package/rtc-rv5c386a/src/rtc.c

   1 /*
   2  * Real Time Clock driver for WL-HDD
   3  *
   4  * Copyright (C) 2007 Andreas Engel
   5  *
   6  * Hacked together mostly by copying the relevant code parts from:
   7  *   drivers/i2c/i2c-bcm5365.c
   8  *   drivers/i2c/i2c-algo-bit.c
   9  *   drivers/char/rtc.c
  10  *
  11  * Note 1:
  12  * This module uses the standard char device (10,135), while the Asus module
  13  * rtcdrv.o uses (12,0). So, both can coexist which might be handy during
  14  * development (but see the comment in rtc_open()).
  15  *
  16  * Note 2:
  17  * You might need to set the clock once after loading the driver the first
  18  * time because the driver switches the chip into 24h mode if it is running
  19  * in 12h mode.
  20  *
  21  * Usage:
  22  * For compatibility reasons with the original asus driver, the time can be
  23  * read and set via the /dev/rtc device entry. The only accepted data format
  24  * is "YYYY:MM:DD:W:HH:MM:SS\n". See OpenWrt wiki for a script which handles
  25  * this format.
  26  *
  27  * In addition, this driver supports the standard ioctl() calls for setting
  28  * and reading the hardware clock, so the ordinary hwclock utility can also
  29  * be used.
  30  *
  31  * This program is free software; you can redistribute it and/or
  32  * modify it under the terms of the GNU General Public License
  33  * as published by the Free Software Foundation; either version
  34  * 2 of the License, or (at your option) any later version.
  35  *
  36  * TODO:
  37  * - add a /proc/driver/rtc interface?
  38  * - make the battery failure bit available through the /proc interface?
  39  *
  40  * $Id: rtc.c 7 2007-05-25 19:37:01Z ae $
  41  */
  42
  43 #include <linux/module.h>
  44 #include <linux/kmod.h>
  45 #include <linux/kernel.h>
  46 #include <linux/types.h>
  47 #include <linux/miscdevice.h>
  48 #include <linux/ioport.h>
  49 #include <linux/fcntl.h>
  50 #include <linux/init.h>
  51 #include <linux/spinlock.h>
  52 #include <linux/rtc.h>
  53 #include <linux/delay.h>
  54 #include <linux/version.h>
  55
  56 #include <asm/uaccess.h>
  57 #include <asm/system.h>
  58
  59 #include "gpio.h"
  60
  61 #define RTC_IS_OPEN             0x01    /* Means /dev/rtc is in use.  */
  62
  63 /* Can be changed via a module parameter.  */
  64 static int rtc_debug = 0;
  65
  66 static unsigned long rtc_status = 0;    /* Bitmapped status byte.       */
  67
  68 static spinlock_t rtc_lock = SPIN_LOCK_UNLOCKED;
  69
  70 /* These settings are platform dependents.  */
  71 unsigned int sda_index = 0;
  72 unsigned int scl_index = 0;
  73
  74 #define I2C_READ_MASK  1
  75 #define I2C_WRITE_MASK 0
  76
  77 #define I2C_ACK 1
  78 #define I2C_NAK 0
  79
  80 #define RTC_EPOCH               1900
  81 #define RTC_I2C_ADDRESS         (0x32 << 1)
  82 #define RTC_24HOUR_MODE_MASK    0x20
  83 #define RTC_PM_MASK             0x20
  84 #define RTC_VDET_MASK           0x40
  85 #define RTC_Y2K_MASK            0x80
  86
  87 /*
  88  * Delay in microseconds for generating the pulses on the I2C bus. We use
  89  * a rather conservative setting here.  See datasheet of the RTC chip.
