// SPDX-License-Identifier: GPL-2.0-only
/*
* drivers/rtc/rtc-spear.c
*
* Copyright (C) 2010 ST Microelectronics
* Rajeev Kumar<[email protected]>
*/
#include <linux/bcd.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
/* RTC registers */
#define TIME_REG 0x00
#define DATE_REG 0x04
#define ALARM_TIME_REG 0x08
#define ALARM_DATE_REG 0x0C
#define CTRL_REG 0x10
#define STATUS_REG 0x14
/* TIME_REG & ALARM_TIME_REG */
#define SECONDS_UNITS (0xf<<0) /* seconds units position */
#define SECONDS_TENS (0x7<<4) /* seconds tens position */
#define MINUTES_UNITS (0xf<<8) /* minutes units position */
#define MINUTES_TENS (0x7<<12) /* minutes tens position */
#define HOURS_UNITS (0xf<<16) /* hours units position */
#define HOURS_TENS (0x3<<20) /* hours tens position */
/* DATE_REG & ALARM_DATE_REG */
#define DAYS_UNITS (0xf<<0) /* days units position */
#define DAYS_TENS (0x3<<4) /* days tens position */
#define MONTHS_UNITS (0xf<<8) /* months units position */
#define MONTHS_TENS (0x1<<12) /* months tens position */
#define YEARS_UNITS (0xf<<16) /* years units position */
#define YEARS_TENS (0xf<<20) /* years tens position */
#define YEARS_HUNDREDS (0xf<<24) /* years hundereds position */
#define YEARS_MILLENIUMS (0xf<<28) /* years millenium position */
/* MASK SHIFT TIME_REG & ALARM_TIME_REG*/
#define SECOND_SHIFT 0x00 /* seconds units */
#define MINUTE_SHIFT 0x08 /* minutes units position */
#define HOUR_SHIFT 0x10 /* hours units position */
#define MDAY_SHIFT 0x00 /* Month day shift */
#define MONTH_SHIFT 0x08 /* Month shift */
#define YEAR_SHIFT 0x10 /* Year shift */
#define SECOND_MASK 0x7F
#define MIN_MASK 0x7F
#define HOUR_MASK 0x3F
#define DAY_MASK 0x3F
#define MONTH_MASK 0x7F
#define YEAR_MASK 0xFFFF
/* date reg equal to time reg, for debug only */
#define TIME_BYP (1<<9)
#define INT_ENABLE (1<<31) /* interrupt enable */
/* STATUS_REG */
#define CLK_UNCONNECTED (1<<0)
#define PEND_WR_TIME (1<<2)
#define PEND_WR_DATE (1<<3)
#define LOST_WR_TIME (1<<4)
#define LOST_WR_DATE (1<<5)
#define RTC_INT_MASK (1<<31)
#define STATUS_BUSY (PEND_WR_TIME | PEND_WR_DATE)
#define STATUS_FAIL (LOST_WR_TIME | LOST_WR_DATE)
struct spear_rtc_config {
struct rtc_device *rtc;
struct clk *clk;
spinlock_t lock;
void __iomem *ioaddr;
unsigned int irq_wake;
};
static inline void spear_rtc_clear_interrupt(struct spear_rtc_config *config)
{
unsigned int val;
unsigned long flags;
spin_lock_irqsave(&config->lock, flags);
val = readl(config->ioaddr + STATUS_REG);
val |= RTC_INT_MASK;
writel(val, config->ioaddr + STATUS_REG);
spin_unlock_irqrestore(&config->lock, flags);
}
static inline void spear_rtc_enable_interrupt(struct spear_rtc_config *config)
{
unsigned int val;
val = readl(config->ioaddr + CTRL_REG);
if (!(val & INT_ENABLE)) {
spear_rtc_clear_interrupt(config);
val |= INT_ENABLE;
writel(val, config->ioaddr + CTRL_REG);
}
}
static inline void spear_rtc_disable_interrupt(struct spear_rtc_config *config)
{
unsigned int val;
val = readl(config->ioaddr + CTRL_REG);
if (val & INT_ENABLE) {
val &= ~INT_ENABLE;
writel(val, config->ioaddr + CTRL_REG);
}
}
static inline int is_write_complete(struct spear_rtc_config *config)
{
int ret = 0;
unsigned long flags;
spin_lock_irqsave(&config->lock, flags);
if ((readl(config->ioaddr + STATUS_REG)) & STATUS_FAIL)
ret = -EIO;
spin_unlock_irqrestore(&config->lock, flags);
return ret;
}
static void rtc_wait_not_busy(struct spear_rtc_config *config)
{
int status, count = 0;
unsigned long flags;
/* Assuming BUSY may stay active for 80 msec) */
for (count = 0; count < 80; count++) {
spin_lock_irqsave(&config->lock, flags);
status = readl(config->ioaddr + STATUS_REG);
spin_unlock_irqrestore(&config->lock, flags);
if ((status & STATUS_BUSY) == 0)
break;
/* check status busy, after each msec */
msleep(1);
}
}
