rtc: snvs: add Freescale rtc-snvs driver
Add an RTC driver for Freescale Secure Non-Volatile Storage (SNVS)
Low Power (LP) RTC.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Kim Phillips <kim.phillips@freescale.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c
new file mode 100644
index 0000000..3c0da33
--- /dev/null
+++ b/drivers/rtc/rtc-snvs.c
@@ -0,0 +1,350 @@
+/*
+ * Copyright (C) 2011-2012 Freescale Semiconductor, Inc.
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+
+/* These register offsets are relative to LP (Low Power) range */
+#define SNVS_LPCR 0x04
+#define SNVS_LPSR 0x18
+#define SNVS_LPSRTCMR 0x1c
+#define SNVS_LPSRTCLR 0x20
+#define SNVS_LPTAR 0x24
+#define SNVS_LPPGDR 0x30
+
+#define SNVS_LPCR_SRTC_ENV (1 << 0)
+#define SNVS_LPCR_LPTA_EN (1 << 1)
+#define SNVS_LPCR_LPWUI_EN (1 << 3)
+#define SNVS_LPSR_LPTA (1 << 0)
+
+#define SNVS_LPPGDR_INIT 0x41736166
+#define CNTR_TO_SECS_SH 15
+
+struct snvs_rtc_data {
+ struct rtc_device *rtc;
+ void __iomem *ioaddr;
+ int irq;
+ spinlock_t lock;
+};
+
+static u32 rtc_read_lp_counter(void __iomem *ioaddr)
+{
+ u64 read1, read2;
+
+ do {
+ read1 = readl(ioaddr + SNVS_LPSRTCMR);
+ read1 <<= 32;
+ read1 |= readl(ioaddr + SNVS_LPSRTCLR);
+
+ read2 = readl(ioaddr + SNVS_LPSRTCMR);
+ read2 <<= 32;
+ read2 |= readl(ioaddr + SNVS_LPSRTCLR);
+ } while (read1 != read2);
+
+ /* Convert 47-bit counter to 32-bit raw second count */
+ return (u32) (read1 >> CNTR_TO_SECS_SH);
+}
+
+static void rtc_write_sync_lp(void __iomem *ioaddr)
+{
+ u32 count1, count2, count3;
+ int i;
+
+ /* Wait for 3 CKIL cycles */
+ for (i = 0; i < 3; i++) {
+ do {
+ count1 = readl(ioaddr + SNVS_LPSRTCLR);
+ count2 = readl(ioaddr + SNVS_LPSRTCLR);
+ } while (count1 != count2);
+
+ /* Now wait until counter value changes */
+ do {
+ do {
+ count2 = readl(ioaddr + SNVS_LPSRTCLR);
+ count3 = readl(ioaddr + SNVS_LPSRTCLR);
+ } while (count2 != count3);
+ } while (count3 == count1);
+ }
+}
+
+static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable)
+{
+ unsigned long flags;
+ int timeout = 1000;
+ u32 lpcr;
+
+ spin_lock_irqsave(&data->lock, flags);
+
+ lpcr = readl(data->ioaddr + SNVS_LPCR);
+ if (enable)
+ lpcr |= SNVS_LPCR_SRTC_ENV;
+ else
+ lpcr &= ~SNVS_LPCR_SRTC_ENV;
+ writel(lpcr, data->ioaddr + SNVS_LPCR);
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ while (--timeout) {
+ lpcr = readl(data->ioaddr + SNVS_LPCR);
+
+ if (enable) {
+ if (lpcr & SNVS_LPCR_SRTC_ENV)
+ break;
+ } else {
+ if (!(lpcr & SNVS_LPCR_SRTC_ENV))
+ break;
+ }
+ }
+
+ if (!timeout)
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static int snvs_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct snvs_rtc_data *data = dev_get_drvdata(dev);
+ unsigned long time = rtc_read_lp_counter(data->ioaddr);
+
+ rtc_time_to_tm(time, tm);
+
+ return 0;
+}
+
+static int snvs_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct snvs_rtc_data *data = dev_get_drvdata(dev);
+ unsigned long time;
+
+ rtc_tm_to_time(tm, &time);
+
+ /* Disable RTC first */
+ snvs_rtc_enable(data, false);
+
+ /* Write 32-bit time to 47-bit timer, leaving 15 LSBs blank */
+ writel(time << CNTR_TO_SECS_SH, data->ioaddr + SNVS_LPSRTCLR);
+ writel(time >> (32 - CNTR_TO_SECS_SH), data->ioaddr + SNVS_LPSRTCMR);
+
+ /* Enable RTC again */
+ snvs_rtc_enable(data, true);
+
+ return 0;
+}
+
+static int snvs_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct snvs_rtc_data *data = dev_get_drvdata(dev);
+ u32 lptar, lpsr;
+
+ lptar = readl(data->ioaddr + SNVS_LPTAR);
+ rtc_time_to_tm(lptar, &alrm->time);
+
+ lpsr = readl(data->ioaddr + SNVS_LPSR);
+ alrm->pending = (lpsr & SNVS_LPSR_LPTA) ? 1 : 0;
+
+ return 0;
+}
+
+static int snvs_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
+{
+ struct snvs_rtc_data *data = dev_get_drvdata(dev);
+ u32 lpcr;
+ unsigned long flags;
+
+ spin_lock_irqsave(&data->lock, flags);
+
+ lpcr = readl(data->ioaddr + SNVS_LPCR);
+ if (enable)
+ lpcr |= (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN);
+ else
+ lpcr &= ~(SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN);
+ writel(lpcr, data->ioaddr + SNVS_LPCR);
