--- /dev/null
+/*
+ * RTC driver for the Armada 38x Marvell SoCs
+ *
+ * Copyright (C) 2015 Marvell
+ *
+ * Gregory Clement <gregory.clement@free-electrons.com>
+ *
+ * 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.
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+
+#define RTC_STATUS 0x0
+#define RTC_STATUS_ALARM1 BIT(0)
+#define RTC_STATUS_ALARM2 BIT(1)
+#define RTC_IRQ1_CONF 0x4
+#define RTC_IRQ1_AL_EN BIT(0)
+#define RTC_IRQ1_FREQ_EN BIT(1)
+#define RTC_IRQ1_FREQ_1HZ BIT(2)
+#define RTC_TIME 0xC
+#define RTC_ALARM1 0x10
+
+#define SOC_RTC_INTERRUPT 0x8
+#define SOC_RTC_ALARM1 BIT(0)
+#define SOC_RTC_ALARM2 BIT(1)
+#define SOC_RTC_ALARM1_MASK BIT(2)
+#define SOC_RTC_ALARM2_MASK BIT(3)
+
+struct armada38x_rtc {
+ struct rtc_device *rtc_dev;
+ void __iomem *regs;
+ void __iomem *regs_soc;
+ spinlock_t lock;
+ /*
+ * While setting the time, the RTC TIME register should not be
+ * accessed. Setting the RTC time involves sleeping during
+ * 100ms, so a mutex instead of a spinlock is used to protect
+ * it
+ */
+ struct mutex mutex_time;
+ int irq;
+};
+
+/*
+ * According to the datasheet, the OS should wait 5us after every
+ * register write to the RTC hard macro so that the required update
+ * can occur without holding off the system bus
+ */
+static void rtc_delayed_write(u32 val, struct armada38x_rtc *rtc, int offset)
+{
+ writel(val, rtc->regs + offset);
+ udelay(5);
+}
+
+static int armada38x_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+ unsigned long time, time_check;
+
+ mutex_lock(&rtc->mutex_time);
+ time = readl(rtc->regs + RTC_TIME);
+ /*
+ * WA for failing time set attempts. As stated in HW ERRATA if
+ * more than one second between two time reads is detected
+ * then read once again.
+ */
+ time_check = readl(rtc->regs + RTC_TIME);
+ if ((time_check - time) > 1)
+ time_check = readl(rtc->regs + RTC_TIME);
+
+ mutex_unlock(&rtc->mutex_time);
+
+ rtc_time_to_tm(time_check, tm);
+
+ return 0;
+}
+
+static int armada38x_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+ int ret = 0;
+ unsigned long time, flags;
+
+ ret = rtc_tm_to_time(tm, &time);
+
+ if (ret)
+ goto out;
+ /*
+ * Setting the RTC time not always succeeds. According to the
+ * errata we need to first write on the status register and
+ * then wait for 100ms before writing to the time register to be
+ * sure that the data will be taken into account.
+ */
+ mutex_lock(&rtc->mutex_time);
+ rtc_delayed_write(0, rtc, RTC_STATUS);
+ msleep(100);
+ rtc_delayed_write(time, rtc, RTC_TIME);
+ mutex_unlock(&rtc->mutex_time);
+
+out:
+ return ret;
+}
+
+static int armada38x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+ unsigned long time, flags;
+ u32 val;
+
+ spin_lock_irqsave(&rtc->lock, flags);
+
+ time = readl(rtc->regs + RTC_ALARM1);
+ val = readl(rtc->regs + RTC_IRQ1_CONF) & RTC_IRQ1_AL_EN;
+
+ spin_unlock_irqrestore(&rtc->lock, flags);
+
+ alrm->enabled = val ? 1 : 0;
+ rtc_time_to_tm(time, &alrm->time);
+
+ return 0;
+}
+
+static int armada38x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+ unsigned long time, flags;
+ int ret = 0;
+ u32 val;
+
+ ret = rtc_tm_to_time(&alrm->time, &time);
+
+ if (ret)
+ goto out;
+
+ spin_lock_irqsave(&rtc->lock, flags);
+
+ rtc_delayed_write(time, rtc, RTC_ALARM1);
+
+ if (alrm->enabled) {
+ rtc_delayed_write(RTC_IRQ1_AL_EN, rtc, RTC_IRQ1_CONF);
+ val = readl(rtc->regs_soc + SOC_RTC_INTERRUPT);
+ writel(val | SOC_RTC_ALARM1_MASK,
+ rtc->regs_soc + SOC_RTC_INTERRUPT);
+ }
+
+ spin_unlock_irqrestore(&rtc->lock, flags);
+
+out:
+ return ret;
+}
+
+static int armada38x_rtc_alarm_irq_enable(struct device *dev,
+ unsigned int enabled)
+{
+ struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+ unsigned long flags;
+
+ spin_lock_irqsave(&rtc->lock, flags);
+
+ if (enabled)
