rtc/ds1302.c

   1 /*
   2  * ds1302.c - Support for the Dallas Semiconductor DS1302 Timekeeping Chip
   3  *
   4  * Rex G. Feany <rfeany@zumanetworks.com>
   5  *
   6  */
   7
   8 #include <common.h>
   9 #include <command.h>
  10 #include <rtc.h>
  11
  12 #if defined(CONFIG_RTC_DS1302) && (CONFIG_COMMANDS & CFG_CMD_DATE)
  13
  14 /* GPP Pins */
  15 #define DATA            0x200
  16 #define SCLK            0x400
  17 #define RST             0x800
  18
  19 /* Happy Fun Defines(tm) */
  20 #define RESET           rtc_go_low(RST), rtc_go_low(SCLK)
  21 #define N_RESET         rtc_go_high(RST), rtc_go_low(SCLK)
  22
  23 #define CLOCK_HIGH      rtc_go_high(SCLK)
  24 #define CLOCK_LOW       rtc_go_low(SCLK)
  25
  26 #define DATA_HIGH       rtc_go_high(DATA)
  27 #define DATA_LOW        rtc_go_low(DATA)
  28 #define DATA_READ       (GTREGREAD(GPP_VALUE) & DATA)
  29
  30 #undef RTC_DEBUG
  31
  32 #ifdef RTC_DEBUG
  33 #  define DPRINTF(x,args...)    printf("ds1302: " x , ##args)
  34 static inline void DUMP(const char *ptr, int num)
  35 {
  36         while (num--) printf("%x ", *ptr++);
  37         printf("]\n");
  38 }
  39 #else
  40 #  define DPRINTF(x,args...)
  41 #  define DUMP(ptr, num)
  42 #endif
  43
  44 /* time data format for DS1302 */
  45 struct ds1302_st
  46 {
  47         unsigned char CH:1;             /* clock halt 1=stop 0=start */
  48         unsigned char sec10:3;
  49         unsigned char sec:4;
  50
  51         unsigned char zero0:1;
  52         unsigned char min10:3;
  53         unsigned char min:4;
  54
  55         unsigned char fmt:1;            /* 1=12 hour 0=24 hour */
  56         unsigned char zero1:1;
  57         unsigned char hr10:2;   /* 10 (0-2) or am/pm (am/pm, 0-1) */
  58         unsigned char hr:4;
  59
  60         unsigned char zero2:2;
  61         unsigned char date10:2;
  62         unsigned char date:4;
  63
  64         unsigned char zero3:3;
  65         unsigned char month10:1;
  66         unsigned char month:4;
  67
  68         unsigned char zero4:5;
  69         unsigned char day:3;            /* day of week */
  70
  71         unsigned char year10:4;
  72         unsigned char year:4;
  73
  74         unsigned char WP:1;             /* write protect 1=protect 0=unprot */
  75         unsigned char zero5:7;
  76 };
  77
  78 static int ds1302_initted=0;
  79
  80 /* Pin control */
  81 static inline void
  82 rtc_go_high(unsigned int mask)
  83 {
  84         unsigned int f = GTREGREAD(GPP_VALUE) | mask;
  85
  86         GT_REG_WRITE(GPP_VALUE, f);
  87 }
  88
  89 static inline void
  90 rtc_go_low(unsigned int mask)
  91 {
  92         unsigned int f = GTREGREAD(GPP_VALUE) & ~mask;
  93
  94         GT_REG_WRITE(GPP_VALUE, f);
  95 }
  96
  97 static inline void
  98 rtc_go_input(unsigned int mask)
  99 {
 100         unsigned int f = GTREGREAD(GPP_IO_CONTROL) & ~mask;
 101
 102         GT_REG_WRITE(GPP_IO_CONTROL, f);
 103 }
 104
 105 static inline void
 106 rtc_go_output(unsigned int mask)
 107 {
 108         unsigned int f = GTREGREAD(GPP_IO_CONTROL) | mask;
 109
 110         GT_REG_WRITE(GPP_IO_CONTROL, f);
 111 }
 112
 113 /* Access data in RTC */
 114
 115 static void
 116 write_byte(unsigned char b)
 117 {
 118         int i;
 119         unsigned char mask=1;
 120
 121         for(i=0;i<8;i++) {
 122                 CLOCK_LOW;                      /* Lower clock */
 123                 (b&mask)?DATA_HIGH:DATA_LOW;    /* set data */
 124                 udelay(1);
 125                 CLOCK_HIGH;             /* latch data with rising clock */
 126                 udelay(1);
 127                 mask=mask<<1;
 128         }
 129 }
 130
 131 static unsigned char
 132 read_byte(void)
 133 {
 134         int i;
 135         unsigned char mask=1;
 136         unsigned char b=0;
 137
 138         for(i=0;i<8;i++) {
 139                 CLOCK_LOW;
 140                 udelay(1);
 141                 if (DATA_READ) b|=mask; /* if this bit is high, set in b */
 142                 CLOCK_HIGH;             /* clock out next bit */
 143                 udelay(1);
 144                 mask=mask<<1;
 145         }
 146         return b;
 147 }
 148
 149 static void
 150 read_ser_drv(unsigned char addr, unsigned char *buf, int count)
 151 {
 152         int i;
 153 #ifdef RTC_DEBUG
 154         char *foo = buf;
 155 #endif
 156
 157         DPRINTF("READ 0x%x bytes @ 0x%x [ ", count, addr);
 158
 159         addr|=1;        /* READ */
 160         N_RESET;
 161         udelay(4);
 162         write_byte(addr);
 163         rtc_go_input(DATA); /* Put gpp pin into input mode */
 164         udelay(1);
 165         for(i=0;i<count;i++) *(buf++)=read_byte();
 166         RESET;
 167         rtc_go_output(DATA);/* Reset gpp for output */
