--- /dev/null
+/*
+ * Copyright (C) 2007-2009 ST-Ericsson AB
+ * License terms: GNU General Public License (GPL) version 2
+ * Real Time Clock interface for ST-Ericsson AB COH 901 331 RTC.
+ * Author: Linus Walleij <linus.walleij@stericsson.com>
+ * Based on rtc-pl031.c by Deepak Saxena <dsaxena@plexity.net>
+ * Copyright 2006 (c) MontaVista Software, Inc.
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/pm.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+
+/*
+ * Registers in the COH 901 331
+ */
+/* Alarm value 32bit (R/W) */
+#define COH901331_ALARM 0x00U
+/* Used to set current time 32bit (R/W) */
+#define COH901331_SET_TIME 0x04U
+/* Indication if current time is valid 32bit (R/-) */
+#define COH901331_VALID 0x08U
+/* Read the current time 32bit (R/-) */
+#define COH901331_CUR_TIME 0x0cU
+/* Event register for the "alarm" interrupt */
+#define COH901331_IRQ_EVENT 0x10U
+/* Mask register for the "alarm" interrupt */
+#define COH901331_IRQ_MASK 0x14U
+/* Force register for the "alarm" interrupt */
+#define COH901331_IRQ_FORCE 0x18U
+
+/*
+ * Reference to RTC block clock
+ * Notice that the frequent clk_enable()/clk_disable() on this
+ * clock is mainly to be able to turn on/off other clocks in the
+ * hierarchy as needed, the RTC clock is always on anyway.
+ */
+struct coh901331_port {
+ struct rtc_device *rtc;
+ struct clk *clk;
+ void __iomem *virtbase;
+ int irq;
+#ifdef CONFIG_PM_SLEEP
+ u32 irqmaskstore;
+#endif
+};
+
+static irqreturn_t coh901331_interrupt(int irq, void *data)
+{
+ struct coh901331_port *rtap = data;
+
+ clk_enable(rtap->clk);
+ /* Ack IRQ */
+ writel(1, rtap->virtbase + COH901331_IRQ_EVENT);
+ /*
+ * Disable the interrupt. This is necessary because
+ * the RTC lives on a lower-clocked line and will
+ * not release the IRQ line until after a few (slower)
+ * clock cycles. The interrupt will be re-enabled when
+ * a new alarm is set anyway.
+ */
+ writel(0, rtap->virtbase + COH901331_IRQ_MASK);
+ clk_disable(rtap->clk);
+
+ /* Set alarm flag */
+ rtc_update_irq(rtap->rtc, 1, RTC_AF);
+
+ return IRQ_HANDLED;
+}
+
+static int coh901331_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct coh901331_port *rtap = dev_get_drvdata(dev);
+
+ clk_enable(rtap->clk);
+ /* Check if the time is valid */
+ if (readl(rtap->virtbase + COH901331_VALID)) {
+ rtc_time_to_tm(readl(rtap->virtbase + COH901331_CUR_TIME), tm);
+ clk_disable(rtap->clk);
+ return rtc_valid_tm(tm);
+ }
+ clk_disable(rtap->clk);
+ return -EINVAL;
+}
+
+static int coh901331_set_mmss(struct device *dev, unsigned long secs)
+{
+ struct coh901331_port *rtap = dev_get_drvdata(dev);
+
+ clk_enable(rtap->clk);
+ writel(secs, rtap->virtbase + COH901331_SET_TIME);
+ clk_disable(rtap->clk);
+
+ return 0;
+}
+
+static int coh901331_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+ struct coh901331_port *rtap = dev_get_drvdata(dev);
+
+ clk_enable(rtap->clk);
+ rtc_time_to_tm(readl(rtap->virtbase + COH901331_ALARM), &alarm->time);
+ alarm->pending = readl(rtap->virtbase + COH901331_IRQ_EVENT) & 1U;
+ alarm->enabled = readl(rtap->virtbase + COH901331_IRQ_MASK) & 1U;
+ clk_disable(rtap->clk);
+
+ return 0;
+}
+
+static int coh901331_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+ struct coh901331_port *rtap = dev_get_drvdata(dev);
+ unsigned long time;
+
+ rtc_tm_to_time(&alarm->time, &time);
+ clk_enable(rtap->clk);
+ writel(time, rtap->virtbase + COH901331_ALARM);
+ writel(alarm->enabled, rtap->virtbase + COH901331_IRQ_MASK);
+ clk_disable(rtap->clk);
+
+ return 0;
+}
+
+static int coh901331_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct coh901331_port *rtap = dev_get_drvdata(dev);
+
+ clk_enable(rtap->clk);
+ if (enabled)
