ref: b0377e84cf31c48afed765c433abe7eebb4135a5
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);
return 0;
}
#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);
return 0;
}
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;
}