rtc-msm6242.c

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/*
 *  Oki MSM6242 RTC Driver
 *
 *  Copyright 2009 Geert Uytterhoeven
 *
 *  Based on the A2000 TOD code in arch/m68k/amiga/config.c
 *  Copyright (C) 1993 Hamish Macdonald
 */

#include <linux/delay.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/slab.h>


enum {
    MSM6242_SECOND1     = 0x0,  /* 1-second digit register */
    MSM6242_SECOND10    = 0x1,  /* 10-second digit register */
    MSM6242_MINUTE1     = 0x2,  /* 1-minute digit register */
    MSM6242_MINUTE10    = 0x3,  /* 10-minute digit register */
    MSM6242_HOUR1       = 0x4,  /* 1-hour digit register */
    MSM6242_HOUR10      = 0x5,  /* PM/AM, 10-hour digit register */
    MSM6242_DAY1        = 0x6,  /* 1-day digit register */
    MSM6242_DAY10       = 0x7,  /* 10-day digit register */
    MSM6242_MONTH1      = 0x8,  /* 1-month digit register */
    MSM6242_MONTH10     = 0x9,  /* 10-month digit register */
    MSM6242_YEAR1       = 0xa,  /* 1-year digit register */
    MSM6242_YEAR10      = 0xb,  /* 10-year digit register */
    MSM6242_WEEK        = 0xc,  /* Week register */
    MSM6242_CD      = 0xd,  /* Control Register D */
    MSM6242_CE      = 0xe,  /* Control Register E */
    MSM6242_CF      = 0xf,  /* Control Register F */
};

#define MSM6242_HOUR10_AM   (0 << 2)
#define MSM6242_HOUR10_PM   (1 << 2)
#define MSM6242_HOUR10_HR_MASK  (3 << 0)

#define MSM6242_WEEK_SUNDAY 0
#define MSM6242_WEEK_MONDAY 1
#define MSM6242_WEEK_TUESDAY    2
#define MSM6242_WEEK_WEDNESDAY  3
#define MSM6242_WEEK_THURSDAY   4
#define MSM6242_WEEK_FRIDAY 5
#define MSM6242_WEEK_SATURDAY   6

#define MSM6242_CD_30_S_ADJ (1 << 3)    /* 30-second adjustment */
#define MSM6242_CD_IRQ_FLAG (1 << 2)
#define MSM6242_CD_BUSY     (1 << 1)
#define MSM6242_CD_HOLD     (1 << 0)

#define MSM6242_CE_T_MASK   (3 << 2)
#define MSM6242_CE_T_64HZ   (0 << 2)    /* period 1/64 second */
#define MSM6242_CE_T_1HZ    (1 << 2)    /* period 1 second */
#define MSM6242_CE_T_1MINUTE    (2 << 2)    /* period 1 minute */
#define MSM6242_CE_T_1HOUR  (3 << 2)    /* period 1 hour */

#define MSM6242_CE_ITRPT_STND   (1 << 1)
#define MSM6242_CE_MASK     (1 << 0)    /* STD.P output control */

#define MSM6242_CF_TEST     (1 << 3)
#define MSM6242_CF_12H      (0 << 2)
#define MSM6242_CF_24H      (1 << 2)
#define MSM6242_CF_STOP     (1 << 1)
#define MSM6242_CF_REST     (1 << 0)    /* reset */


struct msm6242_priv {
    u32 __iomem *regs;
    struct rtc_device *rtc;
};

static inline unsigned int msm6242_read(struct msm6242_priv *priv,
                       unsigned int reg)
{
    return __raw_readl(&priv->regs[reg]) & 0xf;
}

static inline void msm6242_write(struct msm6242_priv *priv, unsigned int val,
                unsigned int reg)
{
    __raw_writel(val, &priv->regs[reg]);
}

static inline void msm6242_set(struct msm6242_priv *priv, unsigned int val,
                   unsigned int reg)
{
    msm6242_write(priv, msm6242_read(priv, reg) | val, reg);
}

static inline void msm6242_clear(struct msm6242_priv *priv, unsigned int val,
                 unsigned int reg)
{
    msm6242_write(priv, msm6242_read(priv, reg) & ~val, reg);
}

static void msm6242_lock(struct msm6242_priv *priv)
{
    int cnt = 5;

    msm6242_set(priv, MSM6242_CD_HOLD, MSM6242_CD);

    while ((msm6242_read(priv, MSM6242_CD) & MSM6242_CD_BUSY) && cnt) {
        msm6242_clear(priv, MSM6242_CD_HOLD, MSM6242_CD);
        udelay(70);
        msm6242_set(priv, MSM6242_CD_HOLD, MSM6242_CD);
        cnt--;
    }

    if (!cnt)
        pr_warning("msm6242: timed out waiting for RTC (0x%x)\n",
               msm6242_read(priv, MSM6242_CD));
}

static void msm6242_unlock(struct msm6242_priv *priv)
{
    msm6242_clear(priv, MSM6242_CD_HOLD, MSM6242_CD);
}

static int msm6242_read_time(struct device *dev, struct rtc_time *tm)
{
    struct msm6242_priv *priv = dev_get_drvdata(dev);

    msm6242_lock(priv);

