linux/drivers/rtc/rtc-ds1374.c
Søren Andersen 920f91e50c drivers/rtc/rtc-ds1374.c: add watchdog support
Add support for the watchdog functionality of the DS1374 rtc.  Based on
the m41t80 watchdog functionality Note: watchdog uses the same registers
as alarm.

[akpm@linux-foundation.org: don't forget mutex_unlock() in ds1374_wdt_open() error path]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Soeren Andersen <san@rosetechnology.dk>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10 17:41:15 -08:00

723 lines
17 KiB
C

/*
* RTC client/driver for the Maxim/Dallas DS1374 Real-Time Clock over I2C
*
* Based on code by Randy Vinson <rvinson@mvista.com>,
* which was based on the m41t00.c by Mark Greer <mgreer@mvista.com>.
*
* Copyright (C) 2014 Rose Technology
* Copyright (C) 2006-2007 Freescale Semiconductor
*
* 2005 (c) MontaVista Software, Inc. This file is licensed under
* the terms of the GNU General Public License version 2. This program
* is licensed "as is" without any warranty of any kind, whether express
* or implied.
*/
/*
* It would be more efficient to use i2c msgs/i2c_transfer directly but, as
* recommened in .../Documentation/i2c/writing-clients section
* "Sending and receiving", using SMBus level communication is preferred.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/workqueue.h>
#include <linux/slab.h>
#include <linux/pm.h>
#ifdef CONFIG_RTC_DRV_DS1374_WDT
#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/miscdevice.h>
#include <linux/reboot.h>
#include <linux/watchdog.h>
#endif
#define DS1374_REG_TOD0 0x00 /* Time of Day */
#define DS1374_REG_TOD1 0x01
#define DS1374_REG_TOD2 0x02
#define DS1374_REG_TOD3 0x03
#define DS1374_REG_WDALM0 0x04 /* Watchdog/Alarm */
#define DS1374_REG_WDALM1 0x05
#define DS1374_REG_WDALM2 0x06
#define DS1374_REG_CR 0x07 /* Control */
#define DS1374_REG_CR_AIE 0x01 /* Alarm Int. Enable */
#define DS1374_REG_CR_WDALM 0x20 /* 1=Watchdog, 0=Alarm */
#define DS1374_REG_CR_WACE 0x40 /* WD/Alarm counter enable */
#define DS1374_REG_SR 0x08 /* Status */
#define DS1374_REG_SR_OSF 0x80 /* Oscillator Stop Flag */
#define DS1374_REG_SR_AF 0x01 /* Alarm Flag */
#define DS1374_REG_TCR 0x09 /* Trickle Charge */
static const struct i2c_device_id ds1374_id[] = {
{ "ds1374", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ds1374_id);
#ifdef CONFIG_OF
static const struct of_device_id ds1374_of_match[] = {
{ .compatible = "dallas,ds1374" },
{ }
};
MODULE_DEVICE_TABLE(of, ds1374_of_match);
#endif
struct ds1374 {
struct i2c_client *client;
struct rtc_device *rtc;
struct work_struct work;
/* The mutex protects alarm operations, and prevents a race
* between the enable_irq() in the workqueue and the free_irq()
* in the remove function.
*/
struct mutex mutex;
int exiting;
};
static struct i2c_driver ds1374_driver;
static int ds1374_read_rtc(struct i2c_client *client, u32 *time,
int reg, int nbytes)
{
u8 buf[4];
int ret;
int i;
if (nbytes > 4) {
WARN_ON(1);
return -EINVAL;
}
ret = i2c_smbus_read_i2c_block_data(client, reg, nbytes, buf);
if (ret < 0)
return ret;
if (ret < nbytes)
return -EIO;
for (i = nbytes - 1, *time = 0; i >= 0; i--)
*time = (*time << 8) | buf[i];
return 0;
}
static int ds1374_write_rtc(struct i2c_client *client, u32 time,
int reg, int nbytes)
{
u8 buf[4];
int i;
if (nbytes > 4) {
WARN_ON(1);
return -EINVAL;
}
for (i = 0; i < nbytes; i++) {
buf[i] = time & 0xff;
time >>= 8;
}
return i2c_smbus_write_i2c_block_data(client, reg, nbytes, buf);
}
static int ds1374_check_rtc_status(struct i2c_client *client)
{
int ret = 0;
int control, stat;
stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
if (stat < 0)
return stat;
if (stat & DS1374_REG_SR_OSF)
dev_warn(&client->dev,
"oscillator discontinuity flagged, time unreliable\n");
stat &= ~(DS1374_REG_SR_OSF | DS1374_REG_SR_AF);
ret = i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
if (ret < 0)
return ret;
/* If the alarm is pending, clear it before requesting
* the interrupt, so an interrupt event isn't reported
* before everything is initialized.
