arch/cris/arch-v10/drivers/ds1302.c

   1 /*!***************************************************************************
   2 *!
   3 *! FILE NAME  : ds1302.c
   4 *!
   5 *! DESCRIPTION: Implements an interface for the DS1302 RTC through Etrax I/O
   6 *!
   7 *! Functions exported: ds1302_readreg, ds1302_writereg, ds1302_init
   8 *!
   9 *! ---------------------------------------------------------------------------
  10 *!
  11 *! (C) Copyright 1999-2007 Axis Communications AB, LUND, SWEDEN
  12 *!
  13 *!***************************************************************************/
  14
  15
  16 #include <linux/fs.h>
  17 #include <linux/init.h>
  18 #include <linux/mm.h>
  19 #include <linux/module.h>
  20 #include <linux/miscdevice.h>
  21 #include <linux/delay.h>
  22 #include <linux/mutex.h>
  23 #include <linux/bcd.h>
  24 #include <linux/capability.h>
  25
  26 #include <asm/uaccess.h>
  27 #include <asm/system.h>
  28 #include <arch/svinto.h>
  29 #include <asm/io.h>
  30 #include <asm/rtc.h>
  31 #include <arch/io_interface_mux.h>
  32
  33 #include "i2c.h"
  34
  35 #define RTC_MAJOR_NR 121 /* local major, change later */
  36
  37 static DEFINE_MUTEX(ds1302_mutex);
  38 static const char ds1302_name[] = "ds1302";
  39
  40 /* The DS1302 might be connected to different bits on different products.
  41  * It has three signals - SDA, SCL and RST. RST and SCL are always outputs,
  42  * but SDA can have a selected direction.
  43  * For now, only PORT_PB is hardcoded.
  44  */
  45
  46 /* The RST bit may be on either the Generic Port or Port PB. */
  47 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
  48 #define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_G_DATA,  port_g_data_shadow,  CONFIG_ETRAX_DS1302_RSTBIT, x)
  49 #define TK_RST_DIR(x)
  50 #else
  51 #define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)
  52 #define TK_RST_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_RSTBIT, x)
  53 #endif
  54
  55
  56 #define TK_SDA_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SDABIT, x)
  57 #define TK_SCL_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SCLBIT, x)
  58
  59 #define TK_SDA_IN()   ((*R_PORT_PB_READ >> CONFIG_ETRAX_DS1302_SDABIT) & 1)
  60 /* 1 is out, 0 is in */
  61 #define TK_SDA_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_SDABIT, x)
  62 #define TK_SCL_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_SCLBIT, x)
  63
  64
  65 /*
  66  * The reason for tempudelay and not udelay is that loops_per_usec
  67  * (used in udelay) is not set when functions here are called from time.c
  68  */
  69
  70 static void tempudelay(int usecs)
  71 {
  72         volatile int loops;
  73
  74         for(loops = usecs * 12; loops > 0; loops--)
  75                 /* nothing */;
  76 }
  77
  78
  79 /* Send 8 bits. */
  80 static void
  81 out_byte(unsigned char x)
  82 {
  83         int i;
  84         TK_SDA_DIR(1);
  85         for (i = 8; i--;) {
  86                 /* The chip latches incoming bits on the rising edge of SCL. */
  87                 TK_SCL_OUT(0);
  88                 TK_SDA_OUT(x & 1);
  89                 tempudelay(1);
  90                 TK_SCL_OUT(1);
  91                 tempudelay(1);
  92                 x >>= 1;
  93         }
  94         TK_SDA_DIR(0);
  95 }
  96
  97 static unsigned char
  98 in_byte(void)
  99 {
 100         unsigned char x = 0;
 101         int i;
 102
 103         /* Read byte. Bits come LSB first, on the falling edge of SCL.
 104          * Assume SDA is in input direction already.
