// SPDX-License-Identifier: GPL-2.0-only
/*
* An rtc driver for the Dallas DS1511
*
* Copyright (C) 2006 Atsushi Nemoto <[email protected]>
* Copyright (C) 2007 Andrew Sharp <[email protected]>
*
* Real time clock driver for the Dallas 1511 chip, which also
* contains a watchdog timer. There is a tiny amount of code that
* platform code could use to mess with the watchdog device a little
* bit, but not a full watchdog driver.
*/
#include <linux/bcd.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/module.h>
#define DS1511_SEC 0x0
#define DS1511_MIN 0x1
#define DS1511_HOUR 0x2
#define DS1511_DOW 0x3
#define DS1511_DOM 0x4
#define DS1511_MONTH 0x5
#define DS1511_YEAR 0x6
#define DS1511_CENTURY 0x7
#define DS1511_AM1_SEC 0x8
#define DS1511_AM2_MIN 0x9
#define DS1511_AM3_HOUR 0xa
#define DS1511_AM4_DATE 0xb
#define DS1511_WD_MSEC 0xc
#define DS1511_WD_SEC 0xd
#define DS1511_CONTROL_A 0xe
#define DS1511_CONTROL_B 0xf
#define DS1511_RAMADDR_LSB 0x10
#define DS1511_RAMDATA 0x13
#define DS1511_BLF1 0x80
#define DS1511_BLF2 0x40
#define DS1511_PRS 0x20
#define DS1511_PAB 0x10
#define DS1511_TDF 0x08
#define DS1511_KSF 0x04
#define DS1511_WDF 0x02
#define DS1511_IRQF 0x01
#define DS1511_TE 0x80
#define DS1511_CS 0x40
#define DS1511_BME 0x20
#define DS1511_TPE 0x10
#define DS1511_TIE 0x08
#define DS1511_KIE 0x04
#define DS1511_WDE 0x02
#define DS1511_WDS 0x01
#define DS1511_RAM_MAX 0x100
struct ds1511_data {
struct rtc_device *rtc;
void __iomem *ioaddr; /* virtual base address */
int irq;
spinlock_t lock;
};
static DEFINE_SPINLOCK(ds1511_lock);
static __iomem char *ds1511_base;
static u32 reg_spacing = 1;
static void rtc_write(uint8_t val, uint32_t reg)
{
writeb(val, ds1511_base + (reg * reg_spacing));
}
static uint8_t rtc_read(uint32_t reg)
{
return readb(ds1511_base + (reg * reg_spacing));
}
static void rtc_disable_update(void)
{
rtc_write((rtc_read(DS1511_CONTROL_B) & ~DS1511_TE), DS1511_CONTROL_B);
}
static void rtc_enable_update(void)
{
rtc_write((rtc_read(DS1511_CONTROL_B) | DS1511_TE), DS1511_CONTROL_B);
}
static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
{
u8 mon, day, dow, hrs, min, sec, yrs, cen;
unsigned long flags;
yrs = rtc_tm->tm_year % 100;
cen = 19 + rtc_tm->tm_year / 100;
mon = rtc_tm->tm_mon + 1; /* tm_mon starts at zero */
day = rtc_tm->tm_mday;
dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */
hrs = rtc_tm->tm_hour;
min = rtc_tm->tm_min;
sec = rtc_tm->tm_sec;
/*
* each register is a different number of valid bits
*/
sec = bin2bcd(sec) & 0x7f;
min = bin2bcd(min) & 0x7f;
hrs = bin2bcd(hrs) & 0x3f;
day = bin2bcd(day) & 0x3f;
mon = bin2bcd(mon) & 0x1f;
yrs = bin2bcd(yrs) & 0xff;
cen = bin2bcd(cen) & 0xff;
spin_lock_irqsave(&ds1511_lock, flags);
rtc_disable_update();
rtc_write(cen, DS1511_CENTURY);
rtc_write(yrs, DS1511_YEAR);
rtc_write((rtc_read(DS1511_MONTH) & 0xe0) | mon, DS1511_MONTH);
rtc_write(day, DS1511_DOM);
rtc_write(hrs, DS1511_HOUR);
rtc_write(min, DS1511_MIN);
rtc_write(sec, DS1511_SEC);
rtc_write(dow, DS1511_DOW);
rtc_enable_update();
spin_unlock_irqrestore(&ds1511_lock, flags);
return 0;
}
static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
{
unsigned int century;
unsigned long flags;
spin_lock_irqsave(&ds1511_lock, flags);
rtc_disable_update();
rtc_tm->tm_sec = rtc_read(DS1511_SEC) & 0x7f;
rtc_tm->tm_min = rtc_read(DS1511_MIN) & 0x7f;
rtc_tm->tm_hour = rtc_read(DS1511_HOUR) & 0x3f;
rtc_tm->tm_mday = rtc_read(DS1511_DOM) & 0x3f;
rtc_tm->tm_wday = rtc_read(DS1511_DOW) & 0x7;
rtc_tm->tm_mon = rtc_read(DS1511_MONTH) & 0x1f;
rtc_tm->tm_year = rtc_read(DS1511_YEAR) & 0x7f;
century = rtc_read(DS1511_CENTURY);
rtc_enable_update();
spin_unlock_irqrestore(&ds1511_lock, flags);
rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
century = bcd2bin(century) * 100;
/*
* Account for differences between how the RTC uses the values
* and how they are defined in a struct rtc_time;
*/
century += rtc_tm->tm_year;
rtc_tm->tm_year = century - 1900;
rtc_tm->tm_mon--;
return 0;
}
static void ds1511_rtc_alarm_enable(unsigned int enabled)
{
rtc_write(rtc_read(DS1511_CONTROL_B) | (enabled ? DS1511_TIE : 0), DS1511_CONTROL_B);
}
static int ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct ds1511_data *ds1511 = dev_get_drvdata(dev);
unsigned long flags;
spin_lock_irqsave(&ds1511->lock, flags);
rtc_write(bin2bcd(alrm->time.tm_mday) & 0x3f, DS1511_AM4_DATE);
rtc_write(bin2bcd(alrm->time.tm_hour) & 0x3f, DS1511_AM3_HOUR);
rtc_write(bin2bcd(alrm->time.tm_min) & 0x7f, DS1511_AM2_MIN);
rtc_write(bin2bcd(alrm->time.tm_sec) & 0x7f, DS1511_AM1_SEC);
ds1511_rtc_alarm_enable(alrm->enabled);
rtc_read(DS1511_CONTROL_A); /* clear interrupts */
spin_unlock_irqrestore(&ds1511->lock, flags);
return 0;
}
static int ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
alrm->time.tm_mday = bcd2bin(rtc_read(DS1511_AM4_DATE) & 0x3f);
alrm->time.tm_hour = bcd2bin(rtc_read(DS1511_AM3_HOUR) & 0x3f);
alrm->time.tm_min = bcd2bin(rtc_read(DS1511_AM2_MIN) & 0x7f);
alrm->time.tm_sec = bcd2bin(rtc_read(DS1511_AM1_SEC) & 0x7f);
alrm->enabled = !!(rtc_read(DS1511_CONTROL_B) & DS1511_TIE);
return 0;
}
static irqreturn_t ds1511_interrupt(int irq, void *dev_id)
{
struct platform_device *pdev = dev_id;
struct ds1511_data *ds1511 = platform_get_drvdata(pdev);
unsigned long events = 0;
spin_lock(&ds1511->lock);
/*
* read and clear interrupt
*/
if (rtc_read(DS1511_CONTROL_A) & DS1511_IRQF) {
events = RTC_IRQF | RTC_AF;
rtc_update_irq(ds1511->rtc, 1, events);
}
spin_unlock(&ds1511->lock);
return events ? IRQ_HANDLED : IRQ_NONE;
}
static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct ds1511_data *ds1511 = dev_get_drvdata(dev);
unsigned long flags;
spin_lock_irqsave(&ds1511->lock, flags);
ds1511_rtc_alarm_enable(enabled);
spin_unlock_irqrestore(&ds1511->lock, flags);
