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/mach-types.h> 17#include <asm/uaccess.h> 18#include <asm/therm.h> 19 20#ifdef CONFIG_PROC_FS 21/* define for /proc interface */ 22#define THERM_USE_PROC 23#endif 24 25/* Definitions for DS1620 chip */ 26#define THERM_START_CONVERT 0xee 27#define THERM_RESET 0xaf 28#define THERM_READ_CONFIG 0xac 29#define THERM_READ_TEMP 0xaa 30#define THERM_READ_TL 0xa2 31#define THERM_READ_TH 0xa1 32#define THERM_WRITE_CONFIG 0x0c 33#define THERM_WRITE_TL 0x02 34#define THERM_WRITE_TH 0x01 35 36#define CFG_CPU 2 37#define CFG_1SHOT 1 38 39static 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 */ 48extern spinlock_t gpio_lock; 49extern unsigned int system_rev; 50 51static inline void netwinder_ds1620_set_clk(int clk) 52{ 53 gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0); 54} 55 56static inline void netwinder_ds1620_set_data(int dat) 57{ 58 gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0); 59} 60 61static inline int netwinder_ds1620_get_data(void) 62{ 63 return gpio_read() & GPIO_DATA; 64} 65 66static inline void netwinder_ds1620_set_data_dir(int dir) 67{ 68 gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0); 69} 70 71static inline void netwinder_ds1620_reset(void) 72{ 73 cpld_modify(CPLD_DS_ENABLE, 0); 74 cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE); 75} 76 77static inline void netwinder_lock(unsigned long *flags) 78{ 79 spin_lock_irqsave(&gpio_lock, *flags); 80} 81 82static inline void netwinder_unlock(unsigned long *flags) 83{ 84 spin_unlock_irqrestore(&gpio_lock, *flags); 85} 86 87static inline void netwinder_set_fan(int i) 88{ 89 unsigned long flags; 90 91 spin_lock_irqsave(&gpio_lock, flags); 92 gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0); 93 spin_unlock_irqrestore(&gpio_lock, flags); 94} 95 96static inline int netwinder_get_fan(void) 97{ 98 if ((system_rev & 0xf000) == 0x4000) 99 return FAN_ALWAYS_ON; 100 101 return (gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF; 102} 103 104/* 105 * End of NetWinder specifics 106 */ 107 108static void ds1620_send_bits(int nr, int value) 109{ 110 int i; 111 112 for (i = 0; i < nr; i++) { 113 netwinder_ds1620_set_data(value & 1); 114 netwinder_ds1620_set_clk(0); 115 udelay(1); 116 netwinder_ds1620_set_clk(1); 117 udelay(1); 118 119 value >>= 1; 120 } 121} 122 123static unsigned int ds1620_recv_bits(int nr) 124{ 125 unsigned int value = 0, mask = 1; 126 int i; 127 128 netwinder_ds1620_set_data(0); 129 130 for (i = 0; i < nr; i++) { 131 netwinder_ds1620_set_clk(0); 132 udelay(1); 133 134 if (netwinder_ds1620_get_data()) 135 value |= mask; 136 137 mask <<= 1; 138 139 netwinder_ds1620_set_clk(1); 140 udelay(1); 141 } 142 143 return value; 144} 145 146static void ds1620_out(int cmd, int bits, int value) 147{ 148 unsigned long flags; 149 150 netwinder_lock(&flags); 151 netwinder_ds1620_set_clk(1); 152 netwinder_ds1620_set_data_dir(0); 153 netwinder_ds1620_reset(); 154 155 udelay(1); 156 157 ds1620_send_bits(8, cmd); 158 if (bits) 159 ds1620_send_bits(bits, value); 160 161 udelay(1); 162 163 netwinder_ds1620_reset(); 164 netwinder_unlock(&flags); 165 166 set_current_state(TASK_INTERRUPTIBLE); 167 schedule_timeout(2); 168} 169 170static unsigned int ds1620_in(int cmd, int bits) 171{ 172 unsigned long flags; 173 unsigned int value; 174 175 netwinder_lock(&flags); 176 netwinder_ds1620_set_clk(1); 177 netwinder_ds1620_set_data_dir(0); 178 netwinder_ds1620_reset(); 179 180 udelay(1); 181 182 ds1620_send_bits(8, cmd); 183 184 netwinder_ds1620_set_data_dir(1); 185 value = ds1620_recv_bits(bits); 186 187 netwinder_ds1620_reset(); 188 netwinder_unlock(&flags); 189 190 return value; 191} 192 193static int cvt_9_to_int(unsigned int val) 194{ 195 if (val & 0x100) 196 val |= 0xfffffe00; 197 198 return val; 199} 200 201static void ds1620_write_state(struct therm *therm) 202{ 203 ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU); 204 ds1620_out(THERM_WRITE_TL, 9, therm->lo); 205 ds1620_out(THERM_WRITE_TH, 9, therm->hi); 206 ds1620_out(THERM_START_CONVERT, 0, 0); 207} 208 209static void ds1620_read_state(struct therm *therm) 210{ 211 therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9)); 