diff options
Diffstat (limited to 'drivers/rtc/ds1302.c')
| -rw-r--r-- | drivers/rtc/ds1302.c | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/drivers/rtc/ds1302.c b/drivers/rtc/ds1302.c new file mode 100644 index 0000000..55af130 --- /dev/null +++ b/drivers/rtc/ds1302.c @@ -0,0 +1,327 @@ +/* + * ds1302.c - Support for the Dallas Semiconductor DS1302 Timekeeping Chip + * + * Rex G. Feany <rfeany@zumanetworks.com> + * + */ + +#include <common.h> +#include <command.h> +#include <rtc.h> + +#if defined(CONFIG_RTC_DS1302) && defined(CONFIG_CMD_DATE) + +/* GPP Pins */ +#define DATA 0x200 +#define SCLK 0x400 +#define RST 0x800 + +/* Happy Fun Defines(tm) */ +#define RESET rtc_go_low(RST), rtc_go_low(SCLK) +#define N_RESET rtc_go_high(RST), rtc_go_low(SCLK) + +#define CLOCK_HIGH rtc_go_high(SCLK) +#define CLOCK_LOW rtc_go_low(SCLK) + +#define DATA_HIGH rtc_go_high(DATA) +#define DATA_LOW rtc_go_low(DATA) +#define DATA_READ (GTREGREAD(GPP_VALUE) & DATA) + +#undef RTC_DEBUG + +#ifdef RTC_DEBUG +# define DPRINTF(x,args...) printf("ds1302: " x , ##args) +static inline void DUMP(const char *ptr, int num) +{ + while (num--) printf("%x ", *ptr++); + printf("]\n"); +} +#else +# define DPRINTF(x,args...) +# define DUMP(ptr, num) +#endif + +/* time data format for DS1302 */ +struct ds1302_st +{ + unsigned char CH:1; /* clock halt 1=stop 0=start */ + unsigned char sec10:3; + unsigned char sec:4; + + unsigned char zero0:1; + unsigned char min10:3; + unsigned char min:4; + + unsigned char fmt:1; /* 1=12 hour 0=24 hour */ + unsigned char zero1:1; + unsigned char hr10:2; /* 10 (0-2) or am/pm (am/pm, 0-1) */ + unsigned char hr:4; + + unsigned char zero2:2; + unsigned char date10:2; + unsigned char date:4; + + unsigned char zero3:3; + unsigned char month10:1; + unsigned char month:4; + + unsigned char zero4:5; + unsigned char day:3; /* day of week */ + + unsigned char year10:4; + unsigned char year:4; + + unsigned char WP:1; /* write protect 1=protect 0=unprot */ + unsigned char zero5:7; +}; + +static int ds1302_initted=0; + +/* Pin control */ +static inline void +rtc_go_high(unsigned int mask) +{ + unsigned int f = GTREGREAD(GPP_VALUE) | mask; + + GT_REG_WRITE(GPP_VALUE, f); +} + +static inline void +rtc_go_low(unsigned int mask) +{ + unsigned int f = GTREGREAD(GPP_VALUE) & ~mask; + + GT_REG_WRITE(GPP_VALUE, f); +} + +static inline void +rtc_go_input(unsigned int mask) +{ + unsigned int f = GTREGREAD(GPP_IO_CONTROL) & ~mask; + + GT_REG_WRITE(GPP_IO_CONTROL, f); +} + +static inline void +rtc_go_output(unsigned int mask) +{ + unsigned int f = GTREGREAD(GPP_IO_CONTROL) | mask; + + GT_REG_WRITE(GPP_IO_CONTROL, f); +} + +/* Access data in RTC */ + +static void +write_byte(unsigned char b) +{ + int i; + unsigned char mask=1; + + for(i=0;i<8;i++) { + CLOCK_LOW; /* Lower clock */ + (b&mask)?DATA_HIGH:DATA_LOW; /* set data */ + udelay(1); + CLOCK_HIGH; /* latch data with rising clock */ + udelay(1); + mask=mask<<1; + } +} + +static unsigned char +read_byte(void) +{ + int i; + unsigned char mask=1; + unsigned char b=0; + + for(i=0;i<8;i++) { + CLOCK_LOW; + udelay(1); + if (DATA_READ) b|=mask; /* if this bit is high, set in b */ + CLOCK_HIGH; /* clock out next bit */ + udelay(1); + mask=mask<<1; + } + return b; +} + +static void +read_ser_drv(unsigned char addr, unsigned char *buf, int count) +{ + int i; +#ifdef RTC_DEBUG + char *foo = buf; +#endif + + DPRINTF("READ 0x%x bytes @ 0x%x [ ", count, addr); + + addr|=1; /* READ */ + N_RESET; + udelay(4); + write_byte(addr); + rtc_go_input(DATA); /* Put gpp pin into input mode */ + udelay(1); + for(i=0;i<count;i++) *(buf++)=read_byte(); + RESET; + rtc_go_output(DATA);/* Reset gpp for output */ + udelay(4); + + DUMP(foo, count); +} + +static void +write_ser_drv(unsigned char addr, unsigned char *buf, int count) +{ + int i; + + DPRINTF("WRITE 0x%x bytes @ 0x%x [ ", count, addr); + DUMP(buf, count); + + addr&=~1; /* WRITE */ + N_RESET; + udelay(4); + write_byte(addr); + for(i=0;i<count;i++) write_byte(*(buf++)); + RESET; + udelay(4); + +} + +void +rtc_init(void) +{ + struct ds1302_st bbclk; + unsigned char b; + int mod; + + DPRINTF("init\n"); + + rtc_go_output(DATA|SCLK|RST); + + /* disable write protect */ + b = 0; + write_ser_drv(0x8e,&b,1); + + /* enable trickle */ + b = 0xa5; /* 1010.0101 */ + write_ser_drv(0x90,&b,1); + + /* read burst */ + read_ser_drv(0xbe, (unsigned char *)&bbclk, 8); + + /* Sanity checks */ + mod = 0; + if (bbclk.CH) { + printf("ds1302: Clock was halted, starting clock\n"); + bbclk.CH=0; + mod=1; + } + + if (bbclk.fmt) { + printf("ds1302: Clock was in 12 hour mode, fixing\n"); + bbclk.fmt=0; + mod=1; + } + + if (bbclk.year>9) { + printf("ds1302: Year was corrupted, fixing\n"); + bbclk.year10=100/10; /* 2000 - why not? ;) */ + bbclk.year=0; + mod=1; + } + + /* Write out the changes if needed */ + if (mod) { + /* enable write protect */ + bbclk.WP = 1; + write_ser_drv(0xbe,(unsigned char *)&bbclk,8); + } else { + /* Else just turn write protect on */ + b = 0x80; + write_ser_drv(0x8e,&b,1); + } + DPRINTF("init done\n"); + + ds1302_initted=1; +} + +void +rtc_reset(void) +{ + if(!ds1302_initted) rtc_init(); + /* TODO */ +} + +void +rtc_get(struct rtc_time *tmp) +{ + struct ds1302_st bbclk; + + if(!ds1302_initted) rtc_init(); + + read_ser_drv(0xbe,(unsigned char *)&bbclk, 8); /* read burst */ + + if (bbclk.CH) { + printf("ds1302: rtc_get: Clock was halted, clock probably " + "corrupt\n"); + } + + tmp->tm_sec=10*bbclk.sec10+bbclk.sec; + tmp->tm_min=10*bbclk.min10+bbclk.min; + tmp->tm_hour=10*bbclk.hr10+bbclk.hr; + tmp->tm_wday=bbclk.day; + tmp->tm_mday=10*bbclk.date10+bbclk.date; + tmp->tm_mon=10*bbclk.month10+bbclk.month; + tmp->tm_year=10*bbclk.year10+bbclk.year + 1900; + + tmp->tm_yday = 0; + tmp->tm_isdst= 0; + + DPRINTF("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", + tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, + tmp->tm_hour, tmp->tm_min, tmp->tm_sec ); +} + +void +rtc_set(struct rtc_time *tmp) +{ + struct ds1302_st bbclk; + unsigned char b=0; + + if(!ds1302_initted) rtc_init(); + + DPRINTF("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", + tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, + tmp->tm_hour, tmp->tm_min, tmp->tm_sec); + + memset(&bbclk,0,sizeof(bbclk)); + bbclk.CH=0; /* dont halt */ + bbclk.WP=1; /* write protect when we're done */ + + bbclk.sec10=tmp->tm_sec/10; + bbclk.sec=tmp->tm_sec%10; + + bbclk.min10=tmp->tm_min/10; + bbclk.min=tmp->tm_min%10; + + bbclk.hr10=tmp->tm_hour/10; + bbclk.hr=tmp->tm_hour%10; + + bbclk.day=tmp->tm_wday; + + bbclk.date10=tmp->tm_mday/10; + bbclk.date=tmp->tm_mday%10; + + bbclk.month10=tmp->tm_mon/10; + bbclk.month=tmp->tm_mon%10; + + tmp->tm_year -= 1900; + bbclk.year10=tmp->tm_year/10; + bbclk.year=tmp->tm_year%10; + + write_ser_drv(0x8e,&b,1); /* disable write protect */ + write_ser_drv(0xbe,(unsigned char *)&bbclk, 8); /* write burst */ +} + +#endif |