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/*!***************************************************************************

*!

*! FILE NAME  : ds1302.c

*!

*! DESCRIPTION: Implements an interface for the DS1302 RTC through Etrax I/O

*!

*! Functions exported: ds1302_readreg, ds1302_writereg, ds1302_init

*!

*! $Log: not supported by cvs2svn $

*! Revision 1.19  2003/06/12 08:02:05  johana

*! Removed faulty comma from printk.

*! Fixed warning () -> (void)

*!

*! Revision 1.18  2003/04/16 09:02:28  oskarp

*! * Merged change_branch--rtc_readonly to main.

*!

*! Revision 1.17  2003/04/01 14:12:06  starvik

*! Added loglevel for lots of printks

*!

*! Revision 1.16  2003/02/19 15:51:16  cedric

*! Start the clock from ds1302_init()

*!

*! Revision 1.15  2002/10/11 16:14:33  johana

*! Added CONFIG_ETRAX_DS1302_TRICKLE_CHARGE and initial setting of the

*! trcklecharge register.

*!

*! Revision 1.14  2002/10/10 12:15:38  magnusmn

*! Added support for having the RST signal on bit g0

*!

*! Revision 1.13  2002/05/29 15:16:08  johana

*! Removed unused variables.

*!

*! Revision 1.12  2002/04/10 15:35:25  johana

*! Moved probe function closer to init function and marked it __init.

*!

*! Revision 1.11  2001/06/14 12:35:52  jonashg

*! The ATA hack is back. It is unfortunately the only way to set g27 to output.

*!

*! Revision 1.9  2001/06/14 10:00:14  jonashg

*! No need for tempudelay to be inline anymore (had to adjust the usec to

*! loops conversion because of this to make it slow enough to be a udelay).

*!

*! Revision 1.8  2001/06/14 08:06:32  jonashg

*! Made tempudelay delay usecs (well, just a tad more).

*!

*! Revision 1.7  2001/06/13 14:18:11  jonashg

*! Only allow processes with SYS_TIME capability to set time and charge.

*!

*! Revision 1.6  2001/06/12 15:22:07  jonashg

*! * Made init function __init.

*! * Parameter to out_byte() is unsigned char.

*! * The magic number 42 has got a name.

*! * Removed comment about /proc (nothing is exported there).

*!

*! Revision 1.5  2001/06/12 14:35:13  jonashg

*! Gave the module a name and added it to printk's.

*!

*! Revision 1.4  2001/05/31 14:53:40  jonashg

*! Made tempudelay() inline so that the watchdog doesn't reset (see

*! function comment).

*!

*! Revision 1.3  2001/03/26 16:03:06  bjornw

*! Needs linux/config.h

*!

*! Revision 1.2  2001/03/20 19:42:00  bjornw

*! Use the ETRAX prefix on the DS1302 options

*!

*! Revision 1.1  2001/03/20 09:13:50  magnusmn

*! Linux 2.4 port

*!

*! Revision 1.10  2000/07/05 15:38:23  bjornw

*! Dont update kernel time when a RTC_SET_TIME is done

*!

*! Revision 1.9  2000/03/02 15:42:59  macce

*! * Hack to make RTC work on all 2100/2400

*!

*! Revision 1.8  2000/02/23 16:59:18  torbjore

*! added setup of R_GEN_CONFIG when RTC is connected to the generic port.

*!

*! Revision 1.7  2000/01/17 15:51:43  johana

*! Added RTC_SET_CHARGE ioctl to enable trickle charger.

*!

*! Revision 1.6  1999/10/27 13:19:47  bjornw

*! Added update_xtime_from_cmos which reads back the updated RTC into the kernel.

*! /dev/rtc calls it now.

*!

*! Revision 1.5  1999/10/27 12:39:37  bjornw

*! Disabled superuser check. Anyone can now set the time.

*!

*! Revision 1.4  1999/09/02 13:27:46  pkj

*! Added shadow for R_PORT_PB_CONFIG.

*! Renamed port_g_shadow to port_g_data_shadow.

*!

*! Revision 1.3  1999/09/02 08:28:06  pkj

*! Made it possible to select either port PB or the generic port for the RST

*! signal line to the DS1302 RTC.

*! Also make sure the RST bit is configured as output on Port PB (if used).

*!

*! Revision 1.2  1999/09/01 14:47:20  bjornw

*! Added support for /dev/rtc operations with ioctl RD_TIME and SET_TIME to read

*! and set the date. Register as major 121.

*!

*! Revision 1.1  1999/09/01 09:45:29  bjornw

*! Implemented a DS1302 RTC driver.

