rtc: add support for spear rtc

Signed-off-by: Rajeev Kumar <rajeev-dlh.kumar@st.com>
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 534 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-spear.c b/drivers/rtc/rtc-spear.c
new file mode 100644
index 00000000000..893bac2bb21
--- /dev/null
+++ b/drivers/rtc/rtc-spear.c
@@ -0,0 +1,534 @@
+/*
+ * drivers/rtc/rtc-spear.c
+ *
+ * Copyright (C) 2010 ST Microelectronics
+ * Rajeev Kumar<rajeev-dlh.kumar@st.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/bcd.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+/* RTC registers */
+#define TIME_REG		0x00
+#define DATE_REG		0x04
+#define ALARM_TIME_REG		0x08
+#define ALARM_DATE_REG		0x0C
+#define CTRL_REG		0x10
+#define STATUS_REG		0x14
+
+/* TIME_REG & ALARM_TIME_REG */
+#define SECONDS_UNITS		(0xf<<0)	/* seconds units position */
+#define SECONDS_TENS		(0x7<<4)	/* seconds tens position */
+#define MINUTES_UNITS		(0xf<<8)	/* minutes units position */
+#define MINUTES_TENS		(0x7<<12)	/* minutes tens position */
+#define HOURS_UNITS		(0xf<<16)	/* hours units position */
+#define HOURS_TENS		(0x3<<20)	/* hours tens position */
+
+/* DATE_REG & ALARM_DATE_REG */
+#define DAYS_UNITS		(0xf<<0)	/* days units position */
+#define DAYS_TENS		(0x3<<4)	/* days tens position */
+#define MONTHS_UNITS		(0xf<<8)	/* months units position */
+#define MONTHS_TENS		(0x1<<12)	/* months tens position */
+#define YEARS_UNITS		(0xf<<16)	/* years units position */
+#define YEARS_TENS		(0xf<<20)	/* years tens position */
+#define YEARS_HUNDREDS		(0xf<<24)	/* years hundereds position */
+#define YEARS_MILLENIUMS	(0xf<<28)	/* years millenium position */
+
+/* MASK SHIFT TIME_REG & ALARM_TIME_REG*/
+#define SECOND_SHIFT		0x00		/* seconds units */
+#define MINUTE_SHIFT		0x08		/* minutes units position */
+#define HOUR_SHIFT		0x10		/* hours units position */
+#define MDAY_SHIFT		0x00		/* Month day shift */
+#define MONTH_SHIFT		0x08		/* Month shift */
+#define YEAR_SHIFT		0x10		/* Year shift */
+
+#define SECOND_MASK		0x7F
+#define MIN_MASK		0x7F
+#define HOUR_MASK		0x3F
+#define DAY_MASK		0x3F
+#define MONTH_MASK		0x7F
+#define YEAR_MASK		0xFFFF
+
+/* date reg equal to time reg, for debug only */
+#define TIME_BYP		(1<<9)
+#define INT_ENABLE		(1<<31)		/* interrupt enable */
+
+/* STATUS_REG */
+#define CLK_UNCONNECTED		(1<<0)
+#define PEND_WR_TIME		(1<<2)
+#define PEND_WR_DATE		(1<<3)
+#define LOST_WR_TIME		(1<<4)
+#define LOST_WR_DATE		(1<<5)
+#define RTC_INT_MASK		(1<<31)
+#define STATUS_BUSY		(PEND_WR_TIME | PEND_WR_DATE)
+#define STATUS_FAIL		(LOST_WR_TIME | LOST_WR_DATE)
+
+struct spear_rtc_config {
+	struct clk *clk;
+	spinlock_t lock;
+	void __iomem *ioaddr;
+};
+
+static inline void spear_rtc_clear_interrupt(struct spear_rtc_config *config)
+{
+	unsigned int val;
+	unsigned long flags;
+
+	spin_lock_irqsave(&config->lock, flags);
+	val = readl(config->ioaddr + STATUS_REG);
+	val |= RTC_INT_MASK;
+	writel(val, config->ioaddr + STATUS_REG);
+	spin_unlock_irqrestore(&config->lock, flags);
+}
+
+static inline void spear_rtc_enable_interrupt(struct spear_rtc_config *config)
+{
+	unsigned int val;
+
+	val = readl(config->ioaddr + CTRL_REG);
+	if (!(val & INT_ENABLE)) {
+		spear_rtc_clear_interrupt(config);
+		val |= INT_ENABLE;
+		writel(val, config->ioaddr + CTRL_REG);
+	}
+}
+
+static inline void spear_rtc_disable_interrupt(struct spear_rtc_config *config)
