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 #if LINUX_VERSION_CODE < KERNEL_VERSION(3,4,0)
  61 #include <asm/system.h>
  62 #endif
  63
  64 #include <bcm47xx.h>
  65 #include <bcm47xx_nvram.h>
  66
  67 #define RTC_IS_OPEN             0x01    /* Means /dev/rtc is in use.  */
  68
  69 /* Can be changed via a module parameter.  */
  70 static int rtc_debug = 0;
  71
  72 static unsigned long rtc_status = 0;    /* Bitmapped status byte.       */
  73
  74 /* These settings are platform dependents.  */
  75 unsigned int sda_index = 0;
  76 unsigned int scl_index = 0;
  77
  78 #define I2C_READ_MASK  1
  79 #define I2C_WRITE_MASK 0
  80
  81 #define I2C_ACK 1
  82 #define I2C_NAK 0
  83
  84 #define RTC_EPOCH               1900
  85 #define RTC_I2C_ADDRESS         (0x32 << 1)
  86 #define RTC_24HOUR_MODE_MASK    0x20
  87 #define RTC_PM_MASK             0x20
  88 #define RTC_VDET_MASK           0x40
  89 #define RTC_Y2K_MASK            0x80
  90
  91 /*
  92  * Delay in microseconds for generating the pulses on the I2C bus. We use
  93  * a rather conservative setting here.  See datasheet of the RTC chip.
  94  */
  95 #define ADAP_DELAY 50
  96
  97 /* Avoid spurious compiler warnings.  */
  98 #define UNUSED __attribute__((unused))
  99
 100 MODULE_AUTHOR("Andreas Engel");
 101 MODULE_LICENSE("GPL");
 102
 103 /* Test stolen from switch-adm.c.  */
 104 module_param(rtc_debug, int, 0);
 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         // ssb_gpio_control(&ssb, 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         spin_lock_irq(&rtc_lock);
 311         i2c_start();
 312         i2c_outb(RTC_I2C_ADDRESS | I2C_READ_MASK);
 313         cr2             = i2c_inb(I2C_ACK);
 314         rtc_tm->tm_sec  = i2c_inb(I2C_ACK);
 315         rtc_tm->tm_min  = i2c_inb(I2C_ACK);
 316         rtc_tm->tm_hour = i2c_inb(I2C_ACK);
 317         rtc_tm->tm_wday = i2c_inb(I2C_ACK);
 318         rtc_tm->tm_mday = i2c_inb(I2C_ACK);
 319         rtc_tm->tm_mon  = i2c_inb(I2C_ACK);
 320         rtc_tm->tm_year = i2c_inb(I2C_NAK);
 321         i2c_stop();
 322         spin_unlock_irq(&rtc_lock);
 323
 324         if (cr2 & RTC_VDET_MASK) {
 325                 printk(KERN_WARNING "***RTC BATTERY FAILURE***\n");
 326         }
 327
 328         /* Handle century bit */
 329         if (rtc_tm->tm_mon & RTC_Y2K_MASK) {
 330                 rtc_tm->tm_mon &= ~RTC_Y2K_MASK;
 331                 rtc_tm->tm_year += 0x100;
 332         }
 333
 334         rtc_tm->tm_sec  = from_bcd(rtc_tm->tm_sec);
 335         rtc_tm->tm_min  = from_bcd(rtc_tm->tm_min);
 336         rtc_tm->tm_hour = from_bcd(rtc_tm->tm_hour);
 337         rtc_tm->tm_mday = from_bcd(rtc_tm->tm_mday);
 338         rtc_tm->tm_mon  = from_bcd(rtc_tm->tm_mon) - 1;
 339         rtc_tm->tm_year = from_bcd(rtc_tm->tm_year);
 340
 341         rtc_tm->tm_isdst = -1; /* DST not known */
 342 }
 343
 344 static void set_rtc_time(struct rtc_time *rtc_tm)
 345 {
 346         rtc_tm->tm_sec  = to_bcd(rtc_tm->tm_sec);
 347         rtc_tm->tm_min  = to_bcd(rtc_tm->tm_min);
 348         rtc_tm->tm_hour = to_bcd(rtc_tm->tm_hour);
 349         rtc_tm->tm_mday = to_bcd(rtc_tm->tm_mday);
 350         rtc_tm->tm_mon  = to_bcd(rtc_tm->tm_mon + 1);
 351         rtc_tm->tm_year = to_bcd(rtc_tm->tm_year);
 352
 353         if (rtc_tm->tm_year >= 0x100) {
 354                 rtc_tm->tm_year -= 0x100;
 355                 rtc_tm->tm_mon |= RTC_Y2K_MASK;
 356         }
 357
 358         spin_lock_irq(&rtc_lock);
 359         i2c_start();
 360         i2c_outb(RTC_I2C_ADDRESS | I2C_WRITE_MASK);
 361         i2c_outb(0x00); /* set starting register to 0 (=seconds) */
 362         i2c_outb(rtc_tm->tm_sec);
 363         i2c_outb(rtc_tm->tm_min);
 364         i2c_outb(rtc_tm->tm_hour);
 365         i2c_outb(rtc_tm->tm_wday);
 366         i2c_outb(rtc_tm->tm_mday);