  90  */
  91 #define ADAP_DELAY 50
  92
  93 /* Avoid spurious compiler warnings.  */
  94 #define UNUSED __attribute__((unused))
  95
  96 MODULE_AUTHOR("Andreas Engel");
  97 MODULE_LICENSE("GPL");
  98
  99 /* Test stolen from switch-adm.c.  */
 100 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,52)
 101 module_param(rtc_debug, int, 0);
 102 #else
 103 MODULE_PARM(rtc_debug, "i");
 104 #endif
 105
 106 static inline void sdalo(void)
 107 {
 108         gpio_direction_output(sda_index, 1);
 109         udelay(ADAP_DELAY);
 110 }
 111
 112 static inline void sdahi(void)
 113 {
 114         gpio_direction_input(sda_index);
 115         udelay(ADAP_DELAY);
 116 }
 117
 118 static inline void scllo(void)
 119 {
 120    gpio_direction_output(scl_index, 1);
 121         udelay(ADAP_DELAY);
 122 }
 123
 124 static inline int getscl(void)
 125 {
 126         return (gpio_get_value(scl_index));
 127 }
 128
 129 static inline int getsda(void)
 130 {
 131         return (gpio_get_value(sda_index));
 132 }
 133
 134 /*
 135  * We shouldn't simply set the SCL pin to high. Like SDA, the SCL line is
 136  * bidirectional too. According to the I2C spec, the slave is allowed to
 137  * pull down the SCL line to slow down the clock, so we need to check this.
 138  * Generally, we'd need a timeout here, but in our case, we just check the
 139  * line, assuming the RTC chip behaves well.
 140  */
 141 static int sclhi(void)
 142 {
 143         gpio_direction_input(scl_index);
 144         udelay(ADAP_DELAY);
 145         if (!getscl()) {
 146                 printk(KERN_ERR "SCL pin should be low\n");
 147                 return -ETIMEDOUT;
 148         }
 149         return 0;
 150 }
 151
 152 static void i2c_start(void)
 153 {
 154         sdalo();
 155         scllo();
 156 }
 157
 158 static void i2c_stop(void)
 159 {
 160         sdalo();
 161         sclhi();
 162         sdahi();
 163 }
 164
 165 static int i2c_outb(int c)
 166 {
 167         int i;
 168         int ack;
 169
 170         /* assert: scl is low */
 171         for (i = 7; i >= 0; i--) {
 172                 if (c & ( 1 << i )) {
 173                         sdahi();
 174                 } else {
 175                         sdalo();
 176                 }
 177                 if (sclhi() < 0) { /* timed out */
 178                         sdahi(); /* we don't want to block the net */
 179                         return -ETIMEDOUT;
 180                 };
 181                 scllo();
 182         }
 183         sdahi();
 184         if (sclhi() < 0) {
 185                 return -ETIMEDOUT;
 186         };
 187         /* read ack: SDA should be pulled down by slave */
 188         ack = getsda() == 0;    /* ack: sda is pulled low ->success.     */
 189         scllo();
 190
 191         if (rtc_debug)
 192                 printk(KERN_DEBUG "i2c_outb(0x%02x) -> %s\n",
 193                        c, ack ? "ACK": "NAK");
 194
 195         return ack;             /* return 1 if device acked      */
 196         /* assert: scl is low (sda undef) */
 197 }
 198
 199 static int i2c_inb(int ack)
 200 {
 201         int i;
 202         unsigned int indata = 0;
 203
 204         /* assert: scl is low */
 205
 206         sdahi();
 207         for (i = 0; i < 8; i++) {
 208                 if (sclhi() < 0) {
 209                         return -ETIMEDOUT;
 210                 };
 211                 indata *= 2;
 212                 if (getsda())
 213                         indata |= 0x01;
 214                 scllo();
 215         }
 216         if (ack) {
 217                 sdalo();
 218         } else {
 219                 sdahi();
 220         }
 221
 222         if (sclhi() < 0) {
 223                 sdahi();
 224                 return -ETIMEDOUT;
 225         }
 226         scllo();
 227         sdahi();
 228
 229         if (rtc_debug)
 230                 printk(KERN_DEBUG "i2c_inb() -> 0x%02x\n", indata);
 231
 232         /* assert: scl is low */
 233         return indata & 0xff;
 234 }
 235
 236 static void i2c_init(void)
 237 {
 238     /* no gpio_control for EXTIF */
 239         // gpio_control(sda_mask | scl_mask, 0);
 240
 241    gpio_set_value(sda_index, 0);
 242    gpio_set_value(scl_index, 0);
 243         sdahi();
 244         sclhi();
 245 }
 246
 247 static int rtc_open(UNUSED struct inode *inode, UNUSED struct file *filp)
 248 {
 249         spin_lock_irq(&rtc_lock);
 250
 251         if (rtc_status & RTC_IS_OPEN) {
 252                 spin_unlock_irq(&rtc_lock);
 253                 return -EBUSY;
 254         }
 255
 256         rtc_status |= RTC_IS_OPEN;
 257
 258         /*
 259          * The following call is only necessary if we use both this driver and
 260          * the proprietary one from asus at the same time (which, b.t.w. only
 261          * makes sense during development). Otherwise, each access via the asus
 262          * driver will make access via this driver impossible.
