/*
   * TX4939 internal RTC driver
   * Based on RBTX49xx patch from CELF patch archive.
   *
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   *
   * (C) Copyright TOSHIBA CORPORATION 2005-2007
   */
  #include <linux/rtc.h>
  #include <linux/platform_device.h>
  #include <linux/interrupt.h>
  #include <linux/module.h>
  #include <linux/io.h>
  #include <linux/gfp.h>
  #include <asm/txx9/tx4939.h>
  
  struct tx4939rtc_plat_data {
  	struct rtc_device *rtc;
  	struct tx4939_rtc_reg __iomem *rtcreg;
  	spinlock_t lock;
  };
  
  static struct tx4939rtc_plat_data *get_tx4939rtc_plat_data(struct device *dev)
  {
  	return platform_get_drvdata(to_platform_device(dev));
  }
  
  static int tx4939_rtc_cmd(struct tx4939_rtc_reg __iomem *rtcreg, int cmd)
  {
  	int i = 0;
  
  	__raw_writel(cmd, &rtcreg->ctl);
  	/* This might take 30us (next 32.768KHz clock) */
  	while (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_BUSY) {
  		/* timeout on approx. 100us (@ GBUS200MHz) */
  		if (i++ > 200 * 100)
  			return -EBUSY;
  		cpu_relax();
  	}
  	return 0;
  }
  
  static int tx4939_rtc_set_mmss(struct device *dev, unsigned long secs)
  {
  	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev);
  	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
  	int i, ret;
  	unsigned char buf[6];
  
  	buf[0] = 0;
  	buf[1] = 0;
  	buf[2] = secs;
  	buf[3] = secs >> 8;
  	buf[4] = secs >> 16;
  	buf[5] = secs >> 24;
  	spin_lock_irq(&pdata->lock);
  	__raw_writel(0, &rtcreg->adr);
  	for (i = 0; i < 6; i++)
  		__raw_writel(buf[i], &rtcreg->dat);
  	ret = tx4939_rtc_cmd(rtcreg,
  			     TX4939_RTCCTL_COMMAND_SETTIME |
  			     (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
  	spin_unlock_irq(&pdata->lock);
  	return ret;
  }
  
  static int tx4939_rtc_read_time(struct device *dev, struct rtc_time *tm)
  {
  	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev);
  	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
  	int i, ret;
  	unsigned long sec;
  	unsigned char buf[6];
  
  	spin_lock_irq(&pdata->lock);
  	ret = tx4939_rtc_cmd(rtcreg,
  			     TX4939_RTCCTL_COMMAND_GETTIME |
  			     (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
  	if (ret) {
  		spin_unlock_irq(&pdata->lock);
  		return ret;
  	}
  	__raw_writel(2, &rtcreg->adr);
  	for (i = 2; i < 6; i++)
  		buf[i] = __raw_readl(&rtcreg->dat);
  	spin_unlock_irq(&pdata->lock);
  	sec = (buf[5] << 24) | (buf[4] << 16) | (buf[3] << 8) | buf[2];
  	rtc_time_to_tm(sec, tm);
  	return rtc_valid_tm(tm);
  }
  
  static int tx4939_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev);
  	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
  	int i, ret;
  	unsigned long sec;
  	unsigned char buf[6];
  
  	if (alrm->time.tm_sec < 0 ||
  	    alrm->time.tm_min < 0 ||
  	    alrm->time.tm_hour < 0 ||
  	    alrm->time.tm_mday < 0 ||
  	    alrm->time.tm_mon < 0 ||
  	    alrm->time.tm_year < 0)
  		return -EINVAL;
  	rtc_tm_to_time(&alrm->time, &sec);
  	buf[0] = 0;
  	buf[1] = 0;
  	buf[2] = sec;
  	buf[3] = sec >> 8;
  	buf[4] = sec >> 16;
  	buf[5] = sec >> 24;
  	spin_lock_irq(&pdata->lock);
  	__raw_writel(0, &rtcreg->adr);
  	for (i = 0; i < 6; i++)
  		__raw_writel(buf[i], &rtcreg->dat);
  	ret = tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_SETALARM |
  			     (alrm->enabled ? TX4939_RTCCTL_ALME : 0));
  	spin_unlock_irq(&pdata->lock);
  	return ret;
  }
  
  static int tx4939_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
  {
  	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev);
  	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
  	int i, ret;
  	unsigned long sec;
  	unsigned char buf[6];
  	u32 ctl;
  
  	spin_lock_irq(&pdata->lock);
  	ret = tx4939_rtc_cmd(rtcreg,
  			     TX4939_RTCCTL_COMMAND_GETALARM |
  			     (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
  	if (ret) {
  		spin_unlock_irq(&pdata->lock);
  		return ret;
  	}
  	__raw_writel(2, &rtcreg->adr);
  	for (i = 2; i < 6; i++)
  		buf[i] = __raw_readl(&rtcreg->dat);
  	ctl = __raw_readl(&rtcreg->ctl);
  	alrm->enabled = (ctl & TX4939_RTCCTL_ALME) ? 1 : 0;
  	alrm->pending = (ctl & TX4939_RTCCTL_ALMD) ? 1 : 0;
  	spin_unlock_irq(&pdata->lock);
  	sec = (buf[5] << 24) | (buf[4] << 16) | (buf[3] << 8) | buf[2];
  	rtc_time_to_tm(sec, &alrm->time);
  	return rtc_valid_tm(&alrm->time);
  }
  
