rtc-puv3.c

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/*
 * RTC driver code specific to PKUnity SoC and UniCore ISA
 *
 *  Maintained by GUAN Xue-tao <[email protected]>
 *  Copyright (C) 2001-2010 Guan Xuetao
 *
 * 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.
 */

#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 <linux/uaccess.h>
#include <linux/io.h>

#include <asm/irq.h>
#include <mach/hardware.h>

static struct resource *puv3_rtc_mem;

static int puv3_rtc_alarmno = IRQ_RTCAlarm;
static int puv3_rtc_tickno  = IRQ_RTC;

static DEFINE_SPINLOCK(puv3_rtc_pie_lock);

/* IRQ Handlers */
static irqreturn_t puv3_rtc_alarmirq(int irq, void *id)
{
    struct rtc_device *rdev = id;

    writel(readl(RTC_RTSR) | RTC_RTSR_AL, RTC_RTSR);
    rtc_update_irq(rdev, 1, RTC_AF | RTC_IRQF);
    return IRQ_HANDLED;
}

static irqreturn_t puv3_rtc_tickirq(int irq, void *id)
{
    struct rtc_device *rdev = id;

    writel(readl(RTC_RTSR) | RTC_RTSR_HZ, RTC_RTSR);
    rtc_update_irq(rdev, 1, RTC_PF | RTC_IRQF);
    return IRQ_HANDLED;
}

/* Update control registers */
static void puv3_rtc_setaie(int to)
{
    unsigned int tmp;

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

    tmp = readl(RTC_RTSR) & ~RTC_RTSR_ALE;

    if (to)
        tmp |= RTC_RTSR_ALE;

    writel(tmp, RTC_RTSR);
}

static int puv3_rtc_setpie(struct device *dev, int enabled)
{
    unsigned int tmp;

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

    spin_lock_irq(&puv3_rtc_pie_lock);
    tmp = readl(RTC_RTSR) & ~RTC_RTSR_HZE;

    if (enabled)
        tmp |= RTC_RTSR_HZE;

    writel(tmp, RTC_RTSR);
    spin_unlock_irq(&puv3_rtc_pie_lock);

    return 0;
}

/* Time read/write */
static int puv3_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
{
    rtc_time_to_tm(readl(RTC_RCNR), rtc_tm);

    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);

    return 0;
}

static int puv3_rtc_settime(struct device *dev, struct rtc_time *tm)
{
    unsigned long rtc_count = 0;

    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);

    rtc_tm_to_time(tm, &rtc_count);
    writel(rtc_count, RTC_RCNR);

    return 0;
}

static int puv3_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct rtc_time *alm_tm = &alrm->time;

    rtc_time_to_tm(readl(RTC_RTAR), alm_tm);

    alrm->enabled = readl(RTC_RTSR) & RTC_RTSR_ALE;

    pr_debug("read alarm %02x %02x.%02x.%02x %02x/%02x/%02x\n",
         alrm->enabled,
         alm_tm->tm_year, alm_tm->tm_mon, alm_tm->tm_mday,
         alm_tm->tm_hour, alm_tm->tm_min, alm_tm->tm_sec);

    return 0;
}

static int puv3_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
    struct rtc_time *tm = &alrm->time;
    unsigned long rtcalarm_count = 0;

    pr_debug("puv3_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);

    rtc_tm_to_time(tm, &rtcalarm_count);
    writel(rtcalarm_count, RTC_RTAR);

    puv3_rtc_setaie(alrm->enabled);

    if (alrm->enabled)
        enable_irq_wake(puv3_rtc_alarmno);
    else
        disable_irq_wake(puv3_rtc_alarmno);

    return 0;
}

static int puv3_rtc_proc(struct device *dev, struct seq_file *seq)
{
    seq_printf(seq, "periodic_IRQ\t: %s\n",
             (readl(RTC_RTSR) & RTC_RTSR_HZE) ? "yes" : "no");
    return 0;
}

static int puv3_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(puv3_rtc_alarmno, puv3_rtc_alarmirq,
            0, "pkunity-rtc alarm", rtc_dev);

    if (ret) {
        dev_err(dev, "IRQ%d error %d\n", puv3_rtc_alarmno, ret);
        return ret;
    }

    ret = request_irq(puv3_rtc_tickno, puv3_rtc_tickirq,
            0, "pkunity-rtc tick", rtc_dev);

    if (ret) {
        dev_err(dev, "IRQ%d error %d\n", puv3_rtc_tickno, ret);
        goto tick_err;
    }

    return ret;

