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linux/drivers/rtc/rtc-cadence.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 2019 Cadence
*
* Authors:
* Jan Kotas <jank@cadence.com>
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/io.h>
#include <linux/rtc.h>
#include <linux/clk.h>
#include <linux/bcd.h>
#include <linux/bitfield.h>
#include <linux/interrupt.h>
#include <linux/pm_wakeirq.h>
/* Registers */
#define CDNS_RTC_CTLR 0x00
#define CDNS_RTC_HMR 0x04
#define CDNS_RTC_TIMR 0x08
#define CDNS_RTC_CALR 0x0C
#define CDNS_RTC_TIMAR 0x10
#define CDNS_RTC_CALAR 0x14
#define CDNS_RTC_AENR 0x18
#define CDNS_RTC_EFLR 0x1C
#define CDNS_RTC_IENR 0x20
#define CDNS_RTC_IDISR 0x24
#define CDNS_RTC_IMSKR 0x28
#define CDNS_RTC_STSR 0x2C
#define CDNS_RTC_KRTCR 0x30
/* Control */
#define CDNS_RTC_CTLR_TIME BIT(0)
#define CDNS_RTC_CTLR_CAL BIT(1)
#define CDNS_RTC_CTLR_TIME_CAL (CDNS_RTC_CTLR_TIME | CDNS_RTC_CTLR_CAL)
/* Status */
#define CDNS_RTC_STSR_VT BIT(0)
#define CDNS_RTC_STSR_VC BIT(1)
#define CDNS_RTC_STSR_VTA BIT(2)
#define CDNS_RTC_STSR_VCA BIT(3)
#define CDNS_RTC_STSR_VT_VC (CDNS_RTC_STSR_VT | CDNS_RTC_STSR_VC)
#define CDNS_RTC_STSR_VTA_VCA (CDNS_RTC_STSR_VTA | CDNS_RTC_STSR_VCA)
/* Keep RTC */
#define CDNS_RTC_KRTCR_KRTC BIT(0)
/* Alarm, Event, Interrupt */
#define CDNS_RTC_AEI_HOS BIT(0)
#define CDNS_RTC_AEI_SEC BIT(1)
#define CDNS_RTC_AEI_MIN BIT(2)
#define CDNS_RTC_AEI_HOUR BIT(3)
#define CDNS_RTC_AEI_DATE BIT(4)
#define CDNS_RTC_AEI_MNTH BIT(5)
#define CDNS_RTC_AEI_ALRM BIT(6)
/* Time */
#define CDNS_RTC_TIME_H GENMASK(7, 0)
#define CDNS_RTC_TIME_S GENMASK(14, 8)
#define CDNS_RTC_TIME_M GENMASK(22, 16)
#define CDNS_RTC_TIME_HR GENMASK(29, 24)
#define CDNS_RTC_TIME_PM BIT(30)
#define CDNS_RTC_TIME_CH BIT(31)
/* Calendar */
#define CDNS_RTC_CAL_DAY GENMASK(2, 0)
#define CDNS_RTC_CAL_M GENMASK(7, 3)
#define CDNS_RTC_CAL_D GENMASK(13, 8)
#define CDNS_RTC_CAL_Y GENMASK(23, 16)
#define CDNS_RTC_CAL_C GENMASK(29, 24)
#define CDNS_RTC_CAL_CH BIT(31)
#define CDNS_RTC_MAX_REGS_TRIES 3
struct cdns_rtc {
struct rtc_device *rtc_dev;
struct clk *pclk;
struct clk *ref_clk;
void __iomem *regs;
int irq;
};
static void cdns_rtc_set_enabled(struct cdns_rtc *crtc, bool enabled)
{
u32 reg = enabled ? 0x0 : CDNS_RTC_CTLR_TIME_CAL;
writel(reg, crtc->regs + CDNS_RTC_CTLR);
}
static bool cdns_rtc_get_enabled(struct cdns_rtc *crtc)
{
return !(readl(crtc->regs + CDNS_RTC_CTLR) & CDNS_RTC_CTLR_TIME_CAL);
}
static irqreturn_t cdns_rtc_irq_handler(int irq, void *id)
{
struct device *dev = id;
struct cdns_rtc *crtc = dev_get_drvdata(dev);
/* Reading the register clears it */
if (!(readl(crtc->regs + CDNS_RTC_EFLR) & CDNS_RTC_AEI_ALRM))
return IRQ_NONE;
rtc_update_irq(crtc->rtc_dev, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static u32 cdns_rtc_time2reg(struct rtc_time *tm)
{
return FIELD_PREP(CDNS_RTC_TIME_S, bin2bcd(tm->tm_sec))
| FIELD_PREP(CDNS_RTC_TIME_M, bin2bcd(tm->tm_min))
| FIELD_PREP(CDNS_RTC_TIME_HR, bin2bcd(tm->tm_hour));
}
static void cdns_rtc_reg2time(u32 reg, struct rtc_time *tm)
{
tm->tm_sec = bcd2bin(FIELD_GET(CDNS_RTC_TIME_S, reg));
tm->tm_min = bcd2bin(FIELD_GET(CDNS_RTC_TIME_M, reg));
tm->tm_hour = bcd2bin(FIELD_GET(CDNS_RTC_TIME_HR, reg));
}
static int cdns_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct cdns_rtc *crtc = dev_get_drvdata(dev);
u32 reg;
/* If the RTC is disabled, assume the values are invalid */