 263          */
 264         i2c_init();
 265
 266         spin_unlock_irq(&rtc_lock);
 267
 268         return 0;
 269 }
 270
 271 static int rtc_release(UNUSED struct inode *inode, UNUSED struct file *filp)
 272 {
 273         /* No need for locking here. */
 274         rtc_status &= ~RTC_IS_OPEN;
 275         return 0;
 276 }
 277
 278 static int from_bcd(int bcdnum)
 279 {
 280         int fac, num = 0;
 281
 282         for (fac = 1; bcdnum; fac *= 10) {
 283                 num += (bcdnum % 16) * fac;
 284                 bcdnum /= 16;
 285         }
 286
 287         return num;
 288 }
 289
 290 static int to_bcd(int decnum)
 291 {
 292         int fac, num = 0;
 293
 294         for (fac = 1; decnum; fac *= 16) {
 295                 num += (decnum % 10) * fac;
 296                 decnum /= 10;
 297         }
 298
 299         return num;
 300 }
 301
 302 static void get_rtc_time(struct rtc_time *rtc_tm)
 303 {
 304         int cr2;
 305
 306         /*
 307          * Read date and time from the RTC. We use read method (3).
 308          */
 309
 310         i2c_start();
 311         i2c_outb(RTC_I2C_ADDRESS | I2C_READ_MASK);
 312         cr2             = i2c_inb(I2C_ACK);
 313         rtc_tm->tm_sec  = i2c_inb(I2C_ACK);
 314         rtc_tm->tm_min  = i2c_inb(I2C_ACK);
 315         rtc_tm->tm_hour = i2c_inb(I2C_ACK);
 316         rtc_tm->tm_wday = i2c_inb(I2C_ACK);
 317         rtc_tm->tm_mday = i2c_inb(I2C_ACK);
 318         rtc_tm->tm_mon  = i2c_inb(I2C_ACK);
 319         rtc_tm->tm_year = i2c_inb(I2C_NAK);
 320         i2c_stop();
 321
 322         if (cr2 & RTC_VDET_MASK) {
 323                 printk(KERN_WARNING "***RTC BATTERY FAILURE***\n");
 324         }
 325
 326         /* Handle century bit */
 327         if (rtc_tm->tm_mon & RTC_Y2K_MASK) {
 328                 rtc_tm->tm_mon &= ~RTC_Y2K_MASK;
 329                 rtc_tm->tm_year += 0x100;
 330         }
 331
 332         rtc_tm->tm_sec  = from_bcd(rtc_tm->tm_sec);
 333         rtc_tm->tm_min  = from_bcd(rtc_tm->tm_min);
 334         rtc_tm->tm_hour = from_bcd(rtc_tm->tm_hour);
 335         rtc_tm->tm_mday = from_bcd(rtc_tm->tm_mday);
 336         rtc_tm->tm_mon  = from_bcd(rtc_tm->tm_mon) - 1;
 337         rtc_tm->tm_year = from_bcd(rtc_tm->tm_year);
 338
 339         rtc_tm->tm_isdst = -1; /* DST not known */
 340 }
 341
 342 static void set_rtc_time(struct rtc_time *rtc_tm)
 343 {
 344         rtc_tm->tm_sec  = to_bcd(rtc_tm->tm_sec);
 345         rtc_tm->tm_min  = to_bcd(rtc_tm->tm_min);
 346         rtc_tm->tm_hour = to_bcd(rtc_tm->tm_hour);
 347         rtc_tm->tm_mday = to_bcd(rtc_tm->tm_mday);
 348         rtc_tm->tm_mon  = to_bcd(rtc_tm->tm_mon + 1);
 349         rtc_tm->tm_year = to_bcd(rtc_tm->tm_year);
 350
 351         if (rtc_tm->tm_year >= 0x100) {
 352                 rtc_tm->tm_year -= 0x100;
 353                 rtc_tm->tm_mon |= RTC_Y2K_MASK;
 354         }
 355
 356         i2c_start();
 357         i2c_outb(RTC_I2C_ADDRESS | I2C_WRITE_MASK);
 358         i2c_outb(0x00); /* set starting register to 0 (=seconds) */
 359         i2c_outb(rtc_tm->tm_sec);
 360         i2c_outb(rtc_tm->tm_min);
 361         i2c_outb(rtc_tm->tm_hour);
 362         i2c_outb(rtc_tm->tm_wday);
 363         i2c_outb(rtc_tm->tm_mday);
 364         i2c_outb(rtc_tm->tm_mon);
 365         i2c_outb(rtc_tm->tm_year);
 366         i2c_stop();
 367 }
 368
 369 static ssize_t rtc_write(UNUSED struct file *filp, const char *buf,
 370                          size_t count, loff_t *ppos)
