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linux-sg2042/drivers/rtc/rtc-coh901331.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007-2009 ST-Ericsson AB
* Real Time Clock interface for ST-Ericsson AB COH 901 331 RTC.
* Author: Linus Walleij <linus.walleij@stericsson.com>
* Based on rtc-pl031.c by Deepak Saxena <dsaxena@plexity.net>
* Copyright 2006 (c) MontaVista Software, Inc.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/rtc.h>
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/slab.h>
/*
* Registers in the COH 901 331
*/
/* Alarm value 32bit (R/W) */
#define COH901331_ALARM 0x00U
/* Used to set current time 32bit (R/W) */
#define COH901331_SET_TIME 0x04U
/* Indication if current time is valid 32bit (R/-) */
#define COH901331_VALID 0x08U
/* Read the current time 32bit (R/-) */
#define COH901331_CUR_TIME 0x0cU
/* Event register for the "alarm" interrupt */
#define COH901331_IRQ_EVENT 0x10U
/* Mask register for the "alarm" interrupt */
#define COH901331_IRQ_MASK 0x14U
/* Force register for the "alarm" interrupt */
#define COH901331_IRQ_FORCE 0x18U
/*
* Reference to RTC block clock
* Notice that the frequent clk_enable()/clk_disable() on this
* clock is mainly to be able to turn on/off other clocks in the
* hierarchy as needed, the RTC clock is always on anyway.
*/
struct coh901331_port {
struct rtc_device *rtc;
struct clk *clk;
void __iomem *virtbase;
int irq;
#ifdef CONFIG_PM_SLEEP
u32 irqmaskstore;
#endif
};
static irqreturn_t coh901331_interrupt(int irq, void *data)
{
struct coh901331_port *rtap = data;
clk_enable(rtap->clk);
/* Ack IRQ */
writel(1, rtap->virtbase + COH901331_IRQ_EVENT);
/*
* Disable the interrupt. This is necessary because
* the RTC lives on a lower-clocked line and will
* not release the IRQ line until after a few (slower)
* clock cycles. The interrupt will be re-enabled when
* a new alarm is set anyway.
*/
writel(0, rtap->virtbase + COH901331_IRQ_MASK);
clk_disable(rtap->clk);
/* Set alarm flag */
rtc_update_irq(rtap->rtc, 1, RTC_AF);
return IRQ_HANDLED;
}
static int coh901331_read_time(struct device *dev, struct rtc_time *tm)
{
struct coh901331_port *rtap = dev_get_drvdata(dev);
clk_enable(rtap->clk);
/* Check if the time is valid */
if (!readl(rtap->virtbase + COH901331_VALID)) {
clk_disable(rtap->clk);
return -EINVAL;
}
rtc_time64_to_tm(readl(rtap->virtbase + COH901331_CUR_TIME), tm);
clk_disable(rtap->clk);
return 0;
}
static int coh901331_set_time(struct device *dev, struct rtc_time *tm)
{
struct coh901331_port *rtap = dev_get_drvdata(dev);
clk_enable(rtap->clk);
writel(rtc_tm_to_time64(tm), rtap->virtbase + COH901331_SET_TIME);
clk_disable(rtap->clk);
return 0;
}
static int coh901331_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct coh901331_port *rtap = dev_get_drvdata(dev);
clk_enable(rtap->clk);
rtc_time64_to_tm(readl(rtap->virtbase + COH901331_ALARM), &alarm->time);
alarm->pending = readl(rtap->virtbase + COH901331_IRQ_EVENT) & 1U;
alarm->enabled = readl(rtap->virtbase + COH901331_IRQ_MASK) & 1U;
clk_disable(rtap->clk);
return 0;
}
static int coh901331_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct coh901331_port *rtap = dev_get_drvdata(dev);
unsigned long time = rtc_tm_to_time64(&alarm->time);
clk_enable(rtap->clk);
writel(time, rtap->virtbase + COH901331_ALARM);
writel(alarm->enabled, rtap->virtbase + COH901331_IRQ_MASK);
clk_disable(rtap->clk);
return 0;
}
static int coh901331_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct coh901331_port *rtap = dev_get_drvdata(dev);
clk_enable(rtap->clk);
if (enabled)
writel(1, rtap->virtbase + COH901331_IRQ_MASK);
