rtc.h

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#ifndef __RTC_H__
#define __RTC_H__

   /* Dallas DS1302 clock/calendar register numbers. */
#  define RTC_SECONDS      0
#  define RTC_MINUTES      1
#  define RTC_HOURS        2
#  define RTC_DAY_OF_MONTH 3
#  define RTC_MONTH        4
#  define RTC_WEEKDAY      5
#  define RTC_YEAR         6
#  define RTC_CONTROL      7

   /* Bits in CONTROL register. */
#  define RTC_CONTROL_WRITEPROTECT  0x80
#  define RTC_TRICKLECHARGER        8

  /* Bits in TRICKLECHARGER register TCS TCS TCS TCS DS DS RS RS. */
#  define RTC_TCR_PATTERN   0xA0    /* 1010xxxx */
#  define RTC_TCR_1DIOD     0x04    /* xxxx01xx */
#  define RTC_TCR_2DIOD     0x08    /* xxxx10xx */
#  define RTC_TCR_DISABLED  0x00    /* xxxxxx00 Disabled */
#  define RTC_TCR_2KOHM     0x01    /* xxxxxx01 2KOhm */
#  define RTC_TCR_4KOHM     0x02    /* xxxxxx10 4kOhm */
#  define RTC_TCR_8KOHM     0x03    /* xxxxxx11 8kOhm */

#ifdef CONFIG_DS1302
extern unsigned char ds1302_readreg(int reg);
extern void ds1302_writereg(int reg, unsigned char val);
extern int ds1302_init(void);
#  define CMOS_READ(x) ds1302_readreg(x)
#  define CMOS_WRITE(val,reg) ds1302_writereg(reg,val)
#  define RTC_INIT() ds1302_init()
#else
  /* No RTC configured so we shouldn't try to access any. */
#  define CMOS_READ(x) 42
#  define CMOS_WRITE(x,y)
#  define RTC_INIT() (-1)
#endif

/*
 * The struct used to pass data via the following ioctl. Similar to the
 * struct tm in <time.h>, but it needs to be here so that the kernel
 * source is self contained, allowing cross-compiles, etc. etc.
 */
struct rtc_time {
    int tm_sec;
    int tm_min;
    int tm_hour;
    int tm_mday;
    int tm_mon;
    int tm_year;
    int tm_wday;
    int tm_yday;
    int tm_isdst;
};

/* ioctl() calls that are permitted to the /dev/rtc interface. */
#define RTC_MAGIC 'p'
#define RTC_RD_TIME     _IOR(RTC_MAGIC, 0x09, struct rtc_time)  /* Read RTC time. */
#define RTC_SET_TIME        _IOW(RTC_MAGIC, 0x0a, struct rtc_time)  /* Set RTC time. */
#define RTC_SET_CHARGE      _IOW(RTC_MAGIC, 0x0b, int)
#define RTC_MAX_IOCTL 0x0b

#endif /* __RTC_H__ */