source: rtems/c/src/libchip/rtc/ds1375.c @ b4d0eec3

/* $Id$ */

/* Driver for the Maxim 1375 i2c RTC (TOD only; very simple...) */

/* 
 * Authorship
 * ----------
 * This software was created by
 *
 *     Till Straumann <strauman@slac.stanford.edu>, 2005-2007,
 *         Stanford Linear Accelerator Center, Stanford University.
 * 
 * Acknowledgement of sponsorship
 * ------------------------------
 * The software was produced by
 *     the Stanford Linear Accelerator Center, Stanford University,
 *         under Contract DE-AC03-76SFO0515 with the Department of Energy.
 * 
 * Government disclaimer of liability
 * ----------------------------------
 * Neither the United States nor the United States Department of Energy,
 * nor any of their employees, makes any warranty, express or implied, or
 * assumes any legal liability or responsibility for the accuracy,
 * completeness, or usefulness of any data, apparatus, product, or process
 * disclosed, or represents that its use would not infringe privately owned
 * rights.
 * 
 * Stanford disclaimer of liability
 * --------------------------------
 * Stanford University makes no representations or warranties, express or
 * implied, nor assumes any liability for the use of this software.
 * 
 * Stanford disclaimer of copyright
 * --------------------------------
 * Stanford University, owner of the copyright, hereby disclaims its
 * copyright and all other rights in this software.  Hence, anyone may
 * freely use it for any purpose without restriction.  
 * 
 * Maintenance of notices
 * ----------------------
 * In the interest of clarity regarding the origin and status of this
 * SLAC software, this and all the preceding Stanford University notices
 * are to remain affixed to any copy or derivative of this software made
 * or distributed by the recipient and are to be affixed to any copy of
 * software made or distributed by the recipient that contains a copy or
 * derivative of this software.
 * 
 * ------------------ SLAC Software Notices, Set 4 OTT.002a, 2004 FEB 03
 */ 

/* This driver uses the file-system interface to the i2c bus */

#include <rtems.h>
#include <rtems/rtc.h>
#include <libchip/rtc.h>
#include <libchip/ds1375-rtc.h>

#include <sys/fcntl.h>
#include <sys/errno.h>
#include <stdio.h>
#include <inttypes.h>


#define STATIC static
#undef  DEBUG

/* The RTC driver routines are possibly called during
 * system initialization -- that would be prior to opening
 * the console. At this point it is not safe to use stdio
 * (printf, perror etc.).
 * Our file descriptors may even be 0..2
 */
#define STDIOSAFE(fmt,args...)          \
        do {                                \
                if ( _System_state_Is_up( _System_state_Get() ) ) { \
                        fprintf(stderr,fmt,args);   \
                } else {                        \
                        printk(fmt,args);           \
                }                               \
        } while (0)
 

STATIC uint8_t ds1375_bcd2bin(uint8_t x)
{
uint8_t h = x & 0xf0;

        /* 8*hi + 2*hi + lo */
        return ( h >> 1 ) + ( h >> 3 ) + ( x & 0xf );
}

STATIC uint8_t ds1375_bin2bcd(uint8_t x)
{
uint8_t h = x/10;

        return ( h << 4 ) + ( x - ( ( h << 3 ) + ( h << 1 ) ) );
}

/*
 * Register Definitions and Access Macros
 *
 * The xxx_REG macros are offsets into the register files
 * The xxx_OFF macros are offsets into a in-memory buffer
 *             starting at the seconds (for the 1375 both,
 *             _REG and _OFF happen to be identical).
 */


#define DS1375_SEC_REG  0x0
#define DS1375_SEC_OFF  (DS1375_SEC_REG-DS1375_SEC_REG)
/* Extract seconds and convert to binary */
#define DS1375_SEC(x)   ds1375_bcd2bin( ((x)[DS1375_SEC_OFF]) & 0x7f )

#define DS1375_MIN_REG  0x1
#define DS1375_MIN_OFF  (DS1375_MIN_REG-DS1375_SEC_REG)
/* Extract minutes and convert to binary */
#define DS1375_MIN(x)   ds1375_bcd2bin( ((x)[DS1375_MIN_OFF]) & 0x7f )

#define DS1375_HR_REG   0x2
#define DS1375_HR_OFF   (DS1375_HR_REG-DS1375_SEC_REG)
#define DS1375_HR_1224  (1<<6)
#define DS1375_HR_AMPM  (1<<5)
/* Are hours in AM/PM representation ?   */
#define DS1375_IS_AMPM(x)       (DS1375_HR_1224 & ((x)[DS1375_HR_OFF]))
/* Are we PM ?                           */
#define DS1375_IS_PM(x)         (DS1375_HR_AMPM & ((x)[DS1375_HR_OFF]))
/* Extract hours (12h mode) and convert to binary */
#define DS1375_HR_12(x) ds1375_bcd2bin( ((x)[DS1375_HR_OFF]) & 0x1f )
/* Extract hours (24h mode) and convert to binary */
#define DS1375_HR_24(x) ds1375_bcd2bin( ((x)[DS1375_HR_OFF]) & 0x3f )

#define DS1375_DAY_REG  0x3
#define DS1375_DAY_OFF  (DS1375_DAY_REG-DS1375_SEC_REG)
#define DS1375_DAT_REG  0x4
#define DS1375_DAT_OFF  (DS1375_DAT_REG-DS1375_SEC_REG)
/* Extract date and convert to binary    */
#define DS1375_DAT(x)   ds1375_bcd2bin( ((x)[DS1375_DAT_OFF]) & 0x3f )
#define DS1375_MON_REG  0x5
#define DS1375_MON_OFF  (DS1375_MON_REG-DS1375_SEC_REG)
#define DS1375_MON_CTRY         (1<<7)
/* Is century bit set ?                  */
#define DS1375_IS_CTRY(x)       (((x)[DS1375_MON_OFF]) & DS1375_MON_CTRY)
/* Extract month and convert to binary   */
#define DS1375_MON(x)   ds1375_bcd2bin( ((x)[DS1375_MON_OFF]) & 0x1f )

#define DS1375_YR_REG   0x6
#define DS1375_YR_OFF   (DS1375_YR_REG-DS1375_SEC_REG)
/* Extract year and convert to binary    */
#define DS1375_YR(x)    ds1375_bcd2bin( ((x)[DS1375_YR_OFF]) & 0xff )

/* CR Register and bit definitions       */
#define DS1375_CR_REG   0xe
#define DS1375_CR_ECLK          (1<<7)
#define DS1375_CR_CLKSEL1       (1<<6)
#define DS1375_CR_CLKSEL0       (1<<5)
#define DS1375_CR_RS2           (1<<4)
#define DS1375_CR_RS1           (1<<3)
#define DS1375_CR_INTCN         (1<<2)
#define DS1375_CR_A2IE          (1<<1)
#define DS1375_CR_A1IE          (1<<0)

#define DS1375_CSR_REG  0xf

/* User SRAM (8 bytes)                   */
#define DS1375_RAM              0x10    /* start of 8 bytes user ram */

/* Access Primitives                     */

STATIC int
rd_bytes( int fd, uint32_t off, uint8_t *buf, int len )
{
uint8_t ptr = off;

        return 1 == write( fd, &ptr, 1 ) && len == read( fd, buf, len ) ? 0 : -1;
}

STATIC int
wr_bytes( int fd, uint32_t off, uint8_t *buf, int len )
{
uint8_t d[ len + 1 ];

        /* Must not break up writing of the register pointer and
         * the data to-be-written into multiple write() calls
         * because every 'write()' operation sends START and
         * the chip interprets the first byte after START as
         * the register pointer.
         */
        
        d[0] = off;
        memcpy( d + 1, buf, len );

        return len + 1 == write( fd, d, len + 1 ) ? 0 : -1;
}

/* Helpers                               */

static int
getfd( int minor )
{
        return open( (const char *)RTC_Table[minor].ulCtrlPort1, O_RDWR );
}