static irqreturn_t spear_rtc_irq(int irq, void *dev_id)
{
struct spear_rtc_config *config = dev_id;
unsigned long events = 0;
unsigned int irq_data;
spin_lock(&config->lock);
irq_data = readl(config->ioaddr + STATUS_REG);
spin_unlock(&config->lock);
if ((irq_data & RTC_INT_MASK)) {
spear_rtc_clear_interrupt(config);
events = RTC_IRQF | RTC_AF;
rtc_update_irq(config->rtc, 1, events);
return IRQ_HANDLED;
} else
return IRQ_NONE;
}
static void tm2bcd(struct rtc_time *tm)
{
tm->tm_sec = bin2bcd(tm->tm_sec);
tm->tm_min = bin2bcd(tm->tm_min);
tm->tm_hour = bin2bcd(tm->tm_hour);
tm->tm_mday = bin2bcd(tm->tm_mday);
tm->tm_mon = bin2bcd(tm->tm_mon + 1);
tm->tm_year = bin2bcd(tm->tm_year);
}
static void bcd2tm(struct rtc_time *tm)
{
tm->tm_sec = bcd2bin(tm->tm_sec);
tm->tm_min = bcd2bin(tm->tm_min);
tm->tm_hour = bcd2bin(tm->tm_hour);
tm->tm_mday = bcd2bin(tm->tm_mday);
tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
/* epoch == 1900 */
tm->tm_year = bcd2bin(tm->tm_year);
}
/*
* spear_rtc_read_time - set the time
* @dev: rtc device in use
* @tm: holds date and time
*
* This function read time and date. On success it will return 0
* otherwise -ve error is returned.
*/
static int spear_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct spear_rtc_config *config = dev_get_drvdata(dev);
unsigned int time, date;
/* we don't report wday/yday/isdst ... */
rtc_wait_not_busy(config);
do {
time = readl(config->ioaddr + TIME_REG);
date = readl(config->ioaddr + DATE_REG);
} while (time == readl(config->ioaddr + TIME_REG));
tm->tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
tm->tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
tm->tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
tm->tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
tm->tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
tm->tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
bcd2tm(tm);
return 0;
}
/*
* spear_rtc_set_time - set the time
* @dev: rtc device in use
* @tm: holds date and time
*
* This function set time and date. On success it will return 0
* otherwise -ve error is returned.
*/
static int spear_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct spear_rtc_config *config = dev_get_drvdata(dev);
unsigned int time, date;
tm2bcd(tm);
rtc_wait_not_busy(config);
time = (tm->tm_sec << SECOND_SHIFT) | (tm->tm_min << MINUTE_SHIFT) |
(tm->tm_hour << HOUR_SHIFT);
date = (tm->tm_mday << MDAY_SHIFT) | (tm->tm_mon << MONTH_SHIFT) |
(tm->tm_year << YEAR_SHIFT);
writel(time, config->ioaddr + TIME_REG);
writel(date, config->ioaddr + DATE_REG);
return is_write_complete(config);
}
/*
* spear_rtc_read_alarm - read the alarm time
* @dev: rtc device in use
* @alm: holds alarm date and time
*
* This function read alarm time and date. On success it will return 0
* otherwise -ve error is returned.
*/
static int spear_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
struct spear_rtc_config *config = dev_get_drvdata(dev);
unsigned int time, date;
rtc_wait_not_busy(config);
time = readl(config->ioaddr + ALARM_TIME_REG);
date = readl(config->ioaddr + ALARM_DATE_REG);
alm->time.tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
alm->time.tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
alm->time.tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
alm->time.tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
alm->time.tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
alm->time.tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
bcd2tm(&alm->time);
alm->enabled = readl(config->ioaddr + CTRL_REG) & INT_ENABLE;
return 0;
}
/*
* spear_rtc_set_alarm - set the alarm time
* @dev: rtc device in use
* @alm: holds alarm date and time
*
* This function set alarm time and date. On success it will return 0
* otherwise -ve error is returned.