 105          */
 106         TK_SDA_DIR(0);
 107
 108         for (i = 8; i--;) {
 109                 TK_SCL_OUT(0);
 110                 tempudelay(1);
 111                 x >>= 1;
 112                 x |= (TK_SDA_IN() << 7);
 113                 TK_SCL_OUT(1);
 114                 tempudelay(1);
 115         }
 116
 117         return x;
 118 }
 119
 120 /* Prepares for a transaction by de-activating RST (active-low). */
 121
 122 static void
 123 start(void)
 124 {
 125         TK_SCL_OUT(0);
 126         tempudelay(1);
 127         TK_RST_OUT(0);
 128         tempudelay(5);
 129         TK_RST_OUT(1);
 130 }
 131
 132 /* Ends a transaction by taking RST active again. */
 133
 134 static void
 135 stop(void)
 136 {
 137         tempudelay(2);
 138         TK_RST_OUT(0);
 139 }
 140
 141 /* Enable writing. */
 142
 143 static void
 144 ds1302_wenable(void)
 145 {
 146         start();
 147         out_byte(0x8e); /* Write control register  */
 148         out_byte(0x00); /* Disable write protect bit 7 = 0 */
 149         stop();
 150 }
 151
 152 /* Disable writing. */
 153
 154 static void
 155 ds1302_wdisable(void)
 156 {
 157         start();
 158         out_byte(0x8e); /* Write control register  */
 159         out_byte(0x80); /* Disable write protect bit 7 = 0 */
 160         stop();
 161 }
 162
 163
 164
 165 /* Read a byte from the selected register in the DS1302. */
 166
 167 unsigned char
 168 ds1302_readreg(int reg)
 169 {
 170         unsigned char x;
 171
 172         start();
 173         out_byte(0x81 | (reg << 1)); /* read register */
 174         x = in_byte();
 175         stop();
 176
 177         return x;
 178 }
 179
 180 /* Write a byte to the selected register. */
 181
 182 void
 183 ds1302_writereg(int reg, unsigned char val)
 184 {
 185 #ifndef CONFIG_ETRAX_RTC_READONLY
 186         int do_writereg = 1;
 187 #else
 188         int do_writereg = 0;
 189
 190         if (reg == RTC_TRICKLECHARGER)
 191                 do_writereg = 1;
 192 #endif
 193
 194         if (do_writereg) {
 195                 ds1302_wenable();
 196                 start();
 197                 out_byte(0x80 | (reg << 1)); /* write register */
 198                 out_byte(val);
 199                 stop();
 200                 ds1302_wdisable();
 201         }
 202 }
 203
 204 void
 205 get_rtc_time(struct rtc_time *rtc_tm)
 206 {
 207         unsigned long flags;
 208
 209         local_irq_save(flags);
 210
 211         rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
 212         rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
 213         rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
 214         rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
 215         rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);
 216         rtc_tm->tm_year = CMOS_READ(RTC_YEAR);
 217
 218         local_irq_restore(flags);
 219
 220         rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
 221         rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
 222         rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
 223         rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
 224         rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
 225         rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
 226
 227         /*
 228          * Account for differences between how the RTC uses the values
 229          * and how they are defined in a struct rtc_time;
 230          */
 231
 232         if (rtc_tm->tm_year <= 69)
 233                 rtc_tm->tm_year += 100;
 234
 235         rtc_tm->tm_mon--;
 236 }
 237
 238 static unsigned char days_in_mo[] =
 239     {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
 240
 241 /* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */
 242
 243 static int rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 244 {
 245         unsigned long flags;
 246
 247         switch(cmd) {
 248                 case RTC_RD_TIME:       /* read the time/date from RTC  */
 249                 {
 250                         struct rtc_time rtc_tm;
 251
 252                         memset(&rtc_tm, 0, sizeof (struct rtc_time));
 253                         get_rtc_time(&rtc_tm);
 254                         if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))
 255                                 return -EFAULT;
 256                         return 0;
 257                 }
 258
 259                 case RTC_SET_TIME:      /* set the RTC */
 260                 {
 261                         struct rtc_time rtc_tm;
 262                         unsigned char mon, day, hrs, min, sec, leap_yr;