*!

*!

*! ---------------------------------------------------------------------------

*!

*! (C) Copyright 1999, 2000, 2001  Axis Communications AB, LUND, SWEDEN

*!

*! $Id: ds1302.c,v 1.1.1.1 2004-04-15 01:22:27 phoenix Exp $

*!

*!***************************************************************************/

#include <linux/config.h>

#include <linux/fs.h>

#include <linux/init.h>

#include <linux/mm.h>

#include <linux/module.h>

#include <linux/miscdevice.h>

#include <linux/delay.h>

#include <asm/uaccess.h>

#include <asm/system.h>

#include <asm/svinto.h>

#include <asm/io.h>

#include <asm/rtc.h>

#define RTC_MAJOR_NR 121 /* local major, change later */

static const char ds1302_name[] = "ds1302";

/* The DS1302 might be connected to different bits on different products.

 * It has three signals - SDA, SCL and RST. RST and SCL are always outputs,

 * but SDA can have a selected direction.

 * For now, only PORT_PB is hardcoded.

 */

/* The RST bit may be on either the Generic Port or Port PB. */

#ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT

#define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_G_DATA,  port_g_data_shadow,  CONFIG_ETRAX_DS1302_RSTBIT, x)

#define TK_RST_DIR(x)

#else

#define TK_RST_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_RSTBIT, x)

#define TK_RST_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_RSTBIT, x)

#endif

#define TK_SDA_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SDABIT, x)

#define TK_SCL_OUT(x) REG_SHADOW_SET(R_PORT_PB_DATA, port_pb_data_shadow, CONFIG_ETRAX_DS1302_SCLBIT, x)

#define TK_SDA_IN()   ((*R_PORT_PB_READ >> CONFIG_ETRAX_DS1302_SDABIT) & 1)

/* 1 is out, 0 is in */

#define TK_SDA_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_SDABIT, x)

#define TK_SCL_DIR(x) REG_SHADOW_SET(R_PORT_PB_DIR,  port_pb_dir_shadow,  CONFIG_ETRAX_DS1302_SCLBIT, x)

/*

 * The reason for tempudelay and not udelay is that loops_per_usec

 * (used in udelay) is not set when functions here are called from time.c

 */

static void tempudelay(int usecs)

{

        volatile int loops;

        for(loops = usecs * 12; loops > 0; loops--)

                /* nothing */;

}

/* Send 8 bits. */

static void

out_byte(unsigned char x)

{

        int i;

        TK_SDA_DIR(1);

        for (i = 8; i--;) {

                /* The chip latches incoming bits on the rising edge of SCL. */

                TK_SCL_OUT(0);

                TK_SDA_OUT(x & 1);

                tempudelay(1);

                TK_SCL_OUT(1);

                tempudelay(1);

                x >>= 1;

        }

        TK_SDA_DIR(0);

}

static unsigned char

in_byte(void)

{

        unsigned char x = 0;

        int i;

        /* Read byte. Bits come LSB first, on the falling edge of SCL.

         * Assume SDA is in input direction already.

         */

        TK_SDA_DIR(0);

        for (i = 8; i--;) {

                TK_SCL_OUT(0);

                tempudelay(1);

                x >>= 1;

                x |= (TK_SDA_IN() << 7);

                TK_SCL_OUT(1);

                tempudelay(1);

        }

        return x;

}

/* Prepares for a transaction by de-activating RST (active-low). */

static void

start(void)

{

        TK_SCL_OUT(0);

        tempudelay(1);

        TK_RST_OUT(0);

        tempudelay(5);

        TK_RST_OUT(1);

}

/* Ends a transaction by taking RST active again. */

static void

stop(void)

{

        tempudelay(2);

        TK_RST_OUT(0);

}

/* Enable writing. */

static void

ds1302_wenable(void)

{

        start();

        out_byte(0x8e); /* Write control register  */

        out_byte(0x00); /* Disable write protect bit 7 = 0 */

        stop();

}

/* Disable writing. */

static void

ds1302_wdisable(void)

{

        start();

        out_byte(0x8e); /* Write control register  */

        out_byte(0x80); /* Disable write protect bit 7 = 0 */

        stop();

}

/* Read a byte from the selected register in the DS1302. */

unsigned char

ds1302_readreg(int reg)

{

        unsigned char x;

        start();

        out_byte(0x81 | (reg << 1)); /* read register */

        x = in_byte();

        stop();

        return x;

}

/* Write a byte to the selected register. */

void

ds1302_writereg(int reg, unsigned char val)

{

#ifndef CONFIG_ETRAX_RTC_READONLY

        int do_writereg = 1;