 tick_err:
    free_irq(puv3_rtc_alarmno, rtc_dev);
    return ret;
}

static void puv3_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 */
    puv3_rtc_setpie(dev, 0);
    free_irq(puv3_rtc_alarmno, rtc_dev);
    free_irq(puv3_rtc_tickno, rtc_dev);
}

static const struct rtc_class_ops puv3_rtcops = {
    .open       = puv3_rtc_open,
    .release    = puv3_rtc_release,
    .read_time  = puv3_rtc_gettime,
    .set_time   = puv3_rtc_settime,
    .read_alarm = puv3_rtc_getalarm,
    .set_alarm  = puv3_rtc_setalarm,
    .proc           = puv3_rtc_proc,
};

static void puv3_rtc_enable(struct platform_device *pdev, int en)
{
    if (!en) {
        writel(readl(RTC_RTSR) & ~RTC_RTSR_HZE, RTC_RTSR);
    } else {
        /* re-enable the device, and check it is ok */
        if ((readl(RTC_RTSR) & RTC_RTSR_HZE) == 0) {
            dev_info(&pdev->dev, "rtc disabled, re-enabling\n");
            writel(readl(RTC_RTSR) | RTC_RTSR_HZE, RTC_RTSR);
        }
    }
}

static int __devexit puv3_rtc_remove(struct platform_device *dev)
{
    struct rtc_device *rtc = platform_get_drvdata(dev);

    platform_set_drvdata(dev, NULL);
    rtc_device_unregister(rtc);

    puv3_rtc_setpie(&dev->dev, 0);
    puv3_rtc_setaie(0);

    release_resource(puv3_rtc_mem);
    kfree(puv3_rtc_mem);

    return 0;
}

static int __devinit puv3_rtc_probe(struct platform_device *pdev)
{
    struct rtc_device *rtc;
    struct resource *res;
    int ret;

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

    /* find the IRQs */
    puv3_rtc_tickno = platform_get_irq(pdev, 1);
    if (puv3_rtc_tickno < 0) {
        dev_err(&pdev->dev, "no irq for rtc tick\n");
        return -ENOENT;
    }

    puv3_rtc_alarmno = platform_get_irq(pdev, 0);
    if (puv3_rtc_alarmno < 0) {
        dev_err(&pdev->dev, "no irq for alarm\n");
        return -ENOENT;
    }

    pr_debug("PKUnity_rtc: tick irq %d, alarm irq %d\n",
         puv3_rtc_tickno, puv3_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;
    }

    puv3_rtc_mem = request_mem_region(res->start, resource_size(res),
                      pdev->name);

    if (puv3_rtc_mem == NULL) {
        dev_err(&pdev->dev, "failed to reserve memory region\n");
        ret = -ENOENT;
        goto err_nores;
    }

    puv3_rtc_enable(pdev, 1);

    /* register RTC and exit */
    rtc = rtc_device_register("pkunity", &pdev->dev, &puv3_rtcops,
                  THIS_MODULE);

    if (IS_ERR(rtc)) {
        dev_err(&pdev->dev, "cannot attach rtc\n");
        ret = PTR_ERR(rtc);
        goto err_nortc;
    }

    /* platform setup code should have handled this; sigh */
    if (!device_can_wakeup(&pdev->dev))
        device_init_wakeup(&pdev->dev, 1);

    platform_set_drvdata(pdev, rtc);
    return 0;

 err_nortc:
    puv3_rtc_enable(pdev, 0);
    release_resource(puv3_rtc_mem);

 err_nores:
    return ret;
}

#ifdef CONFIG_PM

static int ticnt_save;

static int puv3_rtc_suspend(struct platform_device *pdev, pm_message_t state)
{
    /* save RTAR for anyone using periodic interrupts */
    ticnt_save = readl(RTC_RTAR);
    puv3_rtc_enable(pdev, 0);
    return 0;
}

static int puv3_rtc_resume(struct platform_device *pdev)
{
    puv3_rtc_enable(pdev, 1);
    writel(ticnt_save, RTC_RTAR);
    return 0;
}
#else
#define puv3_rtc_suspend NULL
#define puv3_rtc_resume  NULL
#endif

static struct platform_driver puv3_rtc_driver = {
    .probe      = puv3_rtc_probe,
    .remove     = __devexit_p(puv3_rtc_remove),
    .suspend    = puv3_rtc_suspend,
    .resume     = puv3_rtc_resume,
    .driver     = {
        .name   = "PKUnity-v3-RTC",
        .owner  = THIS_MODULE,
    }
};

module_platform_driver(puv3_rtc_driver);

MODULE_DESCRIPTION("RTC Driver for the PKUnity v3 chip");
MODULE_AUTHOR("Hu Dongliang");
MODULE_LICENSE("GPL v2");