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ rtc_write_sync_lp(data->ioaddr);
+
+ return 0;
+}
+
+static int snvs_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct snvs_rtc_data *data = dev_get_drvdata(dev);
+ struct rtc_time *alrm_tm = &alrm->time;
+ unsigned long time;
+ unsigned long flags;
+ u32 lpcr;
+
+ rtc_tm_to_time(alrm_tm, &time);
+
+ spin_lock_irqsave(&data->lock, flags);
+
+ /* Have to clear LPTA_EN before programming new alarm time in LPTAR */
+ lpcr = readl(data->ioaddr + SNVS_LPCR);
+ lpcr &= ~SNVS_LPCR_LPTA_EN;
+ writel(lpcr, data->ioaddr + SNVS_LPCR);
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ writel(time, data->ioaddr + SNVS_LPTAR);
+
+ /* Clear alarm interrupt status bit */
+ writel(SNVS_LPSR_LPTA, data->ioaddr + SNVS_LPSR);
+
+ return snvs_rtc_alarm_irq_enable(dev, alrm->enabled);
+}
+
+static const struct rtc_class_ops snvs_rtc_ops = {
+ .read_time = snvs_rtc_read_time,
+ .set_time = snvs_rtc_set_time,
+ .read_alarm = snvs_rtc_read_alarm,
+ .set_alarm = snvs_rtc_set_alarm,
+ .alarm_irq_enable = snvs_rtc_alarm_irq_enable,
+};
+
+static irqreturn_t snvs_rtc_irq_handler(int irq, void *dev_id)
+{
+ struct device *dev = dev_id;
+ struct snvs_rtc_data *data = dev_get_drvdata(dev);
+ u32 lpsr;
+ u32 events = 0;
+
+ lpsr = readl(data->ioaddr + SNVS_LPSR);
+
+ if (lpsr & SNVS_LPSR_LPTA) {
+ events |= (RTC_AF | RTC_IRQF);
+
+ /* RTC alarm should be one-shot */
+ snvs_rtc_alarm_irq_enable(dev, 0);
+
+ rtc_update_irq(data->rtc, 1, events);
+ }
+
+ /* clear interrupt status */
+ writel(lpsr, data->ioaddr + SNVS_LPSR);
+
+ return events ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static int __devinit snvs_rtc_probe(struct platform_device *pdev)
+{
+ struct snvs_rtc_data *data;
+ struct resource *res;
+ int ret;
+
+ data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ data->ioaddr = devm_request_and_ioremap(&pdev->dev, res);
+ if (!data->ioaddr)
+ return -EADDRNOTAVAIL;
+
+ data->irq = platform_get_irq(pdev, 0);
+ if (data->irq < 0)
+ return data->irq;
+
+ platform_set_drvdata(pdev, data);
+
+ spin_lock_init(&data->lock);
+
+ /* Initialize glitch detect */
+ writel(SNVS_LPPGDR_INIT, data->ioaddr + SNVS_LPPGDR);
+
+ /* Clear interrupt status */
+ writel(0xffffffff, data->ioaddr + SNVS_LPSR);
+
+ /* Enable RTC */
+ snvs_rtc_enable(data, true);
+
+ device_init_wakeup(&pdev->dev, true);
+
+ ret = devm_request_irq(&pdev->dev, data->irq, snvs_rtc_irq_handler,
+ IRQF_SHARED, "rtc alarm", &pdev->dev);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to request irq %d: %d\n",
+ data->irq, ret);
+ return ret;
+ }
+
+ data->rtc = rtc_device_register(pdev->name, &pdev->dev,
+ &snvs_rtc_ops, THIS_MODULE);
+ if (IS_ERR(data->rtc)) {
+ ret = PTR_ERR(data->rtc);
+ dev_err(&pdev->dev, "failed to register rtc: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int __devexit snvs_rtc_remove(struct platform_device *pdev)
+{
+ struct snvs_rtc_data *data = platform_get_drvdata(pdev);
+
+ rtc_device_unregister(data->rtc);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int snvs_rtc_suspend(struct device *dev)
+{
+ struct snvs_rtc_data *data = dev_get_drvdata(dev);
+
+ if (device_may_wakeup(dev))
+ enable_irq_wake(data->irq);
+
+ return 0;
+}
+
+static int snvs_rtc_resume(struct device *dev)
+{
+ struct snvs_rtc_data *data = dev_get_drvdata(dev);
+
+ if (device_may_wakeup(dev))
+ disable_irq_wake(data->irq);
+
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(snvs_rtc_pm_ops, snvs_rtc_suspend, snvs_rtc_resume);
+
+static const struct of_device_id __devinitconst snvs_dt_ids[] = {
+ { .compatible = "fsl,sec-v4.0-mon-rtc-lp", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, snvs_dt_ids);
+
+static struct platform_driver snvs_rtc_driver = {
+ .driver = {
+ .name = "snvs_rtc",
+ .owner = THIS_MODULE,
+ .pm = &snvs_rtc_pm_ops,
+ .of_match_table = snvs_dt_ids,
+ },
+ .probe = snvs_rtc_probe,
+ .remove = __devexit_p(snvs_rtc_remove),
+};
+module_platform_driver(snvs_rtc_driver);
+
+MODULE_AUTHOR("Freescale Semiconductor, Inc.");
+MODULE_DESCRIPTION("Freescale SNVS RTC Driver");
+MODULE_LICENSE("GPL");