#else

        int do_writereg = 0;

        if (reg == RTC_TRICKLECHARGER)

                do_writereg = 1;

#endif

        if (do_writereg) {

                ds1302_wenable();

                start();

                out_byte(0x80 | (reg << 1)); /* write register */

                out_byte(val);

                stop();

                ds1302_wdisable();

        }

}

void

get_rtc_time(struct rtc_time *rtc_tm)

{

        unsigned long flags;

        save_flags(flags);

        cli();

        rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);

        rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);

        rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);

        rtc_tm->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);

        rtc_tm->tm_mon = CMOS_READ(RTC_MONTH);

        rtc_tm->tm_year = CMOS_READ(RTC_YEAR);

        restore_flags(flags);

        BCD_TO_BIN(rtc_tm->tm_sec);

        BCD_TO_BIN(rtc_tm->tm_min);

        BCD_TO_BIN(rtc_tm->tm_hour);

        BCD_TO_BIN(rtc_tm->tm_mday);

        BCD_TO_BIN(rtc_tm->tm_mon);

        BCD_TO_BIN(rtc_tm->tm_year);

        /*

         * Account for differences between how the RTC uses the values

         * and how they are defined in a struct rtc_time;

         */

        if (rtc_tm->tm_year <= 69)

                rtc_tm->tm_year += 100;

        rtc_tm->tm_mon--;

}

static unsigned char days_in_mo[] =

    {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

/* ioctl that supports RTC_RD_TIME and RTC_SET_TIME (read and set time/date). */

static int

rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,

          unsigned long arg)

{

        unsigned long flags;

        switch(cmd) {

                case RTC_RD_TIME:       /* read the time/date from RTC  */

                {

                        struct rtc_time rtc_tm;

                        memset(&rtc_tm, 0, sizeof (struct rtc_time));

                        get_rtc_time(&rtc_tm);

                        if (copy_to_user((struct rtc_time*)arg, &rtc_tm, sizeof(struct rtc_time)))

                                return -EFAULT;

                        return 0;

                }

                case RTC_SET_TIME:      /* set the RTC */

                {

                        struct rtc_time rtc_tm;

                        unsigned char mon, day, hrs, min, sec, leap_yr;

                        unsigned int yrs;

                        if (!capable(CAP_SYS_TIME))

                                return -EPERM;

                        if (copy_from_user(&rtc_tm, (struct rtc_time*)arg, sizeof(struct rtc_time)))

                                return -EFAULT;

                        yrs = rtc_tm.tm_year + 1900;

                        mon = rtc_tm.tm_mon + 1;   /* tm_mon starts at zero */

                        day = rtc_tm.tm_mday;

                        hrs = rtc_tm.tm_hour;

                        min = rtc_tm.tm_min;

                        sec = rtc_tm.tm_sec;

                        if ((yrs < 1970) || (yrs > 2069))

                                return -EINVAL;

                        leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));

                        if ((mon > 12) || (day == 0))

                                return -EINVAL;

                        if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))

                                return -EINVAL;

                        if ((hrs >= 24) || (min >= 60) || (sec >= 60))

                                return -EINVAL;

                        if (yrs >= 2000)

                                yrs -= 2000;    /* RTC (0, 1, ... 69) */

                        else

                                yrs -= 1900;    /* RTC (70, 71, ... 99) */

                        BIN_TO_BCD(sec);

                        BIN_TO_BCD(min);

                        BIN_TO_BCD(hrs);

                        BIN_TO_BCD(day);

                        BIN_TO_BCD(mon);

                        BIN_TO_BCD(yrs);

                        save_flags(flags);

                        cli();

                        CMOS_WRITE(yrs, RTC_YEAR);

                        CMOS_WRITE(mon, RTC_MONTH);

                        CMOS_WRITE(day, RTC_DAY_OF_MONTH);

                        CMOS_WRITE(hrs, RTC_HOURS);

                        CMOS_WRITE(min, RTC_MINUTES);

                        CMOS_WRITE(sec, RTC_SECONDS);

                        restore_flags(flags);

                        /* Notice that at this point, the RTC is updated but

                         * the kernel is still running with the old time.

                         * You need to set that separately with settimeofday

                         * or adjtimex.