 371 {
 372         struct rtc_time rtc_tm;
 373         char buffer[23];
 374         char *p;
 375
 376         if (!capable(CAP_SYS_TIME))
 377                 return -EACCES;
 378
 379         if (ppos != &filp->f_pos)
 380                 return -ESPIPE;
 381
 382         /*
 383          * For simplicity, the only acceptable format is:
 384          * YYYY:MM:DD:W:HH:MM:SS\n
 385          */
 386
 387         if (count != 22)
 388                 goto err_out;
 389
 390         if (copy_from_user(buffer, buf, count))
 391                 return -EFAULT;
 392
 393         buffer[sizeof(buffer)-1] = '\0';
 394
 395         p = &buffer[0];
 396
 397         rtc_tm.tm_year  = simple_strtoul(p, &p, 10);
 398         if (*p++ != ':') goto err_out;
 399
 400         rtc_tm.tm_mon = simple_strtoul(p, &p, 10) - 1;
 401         if (*p++ != ':') goto err_out;
 402
 403         rtc_tm.tm_mday = simple_strtoul(p, &p, 10);
 404         if (*p++ != ':') goto err_out;
 405
 406         rtc_tm.tm_wday = simple_strtoul(p, &p, 10);
 407         if (*p++ != ':') goto err_out;
 408
 409         rtc_tm.tm_hour = simple_strtoul(p, &p, 10);
 410         if (*p++ != ':') goto err_out;
 411
 412         rtc_tm.tm_min = simple_strtoul(p, &p, 10);
 413         if (*p++ != ':') goto err_out;
 414
 415         rtc_tm.tm_sec = simple_strtoul(p, &p, 10);
 416         if (*p != '\n') goto err_out;
 417
 418         rtc_tm.tm_year -= RTC_EPOCH;
 419
 420         set_rtc_time(&rtc_tm);
 421
 422         *ppos += count;
 423
 424         return count;
 425
 426  err_out:
 427         printk(KERN_ERR "invalid format: use YYYY:MM:DD:W:HH:MM:SS\\n\n");
 428         return -EINVAL;
 429 }
 430
 431
 432 static ssize_t rtc_read(UNUSED struct file *filp, char *buf, size_t count,
 433                         loff_t *ppos)
 434 {
 435         char wbuf[23];
 436         struct rtc_time tm;
 437         ssize_t len;
 438
 439         if (count == 0 || *ppos != 0)
 440                 return 0;
 441
 442         get_rtc_time(&tm);
 443
 444         len = sprintf(wbuf, "%04d:%02d:%02d:%d:%02d:%02d:%02d\n",
 445                       tm.tm_year + RTC_EPOCH,
 446                       tm.tm_mon + 1,
 447                       tm.tm_mday,
 448                       tm.tm_wday,
 449                       tm.tm_hour,
 450                       tm.tm_min,
 451                       tm.tm_sec);
 452
 453         if (len > (ssize_t)count)
 454                 len = count;
 455
 456         if (copy_to_user(buf, wbuf, len))
 457                 return -EFAULT;
 458
 459         *ppos += len;
 460
 461         return len;
 462 }
 463
 464 static int rtc_ioctl(UNUSED struct inode *inode, UNUSED struct file *filp,
 465                      unsigned int cmd, unsigned long arg)
 466 {
 467         struct rtc_time rtc_tm;
 468
 469         switch (cmd) {
 470                 case RTC_RD_TIME:
 471                         memset(&rtc_tm, 0, sizeof(struct rtc_time));
 472                         get_rtc_time(&rtc_tm);
 473                         if (copy_to_user((void *)arg, &rtc_tm, sizeof(rtc_tm)))
 474                                 return -EFAULT;
 475                         break;
 476
 477                 case RTC_SET_TIME:
 478                         if (!capable(CAP_SYS_TIME))
 479                                 return -EACCES;
 480
 481                         if (copy_from_user(&rtc_tm, (struct rtc_time *)arg,
