drivers/rtc/rtc-at32ap700x.c - arm/linux - Git at Google

 /*
  * 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 const 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 <egtvedt@samfundet.no>");
 MODULE_DESCRIPTION("Real time clock for AVR32 AT32AP700x");
 MODULE_LICENSE("GPL");
	/*
	* 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 const 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 <egtvedt@samfundet.no>");
	MODULE_DESCRIPTION("Real time clock for AVR32 AT32AP700x");
	MODULE_LICENSE("GPL");