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path: root/drivers/rtc/rtc-lpc32xx.c
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Diffstat (limited to 'drivers/rtc/rtc-lpc32xx.c')
-rw-r--r--drivers/rtc/rtc-lpc32xx.c360
1 files changed, 360 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-lpc32xx.c b/drivers/rtc/rtc-lpc32xx.c
new file mode 100644
index 000000000..76ad7031a
--- /dev/null
+++ b/drivers/rtc/rtc-lpc32xx.c
@@ -0,0 +1,360 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2010 NXP Semiconductors
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/of.h>
+
+/*
+ * Clock and Power control register offsets
+ */
+#define LPC32XX_RTC_UCOUNT 0x00
+#define LPC32XX_RTC_DCOUNT 0x04
+#define LPC32XX_RTC_MATCH0 0x08
+#define LPC32XX_RTC_MATCH1 0x0C
+#define LPC32XX_RTC_CTRL 0x10
+#define LPC32XX_RTC_INTSTAT 0x14
+#define LPC32XX_RTC_KEY 0x18
+#define LPC32XX_RTC_SRAM 0x80
+
+#define LPC32XX_RTC_CTRL_MATCH0 (1 << 0)
+#define LPC32XX_RTC_CTRL_MATCH1 (1 << 1)
+#define LPC32XX_RTC_CTRL_ONSW_MATCH0 (1 << 2)
+#define LPC32XX_RTC_CTRL_ONSW_MATCH1 (1 << 3)
+#define LPC32XX_RTC_CTRL_SW_RESET (1 << 4)
+#define LPC32XX_RTC_CTRL_CNTR_DIS (1 << 6)
+#define LPC32XX_RTC_CTRL_ONSW_FORCE_HI (1 << 7)
+
+#define LPC32XX_RTC_INTSTAT_MATCH0 (1 << 0)
+#define LPC32XX_RTC_INTSTAT_MATCH1 (1 << 1)
+#define LPC32XX_RTC_INTSTAT_ONSW (1 << 2)
+
+#define LPC32XX_RTC_KEY_ONSW_LOADVAL 0xB5C13F27
+
+#define rtc_readl(dev, reg) \
+ __raw_readl((dev)->rtc_base + (reg))
+#define rtc_writel(dev, reg, val) \
+ __raw_writel((val), (dev)->rtc_base + (reg))
+
+struct lpc32xx_rtc {
+ void __iomem *rtc_base;
+ int irq;
+ unsigned char alarm_enabled;
+ struct rtc_device *rtc;
+ spinlock_t lock;
+};
+
+static int lpc32xx_rtc_read_time(struct device *dev, struct rtc_time *time)
+{
+ unsigned long elapsed_sec;
+ struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
+
+ elapsed_sec = rtc_readl(rtc, LPC32XX_RTC_UCOUNT);
+ rtc_time64_to_tm(elapsed_sec, time);
+
+ return 0;
+}
+
+static int lpc32xx_rtc_set_time(struct device *dev, struct rtc_time *time)
+{
+ struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
+ u32 secs = rtc_tm_to_time64(time);
+ u32 tmp;
+
+ spin_lock_irq(&rtc->lock);
+
+ /* RTC must be disabled during count update */
+ tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
+ rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp | LPC32XX_RTC_CTRL_CNTR_DIS);
+ rtc_writel(rtc, LPC32XX_RTC_UCOUNT, secs);
+ rtc_writel(rtc, LPC32XX_RTC_DCOUNT, 0xFFFFFFFF - secs);
+ rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp &= ~LPC32XX_RTC_CTRL_CNTR_DIS);
+
+ spin_unlock_irq(&rtc->lock);
+
+ return 0;
+}
+
+static int lpc32xx_rtc_read_alarm(struct device *dev,
+ struct rtc_wkalrm *wkalrm)
+{
+ struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
+
+ rtc_time64_to_tm(rtc_readl(rtc, LPC32XX_RTC_MATCH0), &wkalrm->time);
+ wkalrm->enabled = rtc->alarm_enabled;
+ wkalrm->pending = !!(rtc_readl(rtc, LPC32XX_RTC_INTSTAT) &
+ LPC32XX_RTC_INTSTAT_MATCH0);
+
+ return rtc_valid_tm(&wkalrm->time);
+}
+
+static int lpc32xx_rtc_set_alarm(struct device *dev,
+ struct rtc_wkalrm *wkalrm)
+{
+ struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
+ unsigned long alarmsecs;
+ u32 tmp;
+
+ alarmsecs = rtc_tm_to_time64(&wkalrm->time);
+
+ spin_lock_irq(&rtc->lock);
+
+ /* Disable alarm during update */
+ tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
+ rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp & ~LPC32XX_RTC_CTRL_MATCH0);
+
+ rtc_writel(rtc, LPC32XX_RTC_MATCH0, alarmsecs);
+