  static int tx4939_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
  {
  	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev);
  
  	spin_lock_irq(&pdata->lock);
  	tx4939_rtc_cmd(pdata->rtcreg,
  		       TX4939_RTCCTL_COMMAND_NOP |
  		       (enabled ? TX4939_RTCCTL_ALME : 0));
  	spin_unlock_irq(&pdata->lock);
  	return 0;
  }
  
  static irqreturn_t tx4939_rtc_interrupt(int irq, void *dev_id)
  {
  	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev_id);
  	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
  	unsigned long events = RTC_IRQF;
  
  	spin_lock(&pdata->lock);
  	if (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALMD) {
  		events |= RTC_AF;
  		tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_NOP);
  	}
  	spin_unlock(&pdata->lock);
  	if (likely(pdata->rtc))
  		rtc_update_irq(pdata->rtc, 1, events);
  	return IRQ_HANDLED;
  }
  
  static const struct rtc_class_ops tx4939_rtc_ops = {
  	.read_time		= tx4939_rtc_read_time,
  	.read_alarm		= tx4939_rtc_read_alarm,
  	.set_alarm		= tx4939_rtc_set_alarm,
  	.set_mmss		= tx4939_rtc_set_mmss,
  	.alarm_irq_enable	= tx4939_rtc_alarm_irq_enable,
  };
  
  static ssize_t tx4939_rtc_nvram_read(struct file *filp, struct kobject *kobj,
  				     struct bin_attribute *bin_attr,
  				     char *buf, loff_t pos, size_t size)
  {
  	struct device *dev = container_of(kobj, struct device, kobj);
  	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev);
  	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
  	ssize_t count;
  
  	spin_lock_irq(&pdata->lock);
  	for (count = 0; size > 0 && pos < TX4939_RTC_REG_RAMSIZE;
  	     count++, size--) {
  		__raw_writel(pos++, &rtcreg->adr);
  		*buf++ = __raw_readl(&rtcreg->dat);
  	}
  	spin_unlock_irq(&pdata->lock);
  	return count;
  }
  
  static ssize_t tx4939_rtc_nvram_write(struct file *filp, struct kobject *kobj,
  				      struct bin_attribute *bin_attr,
  				      char *buf, loff_t pos, size_t size)
  {
  	struct device *dev = container_of(kobj, struct device, kobj);
  	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev);
  	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
  	ssize_t count;
  
  	spin_lock_irq(&pdata->lock);
  	for (count = 0; size > 0 && pos < TX4939_RTC_REG_RAMSIZE;
  	     count++, size--) {
  		__raw_writel(pos++, &rtcreg->adr);
  		__raw_writel(*buf++, &rtcreg->dat);
  	}
  	spin_unlock_irq(&pdata->lock);
  	return count;
  }
  
  static struct bin_attribute tx4939_rtc_nvram_attr = {
  	.attr = {
  		.name = "nvram",
  		.mode = S_IRUGO | S_IWUSR,
  	},
  	.size = TX4939_RTC_REG_RAMSIZE,
  	.read = tx4939_rtc_nvram_read,
  	.write = tx4939_rtc_nvram_write,
  };
  
  static int __init tx4939_rtc_probe(struct platform_device *pdev)
  {
  	struct rtc_device *rtc;
  	struct tx4939rtc_plat_data *pdata;
  	struct resource *res;
  	int irq, ret;
  
  	irq = platform_get_irq(pdev, 0);
  	if (irq < 0)
  		return -ENODEV;
  	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
  	if (!pdata)
  		return -ENOMEM;
  	platform_set_drvdata(pdev, pdata);
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	pdata->rtcreg = devm_ioremap_resource(&pdev->dev, res);
  	if (IS_ERR(pdata->rtcreg))
  		return PTR_ERR(pdata->rtcreg);
  
  	spin_lock_init(&pdata->lock);
  	tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
  	if (devm_request_irq(&pdev->dev, irq, tx4939_rtc_interrupt,
  			     0, pdev->name, &pdev->dev) < 0)
  		return -EBUSY;
  	rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
  				  &tx4939_rtc_ops, THIS_MODULE);
  	if (IS_ERR(rtc))
  		return PTR_ERR(rtc);
  	pdata->rtc = rtc;
  	ret = sysfs_create_bin_file(&pdev->dev.kobj, &tx4939_rtc_nvram_attr);
  
  	return ret;
  }
  
  static int __exit tx4939_rtc_remove(struct platform_device *pdev)
  {
  	struct tx4939rtc_plat_data *pdata = platform_get_drvdata(pdev);
  
  	sysfs_remove_bin_file(&pdev->dev.kobj, &tx4939_rtc_nvram_attr);
  	spin_lock_irq(&pdata->lock);
  	tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
  	spin_unlock_irq(&pdata->lock);
  	return 0;
  }
  
  static struct platform_driver tx4939_rtc_driver = {
  	.remove		= __exit_p(tx4939_rtc_remove),
  	.driver		= {
  		.name	= "tx4939rtc",
  		.owner	= THIS_MODULE,
  	},
  };
  
  module_platform_driver_probe(tx4939_rtc_driver, tx4939_rtc_probe);
  
  MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
  MODULE_DESCRIPTION("TX4939 internal RTC driver");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:tx4939rtc");