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linux-stable/drivers/rtc/rtc-stk17ta8.c
Alexandre Belloni 8f21092d65 rtc: stk17ta8: make alarms useful 
Currently, the IRQs are disabled when the rtc driver is removed (e.g. when
shutting down the platform).
This means that the RTC will be unable to wakeup the platform.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2018-03-01 10:49:31 +01:00

363 lines
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/*
* A RTC driver for the Simtek STK17TA8
*
* By Thomas Hommel <thomas.hommel@ge.com>
*
* Based on the DS1553 driver from
* Atsushi Nemoto <anemo@mba.ocn.ne.jp>
*
* 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/bcd.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/delay.h>
#include <linux/jiffies.h>
#include <linux/interrupt.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/module.h>
#define RTC_REG_SIZE 0x20000
#define RTC_OFFSET 0x1fff0
#define RTC_FLAGS (RTC_OFFSET + 0)
#define RTC_CENTURY (RTC_OFFSET + 1)
#define RTC_SECONDS_ALARM (RTC_OFFSET + 2)
#define RTC_MINUTES_ALARM (RTC_OFFSET + 3)
#define RTC_HOURS_ALARM (RTC_OFFSET + 4)
#define RTC_DATE_ALARM (RTC_OFFSET + 5)
#define RTC_INTERRUPTS (RTC_OFFSET + 6)
#define RTC_WATCHDOG (RTC_OFFSET + 7)
#define RTC_CALIBRATION (RTC_OFFSET + 8)
#define RTC_SECONDS (RTC_OFFSET + 9)
#define RTC_MINUTES (RTC_OFFSET + 10)
#define RTC_HOURS (RTC_OFFSET + 11)
#define RTC_DAY (RTC_OFFSET + 12)
#define RTC_DATE (RTC_OFFSET + 13)
#define RTC_MONTH (RTC_OFFSET + 14)
#define RTC_YEAR (RTC_OFFSET + 15)
#define RTC_SECONDS_MASK 0x7f
#define RTC_DAY_MASK 0x07
#define RTC_CAL_MASK 0x3f
/* Bits in the Calibration register */
#define RTC_STOP 0x80
/* Bits in the Flags register */
#define RTC_FLAGS_AF 0x40
#define RTC_FLAGS_PF 0x20
#define RTC_WRITE 0x02
#define RTC_READ 0x01
/* Bits in the Interrupts register */
#define RTC_INTS_AIE 0x40
struct rtc_plat_data {
struct rtc_device *rtc;
void __iomem *ioaddr;
unsigned long last_jiffies;
int irq;
unsigned int irqen;
int alrm_sec;
int alrm_min;
int alrm_hour;
int alrm_mday;
spinlock_t lock;
};
static int stk17ta8_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
u8 flags;
flags = readb(pdata->ioaddr + RTC_FLAGS);
writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
writeb(bin2bcd((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY);
writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
return 0;
}
static int stk17ta8_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
unsigned int year, month, day, hour, minute, second, week;
unsigned int century;
u8 flags;
/* give enough time to update RTC in case of continuous read */
if (pdata->last_jiffies == jiffies)
msleep(1);
pdata->last_jiffies = jiffies;
flags = readb(pdata->ioaddr + RTC_FLAGS);
writeb(flags | RTC_READ, ioaddr + RTC_FLAGS);
second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
minute = readb(ioaddr + RTC_MINUTES);
hour = readb(ioaddr + RTC_HOURS);
day = readb(ioaddr + RTC_DATE);
week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
month = readb(ioaddr + RTC_MONTH);
year = readb(ioaddr + RTC_YEAR);
century = readb(ioaddr + RTC_CENTURY);
writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS);
tm->tm_sec = bcd2bin(second);
tm->tm_min = bcd2bin(minute);
tm->tm_hour = bcd2bin(hour);
tm->tm_mday = bcd2bin(day);
tm->tm_wday = bcd2bin(week);
tm->tm_mon = bcd2bin(month) - 1;
/* year is 1900 + tm->tm_year */
tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
if (rtc_valid_tm(tm) < 0) {
dev_err(dev, "retrieved date/time is not valid.\n");
rtc_time_to_tm(0, tm);
}
return 0;
}
static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata)
{
void __iomem *ioaddr = pdata->ioaddr;
unsigned long irqflags;
u8 flags;
spin_lock_irqsave(&pdata->lock, irqflags);
flags = readb(ioaddr + RTC_FLAGS);
writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
0x80 : bin2bcd(pdata->alrm_mday),
ioaddr + RTC_DATE_ALARM);
writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
0x80 : bin2bcd(pdata->alrm_hour),
ioaddr + RTC_HOURS_ALARM);
writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
0x80 : bin2bcd(pdata->alrm_min),
ioaddr + RTC_MINUTES_ALARM);
writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
0x80 : bin2bcd(pdata->alrm_sec),
ioaddr + RTC_SECONDS_ALARM);
writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS);
readb(ioaddr + RTC_FLAGS); /* clear interrupts */
writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
