/*
 * drivers/rtc/rtc-pl031.c
 *
 * Real Time Clock interface for ARM AMBA PrimeCell 031 RTC
 *
 * Author: Deepak Saxena <dsaxena@plexity.net>
 *
 * Copyright 2006 (c) MontaVista Software, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/amba/bus.h>
#include <linux/io.h>

/*
 * Register definitions
 */
#define RTC_DR          0x00    /* Data read register */
#define RTC_MR          0x04    /* Match register */
#define RTC_LR          0x08    /* Data load register */
#define RTC_CR          0x0c    /* Control register */
#define RTC_IMSC        0x10    /* Interrupt mask and set register */
#define RTC_RIS         0x14    /* Raw interrupt status register */
#define RTC_MIS         0x18    /* Masked interrupt status register */
#define RTC_ICR         0x1c    /* Interrupt clear register */

struct pl031_local {
        struct rtc_device *rtc;
        void __iomem *base;
};

static irqreturn_t pl031_interrupt(int irq, void *dev_id)
{
        struct rtc_device *rtc = dev_id;

        rtc_update_irq(rtc, 1, RTC_AF);

        return IRQ_HANDLED;
}

static int pl031_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
        struct pl031_local *ldata = dev_get_drvdata(dev);

        switch (cmd) {
        case RTC_AIE_OFF:
                __raw_writel(1, ldata->base + RTC_MIS);
                return 0;
        case RTC_AIE_ON:
                __raw_writel(0, ldata->base + RTC_MIS);
                return 0;
        }

        return -ENOIOCTLCMD;
}

static int pl031_read_time(struct device *dev, struct rtc_time *tm)
{
        struct pl031_local *ldata = dev_get_drvdata(dev);

        rtc_time_to_tm(__raw_readl(ldata->base + RTC_DR), tm);

        return 0;
}

static int pl031_set_time(struct device *dev, struct rtc_time *tm)
{
        unsigned long time;
        struct pl031_local *ldata = dev_get_drvdata(dev);

        rtc_tm_to_time(tm, &time);
        __raw_writel(time, ldata->base + RTC_LR);

        return 0;
}

static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
        struct pl031_local *ldata = dev_get_drvdata(dev);

        rtc_time_to_tm(__raw_readl(ldata->base + RTC_MR), &alarm->time);
        alarm->pending = __raw_readl(ldata->base + RTC_RIS);
        alarm->enabled = __raw_readl(ldata->base + RTC_IMSC);

        return 0;
}

static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
        struct pl031_local *ldata = dev_get_drvdata(dev);
        unsigned long time;

        rtc_tm_to_time(&alarm->time, &time);

        __raw_writel(time, ldata->base + RTC_MR);
        __raw_writel(!alarm->enabled, ldata->base + RTC_MIS);

        return 0;
}

static const struct rtc_class_ops pl031_ops = {
        .ioctl = pl031_ioctl,
        .read_time = pl031_read_time,
        .set_time = pl031_set_time,
        .read_alarm = pl031_read_alarm,
        .set_alarm = pl031_set_alarm,
};

static int pl031_remove(struct amba_device *adev)
{
        struct pl031_local *ldata = dev_get_drvdata(&adev->dev);

        amba_set_drvdata(adev, NULL);
        free_irq(adev->irq[0], ldata->rtc);
        rtc_device_unregister(ldata->rtc);
        iounmap(ldata->base);
        kfree(ldata);
        amba_release_regions(adev);

        return 0;
}

static int pl031_probe(struct amba_device *adev, struct amba_id *id)
{
        int ret;
        struct pl031_local *ldata;

        ret = amba_request_regions(adev, NULL);
        if (ret)
                goto err_req;

        ldata = kmalloc(sizeof(struct pl031_local), GFP_KERNEL);
        if (!ldata) {
                ret = -ENOMEM;
                goto out;
        }

        ldata->base = ioremap(adev->res.start,
                              adev->res.end - adev->res.start + 1);
        if (!ldata->base) {
                ret = -ENOMEM;
                goto out_no_remap;
        }

        amba_set_drvdata(adev, ldata);

        if (request_irq(adev->irq[0], pl031_interrupt, IRQF_DISABLED,
                        "rtc-pl031", ldata->rtc)) {
                ret = -EIO;
                goto out_no_irq;
        }

        ldata->rtc = rtc_device_register("pl031", &adev->dev, &pl031_ops,
                                         THIS_MODULE);
        if (IS_ERR(ldata->rtc)) {
                ret = PTR_ERR(ldata->rtc);
                goto out_no_rtc;
        }

        return 0;

out_no_rtc:
        free_irq(adev->irq[0], ldata->rtc);
out_no_irq:
        iounmap(ldata->base);
        amba_set_drvdata(adev, NULL);
out_no_remap:
        kfree(ldata);
out:
        amba_release_regions(adev);
err_req:
        return ret;
}

static struct amba_id pl031_ids[] __initdata = {
        {
                 .id = 0x00041031,
                .mask = 0x000fffff, },
        {0, 0},
};

static struct amba_driver pl031_driver = {
        .drv = {
                .name = "rtc-pl031",
        },
        .id_table = pl031_ids,
        .probe = pl031_probe,
        .remove = pl031_remove,
};

static int __init pl031_init(void)
{
        return amba_driver_register(&pl031_driver);
}

static void __exit pl031_exit(void)
{
        amba_driver_unregister(&pl031_driver);
}

module_init(pl031_init);
module_exit(pl031_exit);

MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net");
MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
MODULE_LICENSE("GPL");