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/*
* Gemini OnChip RTC
*
* Copyright (C) 2009 Janos Laube <janos.dev@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Original code for older kernel 2.6.15 are form Stormlinksemi
* first update from Janos Laube for > 2.6.29 kernels
*
* checkpatch fixes and usage off rtc-lib code
* Hans Ulli Kroll <ulli.kroll@googlemail.com>
*/
#include <linux/rtc.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <mach/hardware.h>
#define DRV_NAME "rtc-gemini"
MODULE_DESCRIPTION("RTC driver for Gemini SoC");
MODULE_ALIAS("platform:" DRV_NAME);
MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>");
MODULE_LICENSE("GPL");
struct gemini_rtc {
struct rtc_device *dev;
void __iomem *base;
int irq;
};
enum gemini_rtc_offsets {
GEMINI_RTC_SECOND = 0x00,
GEMINI_RTC_MINUTE = 0x04,
GEMINI_RTC_HOUR = 0x08,
GEMINI_RTC_DAYS = 0x0C,
GEMINI_RTC_ALARM_SECOND = 0x10,
GEMINI_RTC_ALARM_MINUTE = 0x14,
GEMINI_RTC_ALARM_HOUR = 0x18,
GEMINI_RTC_RECORD = 0x1C,
GEMINI_RTC_CR = 0x20
};
static irqreturn_t gemini_rtc_interrupt(int irq, void *dev)
{
return IRQ_HANDLED;
}
/*
* Looks like the RTC in the Gemini SoC is (totaly) broken
* We can't read/write directly the time from RTC registers.
* We must do some "offset" calculation to get the real time
*
* The register "day" seams to be fixed, and the register "hour"
* has his own mind.
*
* Maybe we can write directly the hour and days since EPOCH
* but in this case the RTC will recalucate to some (other) strange values.
* If you write time to the registers you will not read the same values.
*
* This FIX works pretty fine and Stormlinksemi aka Cortina-Networks does
* the same thing, without the rtc-lib.c calls.
*/
static int gemini_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct gemini_rtc *rtc = dev_get_drvdata(dev);
unsigned int days, hour, min, sec;
unsigned long offset, time;
sec = readl(rtc->base + GEMINI_RTC_SECOND);
min = readl(rtc->base + GEMINI_RTC_MINUTE);
hour = readl(rtc->base + GEMINI_RTC_HOUR);
days = readl(rtc->base + GEMINI_RTC_DAYS);
offset = readl(rtc->base + GEMINI_RTC_RECORD);
time = offset + days * 86400 + hour * 3600 + min * 60 + sec;
rtc_time_to_tm(time, tm);
return 0;
}
/*
* Maybe there is some hidden register to care ?
* looks like register GEMINI_RTC_DAY can count
* 365 days * 179 years >= 65535 (uint16)
*/
static int gemini_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct gemini_rtc *rtc = dev_get_drvdata(dev);
unsigned int sec, min, hour, day;
unsigned long offset, time;
if (tm->tm_year >= 2148) /* EPOCH Year + 179 */
return -EINVAL;
rtc_tm_to_time(tm , &time);
sec = readl(rtc->base + GEMINI_RTC_SECOND);
min = readl(rtc->base + GEMINI_RTC_MINUTE);
hour = readl(rtc->base + GEMINI_RTC_HOUR);
day = readl(rtc->base + GEMINI_RTC_DAYS);
offset = time - (day*86400 + hour*3600 + min*60 + sec);
writel(offset, rtc->base + GEMINI_RTC_RECORD);
writel(0x01, rtc->base + GEMINI_RTC_CR);
return 0;
}
static struct rtc_class_ops gemini_rtc_ops = {
.read_time = gemini_rtc_read_time,
.set_time = gemini_rtc_set_time,
};
static int gemini_rtc_probe(struct platform_device *pdev)
{
struct gemini_rtc *rtc;
struct device *dev = &pdev->dev;
struct resource *res;
int ret;
rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
if (unlikely(!rtc))
return -ENOMEM;
platform_set_drvdata(pdev, rtc);
rtc->irq = platform_get_irq(pdev, 0);
if (rtc->irq < 0) {
ret = -rtc->irq;
goto err_mem;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
ret = -ENODEV;
goto err_mem;
}
rtc->base = devm_ioremap(&pdev->dev, res->start,
res->end - res->start + 1);
ret = request_irq(rtc->irq, gemini_rtc_interrupt,
IRQF_SHARED, pdev->name, dev);
if (unlikely(ret))
goto err_mem;
rtc->dev = rtc_device_register(pdev->name, dev,
&gemini_rtc_ops, THIS_MODULE);
if (unlikely(IS_ERR(rtc->dev))) {
ret = PTR_ERR(rtc->dev);
goto err_irq;
}
return 0;
err_irq:
free_irq(rtc->irq, dev);
err_mem:
kfree(rtc);
return ret;
}
static int gemini_rtc_remove(struct platform_device *pdev)
{
struct gemini_rtc *rtc = platform_get_drvdata(pdev);
struct device *dev = &pdev->dev;
free_irq(rtc->irq, dev);
rtc_device_unregister(rtc->dev);
platform_set_drvdata(pdev, NULL);
kfree(rtc);
return 0;
}
static struct platform_driver gemini_rtc_driver = {
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
},
.probe = gemini_rtc_probe,
.remove = gemini_rtc_remove,
};
static int __init gemini_rtc_init(void)
{
int retval;
retval = platform_driver_register(&gemini_rtc_driver);
if (retval == 0)
pr_info(DRV_NAME ": registered successfully");
return retval;
}
static void __exit gemini_rtc_exit(void)
{
platform_driver_unregister(&gemini_rtc_driver);
}
module_init(gemini_rtc_init);
module_exit(gemini_rtc_exit);
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