*/
control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
if (control < 0)
return control;
control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
return i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
}
static int ds1374_read_time(struct device *dev, struct rtc_time *time)
{
struct i2c_client *client = to_i2c_client(dev);
u32 itime;
int ret;
ret = ds1374_read_rtc(client, &itime, DS1374_REG_TOD0, 4);
if (!ret)
rtc_time_to_tm(itime, time);
return ret;
}
static int ds1374_set_time(struct device *dev, struct rtc_time *time)
{
struct i2c_client *client = to_i2c_client(dev);
unsigned long itime;
rtc_tm_to_time(time, &itime);
return ds1374_write_rtc(client, itime, DS1374_REG_TOD0, 4);
}
#ifndef CONFIG_RTC_DRV_DS1374_WDT
/* The ds1374 has a decrementer for an alarm, rather than a comparator.
* If the time of day is changed, then the alarm will need to be
* reset.
*/
static int ds1374_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds1374 *ds1374 = i2c_get_clientdata(client);
u32 now, cur_alarm;
int cr, sr;
int ret = 0;
if (client->irq <= 0)
return -EINVAL;
mutex_lock(&ds1374->mutex);
cr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
if (ret < 0)
goto out;
sr = ret = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
if (ret < 0)
goto out;
ret = ds1374_read_rtc(client, &now, DS1374_REG_TOD0, 4);
if (ret)
goto out;
ret = ds1374_read_rtc(client, &cur_alarm, DS1374_REG_WDALM0, 3);
if (ret)
goto out;
rtc_time_to_tm(now + cur_alarm, &alarm->time);
alarm->enabled = !!(cr & DS1374_REG_CR_WACE);
alarm->pending = !!(sr & DS1374_REG_SR_AF);
out:
mutex_unlock(&ds1374->mutex);
return ret;
}
static int ds1374_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds1374 *ds1374 = i2c_get_clientdata(client);
struct rtc_time now;
unsigned long new_alarm, itime;
int cr;
int ret = 0;
if (client->irq <= 0)
return -EINVAL;
ret = ds1374_read_time(dev, &now);
if (ret < 0)
return ret;
rtc_tm_to_time(&alarm->time, &new_alarm);
rtc_tm_to_time(&now, &itime);
/* This can happen due to races, in addition to dates that are
* truly in the past. To avoid requiring the caller to check for
* races, dates in the past are assumed to be in the recent past
* (i.e. not something that we'd rather the caller know about via
* an error), and the alarm is set to go off as soon as possible.
*/
if (time_before_eq(new_alarm, itime))
new_alarm = 1;
else
new_alarm -= itime;
mutex_lock(&ds1374->mutex);
ret = cr = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
if (ret < 0)
goto out;
/* Disable any existing alarm before setting the new one
* (or lack thereof). */
cr &= ~DS1374_REG_CR_WACE;
ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
if (ret < 0)
goto out;
ret = ds1374_write_rtc(client, new_alarm, DS1374_REG_WDALM0, 3);
if (ret)
goto out;
if (alarm->enabled) {
cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
cr &= ~DS1374_REG_CR_WDALM;
ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, cr);
}
out:
mutex_unlock(&ds1374->mutex);
return ret;
}
#endif
static irqreturn_t ds1374_irq(int irq, void *dev_id)
{
struct i2c_client *client = dev_id;
struct ds1374 *ds1374 = i2c_get_clientdata(client);
disable_irq_nosync(irq);
schedule_work(&ds1374->work);
return IRQ_HANDLED;
}
static void ds1374_work(struct work_struct *work)
{
struct ds1374 *ds1374 = container_of(work, struct ds1374, work);
struct i2c_client *client = ds1374->client;
int stat, control;
mutex_lock(&ds1374->mutex);
stat = i2c_smbus_read_byte_data(client, DS1374_REG_SR);
if (stat < 0)
goto unlock;
if (stat & DS1374_REG_SR_AF) {
stat &= ~DS1374_REG_SR_AF;
i2c_smbus_write_byte_data(client, DS1374_REG_SR, stat);
control = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
if (control < 0)
goto out;
control &= ~(DS1374_REG_CR_WACE | DS1374_REG_CR_AIE);
i2c_smbus_write_byte_data(client, DS1374_REG_CR, control);
