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linux-sg2042/drivers/rtc/rtc-armada38x.c

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/*
* RTC driver for the Armada 38x Marvell SoCs
*
* Copyright (C) 2015 Marvell
*
* Gregory Clement <gregory.clement@free-electrons.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.
*
*/
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#define RTC_STATUS 0x0
#define RTC_STATUS_ALARM1 BIT(0)
#define RTC_STATUS_ALARM2 BIT(1)
#define RTC_IRQ1_CONF 0x4
#define RTC_IRQ1_AL_EN BIT(0)
#define RTC_IRQ1_FREQ_EN BIT(1)
#define RTC_IRQ1_FREQ_1HZ BIT(2)
#define RTC_TIME 0xC
#define RTC_ALARM1 0x10
#define SOC_RTC_INTERRUPT 0x8
#define SOC_RTC_ALARM1 BIT(0)
#define SOC_RTC_ALARM2 BIT(1)
#define SOC_RTC_ALARM1_MASK BIT(2)
#define SOC_RTC_ALARM2_MASK BIT(3)
struct armada38x_rtc {
struct rtc_device *rtc_dev;
void __iomem *regs;
void __iomem *regs_soc;
spinlock_t lock;
/*
* While setting the time, the RTC TIME register should not be
* accessed. Setting the RTC time involves sleeping during
* 100ms, so a mutex instead of a spinlock is used to protect
* it
*/
struct mutex mutex_time;
int irq;
};
/*
* According to the datasheet, the OS should wait 5us after every
* register write to the RTC hard macro so that the required update
* can occur without holding off the system bus
*/
static void rtc_delayed_write(u32 val, struct armada38x_rtc *rtc, int offset)
{
writel(val, rtc->regs + offset);
udelay(5);
}
static int armada38x_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct armada38x_rtc *rtc = dev_get_drvdata(dev);
unsigned long time, time_check;
mutex_lock(&rtc->mutex_time);
time = readl(rtc->regs + RTC_TIME);
/*
* WA for failing time set attempts. As stated in HW ERRATA if
* more than one second between two time reads is detected
* then read once again.
*/
time_check = readl(rtc->regs + RTC_TIME);
if ((time_check - time) > 1)
time_check = readl(rtc->regs + RTC_TIME);
mutex_unlock(&rtc->mutex_time);
rtc_time_to_tm(time_check, tm);
return 0;
}
static int armada38x_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct armada38x_rtc *rtc = dev_get_drvdata(dev);
int ret = 0;
unsigned long time;
ret = rtc_tm_to_time(tm, &time);
if (ret)
goto out;
/*
* Setting the RTC time not always succeeds. According to the
* errata we need to first write on the status register and
* then wait for 100ms before writing to the time register to be
* sure that the data will be taken into account.
*/
mutex_lock(&rtc->mutex_time);
rtc_delayed_write(0, rtc, RTC_STATUS);
msleep(100);
rtc_delayed_write(time, rtc, RTC_TIME);
mutex_unlock(&rtc->mutex_time);
out:
return ret;
}
static int armada38x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct armada38x_rtc *rtc = dev_get_drvdata(dev);
unsigned long time, flags;
u32 val;
spin_lock_irqsave(&rtc->lock, flags);
time = readl(rtc->regs + RTC_ALARM1);
val = readl(rtc->regs + RTC_IRQ1_CONF) & RTC_IRQ1_AL_EN;
spin_unlock_irqrestore(&rtc->lock, flags);
alrm->enabled = val ? 1 : 0;
rtc_time_to_tm(time, &alrm->time);
return 0;
}
static int armada38x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct armada38x_rtc *rtc = dev_get_drvdata(dev);
unsigned long time, flags;
int ret = 0;
u32 val;
ret = rtc_tm_to_time(&alrm->time, &time);
if (ret)
goto out;
spin_lock_irqsave(&rtc->lock, flags);
rtc_delayed_write(time, rtc, RTC_ALARM1);
if (alrm->enabled) {
rtc_delayed_write(RTC_IRQ1_AL_EN, rtc, RTC_IRQ1_CONF);
val = readl(rtc->regs_soc + SOC_RTC_INTERRUPT);
writel(val | SOC_RTC_ALARM1_MASK,
rtc->regs_soc + SOC_RTC_INTERRUPT);
}
spin_unlock_irqrestore(&rtc->lock, flags);
out:
return ret;
}
static int armada38x_rtc_alarm_irq_enable(struct device *dev,
unsigned int enabled)
{
struct armada38x_rtc *rtc = dev_get_drvdata(dev);
