1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/drivers/char/ds1620.c: Dallas Semiconductors DS1620 4 * thermometer driver (as used in the Rebel.com NetWinder) 5 */ 6 #include <linux/module.h> 7 #include <linux/miscdevice.h> 8 #include <linux/delay.h> 9 #include <linux/proc_fs.h> 10 #include <linux/seq_file.h> 11 #include <linux/capability.h> 12 #include <linux/init.h> 13 #include <linux/mutex.h> 14 15 #include <mach/hardware.h> 16 #include <asm/mach-types.h> 17 #include <linux/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 39 static DEFINE_MUTEX(ds1620_mutex); 40 static const char *fan_state[] = { "off", "on", "on (hardwired)" }; 41 42 /* 43 * Start of NetWinder specifics 44 * Note! We have to hold the gpio lock with IRQs disabled over the 45 * whole of our transaction to the Dallas chip, since there is a 46 * chance that the WaveArtist driver could touch these bits to 47 * enable or disable the speaker. 48 */ 49 extern unsigned int system_rev; 50 51 static inline void netwinder_ds1620_set_clk(int clk) 52 { 53 nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0); 54 } 55 56 static inline void netwinder_ds1620_set_data(int dat) 57 { 58 nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0); 59 } 60 61 static inline int netwinder_ds1620_get_data(void) 62 { 63 return nw_gpio_read() & GPIO_DATA; 64 } 65 66 static inline void netwinder_ds1620_set_data_dir(int dir) 67 { 68 nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0); 69 } 70 71 static inline void netwinder_ds1620_reset(void) 72 { 73 nw_cpld_modify(CPLD_DS_ENABLE, 0); 74 nw_cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE); 75 } 76 77 static inline void netwinder_lock(unsigned long *flags) 78 { 79 raw_spin_lock_irqsave(&nw_gpio_lock, *flags); 80 } 81 82 static inline void netwinder_unlock(unsigned long *flags) 83 { 84 raw_spin_unlock_irqrestore(&nw_gpio_lock, *flags); 85 } 86 87 static inline void netwinder_set_fan(int i) 88 { 89 unsigned long flags; 90 91 raw_spin_lock_irqsave(&nw_gpio_lock, flags); 92 nw_gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0); 93 raw_spin_unlock_irqrestore(&nw_gpio_lock, flags); 94 } 95 96 static inline int netwinder_get_fan(void) 97 { 98 if ((system_rev & 0xf000) == 0x4000) 99 return FAN_ALWAYS_ON; 100 101 return (nw_gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF; 102 } 103 104 /* 105 * End of NetWinder specifics 106 */ 107 108 static 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 } 122 123 static 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 } 145 146 static 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 msleep(20); 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 int ds1620_open(struct inode *inode, struct file *file) 215 { 216 return stream_open(inode, file); 217 } 218 219 static ssize_t 220 ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr) 221 { 222 signed int cur_temp; 223 signed char cur_temp_degF; 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 } 235 236 static int 237 ds1620_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 238 { 239 struct therm therm; 240 union { 241 struct therm __user *therm; 242 int __user *i; 243 } uarg; 244 int i; 245 246 uarg.i = (int __user *)arg; 247 248 switch(cmd) { 249 case CMD_SET_THERMOSTATE: 250 case CMD_SET_THERMOSTATE2: 251 if (!capable(CAP_SYS_ADMIN)) 252 return -EPERM; 253 254 if (cmd == CMD_SET_THERMOSTATE) { 255 if (get_user(therm.hi, uarg.i)) 256 return -EFAULT; 257 therm.lo = therm.hi - 3; 258 } else { 259 if (copy_from_user(&therm, uarg.therm, sizeof(therm))) 260 return -EFAULT; 261 } 262 263 therm.lo <<= 1; 264 therm.hi <<= 1; 265 266 ds1620_write_state(&therm); 267 