package/system/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/mc146818rtc.h>
  51 #include <linux/init.h>
  52 #include <linux/spinlock.h>
  53 #include <linux/rtc.h>
  54 #include <linux/delay.h>
  55 #include <linux/version.h>
  56 #include <linux/gpio.h>
  57 #include <linux/uaccess.h>
  58
  59 #include <asm/current.h>
  60 #include <asm/system.h>
  61
  62 #include <bcm47xx.h>
  63 #include <nvram.h>
  64
  65 #define RTC_IS_OPEN             0x01    /* Means /dev/rtc is in use.  */
  66
  67 /* Can be changed via a module parameter.  */
  68 static int rtc_debug = 0;
  69
  70 static unsigned long rtc_status = 0;    /* Bitmapped status byte.       */
  71
  72 /* These settings are platform dependents.  */
  73 unsigned int sda_index = 0;
  74 unsigned int scl_index = 0;
  75
  76 #define I2C_READ_MASK  1
  77 #define I2C_WRITE_MASK 0
  78
  79 #define I2C_ACK 1
  80 #define I2C_NAK 0
  81
  82 #define RTC_EPOCH               1900
  83 #define RTC_I2C_ADDRESS         (0x32 << 1)
  84 #define RTC_24HOUR_MODE_MASK    0x20
  85 #define RTC_PM_MASK             0x20
  86 #define RTC_VDET_MASK           0x40
  87 #define RTC_Y2K_MASK            0x80
  88
  89 /*
  90  * Delay in microseconds for generating the pulses on the I2C bus. We use
  91  * a rather conservative setting here.  See datasheet of the RTC chip.
  92  */
  93 #define ADAP_DELAY 50
  94
  95 /* Avoid spurious compiler warnings.  */
  96 #define UNUSED __attribute__((unused))
  97
  98 MODULE_AUTHOR("Andreas Engel");
  99 MODULE_LICENSE("GPL");
 100
 101 /* Test stolen from switch-adm.c.  */
 102 module_param(rtc_debug, int, 0);
 103
 104 static inline void sdalo(void)
 105 {
 106         gpio_direction_output(sda_index, 1);
 107         udelay(ADAP_DELAY);
 108 }
 109
 110 static inline void sdahi(void)
 111 {
 112         gpio_direction_input(sda_index);
 113         udelay(ADAP_DELAY);
 114 }
 115
 116 static inline void scllo(void)
 117 {
 118    gpio_direction_output(scl_index, 1);
 119         udelay(ADAP_DELAY);
 120 }
 121
 122 static inline int getscl(void)
 123 {
 124         return (gpio_get_value(scl_index));
 125 }
 126
 127 static inline int getsda(void)
 128 {
 129         return (gpio_get_value(sda_index));
 130 }
 131
 132 /*
 133  * We shouldn't simply set the SCL pin to high. Like SDA, the SCL line is
 134  * bidirectional too. According to the I2C spec, the slave is allowed to
 135  * pull down the SCL line to slow down the clock, so we need to check this.
 136  * Generally, we'd need a timeout here, but in our case, we just check the
 137  * line, assuming the RTC chip behaves well.
 138  */
 139 static int sclhi(void)
 140 {
 141         gpio_direction_input(scl_index);
 142         udelay(ADAP_DELAY);
 143         if (!getscl()) {
 144                 printk(KERN_ERR "SCL pin should be low\n");
 145                 return -ETIMEDOUT;
 146         }
 147         return 0;
 148 }
 149
 150 static void i2c_start(void)
 151 {
 152         sdalo();
 153         scllo();
 154 }
 155
 156 static void i2c_stop(void)
 157 {
 158         sdalo();
 159         sclhi();
 160         sdahi();
 161 }
 162
 163 static int i2c_outb(int c)
 164 {
 165         int i;
 166         int ack;
 167
 168         /* assert: scl is low */
 169         for (i = 7; i >= 0; i--) {
 170                 if (c & ( 1 << i )) {
 171                         sdahi();
 172                 } else {
 173                         sdalo();
 174                 }
 175                 if (sclhi() < 0) { /* timed out */
 176                         sdahi(); /* we don't want to block the net */
