Merge branch 'master' of ssh://master.kernel.org/pub/scm/linux/kernel/git/linville...

[mirror_ubuntu-bionic-kernel.git] / drivers / rtc / rtc-s3c.c

/* drivers/rtc/rtc-s3c.c
 *
 * Copyright (c) 2010 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com/
 *
 * 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 <linux/log2.h>
#include <linux/slab.h>

#include <mach/hardware.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <plat/regs-rtc.h>

enum s3c_cpu_type {
        TYPE_S3C2410,
        TYPE_S3C64XX,
};

/* I have yet to find an S3C implementation with more than one
 * of these rtc blocks in */

static struct resource *s3c_rtc_mem;

static struct clk *rtc_clk;
static void __iomem *s3c_rtc_base;
static int s3c_rtc_alarmno = NO_IRQ;
static int s3c_rtc_tickno  = NO_IRQ;
static enum s3c_cpu_type s3c_rtc_cpu_type;

static DEFINE_SPINLOCK(s3c_rtc_pie_lock);

/* 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);

        if (s3c_rtc_cpu_type == TYPE_S3C64XX)
                writeb(S3C2410_INTP_ALM, s3c_rtc_base + S3C2410_INTP);

        return IRQ_HANDLED;
}

static irqreturn_t s3c_rtc_tickirq(int irq, void *id)
{
        struct rtc_device *rdev = id;

        rtc_update_irq(rdev, 1, RTC_PF | RTC_IRQF);

        if (s3c_rtc_cpu_type == TYPE_S3C64XX)
                writeb(S3C2410_INTP_TIC, s3c_rtc_base + S3C2410_INTP);

        return IRQ_HANDLED;
}

/* Update control registers */
static void s3c_rtc_setaie(int to)
{
        unsigned int tmp;

        pr_debug("%s: aie=%d\n", __func__, 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 int s3c_rtc_setpie(struct device *dev, int enabled)
{
        unsigned int tmp;

        pr_debug("%s: pie=%d\n", __func__, enabled);

        spin_lock_irq(&s3c_rtc_pie_lock);

        if (s3c_rtc_cpu_type == TYPE_S3C64XX) {
                tmp = readw(s3c_rtc_base + S3C2410_RTCCON);
                tmp &= ~S3C64XX_RTCCON_TICEN;

                if (enabled)
                        tmp |= S3C64XX_RTCCON_TICEN;

                writew(tmp, s3c_rtc_base + S3C2410_RTCCON);
        } else {
                tmp = readb(s3c_rtc_base + S3C2410_TICNT);
                tmp &= ~S3C2410_TICNT_ENABLE;

                if (enabled)
                        tmp |= S3C2410_TICNT_ENABLE;

                writeb(tmp, s3c_rtc_base + S3C2410_TICNT);
        }

        spin_unlock_irq(&s3c_rtc_pie_lock);

        return 0;
}

static int s3c_rtc_setfreq(struct device *dev, int freq)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct rtc_device *rtc_dev = platform_get_drvdata(pdev);
        unsigned int tmp = 0;

        if (!is_power_of_2(freq))
                return -EINVAL;

        spin_lock_irq(&s3c_rtc_pie_lock);

        if (s3c_rtc_cpu_type == TYPE_S3C2410) {
                tmp = readb(s3c_rtc_base + S3C2410_TICNT);
                tmp &= S3C2410_TICNT_ENABLE;
        }

        tmp |= (rtc_dev->max_user_freq / freq)-1;

        writel(tmp, s3c_rtc_base + S3C2410_TICNT);
        spin_unlock_irq(&s3c_rtc_pie_lock);

        return 0;
}

/* 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 %04d.%02d.%02d %02d:%02d:%02d\n",
                 1900 + rtc_tm->tm_year, rtc_tm->tm_mon, rtc_tm->tm_mday,
                 rtc_tm->tm_hour, rtc_tm->tm_min, rtc_tm->tm_sec);

        rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
        rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
        rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
        rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
        rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
        rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);

        rtc_tm->tm_year += 100;
        rtc_tm->tm_mon -= 1;

        return rtc_valid_tm(rtc_tm);
}

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 %04d.%02d.%02d %02d:%02d:%02d\n",
                 1900 + 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 %d, %04d.%02d.%02d %02d:%02d:%02d\n",
                 alm_en,
                 1900 + 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)
                alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec);
        else
                alm_tm->tm_sec = -1;