unsigned long flags;
spin_lock_irqsave(&rtc->lock, flags);
if (enabled)
rtc_delayed_write(RTC_IRQ1_AL_EN, rtc, RTC_IRQ1_CONF);
else
rtc_delayed_write(0, rtc, RTC_IRQ1_CONF);
spin_unlock_irqrestore(&rtc->lock, flags);
return 0;
}
static irqreturn_t armada38x_rtc_alarm_irq(int irq, void *data)
{
struct armada38x_rtc *rtc = data;
u32 val;
int event = RTC_IRQF | RTC_AF;
dev_dbg(&rtc->rtc_dev->dev, "%s:irq(%d)\n", __func__, irq);
spin_lock(&rtc->lock);
val = readl(rtc->regs_soc + SOC_RTC_INTERRUPT);
writel(val & ~SOC_RTC_ALARM1, rtc->regs_soc + SOC_RTC_INTERRUPT);
val = readl(rtc->regs + RTC_IRQ1_CONF);
/* disable all the interrupts for alarm 1 */
rtc_delayed_write(0, rtc, RTC_IRQ1_CONF);
/* Ack the event */
rtc_delayed_write(RTC_STATUS_ALARM1, rtc, RTC_STATUS);
spin_unlock(&rtc->lock);
if (val & RTC_IRQ1_FREQ_EN) {
if (val & RTC_IRQ1_FREQ_1HZ)
event |= RTC_UF;
else
event |= RTC_PF;
}
rtc_update_irq(rtc->rtc_dev, 1, event);
return IRQ_HANDLED;
}
static struct rtc_class_ops armada38x_rtc_ops = {
.read_time = armada38x_rtc_read_time,
.set_time = armada38x_rtc_set_time,
.read_alarm = armada38x_rtc_read_alarm,
.set_alarm = armada38x_rtc_set_alarm,
.alarm_irq_enable = armada38x_rtc_alarm_irq_enable,
};
static __init int armada38x_rtc_probe(struct platform_device *pdev)
{
struct resource *res;
struct armada38x_rtc *rtc;
int ret;
rtc = devm_kzalloc(&pdev->dev, sizeof(struct armada38x_rtc),
GFP_KERNEL);
if (!rtc)
return -ENOMEM;
spin_lock_init(&rtc->lock);
mutex_init(&rtc->mutex_time);
res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc");
rtc->regs = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(rtc->regs))
return PTR_ERR(rtc->regs);
res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc-soc");
rtc->regs_soc = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(rtc->regs_soc))
return PTR_ERR(rtc->regs_soc);
rtc->irq = platform_get_irq(pdev, 0);
if (rtc->irq < 0) {
dev_err(&pdev->dev, "no irq\n");
return rtc->irq;
}
if (devm_request_irq(&pdev->dev, rtc->irq, armada38x_rtc_alarm_irq,
0, pdev->name, rtc) < 0) {
dev_warn(&pdev->dev, "Interrupt not available.\n");
rtc->irq = -1;
/*
* If there is no interrupt available then we can't
* use the alarm
*/
armada38x_rtc_ops.set_alarm = NULL;
armada38x_rtc_ops.alarm_irq_enable = NULL;
}
platform_set_drvdata(pdev, rtc);
if (rtc->irq != -1)
device_init_wakeup(&pdev->dev, 1);
rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name,
&armada38x_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc->rtc_dev)) {
ret = PTR_ERR(rtc->rtc_dev);
dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
return ret;
}
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int armada38x_rtc_suspend(struct device *dev)
{
if (device_may_wakeup(dev)) {
struct armada38x_rtc *rtc = dev_get_drvdata(dev);
return enable_irq_wake(rtc->irq);
}
return 0;
}
static int armada38x_rtc_resume(struct device *dev)
{
if (device_may_wakeup(dev)) {
struct armada38x_rtc *rtc = dev_get_drvdata(dev);
return disable_irq_wake(rtc->irq);
}
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(armada38x_rtc_pm_ops,
armada38x_rtc_suspend, armada38x_rtc_resume);
#ifdef CONFIG_OF
static const struct of_device_id armada38x_rtc_of_match_table[] = {
{ .compatible = "marvell,armada-380-rtc", },
{}
};
#endif
static struct platform_driver armada38x_rtc_driver = {
.driver = {
.name = "armada38x-rtc",
.pm = &armada38x_rtc_pm_ops,
.of_match_table = of_match_ptr(armada38x_rtc_of_match_table),
},
};
module_platform_driver_probe(armada38x_rtc_driver, armada38x_rtc_probe);
MODULE_DESCRIPTION("Marvell Armada 38x RTC driver");
MODULE_AUTHOR("Gregory CLEMENT <gregory.clement@free-electrons.com>");
MODULE_LICENSE("GPL");
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