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linux/drivers/rtc/rtc-mc13xxx.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
/*
* Real Time Clock driver for Freescale MC13XXX PMIC
*
* (C) 2009 Sascha Hauer, Pengutronix
* (C) 2009 Uwe Kleine-Koenig, Pengutronix
*/
#include <linux/mfd/mc13xxx.h>
#include <linux/platform_device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/slab.h>
#include <linux/rtc.h>
#define DRIVER_NAME "mc13xxx-rtc"
#define MC13XXX_RTCTOD 20
#define MC13XXX_RTCTODA 21
#define MC13XXX_RTCDAY 22
#define MC13XXX_RTCDAYA 23
#define SEC_PER_DAY (24 * 60 * 60)
struct mc13xxx_rtc {
struct rtc_device *rtc;
struct mc13xxx *mc13xxx;
int valid;
};
static int mc13xxx_rtc_irq_enable_unlocked(struct device *dev,
unsigned int enabled, int irq)
{
struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
int (*func)(struct mc13xxx *mc13xxx, int irq);
if (!priv->valid)
return -ENODATA;
func = enabled ? mc13xxx_irq_unmask : mc13xxx_irq_mask;
return func(priv->mc13xxx, irq);
}
static int mc13xxx_rtc_alarm_irq_enable(struct device *dev,
unsigned int enabled)
{
struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
int ret;
mc13xxx_lock(priv->mc13xxx);
ret = mc13xxx_rtc_irq_enable_unlocked(dev, enabled, MC13XXX_IRQ_TODA);
mc13xxx_unlock(priv->mc13xxx);
return ret;
}
static int mc13xxx_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
unsigned int seconds, days1, days2;
if (!priv->valid)
return -ENODATA;
do {
int ret;
ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days1);
if (ret)
return ret;
ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTOD, &seconds);
if (ret)
return ret;
ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days2);
if (ret)
return ret;
} while (days1 != days2);
rtc_time64_to_tm((time64_t)days1 * SEC_PER_DAY + seconds, tm);
return 0;
}
static int mc13xxx_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
unsigned int seconds, days;
unsigned int alarmseconds;
int ret;
days = div_s64_rem(rtc_tm_to_time64(tm), SEC_PER_DAY, &seconds);
mc13xxx_lock(priv->mc13xxx);
/*
* temporarily invalidate alarm to prevent triggering it when the day is
* already updated while the time isn't yet.
*/
ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTODA, &alarmseconds);
if (unlikely(ret))
goto out;
if (alarmseconds < SEC_PER_DAY) {
ret = mc13xxx_reg_write(priv->mc13xxx,
MC13XXX_RTCTODA, 0x1ffff);
if (unlikely(ret))
goto out;
}
/*
* write seconds=0 to prevent a day switch between writing days
* and seconds below
*/
ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTOD, 0);
if (unlikely(ret))
goto out;
ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAY, days);
if (unlikely(ret))
goto out;
ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTOD, seconds);
if (unlikely(ret))
goto out;
/* restore alarm */
if (alarmseconds < SEC_PER_DAY) {
ret = mc13xxx_reg_write(priv->mc13xxx,
MC13XXX_RTCTODA, alarmseconds);
if (unlikely(ret))
goto out;
}
if (!priv->valid) {
ret = mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_RTCRST);
if (unlikely(ret))
goto out;
ret = mc13xxx_irq_unmask(priv->mc13xxx, MC13XXX_IRQ_RTCRST);
}
out:
priv->valid = !ret;
mc13xxx_unlock(priv->mc13xxx);
return ret;
}
static int mc13xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
unsigned int seconds, days;
time64_t s1970;
int enabled, pending;
int ret;
mc13xxx_lock(priv->mc13xxx);
ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTODA, &seconds);
if (unlikely(ret))
goto out;
if (seconds >= SEC_PER_DAY) {
ret = -ENODATA;
goto out;
}
ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days);
if (unlikely(ret))
goto out;
ret = mc13xxx_irq_status(priv->mc13xxx, MC13XXX_IRQ_TODA,
&enabled, &pending);
out:
mc13xxx_unlock(priv->mc13xxx);
if (ret)
return ret;
alarm->enabled = enabled;
alarm->pending = pending;
s1970 = (time64_t)days * SEC_PER_DAY + seconds;
rtc_time64_to_tm(s1970, &alarm->time);