*/
static int spear_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
struct spear_rtc_config *config = dev_get_drvdata(dev);
unsigned int time, date;
int err;
tm2bcd(&alm->time);
rtc_wait_not_busy(config);
time = (alm->time.tm_sec << SECOND_SHIFT) | (alm->time.tm_min <<
MINUTE_SHIFT) | (alm->time.tm_hour << HOUR_SHIFT);
date = (alm->time.tm_mday << MDAY_SHIFT) | (alm->time.tm_mon <<
MONTH_SHIFT) | (alm->time.tm_year << YEAR_SHIFT);
writel(time, config->ioaddr + ALARM_TIME_REG);
writel(date, config->ioaddr + ALARM_DATE_REG);
err = is_write_complete(config);
if (err < 0)
return err;
if (alm->enabled)
spear_rtc_enable_interrupt(config);
else
spear_rtc_disable_interrupt(config);
return 0;
}
static int spear_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct spear_rtc_config *config = dev_get_drvdata(dev);
int ret = 0;
spear_rtc_clear_interrupt(config);
switch (enabled) {
case 0:
/* alarm off */
spear_rtc_disable_interrupt(config);
break;
case 1:
/* alarm on */
spear_rtc_enable_interrupt(config);
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
static const struct rtc_class_ops spear_rtc_ops = {
.read_time = spear_rtc_read_time,
.set_time = spear_rtc_set_time,
.read_alarm = spear_rtc_read_alarm,
.set_alarm = spear_rtc_set_alarm,
.alarm_irq_enable = spear_alarm_irq_enable,
};
static int spear_rtc_probe(struct platform_device *pdev)
{
struct spear_rtc_config *config;
int status = 0;
int irq;
config = devm_kzalloc(&pdev->dev, sizeof(*config), GFP_KERNEL);
if (!config)
return -ENOMEM;
config->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(config->rtc))
return PTR_ERR(config->rtc);
/* alarm irqs */
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
status = devm_request_irq(&pdev->dev, irq, spear_rtc_irq, 0, pdev->name,
config);
if (status) {
dev_err(&pdev->dev, "Alarm interrupt IRQ%d already claimed\n",
irq);
return status;
}
config->ioaddr = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(config->ioaddr))
return PTR_ERR(config->ioaddr);
config->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(config->clk))
return PTR_ERR(config->clk);
status = clk_prepare_enable(config->clk);
if (status < 0)
return status;
spin_lock_init(&config->lock);
platform_set_drvdata(pdev, config);
config->rtc->ops = &spear_rtc_ops;
config->rtc->range_min = RTC_TIMESTAMP_BEGIN_0000;
config->rtc->range_max = RTC_TIMESTAMP_END_9999;
status = devm_rtc_register_device(config->rtc);
if (status)
goto err_disable_clock;
if (!device_can_wakeup(&pdev->dev))
device_init_wakeup(&pdev->dev, 1);
return 0;
err_disable_clock:
clk_disable_unprepare(config->clk);
return status;
}
static void spear_rtc_remove(struct platform_device *pdev)
{
struct spear_rtc_config *config = platform_get_drvdata(pdev);
spear_rtc_disable_interrupt(config);
clk_disable_unprepare(config->clk);
device_init_wakeup(&pdev->dev, 0);
}
#ifdef CONFIG_PM_SLEEP
static int spear_rtc_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct spear_rtc_config *config = platform_get_drvdata(pdev);
int irq;
irq = platform_get_irq(pdev, 0);
if (device_may_wakeup(&pdev->dev)) {
if (!enable_irq_wake(irq))
config->irq_wake = 1;
} else {
spear_rtc_disable_interrupt(config);
clk_disable(config->clk);
}
return 0;
}
static int spear_rtc_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct spear_rtc_config *config = platform_get_drvdata(pdev);
int irq;
irq = platform_get_irq(pdev, 0);
if (device_may_wakeup(&pdev->dev)) {
if (config->irq_wake) {
disable_irq_wake(irq);
config->irq_wake = 0;
}
} else {
clk_enable(config->clk);
spear_rtc_enable_interrupt(config);
}
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(spear_rtc_pm_ops, spear_rtc_suspend, spear_rtc_resume);
static void spear_rtc_shutdown(struct platform_device *pdev)
{
struct spear_rtc_config *config = platform_get_drvdata(pdev);
spear_rtc_disable_interrupt(config);
clk_disable(config->clk);
}
#ifdef CONFIG_OF
static const struct of_device_id spear_rtc_id_table[] = {
{ .compatible = "st,spear600-rtc" },
{}
};
MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
#endif
static struct platform_driver spear_rtc_driver = {
.probe = spear_rtc_probe,
.remove_new = spear_rtc_remove,
.shutdown = spear_rtc_shutdown,
.driver = {
.name = "rtc-spear",
.pm = &spear_rtc_pm_ops,
.of_match_table = of_match_ptr(spear_rtc_id_table),
},
};
module_platform_driver(spear_rtc_driver);
MODULE_ALIAS("platform:rtc-spear");
MODULE_AUTHOR("Rajeev Kumar <[email protected]>");
MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
MODULE_LICENSE("GPL");
Codebase Browser
linux