212 therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9)); 213} 214 215static ssize_t 216ds1620_read(struct file *file, char *buf, size_t count, loff_t *ptr) 217{ 218 signed int cur_temp; 219 signed char cur_temp_degF; 220 221 /* Can't seek (pread) on this device */ 222 if (ptr != &file->f_pos) 223 return -ESPIPE; 224 225 cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1; 226 227 /* convert to Fahrenheit, as per wdt.c */ 228 cur_temp_degF = (cur_temp * 9) / 5 + 32; 229 230 if (copy_to_user(buf, &cur_temp_degF, 1)) 231 return -EFAULT; 232 233 return 1; 234} 235 236static int 237ds1620_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) 238{ 239 struct therm therm; 240 int i; 241 242 switch(cmd) { 243 case CMD_SET_THERMOSTATE: 244 case CMD_SET_THERMOSTATE2: 245 if (!capable(CAP_SYS_ADMIN)) 246 return -EPERM; 247 248 if (cmd == CMD_SET_THERMOSTATE) { 249 if (get_user(therm.hi, (int *)arg)) 250 return -EFAULT; 251 therm.lo = therm.hi - 3; 252 } else { 253 if (copy_from_user(&therm, (void *)arg, sizeof(therm))) 254 return -EFAULT; 255 } 256 257 therm.lo <<= 1; 258 therm.hi <<= 1; 259 260 ds1620_write_state(&therm); 261 break; 262 263 case CMD_GET_THERMOSTATE: 264 case CMD_GET_THERMOSTATE2: 265 ds1620_read_state(&therm); 266 267 therm.lo >>= 1; 268 therm.hi >>= 1; 269 270 if (cmd == CMD_GET_THERMOSTATE) { 271 if (put_user(therm.hi, (int *)arg)) 272 return -EFAULT; 273 } else { 274 if (copy_to_user((void *)arg, &therm, sizeof(therm))) 275 return -EFAULT; 276 } 277 break; 278 279 case CMD_GET_TEMPERATURE: 280 case CMD_GET_TEMPERATURE2: 281 i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)); 282 283 if (cmd == CMD_GET_TEMPERATURE) 284 i >>= 1; 285 286 return put_user(i, (int *)arg) ? -EFAULT : 0; 287 288 case CMD_GET_STATUS: 289 i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3; 290 291 return put_user(i, (int *)arg) ? -EFAULT : 0; 292 293 case CMD_GET_FAN: 294 i = netwinder_get_fan(); 295 296 return put_user(i, (int *)arg) ? -EFAULT : 0; 297 298 case CMD_SET_FAN: 299 if (!capable(CAP_SYS_ADMIN)) 300 return -EPERM; 301 302 if (get_user(i, (int *)arg)) 303 return -EFAULT; 304 305 netwinder_set_fan(i); 306 break; 307 308 default: 309 return -ENOIOCTLCMD; 310 } 311 312 return 0; 313} 314 315#ifdef THERM_USE_PROC 316static int 317proc_therm_ds1620_read(char *buf, char **start, off_t offset, 318 int len, int *eof, void *unused) 319{ 320 struct therm th; 321 int temp; 322 323 ds1620_read_state(&th); 324 temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)); 325 326 len = sprintf(buf, "Thermostat: HI %i.%i, LOW %i.%i; " 327 "temperature: %i.%i C, fan %s\n", 328 th.hi >> 1, th.hi & 1 ? 5 : 0, 329 th.lo >> 1, th.lo & 1 ? 5 : 0, 330 temp >> 1, temp & 1 ? 5 : 0, 331 fan_state[netwinder_get_fan()]); 332 333 return len; 334} 335 336static struct proc_dir_entry *proc_therm_ds1620; 337#endif 338 339static struct file_operations ds1620_fops = { 340 owner: THIS_MODULE, 341 read: ds1620_read, 342 ioctl: ds1620_ioctl, 343}; 344 345static struct miscdevice ds1620_miscdev = { 346 TEMP_MINOR, 347 "temp", 348 &ds1620_fops 349}; 350 351int __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 set_current_state(TASK_INTERRUPTIBLE); 374 schedule_timeout(2*HZ); 375 376 ds1620_write_state(&th); 377 378 ret = misc_register(&ds1620_miscdev); 379 if (ret < 0) 380 return ret; 381 382#ifdef THERM_USE_PROC 383 proc_therm_ds1620 = create_proc_entry("therm", 0, 0); 384 if (proc_therm_ds1620) 385 proc_therm_ds1620->read_proc = proc_therm_ds1620_read; 386 else 387 printk(KERN_ERR "therm: unable to register /proc/therm\n"); 388#endif 389 390 ds1620_read_state(&th); 391 ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)); 392 393 printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, " 394 "current %i.%i C, fan %s.\n", 395 th.hi >> 1, th.hi & 1 ? 5 : 0, 396 th.lo >> 1, th.lo & 1 ? 5 : 0, 397 ret >> 1, ret & 1 ? 5 : 0, 398 fan_state[netwinder_get_fan()]); 399 400 return 0; 401} 402 403void __exit ds1620_exit(void) 404{ 405#ifdef THERM_USE_PROC 406 remove_proc_entry("therm", NULL); 407#endif 408 misc_deregister(&ds1620_miscdev); 409} 410 411module_init(ds1620_init); 412module_exit(ds1620_exit); 413 414MODULE_LICENSE("GPL"); 415