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linux/drivers/rtc/rtc-lpc32xx.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) 2010 NXP Semiconductors
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/of.h>
/*
* Clock and Power control register offsets
*/
#define LPC32XX_RTC_UCOUNT 0x00
#define LPC32XX_RTC_DCOUNT 0x04
#define LPC32XX_RTC_MATCH0 0x08
#define LPC32XX_RTC_MATCH1 0x0C
#define LPC32XX_RTC_CTRL 0x10
#define LPC32XX_RTC_INTSTAT 0x14
#define LPC32XX_RTC_KEY 0x18
#define LPC32XX_RTC_SRAM 0x80
#define LPC32XX_RTC_CTRL_MATCH0 (1 << 0)
#define LPC32XX_RTC_CTRL_MATCH1 (1 << 1)
#define LPC32XX_RTC_CTRL_ONSW_MATCH0 (1 << 2)
#define LPC32XX_RTC_CTRL_ONSW_MATCH1 (1 << 3)
#define LPC32XX_RTC_CTRL_SW_RESET (1 << 4)
#define LPC32XX_RTC_CTRL_CNTR_DIS (1 << 6)
#define LPC32XX_RTC_CTRL_ONSW_FORCE_HI (1 << 7)
#define LPC32XX_RTC_INTSTAT_MATCH0 (1 << 0)
#define LPC32XX_RTC_INTSTAT_MATCH1 (1 << 1)
#define LPC32XX_RTC_INTSTAT_ONSW (1 << 2)
#define LPC32XX_RTC_KEY_ONSW_LOADVAL 0xB5C13F27
#define rtc_readl(dev, reg) \
__raw_readl((dev)->rtc_base + (reg))
#define rtc_writel(dev, reg, val) \
__raw_writel((val), (dev)->rtc_base + (reg))
struct lpc32xx_rtc {
void __iomem *rtc_base;
int irq;
unsigned char alarm_enabled;
struct rtc_device *rtc;
spinlock_t lock;
};
static int lpc32xx_rtc_read_time(struct device *dev, struct rtc_time *time)
{
unsigned long elapsed_sec;
struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
elapsed_sec = rtc_readl(rtc, LPC32XX_RTC_UCOUNT);
rtc_time64_to_tm(elapsed_sec, time);
return 0;
}
static int lpc32xx_rtc_set_time(struct device *dev, struct rtc_time *time)
{
struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
u32 secs = rtc_tm_to_time64(time);
u32 tmp;
spin_lock_irq(&rtc->lock);
/* RTC must be disabled during count update */
tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp | LPC32XX_RTC_CTRL_CNTR_DIS);
rtc_writel(rtc, LPC32XX_RTC_UCOUNT, secs);
rtc_writel(rtc, LPC32XX_RTC_DCOUNT, 0xFFFFFFFF - secs);
rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp &= ~LPC32XX_RTC_CTRL_CNTR_DIS);
spin_unlock_irq(&rtc->lock);
return 0;
}
static int lpc32xx_rtc_read_alarm(struct device *dev,
struct rtc_wkalrm *wkalrm)
{
struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
rtc_time64_to_tm(rtc_readl(rtc, LPC32XX_RTC_MATCH0), &wkalrm->time);
wkalrm->enabled = rtc->alarm_enabled;
wkalrm->pending = !!(rtc_readl(rtc, LPC32XX_RTC_INTSTAT) &
LPC32XX_RTC_INTSTAT_MATCH0);
return rtc_valid_tm(&wkalrm->time);
}
static int lpc32xx_rtc_set_alarm(struct device *dev,
struct rtc_wkalrm *wkalrm)
{
struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
unsigned long alarmsecs;
u32 tmp;
alarmsecs = rtc_tm_to_time64(&wkalrm->time);
spin_lock_irq(&rtc->lock);
/* Disable alarm during update */
tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp & ~LPC32XX_RTC_CTRL_MATCH0);
rtc_writel(rtc, LPC32XX_RTC_MATCH0, alarmsecs);
rtc->alarm_enabled = wkalrm->enabled;
if (wkalrm->enabled) {
rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
LPC32XX_RTC_INTSTAT_MATCH0);
rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp |
LPC32XX_RTC_CTRL_MATCH0);
}
spin_unlock_irq(&rtc->lock);
return 0;
}
static int lpc32xx_rtc_alarm_irq_enable(struct device *dev,
unsigned int enabled)
{
struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
u32 tmp;
spin_lock_irq(&rtc->lock);
tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
if (enabled) {
rtc->alarm_enabled = 1;
tmp |= LPC32XX_RTC_CTRL_MATCH0;
} else {
rtc->alarm_enabled = 0;
tmp &= ~LPC32XX_RTC_CTRL_MATCH0;
}
rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
spin_unlock_irq(&rtc->lock);
return 0;
}
static irqreturn_t lpc32xx_rtc_alarm_interrupt(int irq, void *dev)
{
struct lpc32xx_rtc *rtc = dev;
spin_lock(&rtc->lock);
/* Disable alarm interrupt */
rtc_writel(rtc, LPC32XX_RTC_CTRL,
rtc_readl(rtc, LPC32XX_RTC_CTRL) &
~LPC32XX_RTC_CTRL_MATCH0);
rtc->alarm_enabled = 0;
/*
* Write a large value to the match value so the RTC won't
* keep firing the match status
*/
rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
rtc_writel(rtc, LPC32XX_RTC_INTSTAT, LPC32XX_RTC_INTSTAT_MATCH0);
spin_unlock(&rtc->lock);
rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static const struct rtc_class_ops lpc32xx_rtc_ops = {
.read_time = lpc32xx_rtc_read_time,
.set_time = lpc32xx_rtc_set_time,
.read_alarm = lpc32xx_rtc_read_alarm,
.set_alarm = lpc32xx_rtc_set_alarm,
.alarm_irq_enable = lpc32xx_rtc_alarm_irq_enable,
};
static int lpc32xx_rtc_probe(struct platform_device *pdev)
{
struct lpc32xx_rtc *rtc;
int err;
u32 tmp;
rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
if (unlikely(!rtc))
return -ENOMEM;
rtc->rtc_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(rtc->rtc_base))
return PTR_ERR(rtc->rtc_base);
spin_lock_init(&rtc->lock);
/*
* The RTC is on a separate power domain and can keep it's state
* across a chip power cycle. If the RTC has never been previously
* setup, then set it up now for the first time.
