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linux/drivers/rtc/rtc-stmp3xxx.c
Wolfram Sang 1a71fb84fd rtc: stmp3xxx: add wdt-accessor function 
This RTC also includes a watchdog timer. Provide an accessor function
for setting the watchdog timeout value which will be picked up by a
watchdog driver. Also register the platform_device for the watchdog here
to get the boot-time dependencies right.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2013-03-01 12:40:36 +01:00

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9.8 KiB
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/*
* Freescale STMP37XX/STMP378X Real Time Clock driver
*
* Copyright (c) 2007 Sigmatel, Inc.
* Peter Hartley, <peter.hartley@sigmatel.com>
*
* Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
* Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
* Copyright 2011 Wolfram Sang, Pengutronix e.K.
*/
/*
* The code contained herein is licensed under the GNU General Public
* License. You may obtain a copy of the GNU General Public License
* Version 2 or later at the following locations:
*
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/of_device.h>
#include <linux/of.h>
#include <linux/stmp_device.h>
#include <linux/stmp3xxx_rtc_wdt.h>
#include <mach/common.h>
#define STMP3XXX_RTC_CTRL 0x0
#define STMP3XXX_RTC_CTRL_SET 0x4
#define STMP3XXX_RTC_CTRL_CLR 0x8
#define STMP3XXX_RTC_CTRL_ALARM_IRQ_EN 0x00000001
#define STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN 0x00000002
#define STMP3XXX_RTC_CTRL_ALARM_IRQ 0x00000004
#define STMP3XXX_RTC_CTRL_WATCHDOGEN 0x00000010
#define STMP3XXX_RTC_STAT 0x10
#define STMP3XXX_RTC_STAT_STALE_SHIFT 16
#define STMP3XXX_RTC_STAT_RTC_PRESENT 0x80000000
#define STMP3XXX_RTC_SECONDS 0x30
#define STMP3XXX_RTC_ALARM 0x40
#define STMP3XXX_RTC_WATCHDOG 0x50
#define STMP3XXX_RTC_PERSISTENT0 0x60
#define STMP3XXX_RTC_PERSISTENT0_SET 0x64
#define STMP3XXX_RTC_PERSISTENT0_CLR 0x68
#define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN 0x00000002
#define STMP3XXX_RTC_PERSISTENT0_ALARM_EN 0x00000004
#define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE 0x00000080
#define STMP3XXX_RTC_PERSISTENT1 0x70
/* missing bitmask in headers */
#define STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER 0x80000000
struct stmp3xxx_rtc_data {
struct rtc_device *rtc;
void __iomem *io;
int irq_alarm;
};
#if IS_ENABLED(CONFIG_STMP3XXX_RTC_WATCHDOG)
/**
* stmp3xxx_wdt_set_timeout - configure the watchdog inside the STMP3xxx RTC
* @dev: the parent device of the watchdog (= the RTC)
* @timeout: the desired value for the timeout register of the watchdog.
* 0 disables the watchdog
*
* The watchdog needs one register and two bits which are in the RTC domain.
* To handle the resource conflict, the RTC driver will create another
* platform_device for the watchdog driver as a child of the RTC device.
* The watchdog driver is passed the below accessor function via platform_data
* to configure the watchdog. Locking is not needed because accessing SET/CLR
* registers is atomic.
*/
static void stmp3xxx_wdt_set_timeout(struct device *dev, u32 timeout)
{
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
if (timeout) {
writel(timeout, rtc_data->io + STMP3XXX_RTC_WATCHDOG);
writel(STMP3XXX_RTC_CTRL_WATCHDOGEN,
rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_SET);
writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER,
rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_SET);
} else {
writel(STMP3XXX_RTC_CTRL_WATCHDOGEN,
rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR);
writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER,
rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_CLR);
}
}
static struct stmp3xxx_wdt_pdata wdt_pdata = {
.wdt_set_timeout = stmp3xxx_wdt_set_timeout,
};
static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
{
struct platform_device *wdt_pdev =
platform_device_alloc("stmp3xxx_rtc_wdt", rtc_pdev->id);
if (wdt_pdev) {
wdt_pdev->dev.parent = &rtc_pdev->dev;
wdt_pdev->dev.platform_data = &wdt_pdata;
platform_device_add(wdt_pdev);
}
}
#else
static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
{
}
#endif /* CONFIG_STMP3XXX_RTC_WATCHDOG */
static void stmp3xxx_wait_time(struct stmp3xxx_rtc_data *rtc_data)
{
/*
* The datasheet doesn't say which way round the
* NEW_REGS/STALE_REGS bitfields go. In fact it's 0x1=P0,
* 0x2=P1, .., 0x20=P5, 0x40=ALARM, 0x80=SECONDS
*/
while (readl(rtc_data->io + STMP3XXX_RTC_STAT) &
(0x80 << STMP3XXX_RTC_STAT_STALE_SHIFT))
cpu_relax();
}
/* Time read/write */
static int stmp3xxx_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
{
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
stmp3xxx_wait_time(rtc_data);
rtc_time_to_tm(readl(rtc_data->io + STMP3XXX_RTC_SECONDS), rtc_tm);
return 0;
}
static int stmp3xxx_rtc_set_mmss(struct device *dev, unsigned long t)