 263                         unsigned int yrs;
 264
 265                         if (!capable(CAP_SYS_TIME))
 266                                 return -EPERM;
 267
 268                         if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))
 269                                 return -EFAULT;
 270
 271                         yrs = rtc_tm.tm_year + 1900;
 272                         mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */
 273                         day = rtc_tm.tm_mday;
 274                         hrs = rtc_tm.tm_hour;
 275                         min = rtc_tm.tm_min;
 276                         sec = rtc_tm.tm_sec;
 277
 278
 279                         if ((yrs < 1970) || (yrs > 2069))
 280                                 return -EINVAL;
 281
 282                         leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
 283
 284                         if ((mon > 12) || (day == 0))
 285                                 return -EINVAL;
 286
 287                         if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
 288                                 return -EINVAL;
 289
 290                         if ((hrs >= 24) || (min >= 60) || (sec >= 60))
 291                                 return -EINVAL;
 292
 293                         if (yrs >= 2000)
 294                                 yrs -= 2000;    /* RTC (0, 1, ... 69) */
 295                         else
 296                                 yrs -= 1900;    /* RTC (70, 71, ... 99) */
 297
 298                         sec = bin2bcd(sec);
 299                         min = bin2bcd(min);
 300                         hrs = bin2bcd(hrs);
 301                         day = bin2bcd(day);
 302                         mon = bin2bcd(mon);
 303                         yrs = bin2bcd(yrs);
 304
 305                         local_irq_save(flags);
 306                         CMOS_WRITE(yrs, RTC_YEAR);
 307                         CMOS_WRITE(mon, RTC_MONTH);
 308                         CMOS_WRITE(day, RTC_DAY_OF_MONTH);
 309                         CMOS_WRITE(hrs, RTC_HOURS);
 310                         CMOS_WRITE(min, RTC_MINUTES);
 311                         CMOS_WRITE(sec, RTC_SECONDS);
 312                         local_irq_restore(flags);
 313
 314                         /* Notice that at this point, the RTC is updated but
 315                          * the kernel is still running with the old time.
 316                          * You need to set that separately with settimeofday
 317                          * or adjtimex.
 318                          */
 319                         return 0;
 320                 }
 321
 322                 case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */
 323                 {
 324                         int tcs_val;
 325
 326                         if (!capable(CAP_SYS_TIME))
 327                                 return -EPERM;
 328
 329                         if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))
 330                                 return -EFAULT;
 331
 332                         tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);
 333                         ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);
 334                         return 0;
 335                 }
 336                 case RTC_VL_READ:
 337                 {
 338                         /* TODO:
 339                          * Implement voltage low detection support
 340                          */
 341                         printk(KERN_WARNING "DS1302: RTC Voltage Low detection"
 342                                " is not supported\n");
 343                         return 0;
 344                 }
 345                 case RTC_VL_CLR:
 346                 {
 347                         /* TODO:
 348                          * Nothing to do since Voltage Low detection is not supported
 349                          */
 350                         return 0;
 351                 }
 352                 default:
 353                         return -ENOIOCTLCMD;
 354         }
 355 }
 356
 357 static long rtc_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 358 {
 359         int ret;
 360
 361         mutex_lock(&ds1302_mutex);
 362         ret = rtc_ioctl(file, cmd, arg);
 363         mutex_unlock(&ds1302_mutex);
 364
 365         return ret;
 366 }
 367
 368 static void
 369 print_rtc_status(void)
 370 {
 371         struct rtc_time tm;
 372
 373         get_rtc_time(&tm);
 374
 375         /*
 376          * There is no way to tell if the luser has the RTC set for local
 377          * time or for Universal Standard Time (GMT). Probably local though.
