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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.
*
* Original code for older kernel 2.6.15 are from Stormlinksemi
* first update from Janos Laube for > 2.6.29 kernels
*
* checkpatch fixes and usage of 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>
#define DRV_NAME "rtc-gemini"
MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>");
MODULE_DESCRIPTION("RTC driver for Gemini SoC");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);
struct gemini_rtc {
struct rtc_device *rtc_dev;
void __iomem *rtc_base;
int rtc_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
*
* 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->rtc_base + GEMINI_RTC_SECOND);
min = readl(rtc->rtc_base + GEMINI_RTC_MINUTE);
hour = readl(rtc->rtc_base + GEMINI_RTC_HOUR);
days = readl(rtc->rtc_base + GEMINI_RTC_DAYS);
offset = readl(rtc->rtc_base + GEMINI_RTC_RECORD);
time = offset + days * 86400 + hour * 3600 + min * 60 + sec;
rtc_time_to_tm(time, tm);
return 0;
}
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->rtc_base + GEMINI_RTC_SECOND);
min = readl(rtc->rtc_base + GEMINI_RTC_MINUTE);
hour = readl(rtc->rtc_base + GEMINI_RTC_HOUR);
day = readl(rtc->rtc_base + GEMINI_RTC_DAYS);
offset = time - (day * 86400 + hour * 3600 + min * 60 + sec);
writel(offset, rtc->rtc_base + GEMINI_RTC_RECORD);
writel(0x01, rtc->rtc_base + GEMINI_RTC_CR);
return 0;
}
static const 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 = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
if (unlikely(!rtc))
return -ENOMEM;
platform_set_drvdata(pdev, rtc);
res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (!res)
return -ENODEV;
rtc->rtc_irq = res->start;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENODEV;
rtc->rtc_base = devm_ioremap(dev, res->start,
resource_size(res));
ret = devm_request_irq(dev, rtc->rtc_irq, gemini_rtc_interrupt,
IRQF_SHARED, pdev->name, dev);
if (unlikely(ret))
return ret;
rtc->rtc_dev = rtc_device_register(pdev->name, dev,
&gemini_rtc_ops, THIS_MODULE);
return PTR_ERR_OR_ZERO(rtc->rtc_dev);
}
static int gemini_rtc_remove(struct platform_device *pdev)
{
struct gemini_rtc *rtc = platform_get_drvdata(pdev);
rtc_device_unregister(rtc->rtc_dev);
return 0;
}
static struct platform_driver gemini_rtc_driver = {
.driver = {
.name = DRV_NAME,
},
.probe = gemini_rtc_probe,
.remove = gemini_rtc_remove,
};
module_platform_driver_probe(gemini_rtc_driver, gemini_rtc_probe);
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