if (!cdns_rtc_get_enabled(crtc))
return -EINVAL;
cdns_rtc_set_enabled(crtc, false);
reg = readl(crtc->regs + CDNS_RTC_TIMR);
cdns_rtc_reg2time(reg, tm);
reg = readl(crtc->regs + CDNS_RTC_CALR);
tm->tm_mday = bcd2bin(FIELD_GET(CDNS_RTC_CAL_D, reg));
tm->tm_mon = bcd2bin(FIELD_GET(CDNS_RTC_CAL_M, reg)) - 1;
tm->tm_year = bcd2bin(FIELD_GET(CDNS_RTC_CAL_Y, reg))
+ bcd2bin(FIELD_GET(CDNS_RTC_CAL_C, reg)) * 100 - 1900;
tm->tm_wday = bcd2bin(FIELD_GET(CDNS_RTC_CAL_DAY, reg)) - 1;
cdns_rtc_set_enabled(crtc, true);
return 0;
}
static int cdns_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct cdns_rtc *crtc = dev_get_drvdata(dev);
u32 timr, calr, stsr;
int ret = -EIO;
int year = tm->tm_year + 1900;
int tries;
cdns_rtc_set_enabled(crtc, false);
timr = cdns_rtc_time2reg(tm);
calr = FIELD_PREP(CDNS_RTC_CAL_D, bin2bcd(tm->tm_mday))
| FIELD_PREP(CDNS_RTC_CAL_M, bin2bcd(tm->tm_mon + 1))
| FIELD_PREP(CDNS_RTC_CAL_Y, bin2bcd(year % 100))
| FIELD_PREP(CDNS_RTC_CAL_C, bin2bcd(year / 100))
| FIELD_PREP(CDNS_RTC_CAL_DAY, tm->tm_wday + 1);
/* Update registers, check valid flags */
for (tries = 0; tries < CDNS_RTC_MAX_REGS_TRIES; tries++) {
writel(timr, crtc->regs + CDNS_RTC_TIMR);
writel(calr, crtc->regs + CDNS_RTC_CALR);
stsr = readl(crtc->regs + CDNS_RTC_STSR);
if ((stsr & CDNS_RTC_STSR_VT_VC) == CDNS_RTC_STSR_VT_VC) {
ret = 0;
break;
}
}
cdns_rtc_set_enabled(crtc, true);
return ret;
}
static int cdns_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct cdns_rtc *crtc = dev_get_drvdata(dev);
if (enabled) {
writel((CDNS_RTC_AEI_SEC | CDNS_RTC_AEI_MIN | CDNS_RTC_AEI_HOUR
| CDNS_RTC_AEI_DATE | CDNS_RTC_AEI_MNTH),
crtc->regs + CDNS_RTC_AENR);
writel(CDNS_RTC_AEI_ALRM, crtc->regs + CDNS_RTC_IENR);
} else {
writel(0, crtc->regs + CDNS_RTC_AENR);
writel(CDNS_RTC_AEI_ALRM, crtc->regs + CDNS_RTC_IDISR);
}
return 0;
}
static int cdns_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct cdns_rtc *crtc = dev_get_drvdata(dev);
u32 reg;
reg = readl(crtc->regs + CDNS_RTC_TIMAR);
cdns_rtc_reg2time(reg, &alarm->time);
reg = readl(crtc->regs + CDNS_RTC_CALAR);
alarm->time.tm_mday = bcd2bin(FIELD_GET(CDNS_RTC_CAL_D, reg));
alarm->time.tm_mon = bcd2bin(FIELD_GET(CDNS_RTC_CAL_M, reg)) - 1;
return 0;
}
static int cdns_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct cdns_rtc *crtc = dev_get_drvdata(dev);
int ret = -EIO;
int tries;
u32 timar, calar, stsr;
cdns_rtc_alarm_irq_enable(dev, 0);
timar = cdns_rtc_time2reg(&alarm->time);
calar = FIELD_PREP(CDNS_RTC_CAL_D, bin2bcd(alarm->time.tm_mday))
| FIELD_PREP(CDNS_RTC_CAL_M, bin2bcd(alarm->time.tm_mon + 1));
/* Update registers, check valid alarm flags */
for (tries = 0; tries < CDNS_RTC_MAX_REGS_TRIES; tries++) {
writel(timar, crtc->regs + CDNS_RTC_TIMAR);
writel(calar, crtc->regs + CDNS_RTC_CALAR);
stsr = readl(crtc->regs + CDNS_RTC_STSR);
if ((stsr & CDNS_RTC_STSR_VTA_VCA) == CDNS_RTC_STSR_VTA_VCA) {
ret = 0;
break;
}
}
if (!ret)
cdns_rtc_alarm_irq_enable(dev, alarm->enabled);
return ret;
}
static const struct rtc_class_ops cdns_rtc_ops = {
.read_time = cdns_rtc_read_time,
.set_time = cdns_rtc_set_time,
.read_alarm = cdns_rtc_read_alarm,
.set_alarm = cdns_rtc_set_alarm,
.alarm_irq_enable = cdns_rtc_alarm_irq_enable,
};
static int cdns_rtc_probe(struct platform_device *pdev)
{
struct cdns_rtc *crtc;
int ret;
unsigned long ref_clk_freq;
crtc = devm_kzalloc(&pdev->dev, sizeof(*crtc), GFP_KERNEL);
if (!crtc)
return -ENOMEM;
crtc->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(crtc->regs))
return PTR_ERR(crtc->regs);
crtc->irq = platform_get_irq(pdev, 0);
if (crtc->irq < 0)
return -EINVAL;
crtc->pclk = devm_clk_get(&pdev->dev, "pclk");
if (IS_ERR(crtc->pclk)) {
ret = PTR_ERR(crtc->pclk);
dev_err(&pdev->dev,
"Failed to retrieve the peripheral clock, %d\n", ret);
return ret;
}
crtc->ref_clk = devm_clk_get(&pdev->dev, "ref_clk");
if (IS_ERR(crtc->ref_clk)) {
ret = PTR_ERR(crtc->ref_clk);
dev_err(&pdev->dev,
"Failed to retrieve the reference clock, %d\n", ret);
return ret;
}
crtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(crtc->rtc_dev))
return PTR_ERR(crtc->rtc_dev);
platform_set_drvdata(pdev, crtc);
ret = clk_prepare_enable(crtc->pclk);
if (ret) {
dev_err(&pdev->dev,
"Failed to enable the peripheral clock, %d\n", ret);
return ret;
}
ret = clk_prepare_enable(crtc->ref_clk);
if (ret) {
dev_err(&pdev->dev,
"Failed to enable the reference clock, %d\n", ret);
goto err_disable_pclk;
}
ref_clk_freq = clk_get_rate(crtc->ref_clk);
if ((ref_clk_freq != 1) && (ref_clk_freq != 100)) {
dev_err(&pdev->dev,
"Invalid reference clock frequency %lu Hz.\n",
ref_clk_freq);
ret = -EINVAL;
goto err_disable_ref_clk;
}
ret = devm_request_irq(&pdev->dev, crtc->irq,
cdns_rtc_irq_handler, 0,
dev_name(&pdev->dev), &pdev->dev);
if (ret) {
dev_err(&pdev->dev,
"Failed to request interrupt for the device, %d\n",
ret);
goto err_disable_ref_clk;
}
/* The RTC supports 01.01.1900 - 31.12.2999 */
crtc->rtc_dev->range_min = mktime64(1900, 1, 1, 0, 0, 0);
crtc->rtc_dev->range_max = mktime64(2999, 12, 31, 23, 59, 59);
crtc->rtc_dev->ops = &cdns_rtc_ops;
device_init_wakeup(&pdev->dev, true);
/* Always use 24-hour mode and keep the RTC values */
writel(0, crtc->regs + CDNS_RTC_HMR);
writel(CDNS_RTC_KRTCR_KRTC, crtc->regs + CDNS_RTC_KRTCR);
ret = devm_rtc_register_device(crtc->rtc_dev);
if (ret)
goto err_disable_wakeup;
return 0;
err_disable_wakeup:
device_init_wakeup(&pdev->dev, false);
err_disable_ref_clk:
clk_disable_unprepare(crtc->ref_clk);
err_disable_pclk:
clk_disable_unprepare(crtc->pclk);
return ret;
}
static int cdns_rtc_remove(struct platform_device *pdev)
{
struct cdns_rtc *crtc = platform_get_drvdata(pdev);
cdns_rtc_alarm_irq_enable(&pdev->dev, 0);
device_init_wakeup(&pdev->dev, 0);
clk_disable_unprepare(crtc->pclk);
clk_disable_unprepare(crtc->ref_clk);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int cdns_rtc_suspend(struct device *dev)
{
struct cdns_rtc *crtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
enable_irq_wake(crtc->irq);
return 0;
}
static int cdns_rtc_resume(struct device *dev)
{
struct cdns_rtc *crtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
disable_irq_wake(crtc->irq);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(cdns_rtc_pm_ops, cdns_rtc_suspend, cdns_rtc_resume);
static const struct of_device_id cdns_rtc_of_match[] = {
{ .compatible = "cdns,rtc-r109v3" },
{ },
};
MODULE_DEVICE_TABLE(of, cdns_rtc_of_match);
static struct platform_driver cdns_rtc_driver = {
.driver = {
.name = "cdns-rtc",
.of_match_table = cdns_rtc_of_match,
.pm = &cdns_rtc_pm_ops,
},
.probe = cdns_rtc_probe,
.remove = cdns_rtc_remove,
};
module_platform_driver(cdns_rtc_driver);
MODULE_AUTHOR("Jan Kotas <jank@cadence.com>");
MODULE_DESCRIPTION("Cadence RTC driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:cdns-rtc");
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