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