 177                         return -ETIMEDOUT;
 178                 };
 179                 scllo();
 180         }
 181         sdahi();
 182         if (sclhi() < 0) {
 183                 return -ETIMEDOUT;
 184         };
 185         /* read ack: SDA should be pulled down by slave */
 186         ack = getsda() == 0;    /* ack: sda is pulled low ->success.     */
 187         scllo();
 188
 189         if (rtc_debug)
 190                 printk(KERN_DEBUG "i2c_outb(0x%02x) -> %s\n",
 191                        c, ack ? "ACK": "NAK");
 192
 193         return ack;             /* return 1 if device acked      */
 194         /* assert: scl is low (sda undef) */
 195 }
 196
 197 static int i2c_inb(int ack)
 198 {
 199         int i;
 200         unsigned int indata = 0;
 201
 202         /* assert: scl is low */
 203
 204         sdahi();
 205         for (i = 0; i < 8; i++) {
 206                 if (sclhi() < 0) {
 207                         return -ETIMEDOUT;
 208                 };
 209                 indata *= 2;
 210                 if (getsda())
 211                         indata |= 0x01;
 212                 scllo();
 213         }
 214         if (ack) {
 215                 sdalo();
 216         } else {
 217                 sdahi();
 218         }
 219
 220         if (sclhi() < 0) {
 221                 sdahi();
 222                 return -ETIMEDOUT;
 223         }
 224         scllo();
 225         sdahi();
 226
 227         if (rtc_debug)
 228                 printk(KERN_DEBUG "i2c_inb() -> 0x%02x\n", indata);
 229
 230         /* assert: scl is low */
 231         return indata & 0xff;
 232 }
 233
 234 static void i2c_init(void)
 235 {
 236     /* no gpio_control for EXTIF */
 237         // ssb_gpio_control(&ssb, sda_mask | scl_mask, 0);
 238
 239    gpio_set_value(sda_index, 0);
 240    gpio_set_value(scl_index, 0);
 241         sdahi();
 242         sclhi();
 243 }
 244
 245 static int rtc_open(UNUSED struct inode *inode, UNUSED struct file *filp)
 246 {
 247         spin_lock_irq(&rtc_lock);
 248
 249         if (rtc_status & RTC_IS_OPEN) {
 250                 spin_unlock_irq(&rtc_lock);
 251                 return -EBUSY;
 252         }
 253
 254         rtc_status |= RTC_IS_OPEN;
 255
 256         /*
 257          * The following call is only necessary if we use both this driver and
 258          * the proprietary one from asus at the same time (which, b.t.w. only
 259          * makes sense during development). Otherwise, each access via the asus
 260          * driver will make access via this driver impossible.
 261          */
 262         i2c_init();
 263
 264         spin_unlock_irq(&rtc_lock);
 265
 266         return 0;
 267 }
 268
 269 static int rtc_release(UNUSED struct inode *inode, UNUSED struct file *filp)
 270 {
 271         /* No need for locking here. */
 272         rtc_status &= ~RTC_IS_OPEN;
 273         return 0;
 274 }
 275
 276 static int from_bcd(int bcdnum)
 277 {
 278         int fac, num = 0;
 279
 280         for (fac = 1; bcdnum; fac *= 10) {
 281                 num += (bcdnum % 16) * fac;
 282                 bcdnum /= 16;
 283         }
 284
 285         return num;
 286 }
 287
 288 static int to_bcd(int decnum)
 289 {
 290         int fac, num = 0;
 291
 292         for (fac = 1; decnum; fac *= 16) {
 293                 num += (decnum % 10) * fac;
 294                 decnum /= 10;
 295         }
 296
 297         return num;
 298 }
 299
 300 static void get_rtc_time(struct rtc_time *rtc_tm)
 301 {
 302         int cr2;
 303
 304         /*
 305          * Read date and time from the RTC. We use read method (3).
