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Commit f77fbdf9 authored by Alexey Charkov's avatar Alexey Charkov Committed by Linus Torvalds
Browse files

rtc: add support for the RTC in VIA VT8500 and compatibles 



This adds a driver for the RTC devices in VIA and WonderMedia
Systems-on-Chip.  Alarm, 1Hz interrupts, reading and setting time are
supported.

Signed-off-by: default avatarAlexey Charkov <alchark@gmail.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Alexey Charkov <alchark@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 704f15dd

drivers/rtc/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -884,6 +884,13 @@ config RTC_DRV_PXA 
         This RTC driver uses PXA RTC registers available since pxa27x

         series (RDxR, RYxR) instead of legacy RCNR, RTAR.



config RTC_DRV_VT8500

	tristate "VIA/WonderMedia 85xx SoC RTC"

	depends on ARCH_VT8500

	help

	  If you say Y here you will get access to the real time clock

	  built into your VIA VT8500 SoC or its relatives.





config RTC_DRV_SUN4V

	bool "SUN4V Hypervisor RTC"

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -99,6 +99,7 @@ obj-$(CONFIG_RTC_DRV_TWL4030) += rtc-twl.o 
obj-$(CONFIG_RTC_DRV_TX4939)	+= rtc-tx4939.o

obj-$(CONFIG_RTC_DRV_V3020)	+= rtc-v3020.o

obj-$(CONFIG_RTC_DRV_VR41XX)	+= rtc-vr41xx.o

obj-$(CONFIG_RTC_DRV_VT8500)	+= rtc-vt8500.o

obj-$(CONFIG_RTC_DRV_WM831X)	+= rtc-wm831x.o

obj-$(CONFIG_RTC_DRV_WM8350)	+= rtc-wm8350.o

obj-$(CONFIG_RTC_DRV_X1205)	+= rtc-x1205.o

drivers/rtc/rtc-vt8500.c

0 → 100644
+366 −0
Original line number Diff line number Diff line 
/*

 * drivers/rtc/rtc-vt8500.c

 *

 *  Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>

 *

 * Based on rtc-pxa.c

 *

 * This software is licensed under the terms of the GNU General Public

 * License version 2, as published by the Free Software Foundation, and

 * may be copied, distributed, and modified under those terms.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#include <linux/module.h>

#include <linux/rtc.h>

#include <linux/init.h>

#include <linux/interrupt.h>

#include <linux/io.h>

#include <linux/bcd.h>

#include <linux/platform_device.h>

#include <linux/slab.h>



/*

 * Register definitions

 */

#define VT8500_RTC_TS		0x00	/* Time set */

#define VT8500_RTC_DS		0x04	/* Date set */

#define VT8500_RTC_AS		0x08	/* Alarm set */

#define VT8500_RTC_CR		0x0c	/* Control */

#define VT8500_RTC_TR		0x10	/* Time read */

#define VT8500_RTC_DR		0x14	/* Date read */

#define VT8500_RTC_WS		0x18	/* Write status */

#define VT8500_RTC_CL		0x20	/* Calibration */

#define VT8500_RTC_IS		0x24	/* Interrupt status */

#define VT8500_RTC_ST		0x28	/* Status */



#define INVALID_TIME_BIT	(1 << 31)



#define DATE_CENTURY_S		19

#define DATE_YEAR_S		11

#define DATE_YEAR_MASK		(0xff << DATE_YEAR_S)

#define DATE_MONTH_S		6

#define DATE_MONTH_MASK		(0x1f << DATE_MONTH_S)

#define DATE_DAY_MASK		0x3f



#define TIME_DOW_S		20

#define TIME_DOW_MASK		(0x07 << TIME_DOW_S)

#define TIME_HOUR_S		14

#define TIME_HOUR_MASK		(0x3f << TIME_HOUR_S)

#define TIME_MIN_S		7

#define TIME_MIN_MASK		(0x7f << TIME_MIN_S)

#define TIME_SEC_MASK		0x7f



#define ALARM_DAY_S		20

#define ALARM_DAY_MASK		(0x3f << ALARM_DAY_S)



#define ALARM_DAY_BIT		(1 << 29)

#define ALARM_HOUR_BIT		(1 << 28)

#define ALARM_MIN_BIT		(1 << 27)

#define ALARM_SEC_BIT		(1 << 26)



#define ALARM_ENABLE_MASK	(ALARM_DAY_BIT \

				| ALARM_HOUR_BIT \

				| ALARM_MIN_BIT \

				| ALARM_SEC_BIT)



