drivers/rtc/rtc-coh901331.c - third_party/linux - Git at Google

 /*
  * 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 0;
 	}
 	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 const 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" },
 	{},
 };
 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");
	/*
	* 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 0;
	}
	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 const 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" },
	{},
	};
	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");