spin_unlock_irqrestore(&pdata->lock, irqflags);
}
static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
if (pdata->irq <= 0)
return -EINVAL;
pdata->alrm_mday = alrm->time.tm_mday;
pdata->alrm_hour = alrm->time.tm_hour;
pdata->alrm_min = alrm->time.tm_min;
pdata->alrm_sec = alrm->time.tm_sec;
if (alrm->enabled)
pdata->irqen |= RTC_AF;
stk17ta8_rtc_update_alarm(pdata);
return 0;
}
static int stk17ta8_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
if (pdata->irq <= 0)
return -EINVAL;
alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
return 0;
}
static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id)
{
struct platform_device *pdev = dev_id;
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
unsigned long events = 0;
spin_lock(&pdata->lock);
/* read and clear interrupt */
if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {
events = RTC_IRQF;
if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
events |= RTC_UF;
else
events |= RTC_AF;
rtc_update_irq(pdata->rtc, 1, events);
}
spin_unlock(&pdata->lock);
return events ? IRQ_HANDLED : IRQ_NONE;
}
static int stk17ta8_rtc_alarm_irq_enable(struct device *dev,
unsigned int enabled)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
if (pdata->irq <= 0)
return -EINVAL;
if (enabled)
pdata->irqen |= RTC_AF;
else
pdata->irqen &= ~RTC_AF;
stk17ta8_rtc_update_alarm(pdata);
return 0;
}
static const struct rtc_class_ops stk17ta8_rtc_ops = {
.read_time = stk17ta8_rtc_read_time,
.set_time = stk17ta8_rtc_set_time,
.read_alarm = stk17ta8_rtc_read_alarm,
.set_alarm = stk17ta8_rtc_set_alarm,
.alarm_irq_enable = stk17ta8_rtc_alarm_irq_enable,
};
static ssize_t stk17ta8_nvram_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr, char *buf,
loff_t pos, size_t size)
{
struct device *dev = container_of(kobj, struct device, kobj);
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
ssize_t count;
for (count = 0; count < size; count++)
*buf++ = readb(ioaddr + pos++);
return count;
}
static ssize_t stk17ta8_nvram_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr, char *buf,
loff_t pos, size_t size)
{
struct device *dev = container_of(kobj, struct device, kobj);
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
ssize_t count;
for (count = 0; count < size; count++)
writeb(*buf++, ioaddr + pos++);
return count;
}
static struct bin_attribute stk17ta8_nvram_attr = {
.attr = {
.name = "nvram",
.mode = S_IRUGO | S_IWUSR,
},
.size = RTC_OFFSET,
.read = stk17ta8_nvram_read,
.write = stk17ta8_nvram_write,
};
static int stk17ta8_rtc_probe(struct platform_device *pdev)
{
struct resource *res;
unsigned int cal;
unsigned int flags;
struct rtc_plat_data *pdata;
void __iomem *ioaddr;
int ret = 0;
pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
ioaddr = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(ioaddr))
return PTR_ERR(ioaddr);
pdata->ioaddr = ioaddr;
pdata->irq = platform_get_irq(pdev, 0);
/* turn RTC on if it was not on */
cal = readb(ioaddr + RTC_CALIBRATION);
if (cal & RTC_STOP) {
cal &= RTC_CAL_MASK;
flags = readb(ioaddr + RTC_FLAGS);
writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
writeb(cal, ioaddr + RTC_CALIBRATION);
writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
}
if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF)
dev_warn(&pdev->dev, "voltage-low detected.\n");
spin_lock_init(&pdata->lock);
pdata->last_jiffies = jiffies;
platform_set_drvdata(pdev, pdata);
if (pdata->irq > 0) {
writeb(0, ioaddr + RTC_INTERRUPTS);
if (devm_request_irq(&pdev->dev, pdata->irq,
stk17ta8_rtc_interrupt,
IRQF_SHARED,
pdev->name, pdev) < 0) {
dev_warn(&pdev->dev, "interrupt not available.\n");
pdata->irq = 0;
}
}
pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
&stk17ta8_rtc_ops, THIS_MODULE);
if (IS_ERR(pdata->rtc))
return PTR_ERR(pdata->rtc);
ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
return ret;
}
static int stk17ta8_rtc_remove(struct platform_device *pdev)
{
sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
return 0;
}
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:stk17ta8");
static struct platform_driver stk17ta8_rtc_driver = {
.probe = stk17ta8_rtc_probe,
.remove = stk17ta8_rtc_remove,
.driver = {
.name = "stk17ta8",
},
};
module_platform_driver(stk17ta8_rtc_driver);
MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>");
MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver");
MODULE_LICENSE("GPL");
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