+ writel(1, rtap->virtbase + COH901331_IRQ_MASK);
+ else
+ writel(0, rtap->virtbase + COH901331_IRQ_MASK);
+ clk_disable(rtap->clk);
+
+ return 0;
+}
+
+static struct rtc_class_ops coh901331_ops = {
+ .read_time = coh901331_read_time,
+ .set_mmss = coh901331_set_mmss,
+ .read_alarm = coh901331_read_alarm,
+ .set_alarm = coh901331_set_alarm,
+ .alarm_irq_enable = coh901331_alarm_irq_enable,
+};
+
+static int __exit coh901331_remove(struct platform_device *pdev)
+{
+ struct coh901331_port *rtap = platform_get_drvdata(pdev);
+
+ if (rtap)
+ clk_unprepare(rtap->clk);
+
+ return 0;
+}
+
+
+static int __init coh901331_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct coh901331_port *rtap;
+ struct resource *res;
+
+ rtap = devm_kzalloc(&pdev->dev,
+ sizeof(struct coh901331_port), GFP_KERNEL);
+ if (!rtap)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ rtap->virtbase = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(rtap->virtbase))
+ return PTR_ERR(rtap->virtbase);
+
+ rtap->irq = platform_get_irq(pdev, 0);
+ if (devm_request_irq(&pdev->dev, rtap->irq, coh901331_interrupt, 0,
+ "RTC COH 901 331 Alarm", rtap))
+ return -EIO;
+
+ rtap->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(rtap->clk)) {
+ ret = PTR_ERR(rtap->clk);
+ dev_err(&pdev->dev, "could not get clock\n");
+ return ret;
+ }
+
+ /* We enable/disable the clock only to assure it works */
+ ret = clk_prepare_enable(rtap->clk);
+ if (ret) {
+ dev_err(&pdev->dev, "could not enable clock\n");
+ return ret;
+ }
+ clk_disable(rtap->clk);
+
+ platform_set_drvdata(pdev, rtap);
+ rtap->rtc = devm_rtc_device_register(&pdev->dev, "coh901331",
+ &coh901331_ops, THIS_MODULE);
+ if (IS_ERR(rtap->rtc)) {
+ ret = PTR_ERR(rtap->rtc);
+ goto out_no_rtc;
+ }
+
+ return 0;
+
+ out_no_rtc:
+ clk_unprepare(rtap->clk);
+ return ret;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int coh901331_suspend(struct device *dev)
+{
+ struct coh901331_port *rtap = dev_get_drvdata(dev);
+
+ /*
+ * If this RTC alarm will be used for waking the system up,
+ * don't disable it of course. Else we just disable the alarm
+ * and await suspension.
+ */
+ if (device_may_wakeup(dev)) {
+ enable_irq_wake(rtap->irq);
+ } else {
+ clk_enable(rtap->clk);
+ rtap->irqmaskstore = readl(rtap->virtbase + COH901331_IRQ_MASK);
+ writel(0, rtap->virtbase + COH901331_IRQ_MASK);
+ clk_disable(rtap->clk);
+ }
+ clk_unprepare(rtap->clk);
+ return 0;
+}
+
+static int coh901331_resume(struct device *dev)
+{
+ struct coh901331_port *rtap = dev_get_drvdata(dev);
+
+ clk_prepare(rtap->clk);
+ if (device_may_wakeup(dev)) {
+ disable_irq_wake(rtap->irq);
+ } else {
+ clk_enable(rtap->clk);
+ writel(rtap->irqmaskstore, rtap->virtbase + COH901331_IRQ_MASK);
+ clk_disable(rtap->clk);
+ }
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(coh901331_pm_ops, coh901331_suspend, coh901331_resume);
+
+static void coh901331_shutdown(struct platform_device *pdev)
+{
+ struct coh901331_port *rtap = platform_get_drvdata(pdev);
+
+ clk_enable(rtap->clk);
+ writel(0, rtap->virtbase + COH901331_IRQ_MASK);
+ clk_disable_unprepare(rtap->clk);
+}
+
+static const struct of_device_id coh901331_dt_match[] = {
+ { .compatible = "stericsson,coh901331" },
+ {},
+};
+
+static struct platform_driver coh901331_driver = {
+ .driver = {
+ .name = "rtc-coh901331",
+ .pm = &coh901331_pm_ops,
+ .of_match_table = coh901331_dt_match,
+ },
+ .remove = __exit_p(coh901331_remove),
+ .shutdown = coh901331_shutdown,
+};
+
+module_platform_driver_probe(coh901331_driver, coh901331_probe);
+
+MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
+MODULE_DESCRIPTION("ST-Ericsson AB COH 901 331 RTC Driver");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff