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/* drivers/rtc/rtc-s3c.c

 *

 * Copyright (c) 2004,2006 Simtec Electronics

 *      Ben Dooks, <ben@simtec.co.uk>

 *      http://armlinux.simtec.co.uk/

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * S3C2410/S3C2440/S3C24XX Internal RTC Driver

*/

#include <linux/module.h>

#include <linux/fs.h>

#include <linux/string.h>

#include <linux/init.h>

#include <linux/platform_device.h>

#include <linux/interrupt.h>

#include <linux/rtc.h>

#include <linux/bcd.h>

#include <linux/clk.h>

#include <asm/hardware.h>

#include <asm/uaccess.h>

#include <asm/io.h>

#include <asm/irq.h>

#include <asm/rtc.h>

#include <asm/mach/time.h>

#include <asm/plat-s3c/regs-rtc.h>

/* I have yet to find an S3C implementation with more than one

 * of these rtc blocks in */

static struct resource *s3c_rtc_mem;

static void __iomem *s3c_rtc_base;

static int s3c_rtc_alarmno = NO_IRQ;

static int s3c_rtc_tickno  = NO_IRQ;

static int s3c_rtc_freq    = 1;

static DEFINE_SPINLOCK(s3c_rtc_pie_lock);

static unsigned int tick_count;

/* IRQ Handlers */

static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)

{

        struct rtc_device *rdev = id;

        rtc_update_irq(rdev, 1, RTC_AF | RTC_IRQF);

        return IRQ_HANDLED;

}

static irqreturn_t s3c_rtc_tickirq(int irq, void *id)

{

        struct rtc_device *rdev = id;

        rtc_update_irq(rdev, tick_count++, RTC_PF | RTC_IRQF);

        return IRQ_HANDLED;

}

/* Update control registers */

static void s3c_rtc_setaie(int to)

{

        unsigned int tmp;

        pr_debug("%s: aie=%d\n", __FUNCTION__, to);

        tmp = readb(s3c_rtc_base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;

        if (to)

                tmp |= S3C2410_RTCALM_ALMEN;

        writeb(tmp, s3c_rtc_base + S3C2410_RTCALM);

}

static void s3c_rtc_setpie(int to)

{

        unsigned int tmp;

        pr_debug("%s: pie=%d\n", __FUNCTION__, to);

        spin_lock_irq(&s3c_rtc_pie_lock);

        tmp = readb(s3c_rtc_base + S3C2410_TICNT) & ~S3C2410_TICNT_ENABLE;

        if (to)

                tmp |= S3C2410_TICNT_ENABLE;

        writeb(tmp, s3c_rtc_base + S3C2410_TICNT);

        spin_unlock_irq(&s3c_rtc_pie_lock);

}

static void s3c_rtc_setfreq(int freq)

{

        unsigned int tmp;

        spin_lock_irq(&s3c_rtc_pie_lock);

        tmp = readb(s3c_rtc_base + S3C2410_TICNT) & S3C2410_TICNT_ENABLE;

        s3c_rtc_freq = freq;

        tmp |= (128 / freq)-1;

        writeb(tmp, s3c_rtc_base + S3C2410_TICNT);

        spin_unlock_irq(&s3c_rtc_pie_lock);

}

/* Time read/write */

static int s3c_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)

{

        unsigned int have_retried = 0;

        void __iomem *base = s3c_rtc_base;

 retry_get_time:

        rtc_tm->tm_min  = readb(base + S3C2410_RTCMIN);

        rtc_tm->tm_hour = readb(base + S3C2410_RTCHOUR);

        rtc_tm->tm_mday = readb(base + S3C2410_RTCDATE);

        rtc_tm->tm_mon  = readb(base + S3C2410_RTCMON);

        rtc_tm->tm_year = readb(base + S3C2410_RTCYEAR);

        rtc_tm->tm_sec  = readb(base + S3C2410_RTCSEC);

