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rtc-stmp3xxx.c

/*
 * Freescale STMP37XX/STMP378X Real Time Clock driver
 *
 * Copyright (c) 2007 Sigmatel, Inc.
 * Peter Hartley, <peter.hartley@sigmatel.com>
 *
 * Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved.
 * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
 */

/*
 * The code contained herein is licensed under the GNU General Public
 * License. You may obtain a copy of the GNU General Public License
 * Version 2 or later at the following locations:
 *
 * http://www.opensource.org/licenses/gpl-license.html
 * http://www.gnu.org/copyleft/gpl.html
 */
#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/io.h>
#include <linux/irq.h>
#include <linux/uaccess.h>

#include <mach/stmp3xxx.h>
#include <mach/hardware.h>
#include <mach/platform.h>
#include <mach/irqs.h>
#include <mach/regs-rtc.h>

struct stmp3xxx_rtc_data {
      struct rtc_device *rtc;
      unsigned irq_count;
};

/* Time read/write */
static int stmp3xxx_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
{
      while (__raw_readl(REGS_RTC_BASE + HW_RTC_STAT) & BF(0x80, RTC_STAT_STALE_REGS))
            cpu_relax();

      rtc_time_to_tm(__raw_readl(REGS_RTC_BASE + HW_RTC_SECONDS), rtc_tm);
      return 0;
}

static int stmp3xxx_rtc_settime(struct device *dev, struct rtc_time *rtc_tm)
{
      unsigned long t;
      int rc = rtc_tm_to_time(rtc_tm, &t);

      if (rc == 0) {
            __raw_writel(t, REGS_RTC_BASE + HW_RTC_SECONDS);

            /* The datasheet doesn't say which way round the
             * NEW_REGS/STALE_REGS bitfields go. In fact it's 0x1=P0,
             * 0x2=P1, .., 0x20=P5, 0x40=ALARM, 0x80=SECONDS,
             */
            while (__raw_readl(REGS_RTC_BASE + HW_RTC_STAT) & BF(0x80, RTC_STAT_NEW_REGS))
                  cpu_relax();
      }
      return rc;
}

static irqreturn_t stmp3xxx_rtc_interrupt(int irq, void *dev_id)
{
      struct platform_device *pdev = to_platform_device(dev_id);
      struct stmp3xxx_rtc_data *data = platform_get_drvdata(pdev);
      u32 status;
      u32 events = 0;

      status = __raw_readl(REGS_RTC_BASE + HW_RTC_CTRL) &
                  (BM_RTC_CTRL_ALARM_IRQ | BM_RTC_CTRL_ONEMSEC_IRQ);
      if (status & BM_RTC_CTRL_ALARM_IRQ) {
            __raw_writel(BM_RTC_CTRL_ALARM_IRQ,
                  REGS_RTC_BASE + HW_RTC_CTRL_CLR);
            events |= RTC_AF | RTC_IRQF;
      }
      if (status & BM_RTC_CTRL_ONEMSEC_IRQ) {
            __raw_writel(BM_RTC_CTRL_ONEMSEC_IRQ,
                  REGS_RTC_BASE + HW_RTC_CTRL_CLR);
            if (++data->irq_count % 1000 == 0) {
                  events |= RTC_UF | RTC_IRQF;
                  data->irq_count = 0;
            }
      }

      if (events)
            rtc_update_irq(data->rtc, 1, events);

      return IRQ_HANDLED;
}

static int stmp3xxx_rtc_open(struct device *dev)
{
      int r;

      r = request_irq(IRQ_RTC_ALARM, stmp3xxx_rtc_interrupt,
                  IRQF_DISABLED, "RTC alarm", dev);
      if (r) {
            dev_err(dev, "Cannot claim IRQ%d\n", IRQ_RTC_ALARM);
            goto fail_1;
      }
      r = request_irq(IRQ_RTC_1MSEC, stmp3xxx_rtc_interrupt,
                  IRQF_DISABLED, "RTC tick", dev);
      if (r) {
            dev_err(dev, "Cannot claim IRQ%d\n", IRQ_RTC_1MSEC);
            goto fail_2;
      }

      return 0;
fail_2:
      free_irq(IRQ_RTC_ALARM, dev);
fail_1:
      return r;
}

static void stmp3xxx_rtc_release(struct device *dev)
{
      __raw_writel(BM_RTC_CTRL_ALARM_IRQ_EN | BM_RTC_CTRL_ONEMSEC_IRQ_EN,
            REGS_RTC_BASE + HW_RTC_CTRL_CLR);
      free_irq(IRQ_RTC_ALARM, dev);
      free_irq(IRQ_RTC_1MSEC, dev);
}

static int stmp3xxx_rtc_ioctl(struct device *dev, unsigned int cmd,
                        unsigned long arg)
{
      struct stmp3xxx_rtc_data *data = dev_get_drvdata(dev);

      switch (cmd) {
      case RTC_AIE_OFF:
            __raw_writel(BM_RTC_PERSISTENT0_ALARM_EN |
                        BM_RTC_PERSISTENT0_ALARM_WAKE_EN,
                        REGS_RTC_BASE + HW_RTC_PERSISTENT0_CLR);
            __raw_writel(BM_RTC_CTRL_ALARM_IRQ_EN,
                        REGS_RTC_BASE + HW_RTC_CTRL_CLR);
            break;
      case RTC_AIE_ON:
            __raw_writel(BM_RTC_PERSISTENT0_ALARM_EN |
                        BM_RTC_PERSISTENT0_ALARM_WAKE_EN,
                        REGS_RTC_BASE + HW_RTC_PERSISTENT0_SET);