                         */

                        return 0;

                }

                case RTC_SET_CHARGE: /* set the RTC TRICKLE CHARGE register */

                {

                        int tcs_val;

                        if (!capable(CAP_SYS_TIME))

                                return -EPERM;

                        if(copy_from_user(&tcs_val, (int*)arg, sizeof(int)))

                                return -EFAULT;

                        tcs_val = RTC_TCR_PATTERN | (tcs_val & 0x0F);

                        ds1302_writereg(RTC_TRICKLECHARGER, tcs_val);

                        return 0;

                }

                case RTC_VLOW_RD:

                {

                        /* TODO:

                         * Implement voltage low detection support

                         */

                        printk(KERN_WARNING "DS1302: RTC Voltage Low detection"

                               " is not supported\n");

                        return 0;

                }

                case RTC_VLOW_SET:

                {

                        /* TODO:

                         * Nothing to do since Voltage Low detection is not supported

                         */

                        return 0;

                }

                default:

                        return -ENOIOCTLCMD;

        }

}

static void

print_rtc_status(void)

{

        struct rtc_time tm;

        get_rtc_time(&tm);

        /*

         * There is no way to tell if the luser has the RTC set for local

         * time or for Universal Standard Time (GMT). Probably local though.

         */

        printk(KERN_INFO "rtc_time\t: %02d:%02d:%02d\n",

               tm.tm_hour, tm.tm_min, tm.tm_sec);

        printk(KERN_INFO "rtc_date\t: %04d-%02d-%02d\n",

               tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);

}

/* The various file operations we support. */

static struct file_operations rtc_fops = {

        owner:          THIS_MODULE,

        ioctl:          rtc_ioctl,

};

/* Probe for the chip by writing something to its RAM and try reading it back. */

#define MAGIC_PATTERN 0x42

static int __init

ds1302_probe(void)

{

        int retval, res;

        TK_RST_DIR(1);

        TK_SCL_DIR(1);

        TK_SDA_DIR(0);

        /* Try to talk to timekeeper. */

        ds1302_wenable();

        start();

        out_byte(0xc0); /* write RAM byte 0 */

        out_byte(MAGIC_PATTERN); /* write something magic */

        start();

        out_byte(0xc1); /* read RAM byte 0 */

        if((res = in_byte()) == MAGIC_PATTERN) {

                stop();

                ds1302_wdisable();

                printk(KERN_INFO "%s: RTC found.\n", ds1302_name);

                printk(KERN_INFO "%s: SDA, SCL, RST on PB%i, PB%i, %s%i\n",

                       ds1302_name,

                       CONFIG_ETRAX_DS1302_SDABIT,

                       CONFIG_ETRAX_DS1302_SCLBIT,

#ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT

                       "GENIO",

#else

                       "PB",

#endif

                       CONFIG_ETRAX_DS1302_RSTBIT);

                print_rtc_status();

                retval = 1;

        } else {

                stop();

                retval = 0;

        }

        return retval;

}

/* Just probe for the RTC and register the device to handle the ioctl needed. */

int __init

ds1302_init(void)

{

        if (!ds1302_probe()) {

#ifdef CONFIG_ETRAX_DS1302_RST_ON_GENERIC_PORT

#if CONFIG_ETRAX_DS1302_RSTBIT == 27

                /*

                 * The only way to set g27 to output is to enable ATA.

                 *

                 * Make sure that R_GEN_CONFIG is setup correct.

                 */

                genconfig_shadow = ((genconfig_shadow &

                                     ~IO_MASK(R_GEN_CONFIG, ata)) |

                                   (IO_STATE(R_GEN_CONFIG, ata, select)));

                *R_GEN_CONFIG = genconfig_shadow;

#elif CONFIG_ETRAX_DS1302_RSTBIT == 0

                /* Set the direction of this bit to out. */

                genconfig_shadow = ((genconfig_shadow &

                                     ~IO_MASK(R_GEN_CONFIG, g0dir)) |

                                   (IO_STATE(R_GEN_CONFIG, g0dir, out)));

                *R_GEN_CONFIG = genconfig_shadow;

#endif

                if (!ds1302_probe()) {

                        printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);

                        return -1;

                }

#else

                printk(KERN_WARNING "%s: RTC not found.\n", ds1302_name);

                return -1;

#endif

        }

        if (register_chrdev(RTC_MAJOR_NR, ds1302_name, &rtc_fops)) {

                printk(KERN_INFO "%s: unable to get major %d for rtc\n",

                       ds1302_name, RTC_MAJOR_NR);

                return -1;

        }

        /* Initialise trickle charger */

        ds1302_writereg(RTC_TRICKLECHARGER,

                        RTC_TCR_PATTERN |(CONFIG_ETRAX_DS1302_TRICKLE_CHARGE & 0x0F));

        // Start clock by resetting CLOCK_HALT

        ds1302_writereg(RTC_SECONDS, (ds1302_readreg(RTC_SECONDS) & 0x7F));

        return 0;

}