfffffe00;
 195
 196         return val;
 197 }
 198
 199 static void ds1620_write_state(struct therm *therm)
 200 {
 201         ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
 202         ds1620_out(THERM_WRITE_TL, 9, therm->lo);
 203         ds1620_out(THERM_WRITE_TH, 9, therm->hi);
 204         ds1620_out(THERM_START_CONVERT, 0, 0);
 205 }
 206
 207 static void ds1620_read_state(struct therm *therm)
 208 {
 209         therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9));
 210         therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9));
 211 }
 212
 213 static int ds1620_open(struct inode *inode, struct file *file)
 214 {
 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 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 static long
 321 ds1620_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 322 {
 323         int ret;
 324
 325         mutex_lock(&ds1620_mutex);
 326         ret = ds1620_ioctl(file, cmd, arg);
 327         mutex_unlock(&ds1620_mutex);
 328
 329         return ret;
 330 }
 331
 332 #ifdef THERM_USE_PROC
 333 static int ds1620_proc_therm_show(struct seq_file *m, void *v)
 334 {
 335         struct therm th;
 336         int temp;
 337
 338         ds1620_read_state(&th);
 339         temp =  cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
 340
 341         seq_printf(m, "Thermostat: HI %i.%i, LOW %i.%i; temperature: %i.%i C, fan %s\n",
 342                    th.hi >> 1, th.hi & 1 ? 5 : 0,
 343                    th.lo >> 1, th.lo & 1 ? 5 : 0,
 344                    temp  >> 1, temp  & 1 ? 5 : 0,
 345                    fan_state[netwinder_get_fan()]);
 346         return 0;
 347 }
 348 #endif
 349
 350 static const struct file_operations ds1620_fops = {
 351         .owner          = THIS_MODULE,
 352         .open           = ds1620_open,
 353         .read           = ds1620_read,
 354         .unlocked_ioctl = ds1620_unlocked_ioctl,
 355         .llseek         = no_llseek,
 356 };
 357
 358 static struct miscdevice ds1620_miscdev = {
 359         TEMP_MINOR,
 360         "temp",
 361         &ds1620_fops
 362 };
 363
 364 static int __init ds1620_init(void)
 365 {
 366         int ret;
 367         struct therm th, th_start;
 368
 369         if (!machine_is_netwinder())
 370                 return -ENODEV;
 371
 372         ds1620_out(THERM_RESET, 0, 0);
 373         ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU);
 374         ds1620_out(THERM_START_CONVERT, 0, 0);
 375
 376         /*
 377          * Trigger the fan to start by setting
 378          * temperature high point low.  This kicks
 379          * the fan into action.
 380          */
 381         ds1620_read_state(&th);
 382         th_start.lo = 0;
 383         th_start.hi = 1;
 384         ds1620_write_state(&th_start);
 385
 386         msleep(2000);
 387
 388         ds1620_write_state(&th);
 389
 390         ret = misc_register(&ds1620_miscdev);
 391         if (ret < 0)
 392                 return ret;
 393
 394 #ifdef THERM_USE_PROC
 395         if (!proc_create_single("therm", 0, NULL, ds1620_proc_therm_show))
 396                 printk(KERN_ERR "therm: unable to register /proc/therm\n");
 397 #endif
 398
 399         ds1620_read_state(&th);
 400         ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9));
 401
 402         printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, "
 403                "current %i.%i C, fan %s.\n",
 404                th.hi >> 1, th.hi & 1 ? 5 : 0,
 405                th.lo >> 1, th.lo & 1 ? 5 : 0,
 406                ret   >> 1, ret   & 1 ? 5 : 0,
 407                fan_state[netwinder_get_fan()]);
 408
 409         return 0;
 410 }
 411
 412 static void __exit ds1620_exit(void)
 413 {
 414 #ifdef THERM_USE_PROC
 415         remove_proc_entry("therm", NULL);
 416 #endif
 417         misc_deregister(&ds1620_miscdev);
 418 }
 419
 420 module_init(ds1620_init);
 421 module_exit(ds1620_exit);
 422
 423 MODULE_LICENSE("GPL");