            __raw_writel(BM_RTC_CTRL_ALARM_IRQ_EN,
                        REGS_RTC_BASE + HW_RTC_CTRL_SET);
            break;
      case RTC_UIE_ON:
            data->irq_count = 0;
            __raw_writel(BM_RTC_CTRL_ONEMSEC_IRQ_EN,
                  REGS_RTC_BASE + HW_RTC_CTRL_SET);
            break;
      case RTC_UIE_OFF:
            __raw_writel(BM_RTC_CTRL_ONEMSEC_IRQ_EN,
                  REGS_RTC_BASE + HW_RTC_CTRL_CLR);
            break;
      default:
            return -ENOIOCTLCMD;
      }

      return 0;
}
static int stmp3xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
      u32 t = __raw_readl(REGS_RTC_BASE + HW_RTC_ALARM);

      rtc_time_to_tm(t, &alm->time);

      return 0;
}

static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
      unsigned long t;

      rtc_tm_to_time(&alm->time, &t);
      __raw_writel(t, REGS_RTC_BASE + HW_RTC_ALARM);
      return 0;
}

static struct rtc_class_ops stmp3xxx_rtc_ops = {
      .open       = stmp3xxx_rtc_open,
      .release    = stmp3xxx_rtc_release,
      .ioctl          = stmp3xxx_rtc_ioctl,
      .read_time  = stmp3xxx_rtc_gettime,
      .set_time   = stmp3xxx_rtc_settime,
      .read_alarm = stmp3xxx_rtc_read_alarm,
      .set_alarm  = stmp3xxx_rtc_set_alarm,
};

static int stmp3xxx_rtc_remove(struct platform_device *dev)
{
      struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(dev);

      if (rtc_data) {
            rtc_device_unregister(rtc_data->rtc);
            kfree(rtc_data);
      }

      return 0;
}

static int stmp3xxx_rtc_probe(struct platform_device *pdev)
{
      u32 hwversion = __raw_readl(REGS_RTC_BASE + HW_RTC_VERSION);
      u32 rtc_stat = __raw_readl(REGS_RTC_BASE + HW_RTC_STAT);
      struct stmp3xxx_rtc_data *rtc_data = kzalloc(sizeof *rtc_data,
                                         GFP_KERNEL);

      if ((rtc_stat & BM_RTC_STAT_RTC_PRESENT) == 0)
            return -ENODEV;
      if (!rtc_data)
            return -ENOMEM;

      stmp3xxx_reset_block(REGS_RTC_BASE, 1);

      __raw_writel(BM_RTC_PERSISTENT0_ALARM_EN |
                  BM_RTC_PERSISTENT0_ALARM_WAKE_EN |
                  BM_RTC_PERSISTENT0_ALARM_WAKE,
                 REGS_RTC_BASE + HW_RTC_PERSISTENT0_CLR);
      __raw_writel(BM_RTC_PERSISTENT0_AUTO_RESTART,
                 REGS_RTC_BASE + HW_RTC_PERSISTENT0_SET);

      printk(KERN_INFO "STMP3xxx RTC driver v1.0 hardware v%u.%u.%u\n",
             (hwversion >> 24),
             (hwversion >> 16) & 0xFF,
             hwversion & 0xFFFF);

      rtc_data->rtc = rtc_device_register(pdev->name, &pdev->dev,
                        &stmp3xxx_rtc_ops, THIS_MODULE);
      if (IS_ERR(rtc_data->rtc)) {
            kfree(rtc_data);
            return PTR_ERR(rtc_data->rtc);
      }

      platform_set_drvdata(pdev, rtc_data);

      return 0;
}

#ifdef CONFIG_PM
static int stmp3xxx_rtc_suspend(struct platform_device *dev, pm_message_t state)
{
      return 0;
}

static int stmp3xxx_rtc_resume(struct platform_device *dev)
{
      stmp3xxx_reset_block(REGS_RTC_BASE, 1);
      __raw_writel(BM_RTC_PERSISTENT0_ALARM_EN |
                  BM_RTC_PERSISTENT0_ALARM_WAKE_EN |
                  BM_RTC_PERSISTENT0_ALARM_WAKE,
                 REGS_RTC_BASE + HW_RTC_PERSISTENT0_CLR);
      return 0;
}
#else
#define stmp3xxx_rtc_suspend  NULL
#define stmp3xxx_rtc_resume   NULL
#endif

static struct platform_driver stmp3xxx_rtcdrv = {
      .probe            = stmp3xxx_rtc_probe,
      .remove           = stmp3xxx_rtc_remove,
      .suspend    = stmp3xxx_rtc_suspend,
      .resume           = stmp3xxx_rtc_resume,
      .driver           = {
            .name = "stmp3xxx-rtc",
            .owner      = THIS_MODULE,
      },
};

static int __init stmp3xxx_rtc_init(void)
{
      return platform_driver_register(&stmp3xxx_rtcdrv);
}

static void __exit stmp3xxx_rtc_exit(void)
{
      platform_driver_unregister(&stmp3xxx_rtcdrv);
}

module_init(stmp3xxx_rtc_init);
module_exit(stmp3xxx_rtc_exit);

MODULE_DESCRIPTION("STMP3xxx RTC Driver");
MODULE_AUTHOR("dmitry pervushin <dimka@embeddedalley.com>");
MODULE_LICENSE("GPL");

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