1 files changed, 494 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-spear.c b/drivers/rtc/rtc-spear.c
new file mode 100644
index 000000000..736fe535c
--- /dev/null
+++ b/drivers/rtc/rtc-spear.c
@@ -0,0 +1,494 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * drivers/rtc/rtc-spear.c
+ *
+ * Copyright (C) 2010 ST Microelectronics
+ * Rajeev Kumar<rajeev-dlh.kumar@st.com>
+ */
+
+#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/of.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 rtc_device *rtc;
+	struct clk *clk;
+	spinlock_t lock;
+	void __iomem *ioaddr;
+	unsigned int irq_wake;
+};
+
+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 spear_rtc_config *config = dev_id;
+	unsigned long events = 0;
+	unsigned int irq_data;
+
+	spin_lock(&config->lock);
+	irq_data = readl(config->ioaddr + STATUS_REG);
+	spin_unlock(&config->lock);
+
+	if ((irq_data & RTC_INT_MASK)) {
+		spear_rtc_clear_interrupt(config);
+		events = RTC_IRQF | RTC_AF;
+		rtc_update_irq(config->rtc, 1, events);
+		return IRQ_HANDLED;
+	} else
+		return IRQ_NONE;
+
+}
+
+static void tm2bcd(struct rtc_time *tm)
+{
+	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);
+}
+
+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 spear_rtc_config *config = dev_get_drvdata(dev);
+	unsigned int time, date;
+
+	/* we don't report wday/yday/isdst ... */
+	rtc_wait_not_busy(config);
+
+	do {
+		time = readl(config->ioaddr + TIME_REG);
+		date = readl(config->ioaddr + DATE_REG);
+	} while (time == readl(config->ioaddr + TIME_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 spear_rtc_config *config = dev_get_drvdata(dev);
+	unsigned int time, date;
+
+	tm2bcd(tm);
+
+	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);
+
+	return is_write_complete(config);
+}
+
+/*
+ * 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 spear_rtc_config *config = dev_get_drvdata(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 spear_rtc_config *config = dev_get_drvdata(dev);
+	unsigned int time, date;
+	int err;
+
+	tm2bcd(&alm->time);
+
+	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 int spear_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct spear_rtc_config *config = dev_get_drvdata(dev);
+	int ret = 0;
+
+	spear_rtc_clear_interrupt(config);
+
+	switch (enabled) {
+	case 0:
+		/* alarm off */
+		spear_rtc_disable_interrupt(config);
+		break;
+	case 1:
+		/* alarm on */
+		spear_rtc_enable_interrupt(config);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static const 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,
+	.alarm_irq_enable = spear_alarm_irq_enable,
+};
+
+static int spear_rtc_probe(struct platform_device *pdev)
+{
+	struct spear_rtc_config *config;
+	int status = 0;
+	int irq;
+
+	config = devm_kzalloc(&pdev->dev, sizeof(*config), GFP_KERNEL);
+	if (!config)
+		return -ENOMEM;
+
+	config->rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(config->rtc))
+		return PTR_ERR(config->rtc);
+
+	/* alarm irqs */
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	status = devm_request_irq(&pdev->dev, irq, spear_rtc_irq, 0, pdev->name,
+			config);
+	if (status) {
+		dev_err(&pdev->dev, "Alarm interrupt IRQ%d already claimed\n",
+				irq);
+		return status;
+	}
+
+	config->ioaddr = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(config->ioaddr))
+		return PTR_ERR(config->ioaddr);
+
+	config->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(config->clk))
+		return PTR_ERR(config->clk);
+
+	status = clk_prepare_enable(config->clk);
+	if (status < 0)
+		return status;
+
+	spin_lock_init(&config->lock);
+	platform_set_drvdata(pdev, config);
+
+	config->rtc->ops = &spear_rtc_ops;
+	config->rtc->range_min = RTC_TIMESTAMP_BEGIN_0000;
+	config->rtc->range_max = RTC_TIMESTAMP_END_9999;
+
+	status = devm_rtc_register_device(config->rtc);
+	if (status)
+		goto err_disable_clock;
+
+	if (!device_can_wakeup(&pdev->dev))
+		device_init_wakeup(&pdev->dev, 1);
+
+	return 0;
+
+err_disable_clock:
+	clk_disable_unprepare(config->clk);
+
+	return status;
+}
+
+static int spear_rtc_remove(struct platform_device *pdev)
+{
+	struct spear_rtc_config *config = platform_get_drvdata(pdev);
+
+	spear_rtc_disable_interrupt(config);
+	clk_disable_unprepare(config->clk);
+	device_init_wakeup(&pdev->dev, 0);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int spear_rtc_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct spear_rtc_config *config = platform_get_drvdata(pdev);
+	int irq;
+
+	irq = platform_get_irq(pdev, 0);
+	if (device_may_wakeup(&pdev->dev)) {
+		if (!enable_irq_wake(irq))
+			config->irq_wake = 1;
+	} else {
+		spear_rtc_disable_interrupt(config);
+		clk_disable(config->clk);
+	}
+
+	return 0;
+}
+
+static int spear_rtc_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct spear_rtc_config *config = platform_get_drvdata(pdev);
+	int irq;
+
+	irq = platform_get_irq(pdev, 0);
+
+	if (device_may_wakeup(&pdev->dev)) {
+		if (config->irq_wake) {
+			disable_irq_wake(irq);
+			config->irq_wake = 0;
+		}
+	} else {
+		clk_enable(config->clk);
+		spear_rtc_enable_interrupt(config);
+	}
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(spear_rtc_pm_ops, spear_rtc_suspend, spear_rtc_resume);
+
+static void spear_rtc_shutdown(struct platform_device *pdev)
+{
+	struct spear_rtc_config *config = platform_get_drvdata(pdev);
+
+	spear_rtc_disable_interrupt(config);
+	clk_disable(config->clk);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id spear_rtc_id_table[] = {
+	{ .compatible = "st,spear600-rtc" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
+#endif
+
+static struct platform_driver spear_rtc_driver = {
+	.probe = spear_rtc_probe,
+	.remove = spear_rtc_remove,
+	.shutdown = spear_rtc_shutdown,
+	.driver = {
+		.name = "rtc-spear",
+		.pm = &spear_rtc_pm_ops,
+		.of_match_table = of_match_ptr(spear_rtc_id_table),
+	},
+};
+
+module_platform_driver(spear_rtc_driver);
+
+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");