linux/drivers/rtc/rtc-brcmstb-waketimer.c
Justin Chen 58d3d5e79e rtc: brcmstb-waketimer: Set wktmr prescaler
The HW default is one tick per second, however instead of assuming this,
lets make sure the waketimer is actually one tick per second before
arming the alarm.

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Justin Chen <justinpopo6@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2018-03-17 14:20:51 +01:00

343 lines
7.9 KiB
C

/*
* Copyright © 2014-2017 Broadcom
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/clk.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irqreturn.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/pm_wakeup.h>
#include <linux/reboot.h>
#include <linux/rtc.h>
#include <linux/stat.h>
#include <linux/suspend.h>
struct brcmstb_waketmr {
struct rtc_device *rtc;
struct device *dev;
void __iomem *base;
int irq;
struct notifier_block reboot_notifier;
struct clk *clk;
u32 rate;
};
#define BRCMSTB_WKTMR_EVENT 0x00
#define BRCMSTB_WKTMR_COUNTER 0x04
#define BRCMSTB_WKTMR_ALARM 0x08
#define BRCMSTB_WKTMR_PRESCALER 0x0C
#define BRCMSTB_WKTMR_PRESCALER_VAL 0x10
#define BRCMSTB_WKTMR_DEFAULT_FREQ 27000000
static inline void brcmstb_waketmr_clear_alarm(struct brcmstb_waketmr *timer)
{
writel_relaxed(1, timer->base + BRCMSTB_WKTMR_EVENT);
(void)readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
}
static void brcmstb_waketmr_set_alarm(struct brcmstb_waketmr *timer,
unsigned int secs)
{
brcmstb_waketmr_clear_alarm(timer);
/* Make sure we are actually counting in seconds */
writel_relaxed(timer->rate, timer->base + BRCMSTB_WKTMR_PRESCALER);
writel_relaxed(secs + 1, timer->base + BRCMSTB_WKTMR_ALARM);
}
static irqreturn_t brcmstb_waketmr_irq(int irq, void *data)
{
struct brcmstb_waketmr *timer = data;
pm_wakeup_event(timer->dev, 0);
return IRQ_HANDLED;
}
struct wktmr_time {
u32 sec;
u32 pre;
};
static void wktmr_read(struct brcmstb_waketmr *timer,
struct wktmr_time *t)
{
u32 tmp;
do {
t->sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
tmp = readl_relaxed(timer->base + BRCMSTB_WKTMR_PRESCALER_VAL);
} while (tmp >= timer->rate);
t->pre = timer->rate - tmp;
}
static int brcmstb_waketmr_prepare_suspend(struct brcmstb_waketmr *timer)
{
struct device *dev = timer->dev;
int ret = 0;
if (device_may_wakeup(dev)) {
ret = enable_irq_wake(timer->irq);
if (ret) {
dev_err(dev, "failed to enable wake-up interrupt\n");
return ret;
}
}
return ret;
}
/* If enabled as a wakeup-source, arm the timer when powering off */
static int brcmstb_waketmr_reboot(struct notifier_block *nb,
unsigned long action, void *data)
{
struct brcmstb_waketmr *timer;
timer = container_of(nb, struct brcmstb_waketmr, reboot_notifier);
/* Set timer for cold boot */
if (action == SYS_POWER_OFF)
brcmstb_waketmr_prepare_suspend(timer);
return NOTIFY_DONE;
}
static int brcmstb_waketmr_gettime(struct device *dev,
struct rtc_time *tm)
{
struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
struct wktmr_time now;
wktmr_read(timer, &now);
rtc_time_to_tm(now.sec, tm);
return 0;
}
static int brcmstb_waketmr_settime(struct device *dev,
struct rtc_time *tm)
{
struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
time64_t sec;
sec = rtc_tm_to_time64(tm);
if (sec > U32_MAX || sec < 0)
return -EINVAL;
writel_relaxed(sec, timer->base + BRCMSTB_WKTMR_COUNTER);
return 0;
}
static int brcmstb_waketmr_getalarm(struct device *dev,
struct rtc_wkalrm *alarm)
{
struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
time64_t sec;
u32 reg;
sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_ALARM);
if (sec != 0) {
/* Alarm is enabled */
alarm->enabled = 1;
rtc_time64_to_tm(sec, &alarm->time);
}
reg = readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
alarm->pending = !!(reg & 1);
return 0;
}
static int brcmstb_waketmr_setalarm(struct device *dev,
