[PATCH] rtc: rtc-lpc32xx: Introduce RTC driver for the LPC32XX SoC (v3)
wellsk40 at gmail.com
wellsk40 at gmail.com
Thu Aug 12 17:57:24 EDT 2010
From: Kevin Wells <wellsk40 at gmail.com>
This patch contains the RTC driver for the built-in RTC in
the LPC32XX SoC. This patch includes updates from the initial
review comments and updates from the v2 review.
Signed-off-by: Kevin Wells <wellsk40 at gmail.com>
Signed-off-by: Durgesh Pattamatta <durgesh.pattamatta at nxp.com>
---
drivers/rtc/Kconfig | 9 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-lpc32xx.c | 410 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 420 insertions(+), 0 deletions(-)
create mode 100644 drivers/rtc/rtc-lpc32xx.c
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 48ca713..774a65a 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -952,4 +952,13 @@ config RTC_DRV_JZ4740
This driver can also be buillt as a module. If so, the module
will be called rtc-jz4740.
+config RTC_DRV_LPC32XX
+ depends on ARCH_LPC32XX
+ tristate "NXP LPC32XX RTC"
+ help
+ This enables support for the NXP RTC in the LPC32XX
+
+ This driver can also be buillt as a module. If so, the module
+ will be called rtc-lpc32xx.
+
endif # RTC_CLASS
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 0f207b3..7a7cb32 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_RTC_DRV_IMXDI) += rtc-imxdi.o
obj-$(CONFIG_RTC_DRV_ISL1208) += rtc-isl1208.o
obj-$(CONFIG_RTC_DRV_ISL12022) += rtc-isl12022.o
obj-$(CONFIG_RTC_DRV_JZ4740) += rtc-jz4740.o
+obj-$(CONFIG_RTC_DRV_LPC32XX) += rtc-lpc32xx.o
obj-$(CONFIG_RTC_DRV_M41T80) += rtc-m41t80.o
obj-$(CONFIG_RTC_DRV_M41T94) += rtc-m41t94.o
obj-$(CONFIG_RTC_DRV_M48T35) += rtc-m48t35.o
diff --git a/drivers/rtc/rtc-lpc32xx.c b/drivers/rtc/rtc-lpc32xx.c
new file mode 100644
index 0000000..b63137d
--- /dev/null
+++ b/drivers/rtc/rtc-lpc32xx.c
@@ -0,0 +1,410 @@
+/*
+ * Copyright (C) 2010 NXP Semiconductors
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#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>
+
+/*
+ * 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_MATCH0_EN (1 << 0)
+#define LPC32XX_RTC_MATCH1_EN (1 << 1)
+#define LPC32XX_RTC_ONSW_MATCH0_EN (1 << 2)
+#define LPC32XX_RTC_ONSW_MATCH1_EN (1 << 3)
+#define LPC32XX_RTC_SW_RESET (1 << 4)
+#define LPC32XX_RTC_CNTR_DIS (1 << 6)
+#define LPC32XX_RTC_ONSW_FORCE_HIGH (1 << 7)
+
+#define LPC32XX_RTC_MATCH0_INT_STS (1 << 0)
+#define LPC32XX_RTC_MATCH1_INT_STS (1 << 1)
+#define LPC32XX_RTC_ONSW_INT_STS (1 << 2)
+
+#define LPC32XX_RTC_KEY_ONSW_LOADVAL 0xB5C13F27
+
+#define RTC_NAME "rtc-lpc32xx"
+
+#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_time_to_tm(elapsed_sec, time);
+
+ return rtc_valid_tm(time);
+}
+
+static int lpc32xx_rtc_set_mmss(struct device *dev, unsigned long secs)
+{
+ struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
+ 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_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_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_time_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_MATCH0_INT_STS);
+
+ 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;
+ int ret;
+
+ ret = rtc_tm_to_time(&wkalrm->time, &alarmsecs);
+ if (ret < 0) {
+ dev_warn(dev, "Failed to convert time: %d\n", ret);
+ return ret;
+ }
+
+ 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_MATCH0_EN);
+
+ rtc_writel(rtc, LPC32XX_RTC_MATCH0, alarmsecs);
+
+ rtc->alarm_enabled = wkalrm->enabled;
+ if (wkalrm->enabled) {
+ rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
+ LPC32XX_RTC_MATCH0_INT_STS);
+ rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp |
+ LPC32XX_RTC_MATCH0_EN);
+ }
+
+ 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_MATCH0_EN;
+ } else {
+ rtc->alarm_enabled = 0;
+ tmp &= ~LPC32XX_RTC_MATCH0_EN;
+ }
+
+ 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_MATCH0_EN);
+ 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_MATCH0_INT_STS);
+
+ 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_mmss = lpc32xx_rtc_set_mmss,
+ .read_alarm = lpc32xx_rtc_read_alarm,
+ .set_alarm = lpc32xx_rtc_set_alarm,
+ .alarm_irq_enable = lpc32xx_rtc_alarm_irq_enable,
+};
+
+static int __devinit lpc32xx_rtc_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ struct lpc32xx_rtc *rtc;
+ resource_size_t size;
+ int rtcirq;
+ u32 tmp;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "Can't get memory resource\n");
+ return -ENOENT;
+ }
+
+ rtcirq = platform_get_irq(pdev, 0);
+ if (rtcirq < 0 || rtcirq >= NR_IRQS) {
+ dev_warn(&pdev->dev, "Can't get interrupt resource\n");
+ rtcirq = -1;
+ }
+
+ rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
+ if (unlikely(!rtc)) {
+ dev_err(&pdev->dev, "Can't allocate memory\n");
+ return -ENOMEM;
+ }
+ rtc->irq = rtcirq;
+
+ size = resource_size(res);
+
+ if (!devm_request_mem_region(&pdev->dev, res->start, size,
+ pdev->name)) {
+ dev_err(&pdev->dev, "RTC registers are not free\n");
+ return -EBUSY;
+ }
+
+ rtc->rtc_base = devm_ioremap(&pdev->dev, res->start, size);
+ if (!rtc->rtc_base) {
+ dev_err(&pdev->dev, "Can't map memory\n");
+ return -ENOMEM;
+ }
+
+ spin_lock_init(&rtc->lock);
+
+ /*
+ * The RTC is on a seperate 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_SW_RESET | LPC32XX_RTC_CNTR_DIS |
+ LPC32XX_RTC_MATCH0_EN | LPC32XX_RTC_MATCH1_EN |
+ LPC32XX_RTC_ONSW_MATCH0_EN |
+ LPC32XX_RTC_ONSW_MATCH1_EN |
+ LPC32XX_RTC_ONSW_FORCE_HIGH);
+ 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_MATCH0_INT_STS |
+ LPC32XX_RTC_MATCH1_INT_STS |
+ LPC32XX_RTC_ONSW_INT_STS);
+
+ /* 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_ONSW_MATCH0_EN);
+ }
+
+ platform_set_drvdata(pdev, rtc);
+
+ rtc->rtc = rtc_device_register(RTC_NAME, &pdev->dev, &lpc32xx_rtc_ops,
+ THIS_MODULE);
+ if (IS_ERR(rtc->rtc)) {
+ dev_err(&pdev->dev, "Can't get RTC\n");
+ platform_set_drvdata(pdev, NULL);
+ return PTR_ERR(rtc->rtc);
+ }
+
+ /*
+ * IRQ is enabled after device registration in case alarm IRQ
+ * is pending upon suspend exit.
+ */
+ if (rtc->irq >= 0) {
+ if (devm_request_irq(&pdev->dev, rtc->irq,
+ lpc32xx_rtc_alarm_interrupt,
+ IRQF_DISABLED, 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;
+}
+
+static int __devexit lpc32xx_rtc_remove(struct platform_device *pdev)
+{
+ struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
+
+ if (rtc->irq >= 0)
+ device_init_wakeup(&pdev->dev, 0);
+
+ platform_set_drvdata(pdev, NULL);
+ rtc_device_unregister(rtc->rtc);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int lpc32xx_rtc_suspend(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
+
+ if (rtc->irq >= 0) {
+ if (device_may_wakeup(&pdev->dev))
+ enable_irq_wake(rtc->irq);
+ else
+ disable_irq_wake(rtc->irq);
+ }
+
+ return 0;
+}
+
+static int lpc32xx_rtc_resume(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
+
+ if (rtc->irq >= 0 && device_may_wakeup(&pdev->dev))
+ disable_irq_wake(rtc->irq);
+
+ return 0;
+}
+
+/* Unconditionally disable the alarm */
+static int lpc32xx_rtc_freeze(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
+
+ spin_lock_irq(&rtc->lock);
+
+ rtc_writel(rtc, LPC32XX_RTC_CTRL,
+ rtc_readl(rtc, LPC32XX_RTC_CTRL) & ~LPC32XX_RTC_MATCH0_EN);
+
+ spin_unlock_irq(&rtc->lock);
+
+ return 0;
+}
+
+static int lpc32xx_rtc_thaw(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
+
+ if (rtc->alarm_enabled) {
+ spin_lock_irq(&rtc->lock);
+
+ rtc_writel(rtc, LPC32XX_RTC_CTRL,
+ rtc_readl(rtc, LPC32XX_RTC_CTRL) |
+ LPC32XX_RTC_MATCH0_EN);
+
+ 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
+
+static struct platform_driver lpc32xx_rtc_driver = {
+ .probe = lpc32xx_rtc_probe,
+ .remove = __devexit_p(lpc32xx_rtc_remove),
+ .driver = {
+ .name = RTC_NAME,
+ .owner = THIS_MODULE,
+ .pm = LPC32XX_RTC_PM_OPS
+ },
+};
+
+static int __init lpc32xx_rtc_init(void)
+{
+ return platform_driver_register(&lpc32xx_rtc_driver);
+}
+module_init(lpc32xx_rtc_init);
+
+static void __exit lpc32xx_rtc_exit(void)
+{
+ platform_driver_unregister(&lpc32xx_rtc_driver);
+}
+module_exit(lpc32xx_rtc_exit);
+
+MODULE_AUTHOR("Kevin Wells <wellsk40 at gmail.com");
+MODULE_DESCRIPTION("RTC driver for the LPC32xx SoC");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rtc-lpc32xx");
--
1.7.1.1
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