break; 268 269 case CMD_GET_THERMOSTATE: 270 case CMD_GET_THERMOSTATE2: 271 ds1620_read_state(&therm); 272 273 therm.lo >>= 1; 274 therm.hi >>= 1; 275 276 if (cmd == CMD_GET_THERMOSTATE) { 277 if (put_user(therm.hi, uarg.i)) 278 return -EFAULT; 279 } else { 280 if (copy_to_user(uarg.therm, &therm, sizeof(therm))) 281 return -EFAULT; 282 } 283 break; 284 285 case CMD_GET_TEMPERATURE: 286 case CMD_GET_TEMPERATURE2: 287 i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)); 288 289 if (cmd == CMD_GET_TEMPERATURE) 290 i >>= 1; 291 292 return put_user(i, uarg.i) ? -EFAULT : 0; 293 294 case CMD_GET_STATUS: 295 i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3; 296 297 return put_user(i, uarg.i) ? -EFAULT : 0; 298 299 case CMD_GET_FAN: 300 i = netwinder_get_fan(); 301 302 return put_user(i, uarg.i) ? -EFAULT : 0; 303 304 case CMD_SET_FAN: 305 if (!capable(CAP_SYS_ADMIN)) 306 return -EPERM; 307 308 if (get_user(i, uarg.i)) 309 return -EFAULT; 310 311 netwinder_set_fan(i); 312 break; 313 314 default: 315 return -ENOIOCTLCMD; 316 } 317 318 return 0; 319 } 320 321 static long 322 ds1620_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 323 { 324 int ret; 325 326 mutex_lock(&ds1620_mutex); 327 ret = ds1620_ioctl(file, cmd, arg); 328 mutex_unlock(&ds1620_mutex); 329 330 return ret; 331 } 332 333 #ifdef THERM_USE_PROC 334 static int ds1620_proc_therm_show(struct seq_file *m, void *v) 335 { 336 struct therm th; 337 int temp; 338 339 ds1620_read_state(&th); 340 temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)); 341 342 seq_printf(m, "Thermostat: HI %i.%i, LOW %i.%i; temperature: %i.%i C, fan %s\n", 343 th.hi >> 1, th.hi & 1 ? 5 : 0, 344 th.lo >> 1, th.lo & 1 ? 5 : 0, 345 temp >> 1, temp & 1 ? 5 : 0, 346 fan_state[netwinder_get_fan()]); 347 return 0; 348 } 349 #endif 350 351 static const struct file_operations ds1620_fops = { 352 .owner = THIS_MODULE, 353 .open = ds1620_open, 354 .read = ds1620_read, 355 .unlocked_ioctl = ds1620_unlocked_ioctl, 356 .llseek = no_llseek, 357 }; 358 359 static struct miscdevice ds1620_miscdev = { 360 TEMP_MINOR, 361 "temp", 362 &ds1620_fops 363 }; 364 365 static int __init ds1620_init(void) 366 { 367 int ret; 368 struct therm th, th_start; 369 370 if (!machine_is_netwinder()) 371 return -ENODEV; 372 373 ds1620_out(THERM_RESET, 0, 0); 374 ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU); 375 ds1620_out(THERM_START_CONVERT, 0, 0); 376 377 /* 378 * Trigger the fan to start by setting 379 * temperature high point low. This kicks 380 * the fan into action. 381 */ 382 ds1620_read_state(&th); 383 th_start.lo = 0; 384 th_start.hi = 1; 385 ds1620_write_state(&th_start); 386 387 msleep(2000); 388 389 ds1620_write_state(&th); 390 391 ret = misc_register(&ds1620_miscdev); 392 if (ret < 0) 393 return ret; 394 395 #ifdef THERM_USE_PROC 396 if (!proc_create_single("therm", 0, NULL, ds1620_proc_therm_show)) 397 printk(KERN_ERR "therm: unable to register /proc/therm\n"); 398 #endif 399 400 ds1620_read_state(&th); 401 ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)); 402 403 printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, " 404 "current %i.%i C, fan %s.\n", 405 th.hi >> 1, th.hi & 1 ? 5 : 0, 406 th.lo >> 1, th.lo & 1 ? 5 : 0, 407 ret >> 1, ret & 1 ? 5 : 0, 408 fan_state[netwinder_get_fan()]); 409 410 return 0; 411 } 412 413 static void __exit ds1620_exit(void) 414 { 415 #ifdef THERM_USE_PROC 416 remove_proc_entry("therm", NULL); 417 #endif 418 misc_deregister(&ds1620_miscdev); 419 } 420 421 module_init(ds1620_init); 422 module_exit(ds1620_exit); 423 424 MODULE_DESCRIPTION("Dallas Semiconductor DS1620 thermometer driver"); 425 MODULE_LICENSE("GPL"); 426