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linux/drivers/rtc/rtc-vt8500.c
Bartosz Golaszewski fdcfd85433 rtc: rework rtc_register_device() resource management 
rtc_register_device() is a managed interface but it doesn't use devres
by itself - instead it marks an rtc_device as "registered" and the devres
callback for devm_rtc_allocate_device() takes care of resource release.

This doesn't correspond with the design behind devres where managed
structures should not be aware of being managed. The correct solution
here is to register a separate devres callback for unregistering the
device.

While at it: rename rtc_register_device() to devm_rtc_register_device()
and add it to the list of managed interfaces in devres.rst. This way we
can avoid any potential confusion of driver developers who may expect
there to exist a corresponding unregister function.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201109163409.24301-8-brgl@bgdev.pl
2020-11-19 12:50:12 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* drivers/rtc/rtc-vt8500.c
*
* Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
*
* Based on rtc-pxa.c
*/
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/bcd.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/of.h>
/*
* Register definitions
*/
#define VT8500_RTC_TS 0x00 /* Time set */
#define VT8500_RTC_DS 0x04 /* Date set */
#define VT8500_RTC_AS 0x08 /* Alarm set */
#define VT8500_RTC_CR 0x0c /* Control */
#define VT8500_RTC_TR 0x10 /* Time read */
#define VT8500_RTC_DR 0x14 /* Date read */
#define VT8500_RTC_WS 0x18 /* Write status */
#define VT8500_RTC_CL 0x20 /* Calibration */
#define VT8500_RTC_IS 0x24 /* Interrupt status */
#define VT8500_RTC_ST 0x28 /* Status */
#define INVALID_TIME_BIT (1 << 31)
#define DATE_CENTURY_S 19
#define DATE_YEAR_S 11
#define DATE_YEAR_MASK (0xff << DATE_YEAR_S)
#define DATE_MONTH_S 6
#define DATE_MONTH_MASK (0x1f << DATE_MONTH_S)
#define DATE_DAY_MASK 0x3f
#define TIME_DOW_S 20
#define TIME_DOW_MASK (0x07 << TIME_DOW_S)
#define TIME_HOUR_S 14
#define TIME_HOUR_MASK (0x3f << TIME_HOUR_S)
#define TIME_MIN_S 7
#define TIME_MIN_MASK (0x7f << TIME_MIN_S)
#define TIME_SEC_MASK 0x7f
#define ALARM_DAY_S 20
#define ALARM_DAY_MASK (0x3f << ALARM_DAY_S)
#define ALARM_DAY_BIT (1 << 29)
#define ALARM_HOUR_BIT (1 << 28)
#define ALARM_MIN_BIT (1 << 27)
#define ALARM_SEC_BIT (1 << 26)
#define ALARM_ENABLE_MASK (ALARM_DAY_BIT \
| ALARM_HOUR_BIT \
| ALARM_MIN_BIT \
| ALARM_SEC_BIT)
#define VT8500_RTC_CR_ENABLE (1 << 0) /* Enable RTC */
#define VT8500_RTC_CR_12H (1 << 1) /* 12h time format */
#define VT8500_RTC_CR_SM_ENABLE (1 << 2) /* Enable periodic irqs */
#define VT8500_RTC_CR_SM_SEC (1 << 3) /* 0: 1Hz/60, 1: 1Hz */
#define VT8500_RTC_CR_CALIB (1 << 4) /* Enable calibration */
#define VT8500_RTC_IS_ALARM (1 << 0) /* Alarm interrupt status */
struct vt8500_rtc {
void __iomem *regbase;
int irq_alarm;
struct rtc_device *rtc;
spinlock_t lock; /* Protects this structure */
};
static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
{
struct vt8500_rtc *vt8500_rtc = dev_id;
u32 isr;
unsigned long events = 0;
spin_lock(&vt8500_rtc->lock);
/* clear interrupt sources */
isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);
spin_unlock(&vt8500_rtc->lock);
if (isr & VT8500_RTC_IS_ALARM)
events |= RTC_AF | RTC_IRQF;
rtc_update_irq(vt8500_rtc->rtc, 1, events);
return IRQ_HANDLED;
}
static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
u32 date, time;
date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);
tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S) - 1;
tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)
+ ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;
return 0;
}
static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
writel((bin2bcd(tm->tm_year % 100) << DATE_YEAR_S)
| (bin2bcd(tm->tm_mon + 1) << DATE_MONTH_S)
| (bin2bcd(tm->tm_mday))
| ((tm->tm_year >= 200) << DATE_CENTURY_S),
vt8500_rtc->regbase + VT8500_RTC_DS);
writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
| (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
| (bin2bcd(tm->tm_min) << TIME_MIN_S)
| (bin2bcd(tm->tm_sec)),
vt8500_rtc->regbase + VT8500_RTC_TS);
return 0;
}
static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
u32 isr, alarm;
alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
alrm->pending = (isr & VT8500_RTC_IS_ALARM) ? 1 : 0;
return rtc_valid_tm(&alrm->time);
}
static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
| (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
| (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
| (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
| (bin2bcd(alrm->time.tm_sec)),
vt8500_rtc->regbase + VT8500_RTC_AS);
return 0;
}
static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
if (enabled)
tmp |= ALARM_ENABLE_MASK;
else
tmp &= ~ALARM_ENABLE_MASK;
writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
return 0;
}
static const struct rtc_class_ops vt8500_rtc_ops = {
.read_time = vt8500_rtc_read_time,
.set_time = vt8500_rtc_set_time,
.read_alarm = vt8500_rtc_read_alarm,
.set_alarm = vt8500_rtc_set_alarm,
.alarm_irq_enable = vt8500_alarm_irq_enable,
};
static int vt8500_rtc_probe(struct platform_device *pdev)
{
struct vt8500_rtc *vt8500_rtc;
int ret;
vt8500_rtc = devm_kzalloc(&pdev->dev,
sizeof(struct vt8500_rtc), GFP_KERNEL);
if (!vt8500_rtc)
return -ENOMEM;
spin_lock_init(&vt8500_rtc->lock);
platform_set_drvdata(pdev, vt8500_rtc);
vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
if (vt8500_rtc->irq_alarm < 0)
return vt8500_rtc->irq_alarm;
vt8500_rtc->regbase = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(vt8500_rtc->regbase))
return PTR_ERR(vt8500_rtc->regbase);
/* Enable RTC and set it to 24-hour mode */
writel(VT8500_RTC_CR_ENABLE,
vt8500_rtc->regbase + VT8500_RTC_CR);
vt8500_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(vt8500_rtc->rtc))
return PTR_ERR(vt8500_rtc->rtc);
vt8500_rtc->rtc->ops = &vt8500_rtc_ops;
vt8500_rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
vt8500_rtc->rtc->range_max = RTC_TIMESTAMP_END_2199;
ret = devm_request_irq(&pdev->dev, vt8500_rtc->irq_alarm,
vt8500_rtc_irq, 0, "rtc alarm", vt8500_rtc);
if (ret < 0) {
dev_err(&pdev->dev, "can't get irq %i, err %d\n",
vt8500_rtc->irq_alarm, ret);
return ret;
}
return devm_rtc_register_device(vt8500_rtc->rtc);
}
static int vt8500_rtc_remove(struct platform_device *pdev)
{
struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
/* Disable alarm matching */
writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
return 0;
}
static const struct of_device_id wmt_dt_ids[] = {
{ .compatible = "via,vt8500-rtc", },
{}
};
MODULE_DEVICE_TABLE(of, wmt_dt_ids);
static struct platform_driver vt8500_rtc_driver = {
.probe = vt8500_rtc_probe,
.remove = vt8500_rtc_remove,
.driver = {
.name = "vt8500-rtc",
.of_match_table = wmt_dt_ids,
},
};
module_platform_driver(vt8500_rtc_driver);
MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:vt8500-rtc");
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