 306          */
 307
 308         spin_lock_irq(&rtc_lock);
 309         i2c_start();
 310         i2c_outb(RTC_I2C_ADDRESS | I2C_READ_MASK);
 311         cr2             = i2c_inb(I2C_ACK);
 312         rtc_tm->tm_sec  = i2c_inb(I2C_ACK);
 313         rtc_tm->tm_min  = i2c_inb(I2C_ACK);
 314         rtc_tm->tm_hour = i2c_inb(I2C_ACK);
 315         rtc_tm->tm_wday = i2c_inb(I2C_ACK);
 316         rtc_tm->tm_mday = i2c_inb(I2C_ACK);
 317         rtc_tm->tm_mon  = i2c_inb(I2C_ACK);
 318         rtc_tm->tm_year = i2c_inb(I2C_NAK);
 319         i2c_stop();
 320         spin_unlock_irq(&rtc_lock);
 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         spin_lock_irq(&rtc_lock);
 357         i2c_start();
 358         i2c_outb(RTC_I2C_ADDRESS | I2C_WRITE_MASK);
 359         i2c_outb(0x00); /* set starting register to 0 (=seconds) */
 360         i2c_outb(rtc_tm->tm_sec);
 361         i2c_outb(rtc_tm->tm_min);
 362         i2c_outb(rtc_tm->tm_hour);
 363         i2c_outb(rtc_tm->tm_wday);
 364         i2c_outb(rtc_tm->tm_mday);
 365         i2c_outb(rtc_tm->tm_mon);
 366         i2c_outb(rtc_tm->tm_year);
 367         i2c_stop();
 368         spin_unlock_irq(&rtc_lock);
 369 }
 370
 371 static ssize_t rtc_write(UNUSED struct file *filp, const char *buf,
 372                          size_t count, loff_t *ppos)
 373 {
 374         struct rtc_time rtc_tm;
 375         char buffer[23];
 376         char *p;
 377
 378         if (!capable(CAP_SYS_TIME))
 379                 return -EACCES;
 380
 381         if (ppos != &filp->f_pos)
 382                 return -ESPIPE;
 383
 384         /*
 385          * For simplicity, the only acceptable format is:
 386          * YYYY:MM:DD:W:HH:MM:SS\n
 387          */
 388
 389         if (count != 22)
 390                 goto err_out;
 391
 392         if (copy_from_user(buffer, buf, count))
 393                 return -EFAULT;
 394
 395         buffer[sizeof(buffer)-1] = '\0';
 396
 397         p = &buffer[0];
 398
 399         rtc_tm.tm_year  = simple_strtoul(p, &p, 10);
 400         if (*p++ != ':') goto err_out;
 401
 402         rtc_tm.tm_mon = simple_strtoul(p, &p, 10) - 1;
 403         if (*p++ != ':') goto err_out;
 404
 405         rtc_tm.tm_mday = simple_strtoul(p, &p, 10);
 406         if (*p++ != ':') goto err_out;
 407
 408         rtc_tm.tm_wday = simple_strtoul(p, &p, 10);
 409         if (*p++ != ':') goto err_out;
 410
 411         rtc_tm.tm_hour = simple_strtoul(p, &p, 10);
 412         if (*p++ != ':') goto err_out;
 413
 414         rtc_tm.tm_min = simple_strtoul(p, &p, 10);
 415         if (*p++ != ':') goto err_out;
 416
 417         rtc_tm.tm_sec = simple_strtoul(p, &p, 10);
 418         if (*p != '\n') goto err_out;
 419
 420         rtc_tm.tm_year -= RTC_EPOCH;
 421
 422         set_rtc_time(&rtc_tm);
 423
 424         *ppos += count;
 425
 426         return count;
 427
 428  err_out:
 429         printk(KERN_ERR "invalid format: use YYYY:MM:DD:W:HH:MM:SS\\n\n");
 430         return -EINVAL;
 431 }
 432
 433
 434 static ssize_t rtc_read(UNUSED struct file *filp, char *buf, size_t count,
 435                         loff_t *ppos)
 436 {
 437         char wbuf[23];
 438         struct rtc_time tm;
 439         ssize_t len;
 440
 441         if (count == 0 || *ppos != 0)
 442                 return 0;
 443
 444         get_rtc_time(&tm);
 445
 446         len = sprintf(wbuf, "%04d:%02d:%02d:%d:%02d:%02d:%02d\n",
 447                       tm.tm_year + RTC_EPOCH,
 448                       tm.tm_mon + 1,
 449                       tm.tm_mday,
 450                       tm.tm_wday,
 451                       tm.tm_hour,
 452                       tm.tm_min,
 453                       tm.tm_sec);
 454
 455         if (len > (ssize_t)count)
 456                 len = count;
 457
 458         if (copy_to_user(buf, wbuf, len))
 459                 return -EFAULT;
 460
 461         *ppos += len;
 462
 463         return len;
 464 }
 465
 466 static int rtc_do_ioctl(unsigned int cmd, unsigned long arg)
 467 {
 468         struct rtc_time rtc_tm;
 469
 470         switch (cmd) {
 471                 case RTC_RD_TIME:
 472                         memset(&rtc_tm, 0, sizeof(struct rtc_time));
 473                         get_rtc_time(&rtc_tm);
 474                         if (copy_to_user((void *)arg, &rtc_tm, sizeof(rtc_tm)))
 475                                 return -EFAULT;
