linux/drivers/rtc/rtc-st-lpc.c
Thomas Gleixner b4d0d230cc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public licence as published by
  the free software foundation either version 2 of the licence or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 114 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:27:11 +02:00

328 lines
7.6 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* rtc-st-lpc.c - ST's LPC RTC, powered by the Low Power Timer
*
* Copyright (C) 2014 STMicroelectronics Limited
*
* Author: David Paris <david.paris@st.com> for STMicroelectronics
* Lee Jones <lee.jones@linaro.org> for STMicroelectronics
*
* Based on the original driver written by Stuart Menefy.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <dt-bindings/mfd/st-lpc.h>
/* Low Power Timer */
#define LPC_LPT_LSB_OFF 0x400
#define LPC_LPT_MSB_OFF 0x404
#define LPC_LPT_START_OFF 0x408
/* Low Power Alarm */
#define LPC_LPA_LSB_OFF 0x410
#define LPC_LPA_MSB_OFF 0x414
#define LPC_LPA_START_OFF 0x418
/* LPC as WDT */
#define LPC_WDT_OFF 0x510
#define LPC_WDT_FLAG_OFF 0x514
struct st_rtc {
struct rtc_device *rtc_dev;
struct rtc_wkalrm alarm;
struct resource *res;
struct clk *clk;
unsigned long clkrate;
void __iomem *ioaddr;
bool irq_enabled:1;
spinlock_t lock;
short irq;
};
static void st_rtc_set_hw_alarm(struct st_rtc *rtc,
unsigned long msb, unsigned long lsb)
{
unsigned long flags;
spin_lock_irqsave(&rtc->lock, flags);
writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
writel_relaxed(msb, rtc->ioaddr + LPC_LPA_MSB_OFF);
writel_relaxed(lsb, rtc->ioaddr + LPC_LPA_LSB_OFF);
writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF);
writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
spin_unlock_irqrestore(&rtc->lock, flags);
}
static irqreturn_t st_rtc_handler(int this_irq, void *data)
{
struct st_rtc *rtc = (struct st_rtc *)data;
rtc_update_irq(rtc->rtc_dev, 1, RTC_AF);
return IRQ_HANDLED;
}
static int st_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct st_rtc *rtc = dev_get_drvdata(dev);
unsigned long lpt_lsb, lpt_msb;
unsigned long long lpt;
unsigned long flags;
spin_lock_irqsave(&rtc->lock, flags);
do {
lpt_msb = readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF);
lpt_lsb = readl_relaxed(rtc->ioaddr + LPC_LPT_LSB_OFF);
} while (readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF) != lpt_msb);
spin_unlock_irqrestore(&rtc->lock, flags);
lpt = ((unsigned long long)lpt_msb << 32) | lpt_lsb;
do_div(lpt, rtc->clkrate);
rtc_time64_to_tm(lpt, tm);
return 0;
}
static int st_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct st_rtc *rtc = dev_get_drvdata(dev);
unsigned long long lpt, secs;
unsigned long flags;
secs = rtc_tm_to_time64(tm);
lpt = (unsigned long long)secs * rtc->clkrate;
spin_lock_irqsave(&rtc->lock, flags);
writel_relaxed(lpt >> 32, rtc->ioaddr + LPC_LPT_MSB_OFF);
writel_relaxed(lpt, rtc->ioaddr + LPC_LPT_LSB_OFF);
writel_relaxed(1, rtc->ioaddr + LPC_LPT_START_OFF);
spin_unlock_irqrestore(&rtc->lock, flags);
return 0;
}
static int st_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
{
struct st_rtc *rtc = dev_get_drvdata(dev);
unsigned long flags;
spin_lock_irqsave(&rtc->lock, flags);
memcpy(wkalrm, &rtc->alarm, sizeof(struct rtc_wkalrm));
spin_unlock_irqrestore(&rtc->lock, flags);
return 0;
}
static int st_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct st_rtc *rtc = dev_get_drvdata(dev);
if (enabled && !rtc->irq_enabled) {
enable_irq(rtc->irq);
rtc->irq_enabled = true;
} else if (!enabled && rtc->irq_enabled) {
disable_irq(rtc->irq);
rtc->irq_enabled = false;
}
return 0;
}
static int st_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct st_rtc *rtc = dev_get_drvdata(dev);
struct rtc_time now;
unsigned long long now_secs;