return 0;
}
static const struct rtc_class_ops ds1511_rtc_ops = {
.read_time = ds1511_rtc_read_time,
.set_time = ds1511_rtc_set_time,
.read_alarm = ds1511_rtc_read_alarm,
.set_alarm = ds1511_rtc_set_alarm,
.alarm_irq_enable = ds1511_rtc_alarm_irq_enable,
};
static int ds1511_nvram_read(void *priv, unsigned int pos, void *buf,
size_t size)
{
int i;
rtc_write(pos, DS1511_RAMADDR_LSB);
for (i = 0; i < size; i++)
*(char *)buf++ = rtc_read(DS1511_RAMDATA);
return 0;
}
static int ds1511_nvram_write(void *priv, unsigned int pos, void *buf,
size_t size)
{
int i;
rtc_write(pos, DS1511_RAMADDR_LSB);
for (i = 0; i < size; i++)
rtc_write(*(char *)buf++, DS1511_RAMDATA);
return 0;
}
static int ds1511_rtc_probe(struct platform_device *pdev)
{
struct ds1511_data *ds1511;
int ret = 0;
struct nvmem_config ds1511_nvmem_cfg = {
.name = "ds1511_nvram",
.word_size = 1,
.stride = 1,
.size = DS1511_RAM_MAX,
.reg_read = ds1511_nvram_read,
.reg_write = ds1511_nvram_write,
.priv = &pdev->dev,
};
ds1511 = devm_kzalloc(&pdev->dev, sizeof(*ds1511), GFP_KERNEL);
if (!ds1511)
return -ENOMEM;
ds1511_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(ds1511_base))
return PTR_ERR(ds1511_base);
ds1511->ioaddr = ds1511_base;
ds1511->irq = platform_get_irq(pdev, 0);
/*
* turn on the clock and the crystal, etc.
*/
rtc_write(DS1511_BME, DS1511_CONTROL_B);
rtc_write(0, DS1511_CONTROL_A);
/*
* clear the wdog counter
*/
rtc_write(0, DS1511_WD_MSEC);
rtc_write(0, DS1511_WD_SEC);
/*
* start the clock
*/
rtc_enable_update();
/*
* check for a dying bat-tree
*/
if (rtc_read(DS1511_CONTROL_A) & DS1511_BLF1)
dev_warn(&pdev->dev, "voltage-low detected.\n");
spin_lock_init(&ds1511->lock);
platform_set_drvdata(pdev, ds1511);
ds1511->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(ds1511->rtc))
return PTR_ERR(ds1511->rtc);
ds1511->rtc->ops = &ds1511_rtc_ops;
ds1511->rtc->range_max = RTC_TIMESTAMP_END_2099;
ds1511->rtc->alarm_offset_max = 28 * 24 * 60 * 60 - 1;
/*
* if the platform has an interrupt in mind for this device,
* then by all means, set it
*/
if (ds1511->irq > 0) {
rtc_read(DS1511_CONTROL_A);
if (devm_request_irq(&pdev->dev, ds1511->irq, ds1511_interrupt,
IRQF_SHARED, pdev->name, pdev) < 0) {
dev_warn(&pdev->dev, "interrupt not available.\n");
ds1511->irq = 0;
}
}
if (ds1511->irq == 0)
clear_bit(RTC_FEATURE_ALARM, ds1511->rtc->features);
ret = devm_rtc_register_device(ds1511->rtc);
if (ret)
return ret;
devm_rtc_nvmem_register(ds1511->rtc, &ds1511_nvmem_cfg);
return 0;
}
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:ds1511");
static struct platform_driver ds1511_rtc_driver = {
.probe = ds1511_rtc_probe,
.driver = {
.name = "ds1511",
},
};
module_platform_driver(ds1511_rtc_driver);
MODULE_AUTHOR("Andrew Sharp <[email protected]>");
MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
MODULE_LICENSE("GPL");
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