ref: b54c61c6174251736e0a6bf30fc1631eca79210c
dir: /sys/src/9/imx8/devrtc.c/
/* * NXP PCF8523 real time clock */ #include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h" #include "../port/i2c.h" enum { Seconds= 0x03, Minutes= 0x04, Hours= 0x05, Mday= 0x06, Wday= 0x07, Month= 0x08, Year= 0x09, Nbcd= 1+Year-Seconds, }; typedef struct Rtc Rtc; struct Rtc { int sec; int min; int hour; int mday; int wday; int mon; int year; }; enum{ Qdir = 0, Qrtc, }; Dirtab rtcdir[]={ ".", {Qdir, 0, QTDIR}, 0, 0555, "rtc", {Qrtc, 0}, 0, 0664, }; static ulong rtc2sec(Rtc*); static void sec2rtc(ulong, Rtc*); static I2Cdev *i2c; static Chan* rtcattach(char* spec) { i2c = i2cdev(i2cbus("i2c3"), 0x68); if(i2c == nil) error(Enonexist); i2c->subaddr = 1; i2c->size = 0x14; return devattach('r', spec); } static Walkqid* rtcwalk(Chan* c, Chan *nc, char** name, int nname) { return devwalk(c, nc, name, nname, rtcdir, nelem(rtcdir), devgen); } static int rtcstat(Chan* c, uchar* dp, int n) { return devstat(c, dp, n, rtcdir, nelem(rtcdir), devgen); } static Chan* rtcopen(Chan* c, int omode) { omode = openmode(omode); switch((ulong)c->qid.path){ case Qrtc: if(strcmp(up->user, eve)!=0 && omode!=OREAD) error(Eperm); break; } return devopen(c, omode, rtcdir, nelem(rtcdir), devgen); } static void rtcclose(Chan*) { } #define GETBCD(o) (((bcdclock[o]&0xf)%10) + 10*((bcdclock[o]>>4)%10)) static long _rtctime(void) { uchar bcdclock[Nbcd]; Rtc rtc; /* read clock values */ i2crecv(i2c, bcdclock, Nbcd, Seconds); /* * convert from BCD */ rtc.sec = GETBCD(Seconds-Seconds) % 60; rtc.min = GETBCD(Minutes-Seconds) % 60; rtc.hour = GETBCD(Hours-Seconds) % 24; rtc.mday = GETBCD(Mday-Seconds); rtc.wday = GETBCD(Wday-Seconds) % 7; rtc.mon = GETBCD(Month-Seconds); rtc.year = GETBCD(Year-Seconds) % 100; /* * the world starts jan 1 1970 */ if(rtc.year < 70) rtc.year += 2000; else rtc.year += 1900; return rtc2sec(&rtc); } long rtctime(void) { int i; long t, ot; /* loop till we get two reads in a row the same */ t = _rtctime(); for(i = 0; i < 100; i++){ ot = t; t = _rtctime(); if(ot == t) break; } if(i == 100) print("we are boofheads\n"); return t; } static long rtcread(Chan* c, void* buf, long n, vlong off) { ulong offset = off; if(c->qid.type & QTDIR) return devdirread(c, buf, n, rtcdir, nelem(rtcdir), devgen); switch((ulong)c->qid.path){ case Qrtc: return readnum(offset, buf, n, rtctime(), 12); } error(Ebadarg); } #define PUTBCD(n,o) bcdclock[o] = (n % 10) | (((n / 10) % 10)<<4) static long rtcwrite(Chan* c, void* buf, long n, vlong off) { Rtc rtc; ulong secs; char *cp, sbuf[32]; uchar bcdclock[Nbcd]; ulong offset = off; if(offset!=0) error(Ebadarg); switch((ulong)c->qid.path){ case Qrtc: if(n >= sizeof(sbuf)) error(Ebadarg); strncpy(sbuf, buf, n); sbuf[n] = '\0'; for(cp = sbuf; *cp != '\0'; cp++) if(*cp >= '0' && *cp <= '9') break; secs = strtoul(cp, 0, 0); /* * convert to bcd */ sec2rtc(secs, &rtc); PUTBCD(rtc.sec, Seconds-Seconds); PUTBCD(rtc.min, Minutes-Seconds); PUTBCD(rtc.hour, Hours-Seconds); PUTBCD(rtc.mday, Mday-Seconds); PUTBCD(rtc.wday, Wday-Seconds); PUTBCD(rtc.mon, Month-Seconds); PUTBCD(rtc.year, Year-Seconds); /* * write the clock */ i2csend(i2c, bcdclock, Nbcd, Seconds); return n; } error(Ebadarg); } Dev rtcdevtab = { 'r', "rtc", devreset, devinit, devshutdown, rtcattach, rtcwalk, rtcstat, rtcopen, devcreate, rtcclose, rtcread, devbread, rtcwrite, devbwrite, devremove, devwstat, }; #define SEC2MIN 60L #define SEC2HOUR (60L*SEC2MIN) #define SEC2DAY (24L*SEC2HOUR) /* * days per month plus days/year */ static int dmsize[] = { 365, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; static int ldmsize[] = { 366, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; /* * return the days/month for the given year */ static int* yrsize(int y) { if((y%4) == 0 && ((y%100) != 0 || (y%400) == 0)) return ldmsize; else return dmsize; } /* * compute seconds since Jan 1 1970 */ static ulong rtc2sec(Rtc *rtc) { ulong secs; int i; int *d2m; secs = 0; /* * seconds per year */ for(i = 1970; i < rtc->year; i++){ d2m = yrsize(i); secs += d2m[0] * SEC2DAY; } /* * seconds per month */ d2m = yrsize(rtc->year); for(i = 1; i < rtc->mon; i++) secs += d2m[i] * SEC2DAY; secs += (rtc->mday-1) * SEC2DAY; secs += rtc->hour * SEC2HOUR; secs += rtc->min * SEC2MIN; secs += rtc->sec; return secs; } /* * compute rtc from seconds since Jan 1 1970 */ static void sec2rtc(ulong secs, Rtc *rtc) { int d; long hms, day; int *d2m; /* * break initial number into days */ hms = secs % SEC2DAY; day = secs / SEC2DAY; if(hms < 0) { hms += SEC2DAY; day -= 1; } /* * 19700101 was thursday */ rtc->wday = (day + 7340036L) % 7; /* * generate hours:minutes:seconds */ rtc->sec = hms % 60; d = hms / 60; rtc->min = d % 60; d /= 60; rtc->hour = d; /* * year number */ if(day >= 0) for(d = 1970; day >= *yrsize(d); d++) day -= *yrsize(d); else for (d = 1970; day < 0; d--) day += *yrsize(d-1); rtc->year = d; /* * generate month */ d2m = yrsize(rtc->year); for(d = 1; day >= d2m[d]; d++) day -= d2m[d]; rtc->mday = day + 1; rtc->mon = d; return; }