+ rtc->alarm_enabled = wkalrm->enabled;
+ if (wkalrm->enabled) {
+ rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
+ LPC32XX_RTC_INTSTAT_MATCH0);
+ rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp |
+ LPC32XX_RTC_CTRL_MATCH0);
+ }
+
+ spin_unlock_irq(&rtc->lock);
+
+ return 0;
+}
+
+static int lpc32xx_rtc_alarm_irq_enable(struct device *dev,
+ unsigned int enabled)
+{
+ struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
+ u32 tmp;
+
+ spin_lock_irq(&rtc->lock);
+ tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
+
+ if (enabled) {
+ rtc->alarm_enabled = 1;
+ tmp |= LPC32XX_RTC_CTRL_MATCH0;
+ } else {
+ rtc->alarm_enabled = 0;
+ tmp &= ~LPC32XX_RTC_CTRL_MATCH0;
+ }
+
+ rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
+ spin_unlock_irq(&rtc->lock);
+
+ return 0;
+}
+
+static irqreturn_t lpc32xx_rtc_alarm_interrupt(int irq, void *dev)
+{
+ struct lpc32xx_rtc *rtc = dev;
+
+ spin_lock(&rtc->lock);
+
+ /* Disable alarm interrupt */
+ rtc_writel(rtc, LPC32XX_RTC_CTRL,
+ rtc_readl(rtc, LPC32XX_RTC_CTRL) &
+ ~LPC32XX_RTC_CTRL_MATCH0);
+ rtc->alarm_enabled = 0;
+
+ /*
+ * Write a large value to the match value so the RTC won't
+ * keep firing the match status
+ */
+ rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
+ rtc_writel(rtc, LPC32XX_RTC_INTSTAT, LPC32XX_RTC_INTSTAT_MATCH0);
+
+ spin_unlock(&rtc->lock);
+
+ rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
+
+ return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops lpc32xx_rtc_ops = {
+ .read_time = lpc32xx_rtc_read_time,
+ .set_time = lpc32xx_rtc_set_time,
+ .read_alarm = lpc32xx_rtc_read_alarm,
+ .set_alarm = lpc32xx_rtc_set_alarm,
+ .alarm_irq_enable = lpc32xx_rtc_alarm_irq_enable,
+};
+
+static int lpc32xx_rtc_probe(struct platform_device *pdev)
+{
+ struct lpc32xx_rtc *rtc;
+ int err;
+ u32 tmp;
+
+ rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
+ if (unlikely(!rtc))
+ return -ENOMEM;
+
+ rtc->rtc_base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(rtc->rtc_base))
+ return PTR_ERR(rtc->rtc_base);
+
+ spin_lock_init(&rtc->lock);
+
+ /*
+ * The RTC is on a separate power domain and can keep it's state
+ * across a chip power cycle. If the RTC has never been previously
+ * setup, then set it up now for the first time.
+ */
+ tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
+ if (rtc_readl(rtc, LPC32XX_RTC_KEY) != LPC32XX_RTC_KEY_ONSW_LOADVAL) {
+ tmp &= ~(LPC32XX_RTC_CTRL_SW_RESET |
+ LPC32XX_RTC_CTRL_CNTR_DIS |
+ LPC32XX_RTC_CTRL_MATCH0 |
+ LPC32XX_RTC_CTRL_MATCH1 |
+ LPC32XX_RTC_CTRL_ONSW_MATCH0 |
+ LPC32XX_RTC_CTRL_ONSW_MATCH1 |
+ LPC32XX_RTC_CTRL_ONSW_FORCE_HI);
+ rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
+
+ /* Clear latched interrupt states */
+ rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
+ rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
+ LPC32XX_RTC_INTSTAT_MATCH0 |
+ LPC32XX_RTC_INTSTAT_MATCH1 |
+ LPC32XX_RTC_INTSTAT_ONSW);
+
+ /* Write key value to RTC so it won't reload on reset */
+ rtc_writel(rtc, LPC32XX_RTC_KEY,
+ LPC32XX_RTC_KEY_ONSW_LOADVAL);
+ } else {
+ rtc_writel(rtc, LPC32XX_RTC_CTRL,
+ tmp & ~LPC32XX_RTC_CTRL_MATCH0);
+ }
+
+ platform_set_drvdata(pdev, rtc);
+
+ rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
+ if (IS_ERR(rtc->rtc))
+ return PTR_ERR(rtc->rtc);
+
+ rtc->rtc->ops = &lpc32xx_rtc_ops;
+ rtc->rtc->range_max = U32_MAX;
+
+ err = devm_rtc_register_device(rtc->rtc);
+ if (err)
+ return err;
+
+ /*
+ * IRQ is enabled after device registration in case alarm IRQ
+ * is pending upon suspend exit.
+ */
+ rtc->irq = platform_get_irq(pdev, 0);
+ if (rtc->irq < 0) {
+ dev_warn(&pdev->dev, "Can't get interrupt resource\n");
+ } else {
+ if (devm_request_irq(&pdev->dev, rtc->irq,
+ lpc32xx_rtc_alarm_interrupt,
+ 0, pdev->name, rtc) < 0) {
+ dev_warn(&pdev->dev, "Can't request interrupt.\n");
+ rtc->irq = -1;
+ } else {
+ device_init_wakeup(&pdev->dev, 1);
+ }
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int lpc32xx_rtc_suspend(struct device *dev)
+{
+ struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
+
+ if (rtc->irq >= 0) {
+ if (device_may_wakeup(dev))
+ enable_irq_wake(rtc->irq);
+ else
+ disable_irq_wake(rtc->irq);
+ }
+
+ return 0;
+}
+
+static int lpc32xx_rtc_resume(struct device *dev)
+{
+ struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
+
+ if (rtc->irq >= 0 && device_may_wakeup(dev))
+ disable_irq_wake(rtc->irq);
+
+ return 0;
+}
+
+/* Unconditionally disable the alarm */
+static int lpc32xx_rtc_freeze(struct device *dev)
+{
+ struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
+
+ spin_lock_irq(&rtc->lock);
+
+ rtc_writel(rtc, LPC32XX_RTC_CTRL,
+ rtc_readl(rtc, LPC32XX_RTC_CTRL) &
+ ~LPC32XX_RTC_CTRL_MATCH0);
+
+ spin_unlock_irq(&rtc->lock);
+
+ return 0;
+}
+
+static int lpc32xx_rtc_thaw(struct device *dev)
+{
+ struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
+
+ if (rtc->alarm_enabled) {
+ spin_lock_irq(&rtc->lock);
+
+ rtc_writel(rtc, LPC32XX_RTC_CTRL,
+ rtc_readl(rtc, LPC32XX_RTC_CTRL) |
+ LPC32XX_RTC_CTRL_MATCH0);
+
+ spin_unlock_irq(&rtc->lock);
+ }
+
+ return 0;
+}
+
+static const struct dev_pm_ops lpc32xx_rtc_pm_ops = {
+ .suspend = lpc32xx_rtc_suspend,
+ .resume = lpc32xx_rtc_resume,
+ .freeze = lpc32xx_rtc_freeze,
+ .thaw = lpc32xx_rtc_thaw,
+ .restore = lpc32xx_rtc_resume
+};
+
+#define LPC32XX_RTC_PM_OPS (&lpc32xx_rtc_pm_ops)
+#else
+#define LPC32XX_RTC_PM_OPS NULL
+#endif
+
+#ifdef CONFIG_OF
+static const struct of_device_id lpc32xx_rtc_match[] = {
+ { .compatible = "nxp,lpc3220-rtc" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, lpc32xx_rtc_match);
+#endif
+
+static struct platform_driver lpc32xx_rtc_driver = {
+ .probe = lpc32xx_rtc_probe,
+ .driver = {
+ .name = "rtc-lpc32xx",
+ .pm = LPC32XX_RTC_PM_OPS,
+ .of_match_table = of_match_ptr(lpc32xx_rtc_match),
+ },
+};
+
+module_platform_driver(lpc32xx_rtc_driver);
+
+MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com");
+MODULE_DESCRIPTION("RTC driver for the LPC32xx SoC");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rtc-lpc32xx");