*/
tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
if (rtc_readl(rtc, LPC32XX_RTC_KEY) != LPC32XX_RTC_KEY_ONSW_LOADVAL) {
tmp &= ~(LPC32XX_RTC_CTRL_SW_RESET |
LPC32XX_RTC_CTRL_CNTR_DIS |
LPC32XX_RTC_CTRL_MATCH0 |
LPC32XX_RTC_CTRL_MATCH1 |
LPC32XX_RTC_CTRL_ONSW_MATCH0 |
LPC32XX_RTC_CTRL_ONSW_MATCH1 |
LPC32XX_RTC_CTRL_ONSW_FORCE_HI);
rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
/* Clear latched interrupt states */
rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
LPC32XX_RTC_INTSTAT_MATCH0 |
LPC32XX_RTC_INTSTAT_MATCH1 |
LPC32XX_RTC_INTSTAT_ONSW);
/* Write key value to RTC so it won't reload on reset */
rtc_writel(rtc, LPC32XX_RTC_KEY,
LPC32XX_RTC_KEY_ONSW_LOADVAL);
} else {
rtc_writel(rtc, LPC32XX_RTC_CTRL,
tmp & ~LPC32XX_RTC_CTRL_MATCH0);
}
platform_set_drvdata(pdev, rtc);
rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(rtc->rtc))
return PTR_ERR(rtc->rtc);
rtc->rtc->ops = &lpc32xx_rtc_ops;
rtc->rtc->range_max = U32_MAX;
err = devm_rtc_register_device(rtc->rtc);
if (err)
return err;
/*
* IRQ is enabled after device registration in case alarm IRQ
* is pending upon suspend exit.
*/
rtc->irq = platform_get_irq(pdev, 0);
if (rtc->irq < 0) {
dev_warn(&pdev->dev, "Can't get interrupt resource\n");
} else {
if (devm_request_irq(&pdev->dev, rtc->irq,
lpc32xx_rtc_alarm_interrupt,
0, pdev->name, rtc) < 0) {
dev_warn(&pdev->dev, "Can't request interrupt.\n");
rtc->irq = -1;
} else {
device_init_wakeup(&pdev->dev, 1);
}
}
return 0;
}
#ifdef CONFIG_PM
static int lpc32xx_rtc_suspend(struct device *dev)
{
struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
if (rtc->irq >= 0) {
if (device_may_wakeup(dev))
enable_irq_wake(rtc->irq);
else
disable_irq_wake(rtc->irq);
}
return 0;
}
static int lpc32xx_rtc_resume(struct device *dev)
{
struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
if (rtc->irq >= 0 && device_may_wakeup(dev))
disable_irq_wake(rtc->irq);
return 0;
}
/* Unconditionally disable the alarm */
static int lpc32xx_rtc_freeze(struct device *dev)
{
struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
spin_lock_irq(&rtc->lock);
rtc_writel(rtc, LPC32XX_RTC_CTRL,
rtc_readl(rtc, LPC32XX_RTC_CTRL) &
~LPC32XX_RTC_CTRL_MATCH0);
spin_unlock_irq(&rtc->lock);
return 0;
}
static int lpc32xx_rtc_thaw(struct device *dev)
{
struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
if (rtc->alarm_enabled) {
spin_lock_irq(&rtc->lock);
rtc_writel(rtc, LPC32XX_RTC_CTRL,
rtc_readl(rtc, LPC32XX_RTC_CTRL) |
LPC32XX_RTC_CTRL_MATCH0);
spin_unlock_irq(&rtc->lock);
}
return 0;
}
static const struct dev_pm_ops lpc32xx_rtc_pm_ops = {
.suspend = lpc32xx_rtc_suspend,
.resume = lpc32xx_rtc_resume,
.freeze = lpc32xx_rtc_freeze,
.thaw = lpc32xx_rtc_thaw,
.restore = lpc32xx_rtc_resume
};
#define LPC32XX_RTC_PM_OPS (&lpc32xx_rtc_pm_ops)
#else
#define LPC32XX_RTC_PM_OPS NULL
#endif
#ifdef CONFIG_OF
static const struct of_device_id lpc32xx_rtc_match[] = {
{ .compatible = "nxp,lpc3220-rtc" },
{ }
};
MODULE_DEVICE_TABLE(of, lpc32xx_rtc_match);
#endif
static struct platform_driver lpc32xx_rtc_driver = {
.probe = lpc32xx_rtc_probe,
.driver = {
.name = "rtc-lpc32xx",
.pm = LPC32XX_RTC_PM_OPS,
.of_match_table = of_match_ptr(lpc32xx_rtc_match),
},
};
module_platform_driver(lpc32xx_rtc_driver);
MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com");
MODULE_DESCRIPTION("RTC driver for the LPC32xx SoC");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:rtc-lpc32xx");
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