unsigned long long alarm_secs;
unsigned long long lpa;
st_rtc_read_time(dev, &now);
now_secs = rtc_tm_to_time64(&now);
alarm_secs = rtc_tm_to_time64(&t->time);
/* Invalid alarm time */
if (now_secs > alarm_secs)
return -EINVAL;
memcpy(&rtc->alarm, t, sizeof(struct rtc_wkalrm));
/* Now many secs to fire */
alarm_secs -= now_secs;
lpa = (unsigned long long)alarm_secs * rtc->clkrate;
st_rtc_set_hw_alarm(rtc, lpa >> 32, lpa);
st_rtc_alarm_irq_enable(dev, t->enabled);
return 0;
}
static struct rtc_class_ops st_rtc_ops = {
.read_time = st_rtc_read_time,
.set_time = st_rtc_set_time,
.read_alarm = st_rtc_read_alarm,
.set_alarm = st_rtc_set_alarm,
.alarm_irq_enable = st_rtc_alarm_irq_enable,
};
static int st_rtc_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct st_rtc *rtc;
struct resource *res;
uint32_t mode;
int ret = 0;
ret = of_property_read_u32(np, "st,lpc-mode", &mode);
if (ret) {
dev_err(&pdev->dev, "An LPC mode must be provided\n");
return -EINVAL;
}
/* LPC can either run as a Clocksource or in RTC or WDT mode */
if (mode != ST_LPC_MODE_RTC)
return -ENODEV;
rtc = devm_kzalloc(&pdev->dev, sizeof(struct st_rtc), GFP_KERNEL);
if (!rtc)
return -ENOMEM;
rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(rtc->rtc_dev))
return PTR_ERR(rtc->rtc_dev);
spin_lock_init(&rtc->lock);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
rtc->ioaddr = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(rtc->ioaddr))
return PTR_ERR(rtc->ioaddr);
rtc->irq = irq_of_parse_and_map(np, 0);
if (!rtc->irq) {
dev_err(&pdev->dev, "IRQ missing or invalid\n");
return -EINVAL;
}
ret = devm_request_irq(&pdev->dev, rtc->irq, st_rtc_handler, 0,
pdev->name, rtc);
if (ret) {
dev_err(&pdev->dev, "Failed to request irq %i\n", rtc->irq);
return ret;
}
enable_irq_wake(rtc->irq);
disable_irq(rtc->irq);
rtc->clk = clk_get(&pdev->dev, NULL);
if (IS_ERR(rtc->clk)) {
dev_err(&pdev->dev, "Unable to request clock\n");
return PTR_ERR(rtc->clk);
}
clk_prepare_enable(rtc->clk);
rtc->clkrate = clk_get_rate(rtc->clk);
if (!rtc->clkrate) {
dev_err(&pdev->dev, "Unable to fetch clock rate\n");
return -EINVAL;
}
device_set_wakeup_capable(&pdev->dev, 1);
platform_set_drvdata(pdev, rtc);
rtc->rtc_dev->ops = &st_rtc_ops;
rtc->rtc_dev->range_max = U64_MAX;
do_div(rtc->rtc_dev->range_max, rtc->clkrate);
ret = rtc_register_device(rtc->rtc_dev);
if (ret) {
clk_disable_unprepare(rtc->clk);
return ret;
}
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int st_rtc_suspend(struct device *dev)
{
struct st_rtc *rtc = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
return 0;
writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
writel_relaxed(0, rtc->ioaddr + LPC_LPA_START_OFF);
writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
return 0;
}
static int st_rtc_resume(struct device *dev)
{
struct st_rtc *rtc = dev_get_drvdata(dev);
rtc_alarm_irq_enable(rtc->rtc_dev, 0);
/*
* clean 'rtc->alarm' to allow a new
* .set_alarm to the upper RTC layer
*/
memset(&rtc->alarm, 0, sizeof(struct rtc_wkalrm));
writel_relaxed(0, rtc->ioaddr + LPC_LPA_MSB_OFF);
writel_relaxed(0, rtc->ioaddr + LPC_LPA_LSB_OFF);
writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF);
writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(st_rtc_pm_ops, st_rtc_suspend, st_rtc_resume);
static const struct of_device_id st_rtc_match[] = {
{ .compatible = "st,stih407-lpc" },
{}
};
MODULE_DEVICE_TABLE(of, st_rtc_match);
static struct platform_driver st_rtc_platform_driver = {
.driver = {
.name = "st-lpc-rtc",
.pm = &st_rtc_pm_ops,
.of_match_table = st_rtc_match,
},
.probe = st_rtc_probe,
};
module_platform_driver(st_rtc_platform_driver);
MODULE_DESCRIPTION("STMicroelectronics LPC RTC driver");
MODULE_AUTHOR("David Paris <david.paris@st.com>");
MODULE_LICENSE("GPL");