#define VT8500_RTC_CR_ENABLE	(1 << 0)	/* Enable RTC */

#define VT8500_RTC_CR_24H	(1 << 1)	/* 24h time format */

#define VT8500_RTC_CR_SM_ENABLE	(1 << 2)	/* Enable periodic irqs */

#define VT8500_RTC_CR_SM_SEC	(1 << 3)	/* 0: 1Hz/60, 1: 1Hz */

#define VT8500_RTC_CR_CALIB	(1 << 4)	/* Enable calibration */



struct vt8500_rtc {

	void __iomem		*regbase;

	struct resource		*res;

	int			irq_alarm;

	int			irq_hz;

	struct rtc_device	*rtc;

	spinlock_t		lock;		/* Protects this structure */

};



static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)

{

	struct vt8500_rtc *vt8500_rtc = dev_id;

	u32 isr;

	unsigned long events = 0;



	spin_lock(&vt8500_rtc->lock);



	/* clear interrupt sources */

	isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);

	writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);



	spin_unlock(&vt8500_rtc->lock);



	if (isr & 1)

		events |= RTC_AF | RTC_IRQF;



	/* Only second/minute interrupts are supported */

	if (isr & 2)

		events |= RTC_UF | RTC_IRQF;



	rtc_update_irq(vt8500_rtc->rtc, 1, events);



	return IRQ_HANDLED;

}



static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)

{

	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);

	u32 date, time;



	date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);

	time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);



	tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);

	tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);

	tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);

	tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);

	tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S);

	tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)

			+ ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);

	tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;



	return 0;

}



static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)

{

	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);



	if (tm->tm_year < 100) {

		dev_warn(dev, "Only years 2000-2199 are supported by the "

			      "hardware!\n");

		return -EINVAL;

	}



	writel((bin2bcd(tm->tm_year - 100) << DATE_YEAR_S)

		| (bin2bcd(tm->tm_mon) << DATE_MONTH_S)

		| (bin2bcd(tm->tm_mday)),

		vt8500_rtc->regbase + VT8500_RTC_DS);

	writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)

		| (bin2bcd(tm->tm_hour) << TIME_HOUR_S)

		| (bin2bcd(tm->tm_min) << TIME_MIN_S)

		| (bin2bcd(tm->tm_sec)),

		vt8500_rtc->regbase + VT8500_RTC_TS);



	return 0;

}



static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)

{

	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);

	u32 isr, alarm;



	alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);

	isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);



	alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);

	alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);

	alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);

	alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));



	alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;



	alrm->pending = (isr & 1) ? 1 : 0;

	return rtc_valid_tm(&alrm->time);

}



static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)

{

	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);



	writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)

		| (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)

		| (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)

		| (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)

		| (bin2bcd(alrm->time.tm_sec)),

		vt8500_rtc->regbase + VT8500_RTC_AS);



	return 0;

}



static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)

{

	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);

	unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);



	if (enabled)

		tmp |= ALARM_ENABLE_MASK;

	else

		tmp &= ~ALARM_ENABLE_MASK;



	writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);

	return 0;

}



static int vt8500_update_irq_enable(struct device *dev, unsigned int enabled)

{

	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);

	unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_CR);



	if (enabled)

		tmp |= VT8500_RTC_CR_SM_SEC | VT8500_RTC_CR_SM_ENABLE;

	else

		tmp &= ~VT8500_RTC_CR_SM_ENABLE;



	writel(tmp, vt8500_rtc->regbase + VT8500_RTC_CR);

	return 0;

}



static const struct rtc_class_ops vt8500_rtc_ops = {

	.read_time = vt8500_rtc_read_time,

	.set_time = vt8500_rtc_set_time,

	.read_alarm = vt8500_rtc_read_alarm,

	.set_alarm = vt8500_rtc_set_alarm,

	.alarm_irq_enable = vt8500_alarm_irq_enable,

	.update_irq_enable = vt8500_update_irq_enable,

};



static int __devinit vt8500_rtc_probe(struct platform_device *pdev)

{

	struct vt8500_rtc *vt8500_rtc;

	int ret;



	vt8500_rtc = kzalloc(sizeof(struct vt8500_rtc), GFP_KERNEL);

	if (!vt8500_rtc)

		return -ENOMEM;



	spin_lock_init(&vt8500_rtc->lock);

	platform_set_drvdata(pdev, vt8500_rtc);



	vt8500_rtc->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (!vt8500_rtc->res) {

		dev_err(&pdev->dev, "No I/O memory resource defined\n");

		ret = -ENXIO;

		goto err_free;