+ rtc_delayed_write(RTC_IRQ1_AL_EN, rtc, RTC_IRQ1_CONF);
+ else
+ rtc_delayed_write(0, rtc, RTC_IRQ1_CONF);
+
+ spin_unlock_irqrestore(&rtc->lock, flags);
+
+ return 0;
+}
+
+static irqreturn_t armada38x_rtc_alarm_irq(int irq, void *data)
+{
+ struct armada38x_rtc *rtc = data;
+ u32 val;
+ int event = RTC_IRQF | RTC_AF;
+
+ dev_dbg(&rtc->rtc_dev->dev, "%s:irq(%d)\n", __func__, irq);
+
+ spin_lock(&rtc->lock);
+
+ val = readl(rtc->regs_soc + SOC_RTC_INTERRUPT);
+
+ writel(val & ~SOC_RTC_ALARM1, rtc->regs_soc + SOC_RTC_INTERRUPT);
+ val = readl(rtc->regs + RTC_IRQ1_CONF);
+ /* disable all the interrupts for alarm 1 */
+ rtc_delayed_write(0, rtc, RTC_IRQ1_CONF);
+ /* Ack the event */
+ rtc_delayed_write(RTC_STATUS_ALARM1, rtc, RTC_STATUS);
+
+ spin_unlock(&rtc->lock);
+
+ if (val & RTC_IRQ1_FREQ_EN) {
+ if (val & RTC_IRQ1_FREQ_1HZ)
+ event |= RTC_UF;
+ else
+ event |= RTC_PF;
+ }
+
+ rtc_update_irq(rtc->rtc_dev, 1, event);
+
+ return IRQ_HANDLED;
+}
+
+static struct rtc_class_ops armada38x_rtc_ops = {
+ .read_time = armada38x_rtc_read_time,
+ .set_time = armada38x_rtc_set_time,
+ .read_alarm = armada38x_rtc_read_alarm,
+ .set_alarm = armada38x_rtc_set_alarm,
+ .alarm_irq_enable = armada38x_rtc_alarm_irq_enable,
+};
+
+static __init int armada38x_rtc_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ struct armada38x_rtc *rtc;
+ int ret;
+
+ rtc = devm_kzalloc(&pdev->dev, sizeof(struct armada38x_rtc),
+ GFP_KERNEL);
+ if (!rtc)
+ return -ENOMEM;
+
+ spin_lock_init(&rtc->lock);
+ mutex_init(&rtc->mutex_time);
+
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc");
+ rtc->regs = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(rtc->regs))
+ return PTR_ERR(rtc->regs);
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc-soc");
+ rtc->regs_soc = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(rtc->regs_soc))
+ return PTR_ERR(rtc->regs_soc);
+
+ rtc->irq = platform_get_irq(pdev, 0);
+
+ if (rtc->irq < 0) {
+ dev_err(&pdev->dev, "no irq\n");
+ return rtc->irq;
+ }
+ if (devm_request_irq(&pdev->dev, rtc->irq, armada38x_rtc_alarm_irq,
+ 0, pdev->name, rtc) < 0) {
+ dev_warn(&pdev->dev, "Interrupt not available.\n");
+ rtc->irq = -1;
+ /*
+ * If there is no interrupt available then we can't
+ * use the alarm
+ */
+ armada38x_rtc_ops.set_alarm = NULL;
+ armada38x_rtc_ops.alarm_irq_enable = NULL;
+ }
+ platform_set_drvdata(pdev, rtc);
+ if (rtc->irq != -1)
+ device_init_wakeup(&pdev->dev, 1);
+
+ rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name,
+ &armada38x_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc->rtc_dev)) {
+ ret = PTR_ERR(rtc->rtc_dev);
+ dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
+ return ret;
+ }
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int armada38x_rtc_suspend(struct device *dev)
+{
+ if (device_may_wakeup(dev)) {
+ struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+
+ return enable_irq_wake(rtc->irq);
+ }
+
+ return 0;
+}
+
+static int armada38x_rtc_resume(struct device *dev)
+{
+ if (device_may_wakeup(dev)) {
+ struct armada38x_rtc *rtc = dev_get_drvdata(dev);
+
+ return disable_irq_wake(rtc->irq);
+ }
+
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(armada38x_rtc_pm_ops,
+ armada38x_rtc_suspend, armada38x_rtc_resume);
+
+#ifdef CONFIG_OF
+static const struct of_device_id armada38x_rtc_of_match_table[] = {
+ { .compatible = "marvell,armada-380-rtc", },
+ {}
+};
+#endif
+
+static struct platform_driver armada38x_rtc_driver = {
+ .driver = {
+ .name = "armada38x-rtc",
+ .pm = &armada38x_rtc_pm_ops,
+ .of_match_table = of_match_ptr(armada38x_rtc_of_match_table),
+ },
+};
+
+module_platform_driver_probe(armada38x_rtc_driver, armada38x_rtc_probe);
+
+MODULE_DESCRIPTION("Marvell Armada 38x RTC driver");
+MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff