FreeBSD/Linux Kernel Cross Reference
sys/dev/iicbus/ds1672.c

     /*-
      * Copyright (c) 2006 Sam Leffler.  All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
      * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    /*
     * Dallas Semiconductor DS1672 RTC sitting on the I2C bus.
     */
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/clock.h>
    #include <sys/time.h>
    #include <sys/bus.h>
    #include <sys/resource.h>
    #include <sys/rman.h>
    
    #include <dev/iicbus/iiconf.h>
    
    #include "iicbus_if.h"
    #include "clock_if.h"
    
    #define IIC_M_WR        0       /* write operation */
    
    #define DS1672_ADDR     0xd0    /* slave address */
    
    #define DS1672_COUNTER  0       /* counter (bytes 0-3) */
    #define DS1672_CTRL     4       /* control (1 byte) */
    #define DS1672_TRICKLE  5       /* trickle charger (1 byte) */
    
    #define DS1672_CTRL_EOSC        (1 << 7)        /* Stop/start flag. */
    
    #define NANOSEC         1000000000
    
    #define MAX_IIC_DATA_SIZE       4
    
    struct ds1672_softc {
            device_t                sc_dev;
    };
    
    static int
    ds1672_probe(device_t dev)
    {
            /* XXX really probe? */
            device_set_desc(dev, "Dallas Semiconductor DS1672 RTC");
            return (BUS_PROBE_NOWILDCARD);
    }
    
    static int
    ds1672_read(device_t dev, uint8_t addr, uint8_t *data, uint8_t size)
    {
            struct iic_msg msgs[2] = {
                 { DS1672_ADDR, IIC_M_WR, 1, &addr },
                 { DS1672_ADDR, IIC_M_RD, size, data }
            };
    
            return (iicbus_transfer(dev, msgs, 2));
    }
    
    static int
    ds1672_write(device_t dev, uint8_t addr, uint8_t *data, uint8_t size)
    {
            uint8_t buffer[MAX_IIC_DATA_SIZE + 1];
            struct iic_msg msgs[1] = {
                 { DS1672_ADDR, IIC_M_WR, size + 1, buffer },
            };
            
            if (size > MAX_IIC_DATA_SIZE)
                    return (ENOMEM);
            /* NB: register pointer precedes actual data */
            buffer[0] = addr;
            memcpy(buffer + 1, data, size);
            return (iicbus_transfer(dev, msgs, 1));
    }
    
    static int
    ds1672_init(device_t dev)
   {
           uint8_t ctrl;
           int error;
   
           error = ds1672_read(dev, DS1672_CTRL, &ctrl, 1);
           if (error)
                   return (error);
   
           /*
            * Check if oscialltor is not runned.
            */
           if (ctrl & DS1672_CTRL_EOSC) {
                   device_printf(dev, "RTC oscillator was stopped. Check system"
                       " time and RTC battery.\n");
                   ctrl &= ~DS1672_CTRL_EOSC;      /* Start oscillator. */
                   error = ds1672_write(dev, DS1672_CTRL, &ctrl, 1);
           }
           return (error);
   }
   
   static int
   ds1672_attach(device_t dev)
   {
           struct ds1672_softc *sc = device_get_softc(dev);
           int error;
   
           sc->sc_dev = dev;
           error = ds1672_init(dev);
           if (error)
                   return (error);
           clock_register(dev, 1000);
           return (0);
   }
   
   static int
   ds1672_gettime(device_t dev, struct timespec *ts)
   {
           uint8_t secs[4];
           int error;
   
           error = ds1672_read(dev, DS1672_COUNTER, secs, 4);
           if (error == 0) {
                   /* counter has seconds since epoch */
                   ts->tv_sec = (secs[3] << 24) | (secs[2] << 16)
                              | (secs[1] <<  8) | (secs[0] <<  0);
                   ts->tv_nsec = NANOSEC / 2;
           }
           return (error);
   }
   
   static int
   ds1672_settime(device_t dev, struct timespec *ts)
   {
           uint8_t data[4];
   
           data[0] = (ts->tv_sec >> 0) & 0xff;
           data[1] = (ts->tv_sec >> 8) & 0xff;
           data[2] = (ts->tv_sec >> 16) & 0xff;
           data[3] = (ts->tv_sec >> 24) & 0xff;
   
           return (ds1672_write(dev, DS1672_COUNTER, data, 4));
   }
   
   static device_method_t ds1672_methods[] = {
           DEVMETHOD(device_probe,         ds1672_probe),
           DEVMETHOD(device_attach,        ds1672_attach),
   
           DEVMETHOD(clock_gettime,        ds1672_gettime),
           DEVMETHOD(clock_settime,        ds1672_settime),
   
           {0, 0},
   };
   
   static driver_t ds1672_driver = {
           "ds1672_rtc",
           ds1672_methods,
           sizeof(struct ds1672_softc),
   };
   static devclass_t ds1672_devclass;
   
   DRIVER_MODULE(ds1672, iicbus, ds1672_driver, ds1672_devclass, 0, 0);
   MODULE_VERSION(ds1672, 1);
   MODULE_DEPEND(ds1672, iicbus, 1, 1, 1);

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