rtc_update_irq(ds1374->rtc, 1, RTC_AF | RTC_IRQF);
}
out:
if (!ds1374->exiting)
enable_irq(client->irq);
unlock:
mutex_unlock(&ds1374->mutex);
}
#ifndef CONFIG_RTC_DRV_DS1374_WDT
static int ds1374_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds1374 *ds1374 = i2c_get_clientdata(client);
int ret;
mutex_lock(&ds1374->mutex);
ret = i2c_smbus_read_byte_data(client, DS1374_REG_CR);
if (ret < 0)
goto out;
if (enabled) {
ret |= DS1374_REG_CR_WACE | DS1374_REG_CR_AIE;
ret &= ~DS1374_REG_CR_WDALM;
} else {
ret &= ~DS1374_REG_CR_WACE;
}
ret = i2c_smbus_write_byte_data(client, DS1374_REG_CR, ret);
out:
mutex_unlock(&ds1374->mutex);
return ret;
}
#endif
static const struct rtc_class_ops ds1374_rtc_ops = {
.read_time = ds1374_read_time,
.set_time = ds1374_set_time,
#ifndef CONFIG_RTC_DRV_DS1374_WDT
.read_alarm = ds1374_read_alarm,
.set_alarm = ds1374_set_alarm,
.alarm_irq_enable = ds1374_alarm_irq_enable,
#endif
};
#ifdef CONFIG_RTC_DRV_DS1374_WDT
/*
*****************************************************************************
*
* Watchdog Driver
*
*****************************************************************************
*/
static struct i2c_client *save_client;
/* Default margin */
#define WD_TIMO 131762
#define DRV_NAME "DS1374 Watchdog"
static int wdt_margin = WD_TIMO;
static unsigned long wdt_is_open;
module_param(wdt_margin, int, 0);
MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 32s)");
static const struct watchdog_info ds1374_wdt_info = {
.identity = "DS1374 WTD",
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
};
static int ds1374_wdt_settimeout(unsigned int timeout)
{
int ret = -ENOIOCTLCMD;
int cr;
ret = cr = i2c_smbus_read_byte_data(save_client, DS1374_REG_CR);
if (ret < 0)
goto out;
/* Disable any existing watchdog/alarm before setting the new one */
cr &= ~DS1374_REG_CR_WACE;
ret = i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
if (ret < 0)
goto out;
/* Set new watchdog time */
ret = ds1374_write_rtc(save_client, timeout, DS1374_REG_WDALM0, 3);
if (ret) {
pr_info("rtc-ds1374 - couldn't set new watchdog time\n");
goto out;
}
/* Enable watchdog timer */
cr |= DS1374_REG_CR_WACE | DS1374_REG_CR_WDALM;
cr &= ~DS1374_REG_CR_AIE;
ret = i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
if (ret < 0)
goto out;
return 0;
out:
return ret;
}
/*
* Reload the watchdog timer. (ie, pat the watchdog)
*/
static void ds1374_wdt_ping(void)
{
u32 val;
int ret = 0;
ret = ds1374_read_rtc(save_client, &val, DS1374_REG_WDALM0, 3);
if (ret)
pr_info("WD TICK FAIL!!!!!!!!!! %i\n", ret);
}
static void ds1374_wdt_disable(void)
{
int ret = -ENOIOCTLCMD;
int cr;
cr = i2c_smbus_read_byte_data(save_client, DS1374_REG_CR);
/* Disable watchdog timer */
cr &= ~DS1374_REG_CR_WACE;
ret = i2c_smbus_write_byte_data(save_client, DS1374_REG_CR, cr);
}
/*
* Watchdog device is opened, and watchdog starts running.
*/
static int ds1374_wdt_open(struct inode *inode, struct file *file)
{
struct ds1374 *ds1374 = i2c_get_clientdata(save_client);
if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
mutex_lock(&ds1374->mutex);
if (test_and_set_bit(0, &wdt_is_open)) {
mutex_unlock(&ds1374->mutex);
return -EBUSY;
}
/*
* Activate
*/
wdt_is_open = 1;
mutex_unlock(&ds1374->mutex);
return nonseekable_open(inode, file);
}
return -ENODEV;
}
/*
* Close the watchdog device.
*/
static int ds1374_wdt_release(struct inode *inode, struct file *file)
{
if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
clear_bit(0, &wdt_is_open);
return 0;
}
/*
* Pat the watchdog whenever device is written to.
*/
static ssize_t ds1374_wdt_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
if (len) {
ds1374_wdt_ping();
return 1;
}
return 0;
}
static ssize_t ds1374_wdt_read(struct file *file, char __user *data,
size_t len, loff_t *ppos)
{
return 0;
}
/*
* Handle commands from user-space.