 476                         break;
 477
 478                 case RTC_SET_TIME:
 479                         if (!capable(CAP_SYS_TIME))
 480                                 return -EACCES;
 481
 482                         if (copy_from_user(&rtc_tm, (struct rtc_time *)arg,
 483                                            sizeof(struct rtc_time)))
 484                                 return -EFAULT;
 485
 486                         set_rtc_time(&rtc_tm);
 487                         break;
 488
 489                 default:
 490                         return -ENOTTY;
 491         }
 492
 493         return 0;
 494 }
 495
 496 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 497 {
 498         long ret;
 499         ret = rtc_do_ioctl(cmd, arg);
 500         return ret;
 501 }
 502
 503 static const struct file_operations rtc_fops = {
 504         .owner          = THIS_MODULE,
 505         .llseek         = no_llseek,
 506         .read           = rtc_read,
 507         .write          = rtc_write,
 508         .unlocked_ioctl = rtc_ioctl,
 509         .open           = rtc_open,
 510         .release        = rtc_release,
 511 };
 512
 513 static struct miscdevice rtc_dev = {
 514         .minor = RTC_MINOR,
 515         .name  = "rtc",
 516         .fops  = &rtc_fops,
 517 };
 518
 519 /* Savagely ripped from diag.c.  */
 520 static inline int startswith (char *source, char *cmp)
 521 {
 522         return !strncmp(source, cmp, strlen(cmp));
 523 }
 524
 525 static void platform_detect(void)
 526 {
 527         char buf[20];
 528         int et0phyaddr, et1phyaddr;
 529
 530         /* Based on "model_no".  */
 531         if (nvram_getenv("model_no", buf, sizeof(buf)) >= 0) {
 532                 if (startswith(buf, "WL700")) { /* WL700* */
 533                         sda_index = 2;
 534                         scl_index = 5;
 535                         return;
 536                 }
 537         }
 538
 539         if (nvram_getenv("et0phyaddr", buf, sizeof(buf)) >= 0 )
 540                 et0phyaddr = simple_strtoul(buf, NULL, 0);
 541         if (nvram_getenv("et1phyaddr", buf, sizeof(buf)) >= 0 )
 542                 et1phyaddr = simple_strtoul(buf, NULL, 0);
 543
 544         if (nvram_getenv("hardware_version", buf, sizeof(buf)) >= 0) {
 545                 /* Either WL-300g or WL-HDD, do more extensive checks */
 546                 if (startswith(buf, "WL300-") && et0phyaddr == 0 && et1phyaddr == 1) {
 547                         sda_index = 4;
 548                         scl_index = 5;
 549                         return;
 550                 }
 551         }
 552         /* not found */
 553 }
 554
 555 static int __init rtc_init(void)
 556 {
 557         int cr1;
 558
 559         platform_detect();
 560
 561         if (sda_index == scl_index) {
 562                 printk(KERN_ERR "RTC-RV5C386A: unrecognized platform!\n");
 563                 return -ENODEV;
 564         }
 565
 566         i2c_init();
 567
 568         /*
 569          * Switch RTC to 24h mode
 570          */
 571         spin_lock_irq(&rtc_lock);
 572         i2c_start();
 573         i2c_outb(RTC_I2C_ADDRESS | I2C_WRITE_MASK);
 574         i2c_outb(0xE4); /* start at address 0xE, transmission mode 4 */
 575         cr1 = i2c_inb(I2C_NAK);
 576         i2c_stop();
 577         spin_unlock_irq(&rtc_lock);
 578         if ((cr1 & RTC_24HOUR_MODE_MASK) == 0) {
 579                 /* RTC is running in 12h mode */
 580                 printk(KERN_INFO "rtc.o: switching to 24h mode\n");
 581                 spin_lock_irq(&rtc_lock);
 582                 i2c_start();
 583                 i2c_outb(RTC_I2C_ADDRESS | I2C_WRITE_MASK);
 584                 i2c_outb(0xE0);
 585                 i2c_outb(cr1 | RTC_24HOUR_MODE_MASK);
 586                 i2c_stop();
 587                 spin_unlock_irq(&rtc_lock);
 588         }
 589
 590         misc_register(&rtc_dev);
 591
 592         printk(KERN_INFO "RV5C386A Real Time Clock Driver loaded\n");
 593
 594         return 0;
 595 }
 596
 597 static void __exit rtc_exit (void)
 598 {
 599         misc_deregister(&rtc_dev);
 600         printk(KERN_INFO "Successfully removed RTC RV5C386A driver\n");
 601 }
 602
 603 module_init(rtc_init);
 604 module_exit(rtc_exit);
 605
 606 /*
 607  * Local Variables:
 608  * indent-tabs-mode:t
 609  * c-basic-offset:8
 610  * End:
 611  */