dev_dbg(dev, "%s: %lld\n", __func__, (long long)s1970);
return 0;
}
static int mc13xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
time64_t s1970;
u32 seconds, days;
int ret;
mc13xxx_lock(priv->mc13xxx);
/* disable alarm to prevent false triggering */
ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, 0x1ffff);
if (unlikely(ret))
goto out;
ret = mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TODA);
if (unlikely(ret))
goto out;
s1970 = rtc_tm_to_time64(&alarm->time);
dev_dbg(dev, "%s: %s %lld\n", __func__, alarm->enabled ? "on" : "off",
(long long)s1970);
ret = mc13xxx_rtc_irq_enable_unlocked(dev, alarm->enabled,
MC13XXX_IRQ_TODA);
if (unlikely(ret))
goto out;
days = div_s64_rem(s1970, SEC_PER_DAY, &seconds);
ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAYA, days);
if (unlikely(ret))
goto out;
ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, seconds);
out:
mc13xxx_unlock(priv->mc13xxx);
return ret;
}
static irqreturn_t mc13xxx_rtc_alarm_handler(int irq, void *dev)
{
struct mc13xxx_rtc *priv = dev;
struct mc13xxx *mc13xxx = priv->mc13xxx;
rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_AF);
mc13xxx_irq_ack(mc13xxx, irq);
return IRQ_HANDLED;
}
static const struct rtc_class_ops mc13xxx_rtc_ops = {
.read_time = mc13xxx_rtc_read_time,
.set_time = mc13xxx_rtc_set_time,
.read_alarm = mc13xxx_rtc_read_alarm,
.set_alarm = mc13xxx_rtc_set_alarm,
.alarm_irq_enable = mc13xxx_rtc_alarm_irq_enable,
};
static irqreturn_t mc13xxx_rtc_reset_handler(int irq, void *dev)
{
struct mc13xxx_rtc *priv = dev;
struct mc13xxx *mc13xxx = priv->mc13xxx;
priv->valid = 0;
mc13xxx_irq_mask(mc13xxx, irq);
return IRQ_HANDLED;
}
static int __init mc13xxx_rtc_probe(struct platform_device *pdev)
{
int ret;
struct mc13xxx_rtc *priv;
struct mc13xxx *mc13xxx;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
mc13xxx = dev_get_drvdata(pdev->dev.parent);
priv->mc13xxx = mc13xxx;
priv->valid = 1;
priv->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(priv->rtc))
return PTR_ERR(priv->rtc);
platform_set_drvdata(pdev, priv);
priv->rtc->ops = &mc13xxx_rtc_ops;
/* 15bit days + hours, minutes, seconds */
priv->rtc->range_max = (timeu64_t)(1 << 15) * SEC_PER_DAY - 1;
mc13xxx_lock(mc13xxx);
mc13xxx_irq_ack(mc13xxx, MC13XXX_IRQ_RTCRST);
ret = mc13xxx_irq_request(mc13xxx, MC13XXX_IRQ_RTCRST,
mc13xxx_rtc_reset_handler, DRIVER_NAME, priv);
if (ret)
goto err_irq_request;
ret = mc13xxx_irq_request_nounmask(mc13xxx, MC13XXX_IRQ_TODA,
mc13xxx_rtc_alarm_handler, DRIVER_NAME, priv);
if (ret)
goto err_irq_request;
mc13xxx_unlock(mc13xxx);
ret = devm_rtc_register_device(priv->rtc);
if (ret) {
mc13xxx_lock(mc13xxx);
goto err_irq_request;
}
return 0;
err_irq_request:
mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_TODA, priv);
mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_RTCRST, priv);
mc13xxx_unlock(mc13xxx);
return ret;
}
static int mc13xxx_rtc_remove(struct platform_device *pdev)
{
struct mc13xxx_rtc *priv = platform_get_drvdata(pdev);
mc13xxx_lock(priv->mc13xxx);
mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TODA, priv);
mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_RTCRST, priv);
mc13xxx_unlock(priv->mc13xxx);
return 0;
}
static const struct platform_device_id mc13xxx_rtc_idtable[] = {
{
.name = "mc13783-rtc",
}, {
.name = "mc13892-rtc",
}, {
.name = "mc34708-rtc",
},
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(platform, mc13xxx_rtc_idtable);
static struct platform_driver mc13xxx_rtc_driver = {
.id_table = mc13xxx_rtc_idtable,
.remove = mc13xxx_rtc_remove,
.driver = {
.name = DRIVER_NAME,
},
};
module_platform_driver_probe(mc13xxx_rtc_driver, &mc13xxx_rtc_probe);
MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
MODULE_DESCRIPTION("RTC driver for Freescale MC13XXX PMIC");
MODULE_LICENSE("GPL v2");
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