struct rtc_wkalrm *alarm)
{
struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
time64_t sec;
if (alarm->enabled)
sec = rtc_tm_to_time64(&alarm->time);
else
sec = 0;
if (sec > U32_MAX || sec < 0)
return -EINVAL;
brcmstb_waketmr_set_alarm(timer, sec);
return 0;
}
/*
* Does not do much but keep the RTC class happy. We always support
* alarms.
*/
static int brcmstb_waketmr_alarm_enable(struct device *dev,
unsigned int enabled)
{
return 0;
}
static const struct rtc_class_ops brcmstb_waketmr_ops = {
.read_time = brcmstb_waketmr_gettime,
.set_time = brcmstb_waketmr_settime,
.read_alarm = brcmstb_waketmr_getalarm,
.set_alarm = brcmstb_waketmr_setalarm,
.alarm_irq_enable = brcmstb_waketmr_alarm_enable,
};
static int brcmstb_waketmr_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct brcmstb_waketmr *timer;
struct resource *res;
int ret;
timer = devm_kzalloc(dev, sizeof(*timer), GFP_KERNEL);
if (!timer)
return -ENOMEM;
platform_set_drvdata(pdev, timer);
timer->dev = dev;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
timer->base = devm_ioremap_resource(dev, res);
if (IS_ERR(timer->base))
return PTR_ERR(timer->base);
/*
* Set wakeup capability before requesting wakeup interrupt, so we can
* process boot-time "wakeups" (e.g., from S5 soft-off)
*/
device_set_wakeup_capable(dev, true);
device_wakeup_enable(dev);
timer->irq = platform_get_irq(pdev, 0);
if (timer->irq < 0)
return -ENODEV;
timer->clk = devm_clk_get(dev, NULL);
if (!IS_ERR(timer->clk)) {
ret = clk_prepare_enable(timer->clk);
if (ret)
return ret;
timer->rate = clk_get_rate(timer->clk);
if (!timer->rate)
timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ;
} else {
timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ;
timer->clk = NULL;
}
ret = devm_request_irq(dev, timer->irq, brcmstb_waketmr_irq, 0,
"brcmstb-waketimer", timer);
if (ret < 0)
goto err_clk;
timer->reboot_notifier.notifier_call = brcmstb_waketmr_reboot;
register_reboot_notifier(&timer->reboot_notifier);
timer->rtc = rtc_device_register("brcmstb-waketmr", dev,
&brcmstb_waketmr_ops, THIS_MODULE);
if (IS_ERR(timer->rtc)) {
dev_err(dev, "unable to register device\n");
ret = PTR_ERR(timer->rtc);
goto err_notifier;
}
dev_info(dev, "registered, with irq %d\n", timer->irq);
return 0;
err_notifier:
unregister_reboot_notifier(&timer->reboot_notifier);
err_clk:
if (timer->clk)
clk_disable_unprepare(timer->clk);
return ret;
}
static int brcmstb_waketmr_remove(struct platform_device *pdev)
{
struct brcmstb_waketmr *timer = dev_get_drvdata(&pdev->dev);
unregister_reboot_notifier(&timer->reboot_notifier);
rtc_device_unregister(timer->rtc);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int brcmstb_waketmr_suspend(struct device *dev)
{
struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
return brcmstb_waketmr_prepare_suspend(timer);
}
static int brcmstb_waketmr_resume(struct device *dev)
{
struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
int ret;
if (!device_may_wakeup(dev))
return 0;
ret = disable_irq_wake(timer->irq);
brcmstb_waketmr_clear_alarm(timer);
return ret;
}
#endif /* CONFIG_PM_SLEEP */
static SIMPLE_DEV_PM_OPS(brcmstb_waketmr_pm_ops,
brcmstb_waketmr_suspend, brcmstb_waketmr_resume);
static const struct of_device_id brcmstb_waketmr_of_match[] = {
{ .compatible = "brcm,brcmstb-waketimer" },
{ /* sentinel */ },
};
static struct platform_driver brcmstb_waketmr_driver = {
.probe = brcmstb_waketmr_probe,
.remove = brcmstb_waketmr_remove,
.driver = {
.name = "brcmstb-waketimer",
.pm = &brcmstb_waketmr_pm_ops,
.of_match_table = of_match_ptr(brcmstb_waketmr_of_match),
}
};
module_platform_driver(brcmstb_waketmr_driver);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Brian Norris");
MODULE_AUTHOR("Markus Mayer");
MODULE_DESCRIPTION("Wake-up timer driver for STB chips");