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linux/drivers/rtc/rtc-cadence.c
Uwe Kleine-König 0b9efd82a6 rtc: cadence: Convert to platform remove callback returning void 
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230304133028.2135435-9-u.kleine-koenig@pengutronix.de
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2023-03-17 23:03:17 +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 void 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);
}
#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_new = 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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