/* Driver Access Functions               */

STATIC void
ds1375_initialize( int minor )
{
int     fd;
uint8_t cr;

        if ( ( fd = getfd( minor ) ) >= 0 ) {
                if ( 0 == rd_bytes( fd, DS1375_CR_REG, &cr, 1 ) ) {
                        /* make sure clock is enabled */
                        if ( ! ( DS1375_CR_ECLK & cr ) ) {
                                cr |= DS1375_CR_ECLK;
                                wr_bytes( fd, DS1375_CR_REG, &cr, 1 );
                        }
                }
                close( fd );
        }

}

STATIC int
ds1375_get_time( int minor, rtems_time_of_day *time )
{
int     rval = -1;
int     fd;
uint8_t buf[DS1375_YR_REG + 1 - DS1375_SEC_REG];

        if ( time && ( ( fd = getfd( minor ) ) >= 0 ) ) {
                if ( 0 == rd_bytes( fd, DS1375_SEC_REG, buf, sizeof(buf) ) ) {
                        time->year       =  DS1375_IS_CTRY( buf ) ? 2000 : 1900;
                        time->year  +=  DS1375_YR ( buf );
                        time->month  =  DS1375_MON( buf );
                        time->day    =  DS1375_DAT( buf );      /* DAY is weekday */

                        if ( DS1375_IS_AMPM( buf ) ) {
                                time->hour   = DS1375_HR_12 ( buf );
                                if ( DS1375_IS_PM( buf ) )
                                        time->hour += 12;
                        } else {
                                time->hour   = DS1375_HR_24 ( buf );
                        }

                        time->minute =  DS1375_MIN( buf );
                        time->second =  DS1375_SEC( buf );
                        time->ticks  = 0;
                        rval = 0;
                }
                close( fd );
        }
        return rval;
}

STATIC int
ds1375_set_time( int minor, rtems_time_of_day *time )
{
int       rval = -1;
int       fd   = -1;
time_t    secs;
struct tm tm;
uint8_t   buf[DS1375_YR_REG + 1 - DS1375_SEC_REG];
uint8_t   cr = 0xff;
        /*
         * The clock hardware maintains the day-of-week as a separate counter
         * so we must compute it ourselves (rtems_time_of_day doesn't come
         * with a day of week).
         */
        secs = _TOD_To_seconds( time );
        /* we're only interested in tm_wday... */
        gmtime_r( &secs, &tm );

        buf[DS1375_SEC_OFF] = ds1375_bin2bcd( time->second );
        buf[DS1375_MIN_OFF] = ds1375_bin2bcd( time->minute );
        /* bin2bcd(hour) implicitly selects 24h mode since ms-bit is clear */
        buf[DS1375_HR_OFF]  = ds1375_bin2bcd( time->hour   );
        buf[DS1375_DAY_OFF] = tm.tm_wday + 1;
        buf[DS1375_DAT_OFF] = ds1375_bin2bcd( time->day    );
        buf[DS1375_MON_OFF] = ds1375_bin2bcd( time->month  );
        
        if ( time->year >= 2000 ) {
                buf[DS1375_YR_OFF]   = ds1375_bin2bcd( time->year - 2000 );
                buf[DS1375_MON_OFF] |= DS1375_MON_CTRY;
        } else {
                buf[DS1375_YR_OFF]   = ds1375_bin2bcd( time->year - 1900 );
        }

        /*
         * Stop clock; update registers and restart. This is slightly
         * slower than just writing everyting but if we did that we
         * could get inconsistent registers if this routine would not
         * complete in less than 1s (says the datasheet) and we don't
         * know if we are going to be pre-empted for some time...
         */
        if ( ( fd = getfd( minor ) ) < 0 ) {
                goto cleanup;
        }

        if ( rd_bytes( fd, DS1375_CR_REG, &cr, 1 ) )
                goto cleanup;

        cr &= ~DS1375_CR_ECLK;

