1 files changed, 290 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-coh901331.c b/drivers/rtc/rtc-coh901331.c
new file mode 100644
index 000000000..da59917c9
--- /dev/null
+++ b/drivers/rtc/rtc-coh901331.c
@@ -0,0 +1,290 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2007-2009 ST-Ericsson AB
+ * 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/mod_devicetable.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)) {
+		clk_disable(rtap->clk);
+		return -EINVAL;
+	}
+
+	rtc_time64_to_tm(readl(rtap->virtbase + COH901331_CUR_TIME), tm);
+	clk_disable(rtap->clk);
+	return 0;
+}
+
+static int coh901331_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct coh901331_port *rtap = dev_get_drvdata(dev);
+
+	clk_enable(rtap->clk);
+	writel(rtc_tm_to_time64(tm), 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_time64_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_time64(&alarm->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 const struct rtc_class_ops coh901331_ops = {
+	.read_time = coh901331_read_time,
+	.set_time = coh901331_set_time,
+	.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;
+
+	rtap = devm_kzalloc(&pdev->dev,
+			    sizeof(struct coh901331_port), GFP_KERNEL);
+	if (!rtap)
+		return -ENOMEM;
+
+	rtap->virtbase  = devm_platform_ioremap_resource(pdev, 0);
+	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;
+	}
+
+	rtap->rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(rtap->rtc))
+		return PTR_ERR(rtap->rtc);
+
+	rtap->rtc->ops = &coh901331_ops;
+	rtap->rtc->range_max = U32_MAX;
+
+	/* 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);
+
+	ret = rtc_register_device(rtap->rtc);
+	if (ret)
+		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)
+{
+	int ret;
+	struct coh901331_port *rtap = dev_get_drvdata(dev);
+
+	ret = clk_prepare(rtap->clk);
+	if (ret)
+		return ret;
+
+	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" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, coh901331_dt_match);
+
+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");