rtc8583.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause
    3  *
    4  * Copyright (c) 2017 Hiroki Mori.  All rights reserved.
    5  * Copyright (c) 2017 Ian Lepore.
    6  *
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   26  *
   27  * This code base on isl12xx.c
   28  */
   29 
   30 #include <sys/cdefs.h>
   31 __FBSDID("$FreeBSD$");
   32 
   33 /*
   34  * Driver for realtime clock EPSON RTC-8583
   35  */
   36 
   37 #include "opt_platform.h"
   38 
   39 #include <sys/param.h>
   40 #include <sys/systm.h>
   41 #include <sys/bus.h>
   42 #include <sys/clock.h>
   43 #include <sys/kernel.h>
   44 #include <sys/lock.h>
   45 #include <sys/module.h>
   46 
   47 #ifdef FDT
   48 #include <dev/ofw/ofw_bus.h>
   49 #include <dev/ofw/ofw_bus_subr.h>
   50 #endif
   51 
   52 #include <dev/iicbus/iiconf.h>
   53 #include <dev/iicbus/iicbus.h>
   54 
   55 #include "clock_if.h"
   56 #include "iicbus_if.h"
   57 
   58 #define RTC8583_SC_REG          0x01            /* RTC Seconds */
   59 #define RTC8583_USERSRAM_REG    0x10            /* User SRAM register (first) */
   60 #define MAX_TRANSFER            16
   61 
   62 /*
   63  * A struct laid out in the same order as the time registers in the chip.
   64  */
   65 struct time_regs {
   66         uint8_t msec, sec, min, hour, day, month;
   67 };
   68 
   69 struct rtc8583_softc {
   70         device_t        dev;
   71         device_t        busdev;
   72         struct intr_config_hook 
   73                         init_hook;
   74 };
   75 
   76 #ifdef FDT
   77 static struct ofw_compat_data compat_data[] = {
   78         {"epson,rtc8583", 1},
   79         {NULL,           0},
   80 };
   81 #endif
   82 
   83 static void     rtc8583_init(void *arg);
   84 static int      rtc8583_probe(device_t dev);
   85 static int      rtc8583_attach(device_t dev);
   86 static int      rtc8583_detach(device_t dev);
   87 
   88 static int      rtc8583_gettime(device_t dev, struct timespec *ts);
   89 static int      rtc8583_settime(device_t dev, struct timespec *ts);
   90 
   91 static int      rtc8583_writeto(device_t slavedev, uint8_t regaddr, 
   92                     void *buffer, uint16_t buflen, int waithow);
   93 
   94 /* Implementation */
   95 
   96 static int 
   97 rtc8583_writeto(device_t slavedev, uint8_t regaddr, void *buffer,
   98     uint16_t buflen, int waithow)
   99 {
  100         struct iic_msg  msgs;
  101         uint8_t         slaveaddr;
  102         uint8_t         newbuf[MAX_TRANSFER];
  103 
  104         slaveaddr = iicbus_get_addr(slavedev);
  105 
  106         newbuf[0] = regaddr;
  107         memcpy(newbuf + 1, buffer, buflen);
  108         msgs.slave = slaveaddr;
  109         msgs.flags = IIC_M_WR;
  110         msgs.len   = 1 + buflen;
  111         msgs.buf   = newbuf;
  112 
  113         return (iicbus_transfer_excl(slavedev, &msgs, 1, waithow));
  114 }
  115 
  116 static inline int
  117 rtc8583_read1(struct rtc8583_softc *sc, uint8_t reg, uint8_t *data) 
  118 {
  119 
  120         return (iicdev_readfrom(sc->dev, reg, data, 1, IIC_WAIT));
  121 }
  122 
  123 static inline int
  124 rtc8583_write1(struct rtc8583_softc *sc, uint8_t reg, uint8_t val) 
  125 {
  126 
  127         return (rtc8583_writeto(sc->dev, reg, &val, 1, IIC_WAIT));
  128 }
  129 
  130 static void
  131 rtc8583_init(void *arg)
  132 {
  133         struct rtc8583_softc    *sc;
  134         
  135         sc = (struct rtc8583_softc*)arg;
  136         config_intrhook_disestablish(&sc->init_hook);
  137 
  138         /*
  139          * Register as a system realtime clock.
  140          */
  141         clock_register_flags(sc->dev, 1000000, CLOCKF_SETTIME_NO_ADJ);
  142         clock_schedule(sc->dev, 1);
  143         return;
  144 }
  145 
  146 static int
  147 rtc8583_probe(device_t dev)
  148 {
  149 
  150 #ifdef FDT
  151         if (!ofw_bus_status_okay(dev))
  152                 return (ENXIO);
  153 
  154         if (ofw_bus_search_compatible(dev, compat_data)->ocd_data != 0) {
  155                 device_set_desc(dev, "EPSON RTC-8583");
  156                 return (BUS_PROBE_DEFAULT);
  157         }
  158 #endif
  159         return (ENXIO);
  160 }
  161 
  162 static int
  163 rtc8583_attach(device_t dev)
  164 {
  165         struct rtc8583_softc    *sc;
  166         
  167         sc = device_get_softc(dev);
  168         sc->dev = dev;
  169         sc->busdev = device_get_parent(sc->dev);
  170 
  171         /*
  172          * Chip init must wait until interrupts are enabled.  Often i2c access
  173          * works only when the interrupts are available.
