--- /dev/null
+/*
+ * An RTC driver for the AVR32 AT32AP700x processor series.
+ *
+ * Copyright (C) 2007 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/rtc.h>
+#include <linux/io.h>
+
+/*
+ * This is a bare-bones RTC. It runs during most system sleep states, but has
+ * no battery backup and gets reset during system restart. It must be
+ * initialized from an external clock (network, I2C, etc) before it can be of
+ * much use.
+ *
+ * The alarm functionality is limited by the hardware, not supporting
+ * periodic interrupts.
+ */
+
+#define RTC_CTRL 0x00
+#define RTC_CTRL_EN 0
+#define RTC_CTRL_PCLR 1
+#define RTC_CTRL_TOPEN 2
+#define RTC_CTRL_PSEL 8
+
+#define RTC_VAL 0x04
+
+#define RTC_TOP 0x08
+
+#define RTC_IER 0x10
+#define RTC_IER_TOPI 0
+
+#define RTC_IDR 0x14
+#define RTC_IDR_TOPI 0
+
+#define RTC_IMR 0x18
+#define RTC_IMR_TOPI 0
+
+#define RTC_ISR 0x1c
+#define RTC_ISR_TOPI 0
+
+#define RTC_ICR 0x20
+#define RTC_ICR_TOPI 0
+
+#define RTC_BIT(name) (1 << RTC_##name)
+#define RTC_BF(name, value) ((value) << RTC_##name)
+
+#define rtc_readl(dev, reg) \
+ __raw_readl((dev)->regs + RTC_##reg)
+#define rtc_writel(dev, reg, value) \
+ __raw_writel((value), (dev)->regs + RTC_##reg)
+
+struct rtc_at32ap700x {
+ struct rtc_device *rtc;
+ void __iomem *regs;
+ unsigned long alarm_time;
+ unsigned long irq;
+ /* Protect against concurrent register access. */
+ spinlock_t lock;
+};
+
+static int at32_rtc_readtime(struct device *dev, struct rtc_time *tm)
+{
+ struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
+ unsigned long now;
+
+ now = rtc_readl(rtc, VAL);
+ rtc_time_to_tm(now, tm);
+
+ return 0;
+}
+
+static int at32_rtc_settime(struct device *dev, struct rtc_time *tm)
+{
+ struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
+ unsigned long now;
+ int ret;
+
+ ret = rtc_tm_to_time(tm, &now);
+ if (ret == 0)
+ rtc_writel(rtc, VAL, now);
+
+ return ret;
+}
+
+static int at32_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
+
+ spin_lock_irq(&rtc->lock);
+ rtc_time_to_tm(rtc->alarm_time, &alrm->time);
+ alrm->enabled = rtc_readl(rtc, IMR) & RTC_BIT(IMR_TOPI) ? 1 : 0;
+ alrm->pending = rtc_readl(rtc, ISR) & RTC_BIT(ISR_TOPI) ? 1 : 0;
+ spin_unlock_irq(&rtc->lock);
+
+ return 0;
+}
+
+static int at32_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
+ unsigned long rtc_unix_time;
+ unsigned long alarm_unix_time;
+ int ret;
+
+ rtc_unix_time = rtc_readl(rtc, VAL);
+
+ ret = rtc_tm_to_time(&alrm->time, &alarm_unix_time);
+ if (ret)
+ return ret;
+
+ if (alarm_unix_time < rtc_unix_time)
+ return -EINVAL;
+
+ spin_lock_irq(&rtc->lock);
+ rtc->alarm_time = alarm_unix_time;
+ rtc_writel(rtc, TOP, rtc->alarm_time);
+ if (alrm->enabled)
+ rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
+ | RTC_BIT(CTRL_TOPEN));
+ else
+ rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
+ & ~RTC_BIT(CTRL_TOPEN));
+ spin_unlock_irq(&rtc->lock);
+
+ return ret;
+}
+
+static int at32_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
+ int ret = 0;
+
+ spin_lock_irq(&rtc->lock);
+
+ if (enabled) {
+ if (rtc_readl(rtc, VAL) > rtc->alarm_time) {
+ ret = -EINVAL;
+ goto out;
+ }
+ rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
+ | RTC_BIT(CTRL_TOPEN));
+ rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
+ rtc_writel(rtc, IER, RTC_BIT(IER_TOPI));
+ } else {
+ rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