+{
+	unsigned int val;
+
+	val = readl(config->ioaddr + CTRL_REG);
+	if (val & INT_ENABLE) {
+		val &= ~INT_ENABLE;
+		writel(val, config->ioaddr + CTRL_REG);
+	}
+}
+
+static inline int is_write_complete(struct spear_rtc_config *config)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&config->lock, flags);
+	if ((readl(config->ioaddr + STATUS_REG)) & STATUS_FAIL)
+		ret = -EIO;
+	spin_unlock_irqrestore(&config->lock, flags);
+
+	return ret;
+}
+
+static void rtc_wait_not_busy(struct spear_rtc_config *config)
+{
+	int status, count = 0;
+	unsigned long flags;
+
+	/* Assuming BUSY may stay active for 80 msec) */
+	for (count = 0; count < 80; count++) {
+		spin_lock_irqsave(&config->lock, flags);
+		status = readl(config->ioaddr + STATUS_REG);
+		spin_unlock_irqrestore(&config->lock, flags);
+		if ((status & STATUS_BUSY) == 0)
+			break;
+		/* check status busy, after each msec */
+		msleep(1);
+	}
+}
+
+static irqreturn_t spear_rtc_irq(int irq, void *dev_id)
+{
+	struct rtc_device *rtc = (struct rtc_device *)dev_id;
+	struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
+	unsigned long flags, events = 0;
+	unsigned int irq_data;
+
+	spin_lock_irqsave(&config->lock, flags);
+	irq_data = readl(config->ioaddr + STATUS_REG);
+	spin_unlock_irqrestore(&config->lock, flags);
+
+	if ((irq_data & RTC_INT_MASK)) {
+		spear_rtc_clear_interrupt(config);
+		events = RTC_IRQF | RTC_AF;
+		rtc_update_irq(rtc, 1, events);
+		return IRQ_HANDLED;
+	} else
+		return IRQ_NONE;
+
+}
+
+static int tm2bcd(struct rtc_time *tm)
+{
+	if (rtc_valid_tm(tm) != 0)
+		return -EINVAL;
+	tm->tm_sec = bin2bcd(tm->tm_sec);
+	tm->tm_min = bin2bcd(tm->tm_min);
+	tm->tm_hour = bin2bcd(tm->tm_hour);
+	tm->tm_mday = bin2bcd(tm->tm_mday);
+	tm->tm_mon = bin2bcd(tm->tm_mon + 1);
+	tm->tm_year = bin2bcd(tm->tm_year);
+
+	return 0;
+}
+
+static void bcd2tm(struct rtc_time *tm)
+{
+	tm->tm_sec = bcd2bin(tm->tm_sec);
+	tm->tm_min = bcd2bin(tm->tm_min);
+	tm->tm_hour = bcd2bin(tm->tm_hour);
+	tm->tm_mday = bcd2bin(tm->tm_mday);
+	tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
+	/* epoch == 1900 */
+	tm->tm_year = bcd2bin(tm->tm_year);
+}
+
+/*
+ * spear_rtc_read_time - set the time
+ * @dev: rtc device in use
+ * @tm: holds date and time
+ *
+ * This function read time and date. On success it will return 0
+ * otherwise -ve error is returned.
+ */
+static int spear_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct rtc_device *rtc = platform_get_drvdata(pdev);
+	struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
+	unsigned int time, date;
+
+	/* we don't report wday/yday/isdst ... */
+	rtc_wait_not_busy(config);
+
+	time = readl(config->ioaddr + TIME_REG);
+	date = readl(config->ioaddr + DATE_REG);
+	tm->tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
+	tm->tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
+	tm->tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
+	tm->tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
+	tm->tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
+	tm->tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
+
+	bcd2tm(tm);
+	return 0;
+}
+
+/*
+ * spear_rtc_set_time - set the time
+ * @dev: rtc device in use
+ * @tm: holds date and time
+ *
+ * This function set time and date. On success it will return 0
+ * otherwise -ve error is returned.
+ */
+static int spear_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct rtc_device *rtc = platform_get_drvdata(pdev);
+	struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
+	unsigned int time, date, err = 0;
+
+	if (tm2bcd(tm) < 0)
+		return -EINVAL;
+
+	rtc_wait_not_busy(config);
+	time = (tm->tm_sec << SECOND_SHIFT) | (tm->tm_min << MINUTE_SHIFT) |
+		(tm->tm_hour << HOUR_SHIFT);
+	date = (tm->tm_mday << MDAY_SHIFT) | (tm->tm_mon << MONTH_SHIFT) |
+		(tm->tm_year << YEAR_SHIFT);
+	writel(time, config->ioaddr + TIME_REG);
+	writel(date, config->ioaddr + DATE_REG);
+	err = is_write_complete(config);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+/*
+ * spear_rtc_read_alarm - read the alarm time
+ * @dev: rtc device in use
+ * @alm: holds alarm date and time
+ *
+ * This function read alarm time and date. On success it will return 0
+ * otherwise -ve error is returned.
+ */
+static int spear_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct rtc_device *rtc = platform_get_drvdata(pdev);
+	struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
+	unsigned int time, date;
+
+	rtc_wait_not_busy(config);
+
+	time = readl(config->ioaddr + ALARM_TIME_REG);
+	date = readl(config->ioaddr + ALARM_DATE_REG);
+	alm->time.tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
+	alm->time.tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
+	alm->time.tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
+	alm->time.tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
+	alm->time.tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
+	alm->time.tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
+
+	bcd2tm(&alm->time);
+	alm->enabled = readl(config->ioaddr + CTRL_REG) & INT_ENABLE;
+
+	return 0;
+}
+
+/*
+ * spear_rtc_set_alarm - set the alarm time
+ * @dev: rtc device in use
+ * @alm: holds alarm date and time
+ *
+ * This function set alarm time and date. On success it will return 0
+ * otherwise -ve error is returned.
+ */
+static int spear_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct rtc_device *rtc = platform_get_drvdata(pdev);
+	struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
+	unsigned int time, date, err = 0;
+
+	if (tm2bcd(&alm->time) < 0)
+		return -EINVAL;
+
+	rtc_wait_not_busy(config);
+
+	time = (alm->time.tm_sec << SECOND_SHIFT) | (alm->time.tm_min <<
+			MINUTE_SHIFT) |	(alm->time.tm_hour << HOUR_SHIFT);
+	date = (alm->time.tm_mday << MDAY_SHIFT) | (alm->time.tm_mon <<
+			MONTH_SHIFT) | (alm->time.tm_year << YEAR_SHIFT);
+
+	writel(time, config->ioaddr + ALARM_TIME_REG);
+	writel(date, config->ioaddr + ALARM_DATE_REG);
+	err = is_write_complete(config);
+	if (err < 0)
+		return err;
+
+	if (alm->enabled)
+		spear_rtc_enable_interrupt(config);
+	else
+		spear_rtc_disable_interrupt(config);
+
+	return 0;
+}
+static struct rtc_class_ops spear_rtc_ops = {
+	.read_time = spear_rtc_read_time,
+	.set_time = spear_rtc_set_time,
+	.read_alarm = spear_rtc_read_alarm,
+	.set_alarm = spear_rtc_set_alarm,
+};
+
+static int __devinit spear_rtc_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct rtc_device *rtc;
+	struct spear_rtc_config *config;
+	unsigned int status = 0;
+	int irq;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "no resource defined\n");
+		return -EBUSY;
+	}
+	if (!request_mem_region(res->start, resource_size(res), pdev->name)) {
+		dev_err(&pdev->dev, "rtc region already claimed\n");
+		return -EBUSY;
+	}
+
+	config = kzalloc(sizeof(*config), GFP_KERNEL);
+	if (!config) {
+		dev_err(&pdev->dev, "out of memory\n");
+		status = -ENOMEM;
+		goto err_release_region;
+	}
+
+	config->clk = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(config->clk)) {
+		status = PTR_ERR(config->clk);
+		goto err_kfree;
+	}
+
+	status = clk_enable(config->clk);
+	if (status < 0)
+		goto err_clk_put;
+
+	config->ioaddr = ioremap(res->start, resource_size(res));
