Commit fa04e78b authored by Hans-Christian Egtvedt's avatar Hans-Christian Egtvedt Committed by Linus Torvalds
Browse files

Driver for the Atmel on-chip RTC on AT32AP700x devices 

Tested on the AT32AP7000/ATSTK1000.  Driver does only suport time, wake up
and a very simple alarm, because of hardware limitations.

Hardware documentation can be found in the AT32AP7000 data sheet, which can
be downloaded from

http://www.atmel.com/dyn/products/datasheets.asp?family_id=682



From: David Brownell <david-b@pacbell.net>

 - Strike some alarm setup code that's no longer needed.
   (This patch seems to have gotten lost somewhere...)

 - Make the driver name (and its module alias) match what
   the platform setup code uses, so the driver can bind
   and hotplug.

[akpm@linux-foundation.org: fix several checkpatch.pl warnings]
Signed-off-by: default avatarHans-Christian Egtvedt <hcegtvedt@atmel.com>
Signed-off-by: default avatarHaavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ac495bf8

drivers/rtc/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -379,6 +379,13 @@ config RTC_DRV_PL031 
	  To compile this driver as a module, choose M here: the

	  module will be called rtc-pl031.



config RTC_DRV_AT32AP700X

	tristate "AT32AP700X series RTC"

	depends on RTC_CLASS && PLATFORM_AT32AP

	help

	  Driver for the internal RTC (Realtime Clock) on Atmel AVR32

	  AT32AP700x family processors.



config RTC_DRV_AT91RM9200

	tristate "AT91RM9200"

	depends on RTC_CLASS && ARCH_AT91RM9200

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ obj-$(CONFIG_RTC_DRV_CMOS) += rtc-cmos.o 
obj-$(CONFIG_RTC_DRV_X1205)	+= rtc-x1205.o

obj-$(CONFIG_RTC_DRV_ISL1208)	+= rtc-isl1208.o

obj-$(CONFIG_RTC_DRV_TEST)	+= rtc-test.o

obj-$(CONFIG_RTC_DRV_AT32AP700X)	+= rtc-at32ap700x.o

obj-$(CONFIG_RTC_DRV_DS1307)	+= rtc-ds1307.o

obj-$(CONFIG_RTC_DRV_DS1672)	+= rtc-ds1672.o

obj-$(CONFIG_RTC_DRV_DS1742)	+= rtc-ds1742.o

drivers/rtc/rtc-at32ap700x.c

0 → 100644
+317 −0
Original line number Diff line number Diff line 
/*

 * 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/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);



	rtc_time_to_tm(rtc->alarm_time, &alrm->time);

	alrm->pending = rtc_readl(rtc, IMR) & RTC_BIT(IMR_TOPI) ? 1 : 0;



	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->pending)

		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_ioctl(struct device *dev, unsigned int cmd,

			unsigned long arg)

{

	struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);

	int ret = 0;



	spin_lock_irq(&rtc->lock);



	switch (cmd) {

	case RTC_AIE_ON:

		if (rtc_readl(rtc, VAL) > rtc->alarm_time) {

			ret = -EINVAL;

			break;

		}

		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));

		break;

	case RTC_AIE_OFF:

		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));

		break;

	default:

		ret = -ENOIOCTLCMD;

		break;

	}



	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 = {

	.ioctl		= at32_rtc_ioctl,

	.read_time	= at32_rtc_readtime,

	.set_time	= at32_rtc_settime,

	.read_alarm	= at32_rtc_readalarm,

	.set_alarm	= at32_rtc_setalarm,

};



static int __init at32_rtc_probe(struct platform_device *pdev)

{

	struct resource	*regs;

	struct rtc_at32ap700x *rtc;

	int irq = -1;

	int ret;



	rtc = kzalloc(sizeof(struct rtc_at32ap700x), GFP_KERNEL);

	if (!rtc) {

		dev_dbg(&pdev->dev, "out of memory\n");

		return -ENOMEM;

	}



	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (!regs) {

		dev_dbg(&pdev->dev, "no mmio resource defined\n");

		ret = -ENXIO;

		goto out;

	}



	irq = platform_get_irq(pdev, 0);

	if (irq < 0) {

		dev_dbg(&pdev->dev, "could not get irq\n");

		ret = -ENXIO;

		goto out;

	}



	ret = request_irq(irq, at32_rtc_interrupt, IRQF_SHARED, "rtc", rtc);

	if (ret) {

		dev_dbg(&pdev->dev, "could not request irq %d\n", irq);

		goto out;

	}



	rtc->irq = irq;

	rtc->regs = ioremap(regs->start, regs->end - regs->start + 1);

	if (!rtc->regs) {

		ret = -ENOMEM;

		dev_dbg(&pdev->dev, "could not map I/O memory\n");

		goto out_free_irq;

	}

	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));

	}



	rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,

				&at32_rtc_ops, THIS_MODULE);

	if (IS_ERR(rtc->rtc)) {

		dev_dbg(&pdev->dev, "could not register rtc device\n");

		ret = PTR_ERR(rtc->rtc);

		goto out_iounmap;

	}



	platform_set_drvdata(pdev, rtc);



	dev_info(&pdev->dev, "Atmel RTC for AT32AP700x at %08lx irq %ld\n",

			(unsigned long)rtc->regs, rtc->irq);



	return 0;



out_iounmap:

	iounmap(rtc->regs);

out_free_irq:

	free_irq(irq, rtc);

out:

	kfree(rtc);

	return ret;

}



static int __exit at32_rtc_remove(struct platform_device *pdev)

{

	struct rtc_at32ap700x *rtc = platform_get_drvdata(pdev);



	free_irq(rtc->irq, rtc);

	iounmap(rtc->regs);

	rtc_device_unregister(rtc->rtc);

	kfree(rtc);

	platform_set_drvdata(pdev, NULL);



	return 0;

}



MODULE_ALIAS("at32ap700x_rtc");



static struct platform_driver at32_rtc_driver = {

	.remove		= __exit_p(at32_rtc_remove),

	.driver		= {

		.name	= "at32ap700x_rtc",

		.owner	= THIS_MODULE,

	},

};



static int __init at32_rtc_init(void)

{

	return platform_driver_probe(&at32_rtc_driver, at32_rtc_probe);

}

module_init(at32_rtc_init);



static void __exit at32_rtc_exit(void)

{

	platform_driver_unregister(&at32_rtc_driver);

}

module_exit(at32_rtc_exit);



MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");

MODULE_DESCRIPTION("Real time clock for AVR32 AT32AP700x");

MODULE_LICENSE("GPL");

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