+ & ~RTC_BIT(CTRL_TOPEN));
+ rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
+ rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
+ }
+out:
+ spin_unlock_irq(&rtc->lock);
+
+ return ret;
+}
+
+static irqreturn_t at32_rtc_interrupt(int irq, void *dev_id)
+{
+ struct rtc_at32ap700x *rtc = (struct rtc_at32ap700x *)dev_id;
+ unsigned long isr = rtc_readl(rtc, ISR);
+ unsigned long events = 0;
+ int ret = IRQ_NONE;
+
+ spin_lock(&rtc->lock);
+
+ if (isr & RTC_BIT(ISR_TOPI)) {
+ rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
+ rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
+ rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
+ & ~RTC_BIT(CTRL_TOPEN));
+ rtc_writel(rtc, VAL, rtc->alarm_time);
+ events = RTC_AF | RTC_IRQF;
+ rtc_update_irq(rtc->rtc, 1, events);
+ ret = IRQ_HANDLED;
+ }
+
+ spin_unlock(&rtc->lock);
+
+ return ret;
+}
+
+static struct rtc_class_ops at32_rtc_ops = {
+ .read_time = at32_rtc_readtime,
+ .set_time = at32_rtc_settime,
+ .read_alarm = at32_rtc_readalarm,
+ .set_alarm = at32_rtc_setalarm,
+ .alarm_irq_enable = at32_rtc_alarm_irq_enable,
+};
+
+static int __init at32_rtc_probe(struct platform_device *pdev)
+{
+ struct resource *regs;
+ struct rtc_at32ap700x *rtc;
+ int irq;
+ int ret;
+
+ rtc = devm_kzalloc(&pdev->dev, sizeof(struct rtc_at32ap700x),
+ GFP_KERNEL);
+ if (!rtc)
+ return -ENOMEM;
+
+ regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!regs) {
+ dev_dbg(&pdev->dev, "no mmio resource defined\n");
+ return -ENXIO;
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq <= 0) {
+ dev_dbg(&pdev->dev, "could not get irq\n");
+ return -ENXIO;
+ }
+
+ rtc->irq = irq;
+ rtc->regs = devm_ioremap(&pdev->dev, regs->start, resource_size(regs));
+ if (!rtc->regs) {
+ dev_dbg(&pdev->dev, "could not map I/O memory\n");
+ return -ENOMEM;
+ }
+ spin_lock_init(&rtc->lock);
+
+ /*
+ * Maybe init RTC: count from zero at 1 Hz, disable wrap irq.
+ *
+ * Do not reset VAL register, as it can hold an old time
+ * from last JTAG reset.
+ */
+ if (!(rtc_readl(rtc, CTRL) & RTC_BIT(CTRL_EN))) {
+ rtc_writel(rtc, CTRL, RTC_BIT(CTRL_PCLR));
+ rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
+ rtc_writel(rtc, CTRL, RTC_BF(CTRL_PSEL, 0xe)
+ | RTC_BIT(CTRL_EN));
+ }
+
+ ret = devm_request_irq(&pdev->dev, irq, at32_rtc_interrupt, IRQF_SHARED,
+ "rtc", rtc);
+ if (ret) {
+ dev_dbg(&pdev->dev, "could not request irq %d\n", irq);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, rtc);
+
+ rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
+ &at32_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc->rtc)) {
+ dev_dbg(&pdev->dev, "could not register rtc device\n");
+ return PTR_ERR(rtc->rtc);
+ }
+
+ device_init_wakeup(&pdev->dev, 1);
+
+ dev_info(&pdev->dev, "Atmel RTC for AT32AP700x at %08lx irq %ld\n",
+ (unsigned long)rtc->regs, rtc->irq);
+
+ return 0;
+}
+
+static int __exit at32_rtc_remove(struct platform_device *pdev)
+{
+ device_init_wakeup(&pdev->dev, 0);
+
+ return 0;
+}
+
+MODULE_ALIAS("platform:at32ap700x_rtc");
+
+static struct platform_driver at32_rtc_driver = {
+ .remove = __exit_p(at32_rtc_remove),
+ .driver = {
+ .name = "at32ap700x_rtc",
+ },
+};
+
+module_platform_driver_probe(at32_rtc_driver, at32_rtc_probe);
+
+MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
+MODULE_DESCRIPTION("Real time clock for AVR32 AT32AP700x");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff