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kernel/drivers/rtc/rtc-mt2712.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
/*
* Copyright (c) 2019 MediaTek Inc.
* Author: Ran Bi <ran.bi@mediatek.com>
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#define MT2712_BBPU 0x0000
#define MT2712_BBPU_CLRPKY BIT(4)
#define MT2712_BBPU_RELOAD BIT(5)
#define MT2712_BBPU_CBUSY BIT(6)
#define MT2712_BBPU_KEY (0x43 << 8)
#define MT2712_IRQ_STA 0x0004
#define MT2712_IRQ_STA_AL BIT(0)
#define MT2712_IRQ_STA_TC BIT(1)
#define MT2712_IRQ_EN 0x0008
#define MT2712_IRQ_EN_AL BIT(0)
#define MT2712_IRQ_EN_TC BIT(1)
#define MT2712_IRQ_EN_ONESHOT BIT(2)
#define MT2712_CII_EN 0x000c
#define MT2712_AL_MASK 0x0010
#define MT2712_AL_MASK_DOW BIT(4)
#define MT2712_TC_SEC 0x0014
#define MT2712_TC_MIN 0x0018
#define MT2712_TC_HOU 0x001c
#define MT2712_TC_DOM 0x0020
#define MT2712_TC_DOW 0x0024
#define MT2712_TC_MTH 0x0028
#define MT2712_TC_YEA 0x002c
#define MT2712_AL_SEC 0x0030
#define MT2712_AL_MIN 0x0034
#define MT2712_AL_HOU 0x0038
#define MT2712_AL_DOM 0x003c
#define MT2712_AL_DOW 0x0040
#define MT2712_AL_MTH 0x0044
#define MT2712_AL_YEA 0x0048
#define MT2712_SEC_MASK 0x003f
#define MT2712_MIN_MASK 0x003f
#define MT2712_HOU_MASK 0x001f
#define MT2712_DOM_MASK 0x001f
#define MT2712_DOW_MASK 0x0007
#define MT2712_MTH_MASK 0x000f
#define MT2712_YEA_MASK 0x007f
#define MT2712_POWERKEY1 0x004c
#define MT2712_POWERKEY2 0x0050
#define MT2712_POWERKEY1_KEY 0xa357
#define MT2712_POWERKEY2_KEY 0x67d2
#define MT2712_CON0 0x005c
#define MT2712_CON1 0x0060
#define MT2712_PROT 0x0070
#define MT2712_PROT_UNLOCK1 0x9136
#define MT2712_PROT_UNLOCK2 0x586a
#define MT2712_WRTGR 0x0078
#define MT2712_RTC_TIMESTAMP_END_2127 4985971199LL
struct mt2712_rtc {
struct rtc_device *rtc;
void __iomem *base;
int irq;
u8 irq_wake_enabled;
u8 powerlost;
};
static inline u32 mt2712_readl(struct mt2712_rtc *mt2712_rtc, u32 reg)
{
return readl(mt2712_rtc->base + reg);
}
static inline void mt2712_writel(struct mt2712_rtc *mt2712_rtc,
u32 reg, u32 val)
{
writel(val, mt2712_rtc->base + reg);
}
static void mt2712_rtc_write_trigger(struct mt2712_rtc *mt2712_rtc)
{
unsigned long timeout = jiffies + HZ / 10;
mt2712_writel(mt2712_rtc, MT2712_WRTGR, 1);
while (1) {
if (!(mt2712_readl(mt2712_rtc, MT2712_BBPU)
& MT2712_BBPU_CBUSY))
break;
if (time_after(jiffies, timeout)) {
dev_err(&mt2712_rtc->rtc->dev,
"%s time out!\n", __func__);
break;
}
cpu_relax();
}
}
static void mt2712_rtc_writeif_unlock(struct mt2712_rtc *mt2712_rtc)
{
mt2712_writel(mt2712_rtc, MT2712_PROT, MT2712_PROT_UNLOCK1);
mt2712_rtc_write_trigger(mt2712_rtc);
mt2712_writel(mt2712_rtc, MT2712_PROT, MT2712_PROT_UNLOCK2);
mt2712_rtc_write_trigger(mt2712_rtc);
}
static irqreturn_t rtc_irq_handler_thread(int irq, void *data)
{
struct mt2712_rtc *mt2712_rtc = data;
u16 irqsta;
/* Clear interrupt */
irqsta = mt2712_readl(mt2712_rtc, MT2712_IRQ_STA);
if (irqsta & MT2712_IRQ_STA_AL) {
rtc_update_irq(mt2712_rtc->rtc, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
static void __mt2712_rtc_read_time(struct mt2712_rtc *mt2712_rtc,
struct rtc_time *tm, int *sec)
{
tm->tm_sec = mt2712_readl(mt2712_rtc, MT2712_TC_SEC)
& MT2712_SEC_MASK;
tm->tm_min = mt2712_readl(mt2712_rtc, MT2712_TC_MIN)
& MT2712_MIN_MASK;
tm->tm_hour = mt2712_readl(mt2712_rtc, MT2712_TC_HOU)
& MT2712_HOU_MASK;
tm->tm_mday = mt2712_readl(mt2712_rtc, MT2712_TC_DOM)
& MT2712_DOM_MASK;
tm->tm_mon = (mt2712_readl(mt2712_rtc, MT2712_TC_MTH) - 1)
& MT2712_MTH_MASK;
tm->tm_year = (mt2712_readl(mt2712_rtc, MT2712_TC_YEA) + 100)
& MT2712_YEA_MASK;
*sec = mt2712_readl(mt2712_rtc, MT2712_TC_SEC) & MT2712_SEC_MASK;
}
static int mt2712_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct mt2712_rtc *mt2712_rtc = dev_get_drvdata(dev);
int sec;
if (mt2712_rtc->powerlost)
return -EINVAL;
do {
__mt2712_rtc_read_time(mt2712_rtc, tm, &sec);
} while (sec < tm->tm_sec); /* SEC has carried */
return 0;
}
static int mt2712_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct mt2712_rtc *mt2712_rtc = dev_get_drvdata(dev);
mt2712_writel(mt2712_rtc, MT2712_TC_SEC, tm->tm_sec & MT2712_SEC_MASK);
mt2712_writel(mt2712_rtc, MT2712_TC_MIN, tm->tm_min & MT2712_MIN_MASK);
mt2712_writel(mt2712_rtc, MT2712_TC_HOU, tm->tm_hour & MT2712_HOU_MASK);
mt2712_writel(mt2712_rtc, MT2712_TC_DOM, tm->tm_mday & MT2712_DOM_MASK);
mt2712_writel(mt2712_rtc, MT2712_TC_MTH,
(tm->tm_mon + 1) & MT2712_MTH_MASK);
mt2712_writel(mt2712_rtc, MT2712_TC_YEA,
(tm->tm_year - 100) & MT2712_YEA_MASK);
mt2712_rtc_write_trigger(mt2712_rtc);
if (mt2712_rtc->powerlost)
mt2712_rtc->powerlost = false;
return 0;
}
static int mt2712_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
struct mt2712_rtc *mt2712_rtc = dev_get_drvdata(dev);
struct rtc_time *tm = &alm->time;
u16 irqen;
irqen = mt2712_readl(mt2712_rtc, MT2712_IRQ_EN);
alm->enabled = !!(irqen & MT2712_IRQ_EN_AL);
tm->tm_sec = mt2712_readl(mt2712_rtc, MT2712_AL_SEC) & MT2712_SEC_MASK;
tm->tm_min = mt2712_readl(mt2712_rtc, MT2712_AL_MIN) & MT2712_MIN_MASK;
tm->tm_hour = mt2712_readl(mt2712_rtc, MT2712_AL_HOU) & MT2712_HOU_MASK;
tm->tm_mday = mt2712_readl(mt2712_rtc, MT2712_AL_DOM) & MT2712_DOM_MASK;
tm->tm_mon = (mt2712_readl(mt2712_rtc, MT2712_AL_MTH) - 1)
& MT2712_MTH_MASK;
tm->tm_year = (mt2712_readl(mt2712_rtc, MT2712_AL_YEA) + 100)
& MT2712_YEA_MASK;
return 0;
}
static int mt2712_rtc_alarm_irq_enable(struct device *dev,
unsigned int enabled)
{
struct mt2712_rtc *mt2712_rtc = dev_get_drvdata(dev);
u16 irqen;
irqen = mt2712_readl(mt2712_rtc, MT2712_IRQ_EN);
if (enabled)
irqen |= MT2712_IRQ_EN_AL;
else
irqen &= ~MT2712_IRQ_EN_AL;
mt2712_writel(mt2712_rtc, MT2712_IRQ_EN, irqen);
mt2712_rtc_write_trigger(mt2712_rtc);
return 0;
}
static int mt2712_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
struct mt2712_rtc *mt2712_rtc = dev_get_drvdata(dev);
struct rtc_time *tm = &alm->time;
dev_dbg(&mt2712_rtc->rtc->dev, "set al time: %ptR, alm en: %d\n",
tm, alm->enabled);
mt2712_writel(mt2712_rtc, MT2712_AL_SEC,
(mt2712_readl(mt2712_rtc, MT2712_AL_SEC)
& ~(MT2712_SEC_MASK)) | (tm->tm_sec & MT2712_SEC_MASK));
mt2712_writel(mt2712_rtc, MT2712_AL_MIN,
(mt2712_readl(mt2712_rtc, MT2712_AL_MIN)
& ~(MT2712_MIN_MASK)) | (tm->tm_min & MT2712_MIN_MASK));
mt2712_writel(mt2712_rtc, MT2712_AL_HOU,
(mt2712_readl(mt2712_rtc, MT2712_AL_HOU)
& ~(MT2712_HOU_MASK)) | (tm->tm_hour & MT2712_HOU_MASK));
mt2712_writel(mt2712_rtc, MT2712_AL_DOM,
(mt2712_readl(mt2712_rtc, MT2712_AL_DOM)
& ~(MT2712_DOM_MASK)) | (tm->tm_mday & MT2712_DOM_MASK));
mt2712_writel(mt2712_rtc, MT2712_AL_MTH,
(mt2712_readl(mt2712_rtc, MT2712_AL_MTH)
& ~(MT2712_MTH_MASK))
| ((tm->tm_mon + 1) & MT2712_MTH_MASK));
mt2712_writel(mt2712_rtc, MT2712_AL_YEA,
(mt2712_readl(mt2712_rtc, MT2712_AL_YEA)
& ~(MT2712_YEA_MASK))
| ((tm->tm_year - 100) & MT2712_YEA_MASK));
/* mask day of week */
mt2712_writel(mt2712_rtc, MT2712_AL_MASK, MT2712_AL_MASK_DOW);
mt2712_rtc_write_trigger(mt2712_rtc);
mt2712_rtc_alarm_irq_enable(dev, alm->enabled);
return 0;
}
/* Init RTC register */
static void mt2712_rtc_hw_init(struct mt2712_rtc *mt2712_rtc)
{
u32 p1, p2;
mt2712_writel(mt2712_rtc, MT2712_BBPU,
MT2712_BBPU_KEY | MT2712_BBPU_RELOAD);
mt2712_writel(mt2712_rtc, MT2712_CII_EN, 0);
mt2712_writel(mt2712_rtc, MT2712_AL_MASK, 0);
/* necessary before set MT2712_POWERKEY */
mt2712_writel(mt2712_rtc, MT2712_CON0, 0x4848);
mt2712_writel(mt2712_rtc, MT2712_CON1, 0x0048);
mt2712_rtc_write_trigger(mt2712_rtc);
p1 = mt2712_readl(mt2712_rtc, MT2712_POWERKEY1);
p2 = mt2712_readl(mt2712_rtc, MT2712_POWERKEY2);
if (p1 != MT2712_POWERKEY1_KEY || p2 != MT2712_POWERKEY2_KEY) {
mt2712_rtc->powerlost = true;
dev_dbg(&mt2712_rtc->rtc->dev,
"powerkey not set (lost power)\n");
} else {
mt2712_rtc->powerlost = false;
}
/* RTC need POWERKEY1/2 match, then goto normal work mode */
mt2712_writel(mt2712_rtc, MT2712_POWERKEY1, MT2712_POWERKEY1_KEY);
mt2712_writel(mt2712_rtc, MT2712_POWERKEY2, MT2712_POWERKEY2_KEY);
mt2712_rtc_write_trigger(mt2712_rtc);
mt2712_rtc_writeif_unlock(mt2712_rtc);
}
static const struct rtc_class_ops mt2712_rtc_ops = {
.read_time = mt2712_rtc_read_time,
.set_time = mt2712_rtc_set_time,
.read_alarm = mt2712_rtc_read_alarm,
.set_alarm = mt2712_rtc_set_alarm,
.alarm_irq_enable = mt2712_rtc_alarm_irq_enable,
};
static int mt2712_rtc_probe(struct platform_device *pdev)
{
struct mt2712_rtc *mt2712_rtc;
int ret;
mt2712_rtc = devm_kzalloc(&pdev->dev,
sizeof(struct mt2712_rtc), GFP_KERNEL);
if (!mt2712_rtc)
return -ENOMEM;
mt2712_rtc->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(mt2712_rtc->base))
return PTR_ERR(mt2712_rtc->base);
/* rtc hw init */
mt2712_rtc_hw_init(mt2712_rtc);
mt2712_rtc->irq = platform_get_irq(pdev, 0);
if (mt2712_rtc->irq < 0)
return mt2712_rtc->irq;
platform_set_drvdata(pdev, mt2712_rtc);
mt2712_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(mt2712_rtc->rtc))
return PTR_ERR(mt2712_rtc->rtc);
ret = devm_request_threaded_irq(&pdev->dev, mt2712_rtc->irq, NULL,
rtc_irq_handler_thread,
IRQF_ONESHOT | IRQF_TRIGGER_LOW,
dev_name(&mt2712_rtc->rtc->dev),
mt2712_rtc);
if (ret) {
dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
mt2712_rtc->irq, ret);
return ret;
}
device_init_wakeup(&pdev->dev, true);
mt2712_rtc->rtc->ops = &mt2712_rtc_ops;
mt2712_rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
mt2712_rtc->rtc->range_max = MT2712_RTC_TIMESTAMP_END_2127;
return devm_rtc_register_device(mt2712_rtc->rtc);
}
#ifdef CONFIG_PM_SLEEP
static int mt2712_rtc_suspend(struct device *dev)
{
int wake_status = 0;
struct mt2712_rtc *mt2712_rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev)) {
wake_status = enable_irq_wake(mt2712_rtc->irq);
if (!wake_status)
mt2712_rtc->irq_wake_enabled = true;
}
return 0;
}
static int mt2712_rtc_resume(struct device *dev)
{
int wake_status = 0;
struct mt2712_rtc *mt2712_rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev) && mt2712_rtc->irq_wake_enabled) {
wake_status = disable_irq_wake(mt2712_rtc->irq);
if (!wake_status)
mt2712_rtc->irq_wake_enabled = false;
}
return 0;
}
static SIMPLE_DEV_PM_OPS(mt2712_pm_ops, mt2712_rtc_suspend,
mt2712_rtc_resume);
#endif
static const struct of_device_id mt2712_rtc_of_match[] = {
{ .compatible = "mediatek,mt2712-rtc", },
{ },
};
MODULE_DEVICE_TABLE(of, mt2712_rtc_of_match);
static struct platform_driver mt2712_rtc_driver = {
.driver = {
.name = "mt2712-rtc",
.of_match_table = mt2712_rtc_of_match,
#ifdef CONFIG_PM_SLEEP
.pm = &mt2712_pm_ops,
#endif
},
.probe = mt2712_rtc_probe,
};
module_platform_driver(mt2712_rtc_driver);
MODULE_DESCRIPTION("MediaTek MT2712 SoC based RTC Driver");
MODULE_AUTHOR("Ran Bi <ran.bi@mediatek.com>");
MODULE_LICENSE("GPL");
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