        /* the only way to work out wether the system was mid-update

         * when we read it is to check the second counter, and if it

         * is zero, then we re-try the entire read

         */

        if (rtc_tm->tm_sec == 0 && !have_retried) {

                have_retried = 1;

                goto retry_get_time;

        }

        pr_debug("read time %02x.%02x.%02x %02x/%02x/%02x\n",

                 rtc_tm->tm_year, rtc_tm->tm_mon, rtc_tm->tm_mday,

                 rtc_tm->tm_hour, rtc_tm->tm_min, rtc_tm->tm_sec);

        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);

        rtc_tm->tm_year += 100;

        rtc_tm->tm_mon -= 1;

        return 0;

}

static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)

{

        void __iomem *base = s3c_rtc_base;

        int year = tm->tm_year - 100;

        pr_debug("set time %02d.%02d.%02d %02d/%02d/%02d\n",

                 tm->tm_year, tm->tm_mon, tm->tm_mday,

                 tm->tm_hour, tm->tm_min, tm->tm_sec);

        /* we get around y2k by simply not supporting it */

        if (year < 0 || year >= 100) {

                dev_err(dev, "rtc only supports 100 years\n");

                return -EINVAL;

        }

        writeb(BIN2BCD(tm->tm_sec),  base + S3C2410_RTCSEC);

        writeb(BIN2BCD(tm->tm_min),  base + S3C2410_RTCMIN);

        writeb(BIN2BCD(tm->tm_hour), base + S3C2410_RTCHOUR);

        writeb(BIN2BCD(tm->tm_mday), base + S3C2410_RTCDATE);

        writeb(BIN2BCD(tm->tm_mon + 1), base + S3C2410_RTCMON);

        writeb(BIN2BCD(year), base + S3C2410_RTCYEAR);

        return 0;

}

static int s3c_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)

{

        struct rtc_time *alm_tm = &alrm->time;

        void __iomem *base = s3c_rtc_base;

        unsigned int alm_en;

        alm_tm->tm_sec  = readb(base + S3C2410_ALMSEC);

        alm_tm->tm_min  = readb(base + S3C2410_ALMMIN);

        alm_tm->tm_hour = readb(base + S3C2410_ALMHOUR);

        alm_tm->tm_mon  = readb(base + S3C2410_ALMMON);

        alm_tm->tm_mday = readb(base + S3C2410_ALMDATE);

        alm_tm->tm_year = readb(base + S3C2410_ALMYEAR);

        alm_en = readb(base + S3C2410_RTCALM);

        alrm->enabled = (alm_en & S3C2410_RTCALM_ALMEN) ? 1 : 0;

        pr_debug("read alarm %02x %02x.%02x.%02x %02x/%02x/%02x\n",

                 alm_en,

                 alm_tm->tm_year, alm_tm->tm_mon, alm_tm->tm_mday,

                 alm_tm->tm_hour, alm_tm->tm_min, alm_tm->tm_sec);

        /* decode the alarm enable field */

        if (alm_en & S3C2410_RTCALM_SECEN)

                BCD_TO_BIN(alm_tm->tm_sec);

        else

                alm_tm->tm_sec = 0xff;

        if (alm_en & S3C2410_RTCALM_MINEN)

                BCD_TO_BIN(alm_tm->tm_min);

        else

                alm_tm->tm_min = 0xff;

        if (alm_en & S3C2410_RTCALM_HOUREN)

                BCD_TO_BIN(alm_tm->tm_hour);

        else

                alm_tm->tm_hour = 0xff;

        if (alm_en & S3C2410_RTCALM_DAYEN)

                BCD_TO_BIN(alm_tm->tm_mday);

        else

                alm_tm->tm_mday = 0xff;

        if (alm_en & S3C2410_RTCALM_MONEN) {

                BCD_TO_BIN(alm_tm->tm_mon);

                alm_tm->tm_mon -= 1;

        } else {

                alm_tm->tm_mon = 0xff;

        }

        if (alm_en & S3C2410_RTCALM_YEAREN)

                BCD_TO_BIN(alm_tm->tm_year);

        else

                alm_tm->tm_year = 0xffff;

        return 0;