+	if (!config->ioaddr) {
+		dev_err(&pdev->dev, "ioremap fail\n");
+		status = -ENOMEM;
+		goto err_disable_clock;
+	}
+
+	spin_lock_init(&config->lock);
+
+	rtc = rtc_device_register(pdev->name, &pdev->dev, &spear_rtc_ops,
+			THIS_MODULE);
+	if (IS_ERR(rtc)) {
+		dev_err(&pdev->dev, "can't register RTC device, err %ld\n",
+				PTR_ERR(rtc));
+		status = PTR_ERR(rtc);
+		goto err_iounmap;
+	}
+
+	platform_set_drvdata(pdev, rtc);
+	dev_set_drvdata(&rtc->dev, config);
+
+	/* alarm irqs */
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "no update irq?\n");
+		status = irq;
+		goto err_clear_platdata;
+	}
+
+	status = request_irq(irq, spear_rtc_irq, 0, pdev->name, rtc);
+	if (status) {
+		dev_err(&pdev->dev, "Alarm interrupt IRQ%d already \
+				claimed\n", irq);
+		goto err_clear_platdata;
+	}
+
+	if (!device_can_wakeup(&pdev->dev))
+		device_init_wakeup(&pdev->dev, 1);
+
+	return 0;
+
+err_clear_platdata:
+	platform_set_drvdata(pdev, NULL);
+	dev_set_drvdata(&rtc->dev, NULL);
+	rtc_device_unregister(rtc);
+err_iounmap:
+	iounmap(config->ioaddr);
+err_disable_clock:
+	clk_disable(config->clk);
+err_clk_put:
+	clk_put(config->clk);
+err_kfree:
+	kfree(config);
+err_release_region:
+	release_mem_region(res->start, resource_size(res));
+
+	return status;
+}
+
+static int __devexit spear_rtc_remove(struct platform_device *pdev)
+{
+	struct rtc_device *rtc = platform_get_drvdata(pdev);
+	struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
+	int irq;
+	struct resource *res;
+
+	/* leave rtc running, but disable irqs */
+	spear_rtc_disable_interrupt(config);
+	device_init_wakeup(&pdev->dev, 0);
+	irq = platform_get_irq(pdev, 0);
+	if (irq)
+		free_irq(irq, pdev);
+	clk_disable(config->clk);
+	clk_put(config->clk);
+	iounmap(config->ioaddr);
+	kfree(config);
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (res)
+		release_mem_region(res->start, resource_size(res));
+	platform_set_drvdata(pdev, NULL);
+	dev_set_drvdata(&rtc->dev, NULL);
+	rtc_device_unregister(rtc);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+
+static int spear_rtc_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	struct rtc_device *rtc = platform_get_drvdata(pdev);
+	struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
+	int irq;
+
+	irq = platform_get_irq(pdev, 0);
+	if (device_may_wakeup(&pdev->dev))
+		enable_irq_wake(irq);
+	else {
+		spear_rtc_disable_interrupt(config);
+		clk_disable(config->clk);
+	}
+
+	return 0;
+}
+
+static int spear_rtc_resume(struct platform_device *pdev)
+{
+	struct rtc_device *rtc = platform_get_drvdata(pdev);
+	struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
+	int irq;
+
+	irq = platform_get_irq(pdev, 0);
+
+	if (device_may_wakeup(&pdev->dev))
+		disable_irq_wake(irq);
+	else {
+		clk_enable(config->clk);
+		spear_rtc_enable_interrupt(config);
+	}
+
+	return 0;
+}
+
+#else
+#define spear_rtc_suspend	NULL
+#define spear_rtc_resume	NULL
+#endif
+
+static void spear_rtc_shutdown(struct platform_device *pdev)
+{
+	struct rtc_device *rtc = platform_get_drvdata(pdev);
+	struct spear_rtc_config *config = dev_get_drvdata(&rtc->dev);
+
+	spear_rtc_disable_interrupt(config);
+	clk_disable(config->clk);
+}
+
+static struct platform_driver spear_rtc_driver = {
+	.probe = spear_rtc_probe,
+	.remove = __devexit_p(spear_rtc_remove),
+	.suspend = spear_rtc_suspend,
+	.resume = spear_rtc_resume,
+	.shutdown = spear_rtc_shutdown,
+	.driver = {
+		.name = "rtc-spear",
+	},
+};
+
+static int __init rtc_init(void)
+{
+	return platform_driver_register(&spear_rtc_driver);
+}
+module_init(rtc_init);
+
+static void __exit rtc_exit(void)
+{
+	platform_driver_unregister(&spear_rtc_driver);
+}
+module_exit(rtc_exit);
+
+MODULE_ALIAS("platform:rtc-spear");
+MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
+MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
+MODULE_LICENSE("GPL");