*/
static long ds1374_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int new_margin, options;
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user((struct watchdog_info __user *)arg,
&ds1374_wdt_info, sizeof(ds1374_wdt_info)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, (int __user *)arg);
case WDIOC_KEEPALIVE:
ds1374_wdt_ping();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_margin, (int __user *)arg))
return -EFAULT;
if (new_margin < 1 || new_margin > 16777216)
return -EINVAL;
wdt_margin = new_margin;
ds1374_wdt_settimeout(new_margin);
ds1374_wdt_ping();
/* fallthrough */
case WDIOC_GETTIMEOUT:
return put_user(wdt_margin, (int __user *)arg);
case WDIOC_SETOPTIONS:
if (copy_from_user(&options, (int __user *)arg, sizeof(int)))
return -EFAULT;
if (options & WDIOS_DISABLECARD) {
pr_info("rtc-ds1374: disable watchdog\n");
ds1374_wdt_disable();
}
if (options & WDIOS_ENABLECARD) {
pr_info("rtc-ds1374: enable watchdog\n");
ds1374_wdt_settimeout(wdt_margin);
ds1374_wdt_ping();
}
return -EINVAL;
}
return -ENOTTY;
}
static long ds1374_wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int ret;
struct ds1374 *ds1374 = i2c_get_clientdata(save_client);
mutex_lock(&ds1374->mutex);
ret = ds1374_wdt_ioctl(file, cmd, arg);
mutex_unlock(&ds1374->mutex);
return ret;
}
static int ds1374_wdt_notify_sys(struct notifier_block *this,
unsigned long code, void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
/* Disable Watchdog */
ds1374_wdt_disable();
return NOTIFY_DONE;
}
static const struct file_operations ds1374_wdt_fops = {
.owner = THIS_MODULE,
.read = ds1374_wdt_read,
.unlocked_ioctl = ds1374_wdt_unlocked_ioctl,
.write = ds1374_wdt_write,
.open = ds1374_wdt_open,
.release = ds1374_wdt_release,
.llseek = no_llseek,
};
static struct miscdevice ds1374_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &ds1374_wdt_fops,
};
static struct notifier_block ds1374_wdt_notifier = {
.notifier_call = ds1374_wdt_notify_sys,
};
#endif /*CONFIG_RTC_DRV_DS1374_WDT*/
/*
*****************************************************************************
*
* Driver Interface
*
*****************************************************************************
*/
static int ds1374_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ds1374 *ds1374;
int ret;
ds1374 = devm_kzalloc(&client->dev, sizeof(struct ds1374), GFP_KERNEL);
if (!ds1374)
return -ENOMEM;
ds1374->client = client;
i2c_set_clientdata(client, ds1374);
INIT_WORK(&ds1374->work, ds1374_work);
mutex_init(&ds1374->mutex);
ret = ds1374_check_rtc_status(client);
if (ret)
return ret;
if (client->irq > 0) {
ret = devm_request_irq(&client->dev, client->irq, ds1374_irq, 0,
"ds1374", client);
if (ret) {
dev_err(&client->dev, "unable to request IRQ\n");
return ret;
}
device_set_wakeup_capable(&client->dev, 1);
}
ds1374->rtc = devm_rtc_device_register(&client->dev, client->name,
&ds1374_rtc_ops, THIS_MODULE);
if (IS_ERR(ds1374->rtc)) {
dev_err(&client->dev, "unable to register the class device\n");
return PTR_ERR(ds1374->rtc);
}
#ifdef CONFIG_RTC_DRV_DS1374_WDT
save_client = client;
ret = misc_register(&ds1374_miscdev);
if (ret)
return ret;
ret = register_reboot_notifier(&ds1374_wdt_notifier);
if (ret) {
misc_deregister(&ds1374_miscdev);
return ret;
}
ds1374_wdt_settimeout(131072);
#endif
return 0;
}
static int ds1374_remove(struct i2c_client *client)
{
struct ds1374 *ds1374 = i2c_get_clientdata(client);
#ifdef CONFIG_RTC_DRV_DS1374_WDT
int res;
res = misc_deregister(&ds1374_miscdev);
if (!res)
ds1374_miscdev.parent = NULL;
unregister_reboot_notifier(&ds1374_wdt_notifier);
#endif
if (client->irq > 0) {
mutex_lock(&ds1374->mutex);
ds1374->exiting = 1;
mutex_unlock(&ds1374->mutex);
devm_free_irq(&client->dev, client->irq, client);
cancel_work_sync(&ds1374->work);
}
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int ds1374_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
if (client->irq >= 0 && device_may_wakeup(&client->dev))
enable_irq_wake(client->irq);
return 0;
}
static int ds1374_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
if (client->irq >= 0 && device_may_wakeup(&client->dev))
disable_irq_wake(client->irq);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(ds1374_pm, ds1374_suspend, ds1374_resume);
static struct i2c_driver ds1374_driver = {
.driver = {
.name = "rtc-ds1374",
.owner = THIS_MODULE,
.pm = &ds1374_pm,
},
.probe = ds1374_probe,
.remove = ds1374_remove,
.id_table = ds1374_id,
};
module_i2c_driver(ds1374_driver);
MODULE_AUTHOR("Scott Wood <scottwood@freescale.com>");
MODULE_DESCRIPTION("Maxim/Dallas DS1374 RTC Driver");
MODULE_LICENSE("GPL");