}

static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)

{

        struct rtc_time *tm = &alrm->time;

        void __iomem *base = s3c_rtc_base;

        unsigned int alrm_en;

        pr_debug("s3c_rtc_setalarm: %d, %02x/%02x/%02x %02x.%02x.%02x\n",

                 alrm->enabled,

                 tm->tm_mday & 0xff, tm->tm_mon & 0xff, tm->tm_year & 0xff,

                 tm->tm_hour & 0xff, tm->tm_min & 0xff, tm->tm_sec);

        alrm_en = readb(base + S3C2410_RTCALM) & S3C2410_RTCALM_ALMEN;

        writeb(0x00, base + S3C2410_RTCALM);

        if (tm->tm_sec < 60 && tm->tm_sec >= 0) {

                alrm_en |= S3C2410_RTCALM_SECEN;

                writeb(BIN2BCD(tm->tm_sec), base + S3C2410_ALMSEC);

        }

        if (tm->tm_min < 60 && tm->tm_min >= 0) {

                alrm_en |= S3C2410_RTCALM_MINEN;

                writeb(BIN2BCD(tm->tm_min), base + S3C2410_ALMMIN);

        }

        if (tm->tm_hour < 24 && tm->tm_hour >= 0) {

                alrm_en |= S3C2410_RTCALM_HOUREN;

                writeb(BIN2BCD(tm->tm_hour), base + S3C2410_ALMHOUR);

        }

        pr_debug("setting S3C2410_RTCALM to %08x\n", alrm_en);

        writeb(alrm_en, base + S3C2410_RTCALM);

        if (0) {

                alrm_en = readb(base + S3C2410_RTCALM);

                alrm_en &= ~S3C2410_RTCALM_ALMEN;

                writeb(alrm_en, base + S3C2410_RTCALM);

                disable_irq_wake(s3c_rtc_alarmno);

        }

        if (alrm->enabled)

                enable_irq_wake(s3c_rtc_alarmno);

        else

                disable_irq_wake(s3c_rtc_alarmno);

        return 0;

}

static int s3c_rtc_ioctl(struct device *dev,

                         unsigned int cmd, unsigned long arg)

{

        unsigned int ret = -ENOIOCTLCMD;

        switch (cmd) {

        case RTC_AIE_OFF:

        case RTC_AIE_ON:

                s3c_rtc_setaie((cmd == RTC_AIE_ON) ? 1 : 0);

                ret = 0;

                break;

        case RTC_PIE_OFF:

        case RTC_PIE_ON:

                tick_count = 0;

                s3c_rtc_setpie((cmd == RTC_PIE_ON) ? 1 : 0);

                ret = 0;

                break;

        case RTC_IRQP_READ:

                ret = put_user(s3c_rtc_freq, (unsigned long __user *)arg);

                break;

        case RTC_IRQP_SET:

                /* check for power of 2 */

                if ((arg & (arg-1)) != 0 || arg < 1) {

                        ret = -EINVAL;

                        goto exit;

                }

                pr_debug("s3c2410_rtc: setting frequency %ld\n", arg);

                s3c_rtc_setfreq(arg);

                ret = 0;

                break;

        case RTC_UIE_ON:

        case RTC_UIE_OFF:

                ret = -EINVAL;

        }

 exit:

        return ret;

}

static int s3c_rtc_proc(struct device *dev, struct seq_file *seq)

{

        unsigned int ticnt = readb(s3c_rtc_base + S3C2410_TICNT);

        seq_printf(seq, "periodic_IRQ\t: %s\n",

                     (ticnt & S3C2410_TICNT_ENABLE) ? "yes" : "no" );

        seq_printf(seq, "periodic_freq\t: %d\n", s3c_rtc_freq);

        return 0;

}

static int s3c_rtc_open(struct device *dev)