else
writel(0, rtap->virtbase + COH901331_IRQ_MASK);
clk_disable(rtap->clk);
return 0;
}
static const struct rtc_class_ops coh901331_ops = {
.read_time = coh901331_read_time,
.set_time = coh901331_set_time,
.read_alarm = coh901331_read_alarm,
.set_alarm = coh901331_set_alarm,
.alarm_irq_enable = coh901331_alarm_irq_enable,
};
static int __exit coh901331_remove(struct platform_device *pdev)
{
struct coh901331_port *rtap = platform_get_drvdata(pdev);
if (rtap)
clk_unprepare(rtap->clk);
return 0;
}
static int __init coh901331_probe(struct platform_device *pdev)
{
int ret;
struct coh901331_port *rtap;
struct resource *res;
rtap = devm_kzalloc(&pdev->dev,
sizeof(struct coh901331_port), GFP_KERNEL);
if (!rtap)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
rtap->virtbase = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(rtap->virtbase))
return PTR_ERR(rtap->virtbase);
rtap->irq = platform_get_irq(pdev, 0);
if (devm_request_irq(&pdev->dev, rtap->irq, coh901331_interrupt, 0,
"RTC COH 901 331 Alarm", rtap))
return -EIO;
rtap->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(rtap->clk)) {
ret = PTR_ERR(rtap->clk);
dev_err(&pdev->dev, "could not get clock\n");
return ret;
}
rtap->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(rtap->rtc))
return PTR_ERR(rtap->rtc);
rtap->rtc->ops = &coh901331_ops;
rtap->rtc->range_max = U32_MAX;
/* We enable/disable the clock only to assure it works */
ret = clk_prepare_enable(rtap->clk);
if (ret) {
dev_err(&pdev->dev, "could not enable clock\n");
return ret;
}
clk_disable(rtap->clk);
platform_set_drvdata(pdev, rtap);
ret = rtc_register_device(rtap->rtc);
if (ret)
goto out_no_rtc;
return 0;
out_no_rtc:
clk_unprepare(rtap->clk);
return ret;
}
#ifdef CONFIG_PM_SLEEP
static int coh901331_suspend(struct device *dev)
{
struct coh901331_port *rtap = dev_get_drvdata(dev);
/*
* If this RTC alarm will be used for waking the system up,
* don't disable it of course. Else we just disable the alarm
* and await suspension.
*/
if (device_may_wakeup(dev)) {
enable_irq_wake(rtap->irq);
} else {
clk_enable(rtap->clk);
rtap->irqmaskstore = readl(rtap->virtbase + COH901331_IRQ_MASK);
writel(0, rtap->virtbase + COH901331_IRQ_MASK);
clk_disable(rtap->clk);
}
clk_unprepare(rtap->clk);
return 0;
}
static int coh901331_resume(struct device *dev)
{
int ret;
struct coh901331_port *rtap = dev_get_drvdata(dev);
ret = clk_prepare(rtap->clk);
if (ret)
return ret;
if (device_may_wakeup(dev)) {
disable_irq_wake(rtap->irq);
} else {
clk_enable(rtap->clk);
writel(rtap->irqmaskstore, rtap->virtbase + COH901331_IRQ_MASK);
clk_disable(rtap->clk);
}
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(coh901331_pm_ops, coh901331_suspend, coh901331_resume);
static void coh901331_shutdown(struct platform_device *pdev)
{
struct coh901331_port *rtap = platform_get_drvdata(pdev);
clk_enable(rtap->clk);
writel(0, rtap->virtbase + COH901331_IRQ_MASK);
clk_disable_unprepare(rtap->clk);
}
static const struct of_device_id coh901331_dt_match[] = {
{ .compatible = "stericsson,coh901331" },
{},
};
MODULE_DEVICE_TABLE(of, coh901331_dt_match);
static struct platform_driver coh901331_driver = {
.driver = {
.name = "rtc-coh901331",
.pm = &coh901331_pm_ops,
.of_match_table = coh901331_dt_match,
},
.remove = __exit_p(coh901331_remove),
.shutdown = coh901331_shutdown,
};
module_platform_driver_probe(coh901331_driver, coh901331_probe);
MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
MODULE_DESCRIPTION("ST-Ericsson AB COH 901 331 RTC Driver");
MODULE_LICENSE("GPL");
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