 367         i2c_outb(rtc_tm->tm_mon);
 368         i2c_outb(rtc_tm->tm_year);
 369         i2c_stop();
 370         spin_unlock_irq(&rtc_lock);
 371 }
 372
 373 static ssize_t rtc_write(UNUSED struct file *filp, const char *buf,
 374                          size_t count, loff_t *ppos)
 375 {
 376         struct rtc_time rtc_tm;
 377         char buffer[23];
 378         char *p;
 379
 380         if (!capable(CAP_SYS_TIME))
 381                 return -EACCES;
 382
 383         if (ppos != &filp->f_pos)
 384                 return -ESPIPE;
 385
 386         /*
 387          * For simplicity, the only acceptable format is:
 388          * YYYY:MM:DD:W:HH:MM:SS\n
 389          */
 390
 391         if (count != 22)
 392                 goto err_out;
 393
 394         if (copy_from_user(buffer, buf, count))
 395                 return -EFAULT;
 396
 397         buffer[sizeof(buffer)-1] = '\0';
 398
 399         p = &buffer[0];
 400
 401         rtc_tm.tm_year  = simple_strtoul(p, &p, 10);
 402         if (*p++ != ':') goto err_out;
 403
 404         rtc_tm.tm_mon = simple_strtoul(p, &p, 10) - 1;
 405         if (*p++ != ':') goto err_out;
 406
 407         rtc_tm.tm_mday = simple_strtoul(p, &p, 10);
 408         if (*p++ != ':') goto err_out;
 409
 410         rtc_tm.tm_wday = simple_strtoul(p, &p, 10);
 411         if (*p++ != ':') goto err_out;
 412
 413         rtc_tm.tm_hour = simple_strtoul(p, &p, 10);
 414         if (*p++ != ':') goto err_out;
 415
 416         rtc_tm.tm_min = simple_strtoul(p, &p, 10);
 417         if (*p++ != ':') goto err_out;
 418
 419         rtc_tm.tm_sec = simple_strtoul(p, &p, 10);
 420         if (*p != '\n') goto err_out;
 421
 422         rtc_tm.tm_year -= RTC_EPOCH;
 423
 424         set_rtc_time(&rtc_tm);
 425
 426         *ppos += count;
 427
 428         return count;
 429
 430  err_out:
 431         printk(KERN_ERR "invalid format: use YYYY:MM:DD:W:HH:MM:SS\\n\n");
 432         return -EINVAL;
 433 }
 434
 435
 436 static ssize_t rtc_read(UNUSED struct file *filp, char *buf, size_t count,
 437                         loff_t *ppos)
 438 {
 439         char wbuf[23];
 440         struct rtc_time tm;
 441         ssize_t len;
 442
 443         if (count == 0 || *ppos != 0)
 444                 return 0;
 445
 446         get_rtc_time(&tm);
 447
 448         len = sprintf(wbuf, "%04d:%02d:%02d:%d:%02d:%02d:%02d\n",
 449                       tm.tm_year + RTC_EPOCH,
 450                       tm.tm_mon + 1,
 451                       tm.tm_mday,
 452                       tm.tm_wday,
 453                       tm.tm_hour,
 454                       tm.tm_min,
 455                       tm.tm_sec);
 456
 457         if (len > (ssize_t)count)
 458                 len = count;
 459
 460         if (copy_to_user(buf, wbuf, len))
 461                 return -EFAULT;
 462
 463         *ppos += len;
 464
 465         return len;
 466 }
 467
 468 static int rtc_do_ioctl(unsigned int cmd, unsigned long arg)
 469 {
 470         struct rtc_time rtc_tm;
 471
 472         switch (cmd) {
 473                 case RTC_RD_TIME:
 474                         memset(&rtc_tm, 0, sizeof(struct rtc_time));
 475                         get_rtc_time(&rtc_tm);
 476                         if (copy_to_user((void *)arg, &rtc_tm, sizeof(rtc_tm)))
 477                                 return -EFAULT;
 478                         break;
 479
 480                 case RTC_SET_TIME:
 481                         if (!capable(CAP_SYS_TIME))
 482                                 return -EACCES;
 483
 484                         if (copy_from_user(&rtc_tm, (struct rtc_time *)arg,
 485                                            sizeof(struct rtc_time)))
 486                                 return -EFAULT;
 487
 488                         set_rtc_time(&rtc_tm);
 489                         break;
 490
 491                 default:
 492                         return -ENOTTY;
 493         }
 494
 495         return 0;
 496 }
 497
 498 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 499 {
 500         long ret;
 501         ret = rtc_do_ioctl(cmd, arg);
 502         return ret;
 503 }
 504
 505 static const struct file_operations rtc_fops = {
 506         .owner          = THIS_MODULE,
 507         .llseek         = no_llseek,
 508         .read           = rtc_read,
 509         .write          = rtc_write,
 510         .unlocked_ioctl = rtc_ioctl,
 511         .open           = rtc_open,
 512         .release        = rtc_release,
 513 };
 514
 515 static struct miscdevice rtc_dev = {
 516         .minor = RTC_MINOR,
 517         .name  = "rtc",
 518         .fops  = &rtc_fops,
 519 };
 520
 521 /* Savagely ripped from diag.c.  */
 522 static inline int startswith (char *source, char *cmp)
 523 {
 524         return !strncmp(source, cmp, strlen(cmp));
 525 }
 526
 527 static void platform_detect(void)
 528 {
 529         char buf[20];
 530         int et0phyaddr, et1phyaddr;
 531
 532         /* Based on "model_no".  */
 533         if (bcm47xx_nvram_getenv("model_no", buf, sizeof(buf)) >= 0) {
 534                 if (startswith(buf, "WL700")) { /* WL700* */
 535                         sda_index = 2;
 536                         scl_index = 5;
 537                         return;
 538                 }
 539         }
 540
 541         if (bcm47xx_nvram_getenv("et0phyaddr", buf, sizeof(buf)) >= 0 )
 542                 et0phyaddr = simple_strtoul(buf, NULL, 0);
 543         if (bcm47xx_nvram_getenv("et1phyaddr", buf, sizeof(buf)) >= 0 )
 544                 et1phyaddr = simple_strtoul(buf, NULL, 0);
 545
 546         if (bcm47xx_nvram_getenv("hardware_version", buf, sizeof(buf)) >= 0) {
 547                 /* Either WL-300g or WL-HDD, do more extensive checks */
 548                 if (startswith(buf, "WL300-") && et0phyaddr == 0 && et1phyaddr == 1) {
 549                         sda_index = 4;
 550                         scl_index = 5;
 551                         return;
 552                 }
 553         }
 554         /* not found */
 555 }
 556
 557 static int __init rtc_init(void)
 558 {
 559         int cr1;
 560
 561         platform_detect();
 562
 563         if (sda_index == scl_index) {
 564                 printk(KERN_ERR "RTC-RV5C386A: unrecognized platform!\n");
 565                 return -ENODEV;
 566         }
 567
 568         i2c_init();
 569
 570         /*
 571          * Switch RTC to 24h mode
 572          */
 573         spin_lock_irq(&rtc_lock);
 574         i2c_start();
 575         i2c_outb(RTC_I2C_ADDRESS | I2C_WRITE_MASK);
 576         i2c_outb(0xE4); /* start at address 0xE, transmission mode 4 */
 577         cr1 = i2c_inb(I2C_NAK);
 578         i2c_stop();
 579         spin_unlock_irq(&rtc_lock);
 580         if ((cr1 & RTC_24HOUR_MODE_MASK) == 0) {
 581                 /* RTC is running in 12h mode */
 582                 printk(KERN_INFO "rtc.o: switching to 24h mode\n");
 583                 spin_lock_irq(&rtc_lock);
 584                 i2c_start();
 585                 i2c_outb(RTC_I2C_ADDRESS | I2C_WRITE_MASK);
 586                 i2c_outb(0xE0);
 587                 i2c_outb(cr1 | RTC_24HOUR_MODE_MASK);
 588                 i2c_stop();
 589                 spin_unlock_irq(&rtc_lock);
 590         }
 591
 592         misc_register(&rtc_dev);
 593
 594         printk(KERN_INFO "RV5C386A Real Time Clock Driver loaded\n");
 595
 596         return 0;
 597 }
 598
 599 static void __exit rtc_exit (void)
 600 {
 601         misc_deregister(&rtc_dev);
 602         printk(KERN_INFO "Successfully removed RTC RV5C386A driver\n");
 603 }
 604
 605 module_init(rtc_init);
 606 module_exit(rtc_exit);
 607
 608 /*
 609  * Local Variables:
 610  * indent-tabs-mode:t
 611  * c-basic-offset:8
 612  * End:
 613  */