{

        struct platform_device *pdev = to_platform_device(dev);

        struct rtc_device *rtc_dev = platform_get_drvdata(pdev);

        int ret;

        ret = request_irq(s3c_rtc_alarmno, s3c_rtc_alarmirq,

                          IRQF_DISABLED,  "s3c2410-rtc alarm", rtc_dev);

        if (ret) {

                dev_err(dev, "IRQ%d error %d\n", s3c_rtc_alarmno, ret);

                return ret;

        }

        ret = request_irq(s3c_rtc_tickno, s3c_rtc_tickirq,

                          IRQF_DISABLED,  "s3c2410-rtc tick", rtc_dev);

        if (ret) {

                dev_err(dev, "IRQ%d error %d\n", s3c_rtc_tickno, ret);

                goto tick_err;

        }

        return ret;

 tick_err:

        free_irq(s3c_rtc_alarmno, rtc_dev);

        return ret;

}

static void s3c_rtc_release(struct device *dev)

{

        struct platform_device *pdev = to_platform_device(dev);

        struct rtc_device *rtc_dev = platform_get_drvdata(pdev);

        /* do not clear AIE here, it may be needed for wake */

        s3c_rtc_setpie(0);

        free_irq(s3c_rtc_alarmno, rtc_dev);

        free_irq(s3c_rtc_tickno, rtc_dev);

}

static const struct rtc_class_ops s3c_rtcops = {

        .open           = s3c_rtc_open,

        .release        = s3c_rtc_release,

        .ioctl          = s3c_rtc_ioctl,

        .read_time      = s3c_rtc_gettime,

        .set_time       = s3c_rtc_settime,

        .read_alarm     = s3c_rtc_getalarm,

        .set_alarm      = s3c_rtc_setalarm,

        .proc           = s3c_rtc_proc,

};

static void s3c_rtc_enable(struct platform_device *pdev, int en)

{

        void __iomem *base = s3c_rtc_base;

        unsigned int tmp;

        if (s3c_rtc_base == NULL)

                return;

        if (!en) {

                tmp = readb(base + S3C2410_RTCCON);

                writeb(tmp & ~S3C2410_RTCCON_RTCEN, base + S3C2410_RTCCON);

                tmp = readb(base + S3C2410_TICNT);

                writeb(tmp & ~S3C2410_TICNT_ENABLE, base + S3C2410_TICNT);

        } else {

                /* re-enable the device, and check it is ok */

                if ((readb(base+S3C2410_RTCCON) & S3C2410_RTCCON_RTCEN) == 0){

                        dev_info(&pdev->dev, "rtc disabled, re-enabling\n");

                        tmp = readb(base + S3C2410_RTCCON);

                        writeb(tmp|S3C2410_RTCCON_RTCEN, base+S3C2410_RTCCON);

                }

                if ((readb(base + S3C2410_RTCCON) & S3C2410_RTCCON_CNTSEL)){

                        dev_info(&pdev->dev, "removing RTCCON_CNTSEL\n");

                        tmp = readb(base + S3C2410_RTCCON);

                        writeb(tmp& ~S3C2410_RTCCON_CNTSEL, base+S3C2410_RTCCON);

                }

                if ((readb(base + S3C2410_RTCCON) & S3C2410_RTCCON_CLKRST)){

                        dev_info(&pdev->dev, "removing RTCCON_CLKRST\n");

                        tmp = readb(base + S3C2410_RTCCON);

                        writeb(tmp & ~S3C2410_RTCCON_CLKRST, base+S3C2410_RTCCON);

                }

        }

}

static int s3c_rtc_remove(struct platform_device *dev)

{

        struct rtc_device *rtc = platform_get_drvdata(dev);

        platform_set_drvdata(dev, NULL);

        rtc_device_unregister(rtc);

        s3c_rtc_setpie(0);

        s3c_rtc_setaie(0);

        iounmap(s3c_rtc_base);

        release_resource(s3c_rtc_mem);

        kfree(s3c_rtc_mem);

        return 0;

}

static int s3c_rtc_probe(struct platform_device *pdev)

{

        struct rtc_device *rtc;

        struct resource *res;

        int ret;

        pr_debug("%s: probe=%p\n", __FUNCTION__, pdev);