        if (alm_en & S3C2410_RTCALM_MINEN)
                alm_tm->tm_min = bcd2bin(alm_tm->tm_min);
        else
                alm_tm->tm_min = -1;

        if (alm_en & S3C2410_RTCALM_HOUREN)
                alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour);
        else
                alm_tm->tm_hour = -1;

        if (alm_en & S3C2410_RTCALM_DAYEN)
                alm_tm->tm_mday = bcd2bin(alm_tm->tm_mday);
        else
                alm_tm->tm_mday = -1;

        if (alm_en & S3C2410_RTCALM_MONEN) {
                alm_tm->tm_mon = bcd2bin(alm_tm->tm_mon);
                alm_tm->tm_mon -= 1;
        } else {
                alm_tm->tm_mon = -1;
        }

        if (alm_en & S3C2410_RTCALM_YEAREN)
                alm_tm->tm_year = bcd2bin(alm_tm->tm_year);
        else
                alm_tm->tm_year = -1;

        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, %04d.%02d.%02d %02d:%02d:%02d\n",
                 alrm->enabled,
                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
                 tm->tm_hour, tm->tm_min, 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);

        s3c_rtc_setaie(alrm->enabled);

        return 0;
}

static int s3c_rtc_proc(struct device *dev, struct seq_file *seq)
{
        unsigned int ticnt;

        if (s3c_rtc_cpu_type == TYPE_S3C64XX) {
                ticnt = readw(s3c_rtc_base + S3C2410_RTCCON);
                ticnt &= S3C64XX_RTCCON_TICEN;
        } else {
                ticnt = readb(s3c_rtc_base + S3C2410_TICNT);
                ticnt &= S3C2410_TICNT_ENABLE;
        }

        seq_printf(seq, "periodic_IRQ\t: %s\n", ticnt  ? "yes" : "no");
        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(dev, 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,
        .read_time      = s3c_rtc_gettime,
        .set_time       = s3c_rtc_settime,
        .read_alarm     = s3c_rtc_getalarm,
        .set_alarm      = s3c_rtc_setalarm,
        .irq_set_freq   = s3c_rtc_setfreq,
        .irq_set_state  = s3c_rtc_setpie,
        .proc           = s3c_rtc_proc,
        .alarm_irq_enable = s3c_rtc_setaie,
};

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 = readw(base + S3C2410_RTCCON);
                if (s3c_rtc_cpu_type == TYPE_S3C64XX)
                        tmp &= ~S3C64XX_RTCCON_TICEN;
                tmp &= ~S3C2410_RTCCON_RTCEN;
                writew(tmp, base + S3C2410_RTCCON);

                if (s3c_rtc_cpu_type == TYPE_S3C2410) {
                        tmp = readb(base + S3C2410_TICNT);
                        tmp &= ~S3C2410_TICNT_ENABLE;
                        writeb(tmp, base + S3C2410_TICNT);
                }
        } else {
                /* re-enable the device, and check it is ok */

                if ((readw(base+S3C2410_RTCCON) & S3C2410_RTCCON_RTCEN) == 0) {
                        dev_info(&pdev->dev, "rtc disabled, re-enabling\n");

                        tmp = readw(base + S3C2410_RTCCON);
                        writew(tmp | S3C2410_RTCCON_RTCEN,
                                base + S3C2410_RTCCON);
                }

                if ((readw(base + S3C2410_RTCCON) & S3C2410_RTCCON_CNTSEL)) {
                        dev_info(&pdev->dev, "removing RTCCON_CNTSEL\n");

                        tmp = readw(base + S3C2410_RTCCON);
                        writew(tmp & ~S3C2410_RTCCON_CNTSEL,
                                base + S3C2410_RTCCON);
                }

                if ((readw(base + S3C2410_RTCCON) & S3C2410_RTCCON_CLKRST)) {
                        dev_info(&pdev->dev, "removing RTCCON_CLKRST\n");