 378          */
 379
 380         printk(KERN_INFO "rtc_time\t: %02d:%02d:%02d\n",
 381                tm.tm_hour, tm.tm_min, tm.tm_sec);
 382         printk(KERN_INFO "rtc_date\t: %04d-%02d-%02d\n",
 383                tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
 384 }
 385
 386 /* The various file operations we support. */
 387
 388 static const struct file_operations rtc_fops = {
 389         .owner          = THIS_MODULE,
 390         .unlocked_ioctl = rtc_unlocked_ioctl,
 391         .llseek         = noop_llseek,
 392 };
 393
 394 /* Probe for the chip by writing something to its RAM and try reading it back. */
 395
 396 #define MAGIC_PATTERN 0x42
 397
 398 static int __init
 399 ds1302_probe(void)
 400 {
 401         int retval, res;
 402
 403         TK_RST_DIR(1);
 404         TK_SCL_DIR(1);
 405         TK_SDA_DIR(0);
 406
 407         /* Try to talk to timekeeper. */
 408
 409         ds1302_wenable();
 410         start();
 411         out_byte(0xc0); /* write RAM byte 0 */
 412         out_byte(MAGIC_PATTERN); /* write something magic */
 413         start();
 414         out_byte(0xc1); /* read RAM byte 0 */
 415
 416         if((res = in_byte()) == MAGIC_PATTERN) {
 417                 stop();
 418                 ds1302_wdisable();
 419                 printk(KERN_INFO "%s: RTC found.\n", ds1302_name);
 420                 printk(KERN_INFO "%s: SDA, SCL, RST on PB%i, PB%i, %s%i\n",
 421                        ds1302_name,
 422                        CONFIG_ETRAX_DS1302_SDABIT,
 423                        CONFIG_ETRAX_DS1302_SCLBIT,
 424 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
 425                        "GENIO",
 426 #else
 427                        "PB",
 428 #endif
 429                        CONFIG_ETRAX_DS1302_RSTBIT);
 430                        print_rtc_status();
 431                 retval = 1;
 432         } else {
 433                 stop();
 434                 retval = 0;
 435         }
 436
 437         return retval;
 438 }
 439
 440
 441 /* Just probe for the RTC and register the device to handle the ioctl needed. */
 442
 443 int __init
 444 ds1302_init(void)
 445 {
 446 #ifdef CONFIG_ETRAX_I2C
 447         i2c_init();
 448 #endif
 449
 450         if (!ds1302_probe()) {
 451 #ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT
 452 #if CONFIG_ETRAX_DS1302_RSTBIT == 27
 453                 /*
 454                  * The only way to set g27 to output is to enable ATA.
 455                  *
 456                  * Make sure that R_GEN_CONFIG is setup correct.
 457                  */
 458                 /* Allocating the ATA interface will grab almost all
 459                  * pins in I/O groups a, b, c and d.  A consequence of
 460                  * allocating the ATA interface is that the fixed
 461                  * interfaces shared RAM, parallel port 0, parallel
 462                  * port 1, parallel port W, SCSI-8 port 0, SCSI-8 port
 463                  * 1, SCSI-W, serial port 2, serial port 3,
 464                  * synchronous serial port 3 and USB port 2 and almost
 465                  * all GPIO pins on port g cannot be used.
 466                  */
 467                 if (cris_request_io_interface(if_ata, "ds1302/ATA")) {
 468                         printk(KERN_WARNING "ds1302: Failed to get IO interface\n");
 469                         return -1;
 470                 }
 471
 472 #elif CONFIG_ETRAX_DS1302_RSTBIT == 0
 473                 if (cris_io_interface_allocate_pins(if_gpio_grp_a,
 474                                                     'g',
 475                                                     CONFIG_ETRAX_DS1302_RSTBIT,
 476                                                     CONFIG_ETRAX_DS1302_RSTBIT)) {
 477                         printk(KERN_WARNING "ds1302: Failed to get IO interface\n");
 478                         return -1;
 479                 }
 480
 481                 /* Set the direction of this bit to out. */
 482                 genconfig_shadow = ((genconfig_shadow &
 483                                      ~IO_MASK(R_GEN_CONFIG, g0dir)) |
 484                                    (IO_STATE(R_GEN_CONFIG, g0dir, out)));
 485                 *R_GEN_CONFIG = genconfig_shadow;
 486 #endif
 487                 if (!ds1302_probe()) {
 488                         printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
 489                         return -1;
 490                 }
 491 #else
 492                 printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);
 493                 return -1;
 494 #endif
 495         }
 496         /* Initialise trickle charger */
 497         ds1302_writereg(RTC_TRICKLECHARGER,
 498                         RTC_TCR_PATTERN |(CONFIG_ETRAX_DS1302_TRICKLE_CHARGE & 0x0F));
 499         /* Start clock by resetting CLOCK_HALT */
 500         ds1302_writereg(RTC_SECONDS, (ds1302_readreg(RTC_SECONDS) & 0x7F));
 501         return 0;
 502 }
 503
 504 static int __init ds1302_register(void)
 505 {
 506         ds1302_init();
 507         if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {
 508                 printk(KERN_INFO "%s: unable to get major %d for rtc\n",
 509                        ds1302_name, RTC_MAJOR_NR);
 510                 return -1;
 511         }
 512         return 0;
 513
 514 }
 515
 516 module_init(ds1302_register);