        /* This stops the clock */
        if ( wr_bytes( fd, DS1375_CR_REG, &cr, 1 ) )
                goto cleanup;

        /* write new contents */
        if ( wr_bytes( fd, DS1375_SEC_REG, buf, sizeof(buf) ) )
                goto cleanup;

        rval = 0;
        
cleanup:
        if ( fd >= 0 ) {
                if ( ! ( DS1375_CR_ECLK & cr ) ) {
                        /* start clock; this handles some cases of failure
                         * after stopping the clock by restarting it again
                         */
                        cr |= DS1375_CR_ECLK;
                        if ( wr_bytes( fd, DS1375_CR_REG, &cr, 1 ) )
                                rval = -1;
                }
                close( fd );
        }
        return rval;
}

/* Debugging / Testing                   */

#ifdef DEBUG

/* Don't forget to set "TZ" when using these test routines */

/* What is rtems_time_of_day good for ? Why not use std types ? */

uint32_t
ds1375_get_time_tst()
{
rtems_time_of_day rtod;
time_t            secs;
        
        ds1375_get_time( 0, &rtod );            
        secs = _TOD_To_seconds( &rtod );
        printf( "%s\n", ctime( &secs ) );
        return secs;
}

int
ds1375_set_time_tst( const char *datstr, rtems_time_of_day *prt )
{
struct tm         tm;
time_t            secs;
rtems_time_of_day rt;

        if ( !datstr )
                return -1;

        if ( ! strptime( datstr, "%Y-%m-%d/%T", &tm ) )
                return -2;

        if ( ! prt )
                prt = &rt;
        
        secs = mktime( &tm );

        /* convert to UTC */
        gmtime_r( &secs, &tm );

        printf("Y: %"PRIu32" ",  (prt->year    = tm.tm_year + 1900) );
        printf("M: %"PRIu32" ",  (prt->month   = tm.tm_mon  +    1) );
        printf("D: %"PRIu32" ",  (prt->day     = tm.tm_mday       ) );
        printf("h: %"PRIu32" ",  (prt->hour    = tm.tm_hour       ) );
        printf("m: %"PRIu32" ",  (prt->minute  = tm.tm_min        ) );
        printf("s: %"PRIu32"\n", (prt->second  = tm.tm_sec        ) );
        prt->ticks = 0;

        return ( prt == &rt ) ? ds1375_set_time( 0, &rt ) : 0;
}

#endif


uint32_t
rtc_ds1375_get_register( uint32_t port, uint8_t reg )
{
int      fd;
uint8_t  v;
uint32_t rval = -1;

        if ( ( fd = open( (const char*)port, O_RDWR ) ) >= 0 ) {

                if ( 0 == rd_bytes( fd, reg, &v, 1 ) ) {
                        rval = v;
                }
                close( fd );
        }

        return rval;
}

void
rtc_ds1375_set_register( uint32_t port, uint8_t reg, uint32_t value )
{
int     fd;
uint8_t v = value;
        
        if ( ( fd = open( (const char*)port, O_RDWR ) ) >= 0 ) {
                wr_bytes( fd, reg, &v, 1 );
                close( fd );
        }

}

bool
rtc_ds1375_device_probe( int minor )
{
int fd;

        if ( ( fd = getfd( minor ) ) < 0 ) {
                STDIOSAFE( "ds1375_probe (open): %s\n", strerror( errno ) );
                return false;
        }

        /* Try to set file pointer */
        if ( 0 != wr_bytes( fd, DS1375_SEC_REG, 0, 0 ) ) {
                STDIOSAFE( "ds1375_probe (wr_bytes): %s\n", strerror( errno ) );
                close( fd );
                return false;
        }

        if ( close( fd ) ) {
                STDIOSAFE( "ds1375_probe (close): %s\n", strerror( errno ) );
                return false;
        }

        return true;
}

rtc_fns rtc_ds1375_fns = {
        deviceInitialize:       ds1375_initialize,
        deviceGetTime:          ds1375_get_time,
        deviceSetTime:          ds1375_set_time,
};