        /* find the IRQs */

        s3c_rtc_tickno = platform_get_irq(pdev, 1);

        if (s3c_rtc_tickno < 0) {

                dev_err(&pdev->dev, "no irq for rtc tick\n");

                return -ENOENT;

        }

        s3c_rtc_alarmno = platform_get_irq(pdev, 0);

        if (s3c_rtc_alarmno < 0) {

                dev_err(&pdev->dev, "no irq for alarm\n");

                return -ENOENT;

        }

        pr_debug("s3c2410_rtc: tick irq %d, alarm irq %d\n",

                 s3c_rtc_tickno, s3c_rtc_alarmno);

        /* get the memory region */

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

        if (res == NULL) {

                dev_err(&pdev->dev, "failed to get memory region resource\n");

                return -ENOENT;

        }

        s3c_rtc_mem = request_mem_region(res->start,

                                         res->end-res->start+1,

                                         pdev->name);

        if (s3c_rtc_mem == NULL) {

                dev_err(&pdev->dev, "failed to reserve memory region\n");

                ret = -ENOENT;

                goto err_nores;

        }

        s3c_rtc_base = ioremap(res->start, res->end - res->start + 1);

        if (s3c_rtc_base == NULL) {

                dev_err(&pdev->dev, "failed ioremap()\n");

                ret = -EINVAL;

                goto err_nomap;

        }

        /* check to see if everything is setup correctly */

        s3c_rtc_enable(pdev, 1);

        pr_debug("s3c2410_rtc: RTCCON=%02x\n",

                 readb(s3c_rtc_base + S3C2410_RTCCON));

        s3c_rtc_setfreq(s3c_rtc_freq);

        /* register RTC and exit */

        rtc = rtc_device_register("s3c", &pdev->dev, &s3c_rtcops,

                                  THIS_MODULE);

        if (IS_ERR(rtc)) {

                dev_err(&pdev->dev, "cannot attach rtc\n");

                ret = PTR_ERR(rtc);

                goto err_nortc;

        }

        rtc->max_user_freq = 128;

        platform_set_drvdata(pdev, rtc);

        return 0;

 err_nortc:

        s3c_rtc_enable(pdev, 0);

        iounmap(s3c_rtc_base);

 err_nomap:

        release_resource(s3c_rtc_mem);

 err_nores:

        return ret;

}

#ifdef CONFIG_PM

/* RTC Power management control */

static int ticnt_save;

static int s3c_rtc_suspend(struct platform_device *pdev, pm_message_t state)

{

        /* save TICNT for anyone using periodic interrupts */

        ticnt_save = readb(s3c_rtc_base + S3C2410_TICNT);

        s3c_rtc_enable(pdev, 0);

        return 0;

}

static int s3c_rtc_resume(struct platform_device *pdev)

{

        s3c_rtc_enable(pdev, 1);

        writeb(ticnt_save, s3c_rtc_base + S3C2410_TICNT);

        return 0;

}

#else

#define s3c_rtc_suspend NULL

#define s3c_rtc_resume  NULL

#endif

static struct platform_driver s3c2410_rtcdrv = {

        .probe          = s3c_rtc_probe,

        .remove         = s3c_rtc_remove,

        .suspend        = s3c_rtc_suspend,

        .resume         = s3c_rtc_resume,

        .driver         = {

                .name   = "s3c2410-rtc",

                .owner  = THIS_MODULE,

        },

};

static char __initdata banner[] = "S3C24XX RTC, (c) 2004,2006 Simtec Electronics\n";

static int __init s3c_rtc_init(void)

{

        printk(banner);

        return platform_driver_register(&s3c2410_rtcdrv);

}

static void __exit s3c_rtc_exit(void)

{

        platform_driver_unregister(&s3c2410_rtcdrv);

}

module_init(s3c_rtc_init);

module_exit(s3c_rtc_exit);

MODULE_DESCRIPTION("Samsung S3C RTC Driver");

MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");

MODULE_LICENSE("GPL");