                        tmp = readw(base + S3C2410_RTCCON);
                        writew(tmp & ~S3C2410_RTCCON_CLKRST,
                                base + S3C2410_RTCCON);
                }
        }
}

static int __devexit 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(&dev->dev, 0);
        s3c_rtc_setaie(0);

        clk_disable(rtc_clk);
        clk_put(rtc_clk);
        rtc_clk = NULL;

        iounmap(s3c_rtc_base);
        release_resource(s3c_rtc_mem);
        kfree(s3c_rtc_mem);

        return 0;
}

static int __devinit s3c_rtc_probe(struct platform_device *pdev)
{
        struct rtc_device *rtc;
        struct rtc_time rtc_tm;
        struct resource *res;
        int ret;

        pr_debug("%s: probe=%p\n", __func__, 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;
        }

        rtc_clk = clk_get(&pdev->dev, "rtc");
        if (IS_ERR(rtc_clk)) {
                dev_err(&pdev->dev, "failed to find rtc clock source\n");
                ret = PTR_ERR(rtc_clk);
                rtc_clk = NULL;
                goto err_clk;
        }

        clk_enable(rtc_clk);

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

        s3c_rtc_enable(pdev, 1);

        pr_debug("s3c2410_rtc: RTCCON=%02x\n",
                 readw(s3c_rtc_base + S3C2410_RTCCON));

        device_init_wakeup(&pdev->dev, 1);

        /* 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;
        }

        s3c_rtc_cpu_type = platform_get_device_id(pdev)->driver_data;

        /* Check RTC Time */

        s3c_rtc_gettime(NULL, &rtc_tm);

        if (rtc_valid_tm(&rtc_tm)) {
                rtc_tm.tm_year  = 100;
                rtc_tm.tm_mon   = 0;
                rtc_tm.tm_mday  = 1;
                rtc_tm.tm_hour  = 0;
                rtc_tm.tm_min   = 0;
                rtc_tm.tm_sec   = 0;

                s3c_rtc_settime(NULL, &rtc_tm);

                dev_warn(&pdev->dev, "warning: invalid RTC value so initializing it\n");
        }

        if (s3c_rtc_cpu_type == TYPE_S3C64XX)
                rtc->max_user_freq = 32768;
        else
                rtc->max_user_freq = 128;

        platform_set_drvdata(pdev, rtc);

        s3c_rtc_setfreq(&pdev->dev, 1);

        return 0;

 err_nortc:
        s3c_rtc_enable(pdev, 0);
        clk_disable(rtc_clk);
        clk_put(rtc_clk);

 err_clk:
        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, ticnt_en_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);
        if (s3c_rtc_cpu_type == TYPE_S3C64XX) {
                ticnt_en_save = readw(s3c_rtc_base + S3C2410_RTCCON);
                ticnt_en_save &= S3C64XX_RTCCON_TICEN;
        }
        s3c_rtc_enable(pdev, 0);

        if (device_may_wakeup(&pdev->dev))
                enable_irq_wake(s3c_rtc_alarmno);

        return 0;
}

static int s3c_rtc_resume(struct platform_device *pdev)
{
        unsigned int tmp;

        s3c_rtc_enable(pdev, 1);
        writeb(ticnt_save, s3c_rtc_base + S3C2410_TICNT);
        if (s3c_rtc_cpu_type == TYPE_S3C64XX && ticnt_en_save) {
                tmp = readw(s3c_rtc_base + S3C2410_RTCCON);
                writew(tmp | ticnt_en_save, s3c_rtc_base + S3C2410_RTCCON);
        }

        if (device_may_wakeup(&pdev->dev))
                disable_irq_wake(s3c_rtc_alarmno);

        return 0;
}
#else
#define s3c_rtc_suspend NULL
#define s3c_rtc_resume  NULL
#endif

static struct platform_device_id s3c_rtc_driver_ids[] = {
        {
                .name           = "s3c2410-rtc",
                .driver_data    = TYPE_S3C2410,
        }, {
                .name           = "s3c64xx-rtc",
                .driver_data    = TYPE_S3C64XX,
        },
        { }
};

MODULE_DEVICE_TABLE(platform, s3c_rtc_driver_ids);

static struct platform_driver s3c_rtc_driver = {
        .probe          = s3c_rtc_probe,
        .remove         = __devexit_p(s3c_rtc_remove),
        .suspend        = s3c_rtc_suspend,
        .resume         = s3c_rtc_resume,
        .id_table       = s3c_rtc_driver_ids,
        .driver         = {
                .name   = "s3c-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(&s3c_rtc_driver);
}

static void __exit s3c_rtc_exit(void)
{
        platform_driver_unregister(&s3c_rtc_driver);
}

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");
MODULE_ALIAS("platform:s3c2410-rtc");