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/*
* 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 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 <hcegtvedt@atmel.com>");
MODULE_DESCRIPTION("Real time clock for AVR32 AT32AP700x");
MODULE_LICENSE("GPL");
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