  174          */
  175         sc->init_hook.ich_func = rtc8583_init;
  176         sc->init_hook.ich_arg = sc;
  177         if (config_intrhook_establish(&sc->init_hook) != 0)
  178                 return (ENOMEM);
  179 
  180         return (0);
  181 }
  182 
  183 static int
  184 rtc8583_detach(device_t dev)
  185 {
  186 
  187         clock_unregister(dev);
  188         return (0);
  189 }
  190 
  191 static int
  192 rtc8583_gettime(device_t dev, struct timespec *ts)
  193 {
  194         struct rtc8583_softc    *sc;
  195         struct bcd_clocktime     bct;
  196         struct time_regs         tregs;
  197         uint8_t                  y, ytmp, sreg;
  198         int                      err;
  199 
  200         sc = device_get_softc(dev);
  201 
  202         /* Read the bcd time registers. */
  203         if ((err = iicdev_readfrom(sc->dev, RTC8583_SC_REG, &tregs, sizeof(tregs),
  204             IIC_WAIT)) != 0)
  205                 return (err);
  206 
  207         y = tregs.day >> 6;
  208         /* Get year from user SRAM */
  209         rtc8583_read1(sc, RTC8583_USERSRAM_REG,  &sreg);
  210         
  211         /* 
  212          * Check if year adjustment is required.
  213          * RTC has only 2 bits for year value (i.e. maximum is 4 years), so
  214          * full year value is stored in user SRAM and updated manually or 
  215          * by this code.
  216          */
  217         ytmp = sreg & 0x03;
  218         if (ytmp != y) {
  219                 /* shift according to difference */
  220                 sreg += y - ytmp;
  221                 
  222                 /* check if overflow happened */
  223                 if (ytmp > y)
  224                         sreg += 4;
  225                 
  226                 if ((err = iicbus_request_bus(sc->busdev, sc->dev, IIC_WAIT)) != 0)
  227                         return (err);
  228                 rtc8583_write1(sc, RTC8583_USERSRAM_REG, sreg);
  229                 iicbus_release_bus(sc->busdev, sc->dev);
  230         }
  231 
  232         if (!validbcd(tregs.msec))
  233                 return (EINVAL);
  234 
  235         /* The 'msec' reg is actually 1/100ths, in bcd.  */
  236         bct.nsec = bcd2bin(tregs.msec) * 10 * 1000 * 1000;
  237         bct.sec  = tregs.sec;
  238         bct.min  = tregs.min;
  239         bct.hour = tregs.hour & 0x3f;
  240         bct.day  = tregs.day & 0x3f;
  241         bct.mon  = tregs.month & 0x1f;
  242         bct.year = bin2bcd(sreg % 100);
  243 
  244         clock_dbgprint_bcd(sc->dev, CLOCK_DBG_READ, &bct); 
  245         return (clock_bcd_to_ts(&bct, ts, false));
  246 }
  247 
  248 static int
  249 rtc8583_settime(device_t dev, struct timespec *ts)
  250 {
  251         struct rtc8583_softc    *sc;
  252         struct bcd_clocktime     bct;
  253         struct time_regs         tregs;
  254         uint8_t                  sreg;
  255         int                      err;
  256 
  257         sc = device_get_softc(dev);
  258         ts->tv_sec -= utc_offset();
  259         clock_ts_to_bcd(ts, &bct, false);
  260         clock_dbgprint_bcd(sc->dev, CLOCK_DBG_WRITE, &bct);
  261 
  262         /* The 'msec' reg is actually 1/100ths, in bcd.  */
  263         tregs.msec  = bin2bcd(ts->tv_nsec / (10 * 1000 * 1000));
  264         tregs.sec   = bct.sec;
  265         tregs.min   = bct.min;
  266         tregs.hour  = bct.hour;
  267         tregs.day   = bct.day | (bct.year & 0x03 << 6);
  268         tregs.month = bct.mon;
  269 
  270         if ((err = iicbus_request_bus(sc->busdev, sc->dev, IIC_WAIT)) != 0)
  271                 return (err);
  272         err = rtc8583_writeto(sc->dev, RTC8583_SC_REG, &tregs,
  273             sizeof(tregs), IIC_WAIT);
  274         sreg = bcd2bin(bct.year & 0xff);
  275         /* save to year to sram */
  276         rtc8583_write1(sc, RTC8583_USERSRAM_REG, sreg);
  277         iicbus_release_bus(sc->busdev, sc->dev);
  278 
  279         return (err);
  280 }
  281 
  282 static device_method_t rtc8583_methods[] = {
  283         /* device_if methods */
  284         DEVMETHOD(device_probe,         rtc8583_probe),
  285         DEVMETHOD(device_attach,        rtc8583_attach),
  286         DEVMETHOD(device_detach,        rtc8583_detach),
  287 
  288         /* clock_if methods */
  289         DEVMETHOD(clock_gettime,        rtc8583_gettime),
  290         DEVMETHOD(clock_settime,        rtc8583_settime),
  291 
  292         DEVMETHOD_END,
  293 };
  294 
  295 static driver_t rtc8583_driver = {
  296         "rtc8583",
  297         rtc8583_methods,
  298         sizeof(struct rtc8583_softc),
  299 };
  300 
  301 DRIVER_MODULE(rtc8583, iicbus, rtc8583_driver, NULL, NULL);
  302 MODULE_VERSION(rtc8583, 1);
  303 MODULE_DEPEND(rtc8583, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
  304 IICBUS_FDT_PNP_INFO(compat_data);

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FreeBSD/Linux Kernel Cross Reference sys/dev/iicbus/rtc8583.c

FreeBSD/Linux Kernel Cross Reference
sys/dev/iicbus/rtc8583.c