 168         udelay(4);
 169
 170         DUMP(foo, count);
 171 }
 172
 173 static void
 174 write_ser_drv(unsigned char addr, unsigned char *buf, int count)
 175 {
 176         int i;
 177
 178         DPRINTF("WRITE 0x%x bytes @ 0x%x [ ", count, addr);
 179         DUMP(buf, count);
 180
 181         addr&=~1;       /* WRITE */
 182         N_RESET;
 183         udelay(4);
 184         write_byte(addr);
 185         for(i=0;i<count;i++) write_byte(*(buf++));
 186         RESET;
 187         udelay(4);
 188
 189 }
 190
 191 void
 192 rtc_init(void)
 193 {
 194         struct ds1302_st bbclk;
 195         unsigned char b;
 196         int mod;
 197
 198         DPRINTF("init\n");
 199
 200         rtc_go_output(DATA|SCLK|RST);
 201
 202         /* disable write protect */
 203         b = 0;
 204         write_ser_drv(0x8e,&b,1);
 205
 206         /* enable trickle */
 207         b = 0xa5;       /* 1010.0101 */
 208         write_ser_drv(0x90,&b,1);
 209
 210         /* read burst */
 211         read_ser_drv(0xbe, (unsigned char *)&bbclk, 8);
 212
 213         /* Sanity checks */
 214         mod = 0;
 215         if (bbclk.CH) {
 216                 printf("ds1302: Clock was halted, starting clock\n");
 217                 bbclk.CH=0;
 218                 mod=1;
 219         }
 220
 221         if (bbclk.fmt) {
 222                 printf("ds1302: Clock was in 12 hour mode, fixing\n");
 223                 bbclk.fmt=0;
 224                 mod=1;
 225         }
 226
 227         if (bbclk.year>9) {
 228                 printf("ds1302: Year was corrupted, fixing\n");
 229                 bbclk.year10=100/10;    /* 2000 - why not? ;) */
 230                 bbclk.year=0;
 231                 mod=1;
 232         }
 233
 234         /* Write out the changes if needed */
 235         if (mod) {
 236                 /* enable write protect */
 237                 bbclk.WP = 1;
 238                 write_ser_drv(0xbe,(unsigned char *)&bbclk,8);
 239         } else {
 240                 /* Else just turn write protect on */
 241                 b = 0x80;
 242                 write_ser_drv(0x8e,&b,1);
 243         }
 244         DPRINTF("init done\n");
 245
 246         ds1302_initted=1;
 247 }
 248
 249 void
 250 rtc_reset(void)
 251 {
 252         if(!ds1302_initted) rtc_init();
 253         /* TODO */
 254 }
 255
 256 void
 257 rtc_get(struct rtc_time *tmp)
 258 {
 259         struct ds1302_st bbclk;
 260
 261         if(!ds1302_initted) rtc_init();
 262
 263         read_ser_drv(0xbe,(unsigned char *)&bbclk, 8);      /* read burst */
 264
 265         if (bbclk.CH) {
 266                 printf("ds1302: rtc_get: Clock was halted, clock probably "
 267                         "corrupt\n");
 268         }
 269
 270         tmp->tm_sec=10*bbclk.sec10+bbclk.sec;
 271         tmp->tm_min=10*bbclk.min10+bbclk.min;
 272         tmp->tm_hour=10*bbclk.hr10+bbclk.hr;
 273         tmp->tm_wday=bbclk.day;
 274         tmp->tm_mday=10*bbclk.date10+bbclk.date;
 275         tmp->tm_mon=10*bbclk.month10+bbclk.month;
 276         tmp->tm_year=10*bbclk.year10+bbclk.year + 1900;
 277
 278         tmp->tm_yday = 0;
 279         tmp->tm_isdst= 0;
 280
 281         DPRINTF("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 282                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 283                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
 284 }
 285
 286 void
 287 rtc_set(struct rtc_time *tmp)
 288 {
 289         struct ds1302_st bbclk;
 290         unsigned char b=0;
 291
 292         if(!ds1302_initted) rtc_init();
 293
 294         DPRINTF("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 295                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 296                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 297
 298         memset(&bbclk,0,sizeof(bbclk));
 299         bbclk.CH=0; /* dont halt */
 300         bbclk.WP=1; /* write protect when we're done */
 301
 302         bbclk.sec10=tmp->tm_sec/10;
 303         bbclk.sec=tmp->tm_sec%10;
 304
 305         bbclk.min10=tmp->tm_min/10;
 306         bbclk.min=tmp->tm_min%10;
 307
 308         bbclk.hr10=tmp->tm_hour/10;
 309         bbclk.hr=tmp->tm_hour%10;
 310
 311         bbclk.day=tmp->tm_wday;
 312
 313         bbclk.date10=tmp->tm_mday/10;
 314         bbclk.date=tmp->tm_mday%10;
 315
 316         bbclk.month10=tmp->tm_mon/10;
 317         bbclk.month=tmp->tm_mon%10;
 318
 319         tmp->tm_year -= 1900;
 320         bbclk.year10=tmp->tm_year/10;
 321         bbclk.year=tmp->tm_year%10;
 322
 323         write_ser_drv(0x8e,&b,1);           /* disable write protect */
 324         write_ser_drv(0xbe,(unsigned char *)&bbclk, 8);     /* write burst */
 325 }
 326
 327 #endif