{
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
writel(t, rtc_data->io + STMP3XXX_RTC_SECONDS);
stmp3xxx_wait_time(rtc_data);
return 0;
}
/* interrupt(s) handler */
static irqreturn_t stmp3xxx_rtc_interrupt(int irq, void *dev_id)
{
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev_id);
u32 status = readl(rtc_data->io + STMP3XXX_RTC_CTRL);
if (status & STMP3XXX_RTC_CTRL_ALARM_IRQ) {
writel(STMP3XXX_RTC_CTRL_ALARM_IRQ,
rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
rtc_update_irq(rtc_data->rtc, 1, RTC_AF | RTC_IRQF);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
if (enabled) {
writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
rtc_data->io + STMP3XXX_RTC_PERSISTENT0_SET);
writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
rtc_data->io + STMP3XXX_RTC_CTRL_SET);
} else {
writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN,
rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
}
return 0;
}
static int stmp3xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
rtc_time_to_tm(readl(rtc_data->io + STMP3XXX_RTC_ALARM), &alm->time);
return 0;
}
static int stmp3xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
unsigned long t;
struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
rtc_tm_to_time(&alm->time, &t);
writel(t, rtc_data->io + STMP3XXX_RTC_ALARM);
stmp3xxx_alarm_irq_enable(dev, alm->enabled);
return 0;
}
static struct rtc_class_ops stmp3xxx_rtc_ops = {
.alarm_irq_enable =
stmp3xxx_alarm_irq_enable,
.read_time = stmp3xxx_rtc_gettime,
.set_mmss = stmp3xxx_rtc_set_mmss,
.read_alarm = stmp3xxx_rtc_read_alarm,
.set_alarm = stmp3xxx_rtc_set_alarm,
};
static int stmp3xxx_rtc_remove(struct platform_device *pdev)
{
struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(pdev);
if (!rtc_data)
return 0;
writel(STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
free_irq(rtc_data->irq_alarm, &pdev->dev);
rtc_device_unregister(rtc_data->rtc);
platform_set_drvdata(pdev, NULL);
iounmap(rtc_data->io);
kfree(rtc_data);
return 0;
}
static int stmp3xxx_rtc_probe(struct platform_device *pdev)
{
struct stmp3xxx_rtc_data *rtc_data;
struct resource *r;
int err;
rtc_data = kzalloc(sizeof *rtc_data, GFP_KERNEL);
if (!rtc_data)
return -ENOMEM;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!r) {
dev_err(&pdev->dev, "failed to get resource\n");
err = -ENXIO;
goto out_free;
}
rtc_data->io = ioremap(r->start, resource_size(r));
if (!rtc_data->io) {
dev_err(&pdev->dev, "ioremap failed\n");
err = -EIO;
goto out_free;
}
rtc_data->irq_alarm = platform_get_irq(pdev, 0);
if (!(readl(STMP3XXX_RTC_STAT + rtc_data->io) &
STMP3XXX_RTC_STAT_RTC_PRESENT)) {
dev_err(&pdev->dev, "no device onboard\n");
err = -ENODEV;
goto out_remap;
}
platform_set_drvdata(pdev, rtc_data);
mxs_reset_block(rtc_data->io);
writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
writel(STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN |
STMP3XXX_RTC_CTRL_ALARM_IRQ_EN,
rtc_data->io + STMP3XXX_RTC_CTRL_CLR);
rtc_data->rtc = rtc_device_register(pdev->name, &pdev->dev,
&stmp3xxx_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc_data->rtc)) {
err = PTR_ERR(rtc_data->rtc);
goto out_remap;
}
err = request_irq(rtc_data->irq_alarm, stmp3xxx_rtc_interrupt, 0,
"RTC alarm", &pdev->dev);
if (err) {
dev_err(&pdev->dev, "Cannot claim IRQ%d\n",
rtc_data->irq_alarm);
goto out_irq_alarm;
}
stmp3xxx_wdt_register(pdev);
return 0;
out_irq_alarm:
rtc_device_unregister(rtc_data->rtc);
out_remap:
platform_set_drvdata(pdev, NULL);
iounmap(rtc_data->io);
out_free:
kfree(rtc_data);
return err;
}
#ifdef CONFIG_PM
static int stmp3xxx_rtc_suspend(struct platform_device *dev, pm_message_t state)
{
return 0;
}
static int stmp3xxx_rtc_resume(struct platform_device *dev)
{
struct stmp3xxx_rtc_data *rtc_data = platform_get_drvdata(dev);
mxs_reset_block(rtc_data->io);
writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN |
STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE,
rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR);
return 0;
}
#else
#define stmp3xxx_rtc_suspend NULL
#define stmp3xxx_rtc_resume NULL
#endif
static const struct of_device_id rtc_dt_ids[] = {
{ .compatible = "fsl,stmp3xxx-rtc", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, rtc_dt_ids);
static struct platform_driver stmp3xxx_rtcdrv = {
.probe = stmp3xxx_rtc_probe,
.remove = stmp3xxx_rtc_remove,
.suspend = stmp3xxx_rtc_suspend,
.resume = stmp3xxx_rtc_resume,
.driver = {
.name = "stmp3xxx-rtc",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(rtc_dt_ids),
},
};
module_platform_driver(stmp3xxx_rtcdrv);
MODULE_DESCRIPTION("STMP3xxx RTC Driver");
MODULE_AUTHOR("dmitry pervushin <dpervushin@embeddedalley.com> and "
"Wolfram Sang <w.sang@pengutronix.de>");
MODULE_LICENSE("GPL");
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