    tm->tm_sec  = msm6242_read(priv, MSM6242_SECOND10) * 10 +
              msm6242_read(priv, MSM6242_SECOND1);
    tm->tm_min  = msm6242_read(priv, MSM6242_MINUTE10) * 10 +
              msm6242_read(priv, MSM6242_MINUTE1);
    tm->tm_hour = (msm6242_read(priv, MSM6242_HOUR10 & 3)) * 10 +
              msm6242_read(priv, MSM6242_HOUR1);
    tm->tm_mday = msm6242_read(priv, MSM6242_DAY10) * 10 +
              msm6242_read(priv, MSM6242_DAY1);
    tm->tm_wday = msm6242_read(priv, MSM6242_WEEK);
    tm->tm_mon  = msm6242_read(priv, MSM6242_MONTH10) * 10 +
              msm6242_read(priv, MSM6242_MONTH1) - 1;
    tm->tm_year = msm6242_read(priv, MSM6242_YEAR10) * 10 +
              msm6242_read(priv, MSM6242_YEAR1);
    if (tm->tm_year <= 69)
        tm->tm_year += 100;

    if (!(msm6242_read(priv, MSM6242_CF) & MSM6242_CF_24H)) {
        unsigned int pm = msm6242_read(priv, MSM6242_HOUR10) &
                  MSM6242_HOUR10_PM;
        if (!pm && tm->tm_hour == 12)
            tm->tm_hour = 0;
        else if (pm && tm->tm_hour != 12)
            tm->tm_hour += 12;
    }

    msm6242_unlock(priv);

    return rtc_valid_tm(tm);
}

static int msm6242_set_time(struct device *dev, struct rtc_time *tm)
{
    struct msm6242_priv *priv = dev_get_drvdata(dev);

    msm6242_lock(priv);

    msm6242_write(priv, tm->tm_sec / 10, MSM6242_SECOND10);
    msm6242_write(priv, tm->tm_sec % 10, MSM6242_SECOND1);
    msm6242_write(priv, tm->tm_min / 10, MSM6242_MINUTE10);
    msm6242_write(priv, tm->tm_min % 10, MSM6242_MINUTE1);
    if (msm6242_read(priv, MSM6242_CF) & MSM6242_CF_24H)
        msm6242_write(priv, tm->tm_hour / 10, MSM6242_HOUR10);
    else if (tm->tm_hour >= 12)
        msm6242_write(priv, MSM6242_HOUR10_PM + (tm->tm_hour - 12) / 10,
                  MSM6242_HOUR10);
    else
        msm6242_write(priv, tm->tm_hour / 10, MSM6242_HOUR10);
    msm6242_write(priv, tm->tm_hour % 10, MSM6242_HOUR1);
    msm6242_write(priv, tm->tm_mday / 10, MSM6242_DAY10);
    msm6242_write(priv, tm->tm_mday % 10, MSM6242_DAY1);
    if (tm->tm_wday != -1)
        msm6242_write(priv, tm->tm_wday, MSM6242_WEEK);
    msm6242_write(priv, (tm->tm_mon + 1) / 10, MSM6242_MONTH10);
    msm6242_write(priv, (tm->tm_mon + 1) % 10, MSM6242_MONTH1);
    if (tm->tm_year >= 100)
        tm->tm_year -= 100;
    msm6242_write(priv, tm->tm_year / 10, MSM6242_YEAR10);
    msm6242_write(priv, tm->tm_year % 10, MSM6242_YEAR1);

    msm6242_unlock(priv);
    return 0;
}

static const struct rtc_class_ops msm6242_rtc_ops = {
    .read_time  = msm6242_read_time,
    .set_time   = msm6242_set_time,
};

static int __init msm6242_rtc_probe(struct platform_device *dev)
{
    struct resource *res;
    struct msm6242_priv *priv;
    struct rtc_device *rtc;
    int error;

    res = platform_get_resource(dev, IORESOURCE_MEM, 0);
    if (!res)
        return -ENODEV;

    priv = kzalloc(sizeof(*priv), GFP_KERNEL);
    if (!priv)
        return -ENOMEM;

    priv->regs = ioremap(res->start, resource_size(res));
    if (!priv->regs) {
        error = -ENOMEM;
        goto out_free_priv;
    }
    platform_set_drvdata(dev, priv);

    rtc = rtc_device_register("rtc-msm6242", &dev->dev, &msm6242_rtc_ops,
                  THIS_MODULE);
    if (IS_ERR(rtc)) {
        error = PTR_ERR(rtc);
        goto out_unmap;
    }

    priv->rtc = rtc;
    return 0;

out_unmap:
    platform_set_drvdata(dev, NULL);
    iounmap(priv->regs);
out_free_priv:
    kfree(priv);
    return error;
}

static int __exit msm6242_rtc_remove(struct platform_device *dev)
{
    struct msm6242_priv *priv = platform_get_drvdata(dev);

    rtc_device_unregister(priv->rtc);
    iounmap(priv->regs);
    kfree(priv);
    return 0;
}

static struct platform_driver msm6242_rtc_driver = {
    .driver = {
        .name   = "rtc-msm6242",
        .owner  = THIS_MODULE,
    },
    .remove = __exit_p(msm6242_rtc_remove),
};

static int __init msm6242_rtc_init(void)
{
    return platform_driver_probe(&msm6242_rtc_driver, msm6242_rtc_probe);
}

static void __exit msm6242_rtc_fini(void)
{
    platform_driver_unregister(&msm6242_rtc_driver);
}

module_init(msm6242_rtc_init);
module_exit(msm6242_rtc_fini);

MODULE_AUTHOR("Geert Uytterhoeven <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Oki MSM6242 RTC driver");
MODULE_ALIAS("platform:rtc-msm6242");