	}



	vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);

	if (vt8500_rtc->irq_alarm < 0) {

		dev_err(&pdev->dev, "No alarm IRQ resource defined\n");

		ret = -ENXIO;

		goto err_free;

	}



	vt8500_rtc->irq_hz = platform_get_irq(pdev, 1);

	if (vt8500_rtc->irq_hz < 0) {

		dev_err(&pdev->dev, "No 1Hz IRQ resource defined\n");

		ret = -ENXIO;

		goto err_free;

	}



	vt8500_rtc->res = request_mem_region(vt8500_rtc->res->start,

					     resource_size(vt8500_rtc->res),

					     "vt8500-rtc");

	if (vt8500_rtc->res == NULL) {

		dev_err(&pdev->dev, "failed to request I/O memory\n");

		ret = -EBUSY;

		goto err_free;

	}



	vt8500_rtc->regbase = ioremap(vt8500_rtc->res->start,

				      resource_size(vt8500_rtc->res));

	if (!vt8500_rtc->regbase) {

		dev_err(&pdev->dev, "Unable to map RTC I/O memory\n");

		ret = -EBUSY;

		goto err_release;

	}



	/* Enable the second/minute interrupt generation and enable RTC */

	writel(VT8500_RTC_CR_ENABLE | VT8500_RTC_CR_24H

		| VT8500_RTC_CR_SM_ENABLE | VT8500_RTC_CR_SM_SEC,

	       vt8500_rtc->regbase + VT8500_RTC_CR);



	vt8500_rtc->rtc = rtc_device_register("vt8500-rtc", &pdev->dev,

					      &vt8500_rtc_ops, THIS_MODULE);

	if (IS_ERR(vt8500_rtc->rtc)) {

		ret = PTR_ERR(vt8500_rtc->rtc);

		dev_err(&pdev->dev,

			"Failed to register RTC device -> %d\n", ret);

		goto err_unmap;

	}



	ret = request_irq(vt8500_rtc->irq_hz, vt8500_rtc_irq, 0,

			  "rtc 1Hz", vt8500_rtc);

	if (ret < 0) {

		dev_err(&pdev->dev, "can't get irq %i, err %d\n",

			vt8500_rtc->irq_hz, ret);

		goto err_unreg;

	}



	ret = request_irq(vt8500_rtc->irq_alarm, vt8500_rtc_irq, 0,

			  "rtc alarm", vt8500_rtc);

	if (ret < 0) {

		dev_err(&pdev->dev, "can't get irq %i, err %d\n",

			vt8500_rtc->irq_alarm, ret);

		goto err_free_hz;

	}



	return 0;



err_free_hz:

	free_irq(vt8500_rtc->irq_hz, vt8500_rtc);

err_unreg:

	rtc_device_unregister(vt8500_rtc->rtc);

err_unmap:

	iounmap(vt8500_rtc->regbase);

err_release:

	release_mem_region(vt8500_rtc->res->start,

			   resource_size(vt8500_rtc->res));

err_free:

	kfree(vt8500_rtc);

	return ret;

}



static int __devexit vt8500_rtc_remove(struct platform_device *pdev)

{

	struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);



	free_irq(vt8500_rtc->irq_alarm, vt8500_rtc);

	free_irq(vt8500_rtc->irq_hz, vt8500_rtc);



	rtc_device_unregister(vt8500_rtc->rtc);



	/* Disable alarm matching */

	writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);

	iounmap(vt8500_rtc->regbase);

	release_mem_region(vt8500_rtc->res->start,

			   resource_size(vt8500_rtc->res));



	kfree(vt8500_rtc);

	platform_set_drvdata(pdev, NULL);



	return 0;

}



static struct platform_driver vt8500_rtc_driver = {

	.probe		= vt8500_rtc_probe,

	.remove		= __devexit_p(vt8500_rtc_remove),

	.driver		= {

		.name	= "vt8500-rtc",

		.owner	= THIS_MODULE,

	},

};



static int __init vt8500_rtc_init(void)

{

	return platform_driver_register(&vt8500_rtc_driver);

}

module_init(vt8500_rtc_init);



static void __exit vt8500_rtc_exit(void)

{

	platform_driver_unregister(&vt8500_rtc_driver);

}

module_exit(vt8500_rtc_exit);



MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");

MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");

MODULE_LICENSE("GPL");

MODULE_ALIAS("platform:vt8500-rtc");