linux/drivers/char/ds1620.c
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   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
  39static DEFINE_MUTEX(ds1620_mutex);
  40static 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 */
  49extern unsigned int system_rev;
  50
  51static inline void netwinder_ds1620_set_clk(int clk)
  52{
  53        nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0);
  54}
  55
  56static inline void netwinder_ds1620_set_data(int dat)
  57{
  58        nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0);
  59}
  60
  61static inline int netwinder_ds1620_get_data(void)
  62{
  63        return nw_gpio_read() & GPIO_DATA;
  64}
  65
  66static inline void netwinder_ds1620_set_data_dir(int dir)
  67{
  68        nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0);
  69}
  70
  71static 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
  77static inline void netwinder_lock(unsigned long *flags)
  78{
  79        raw_spin_lock_irqsave(&nw_gpio_lock, *flags);
  80}
  81
  82static inline void netwinder_unlock(unsigned long *flags)
  83{
  84        raw_spin_unlock_irqrestore(&nw_gpio_lock, *flags);
  85}
  86
  87static 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
  96static 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
 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        msleep(20);
 167}
 168
 169static 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
 192static int cvt_9_to_int(unsigned int val)
 193{
 194        if (val & 0x100)
 195                val |= 0xfffffe00;
 196
 197        return val;
 198}
 199
 200static 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
 208static 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
 214static int ds1620_open(struct inode *inode, struct file *file)
 215{
 216        return stream_open(inode, file);
 217}
 218
 219static ssize_t
 220ds1620_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
 236static int
 237ds1620_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
 321static long
 322ds1620_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
 334static 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
 351static 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
 359static struct miscdevice ds1620_miscdev = {
 360        TEMP_MINOR,
 361        "temp",
 362        &ds1620_fops
 363};
 364
 365static 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
 413static 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
 421module_init(ds1620_init);
 422module_exit(ds1620_exit);
 423
 424MODULE_LICENSE("GPL");
 425