 482                                            sizeof(struct rtc_time)))
 483                                 return -EFAULT;
 484
 485                         set_rtc_time(&rtc_tm);
 486                         break;
 487
 488                 default:
 489                         return -ENOTTY;
 490         }
 491
 492         return 0;
 493 }
 494
 495 static struct file_operations rtc_fops = {
 496         .owner   = THIS_MODULE,
 497         .llseek  = no_llseek,
 498         .read    = rtc_read,
 499         .write   = rtc_write,
 500         .ioctl   = rtc_ioctl,
 501         .open    = rtc_open,
 502         .release = rtc_release,
 503 };
 504
 505 static struct miscdevice rtc_dev = {
 506         .minor = RTC_MINOR,
 507         .name  = "rtc",
 508         .fops  = &rtc_fops,
 509 };
 510
 511 /* Savagely ripped from diag.c.  */
 512 extern char *nvram_get(char *str);
 513 #define getvar(str) (nvram_get(str)?:"")
 514 static inline int startswith (char *source, char *cmp)
 515 {       return !strncmp(source,cmp,strlen(cmp)); }
 516 static void platform_detect(void)
 517 {
 518         char *buf;
 519
 520         /* Based on "model_no".  */
 521         if ((buf = nvram_get("model_no"))) {
 522                 if (startswith(buf,"WL700")) { /* WL700* */
 523                         sda_index = 2;
 524                         scl_index = 5;
 525                         return;
 526                 }
 527         }
 528
 529         if (startswith(getvar("hardware_version"), "WL300-")) {
 530                 /* Either WL-300g or WL-HDD, do more extensive checks */
 531                 if ((simple_strtoul(getvar("et0phyaddr"), NULL, 0) == 0) &&
 532                          (simple_strtoul(getvar("et1phyaddr"), NULL, 0) == 1)) {
 533                         sda_index = 4;
 534                         scl_index = 5;
 535                         return;
 536                 }
 537         }
 538         /* not found */
 539 }
 540
 541 static int __init rtc_init(void)
 542 {
 543         int cr1;
 544
 545         platform_detect();
 546
 547         if (sda_index == scl_index) {
 548                 printk(KERN_ERR "RTC-RV5C386A: unrecognized platform!\n");
 549                 return -ENODEV;
 550         }
 551
 552         i2c_init();
 553
 554         /*
 555          * Switch RTC to 24h mode
 556          */
 557         i2c_start();
 558         i2c_outb(RTC_I2C_ADDRESS | I2C_WRITE_MASK);
 559         i2c_outb(0xE4); /* start at address 0xE, transmission mode 4 */
 560         cr1 = i2c_inb(I2C_NAK);
 561         i2c_stop();
 562         if ((cr1 & RTC_24HOUR_MODE_MASK) == 0) {
 563                 /* RTC is running in 12h mode */
 564                 printk(KERN_INFO "rtc.o: switching to 24h mode\n");
 565                 i2c_start();
 566                 i2c_outb(RTC_I2C_ADDRESS | I2C_WRITE_MASK);
 567                 i2c_outb(0xE0);
 568                 i2c_outb(cr1 | RTC_24HOUR_MODE_MASK);
 569                 i2c_stop();
 570         }
 571
 572         misc_register(&rtc_dev);
 573
 574         printk(KERN_INFO "RV5C386A Real Time Clock Driver loaded\n");
 575
 576         return 0;
 577 }
 578
 579 static void __exit rtc_exit (void)
 580 {
 581         misc_deregister(&rtc_dev);
 582         printk(KERN_INFO "Successfully removed RTC RV5C386A driver\n");
 583 }
 584
 585 module_init(rtc_init);
 586 module_exit(rtc_exit);
 587
 588 /*
 589  * Local Variables:
 590  * indent-tabs-mode:t
 591  * c-basic-offset:8
 592  * End:
 593  */