drivers/rtc/rtc-ds1374.c: add watchdog support
authorSøren Andersen <san@rosetechnology.dk>
Wed, 10 Dec 2014 23:53:54 +0000 (15:53 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 11 Dec 2014 01:41:15 +0000 (17:41 -0800)
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>
drivers/rtc/Kconfig
drivers/rtc/rtc-ds1374.c

index b682651b5307b7f7c908052557da9c57300339df..4511ddc1ac31b2ed1a0c0c9a5d60bf40bcd7d53c 100644 (file)
@@ -192,6 +192,14 @@ config RTC_DRV_DS1374
          This driver can also be built as a module. If so, the module
          will be called rtc-ds1374.
 
+config RTC_DRV_DS1374_WDT
+       bool "Dallas/Maxim DS1374 watchdog timer"
+       depends on RTC_DRV_DS1374
+       help
+         If you say Y here you will get support for the
+         watchdog timer in the Dallas Semiconductor DS1374
+         real-time clock chips.
+
 config RTC_DRV_DS1672
        tristate "Dallas/Maxim DS1672"
        help
index 9e6e14fb53d740bd4a8085fe617506245131443a..8605fde394b2afdb61a18ede4062b4079c5aee1f 100644 (file)
@@ -4,6 +4,7 @@
  * 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
 #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
@@ -49,6 +57,14 @@ static const struct i2c_device_id ds1374_id[] = {
 };
 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;
@@ -162,6 +178,7 @@ static int ds1374_set_time(struct device *dev, struct rtc_time *time)
        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.
@@ -263,6 +280,7 @@ out:
        mutex_unlock(&ds1374->mutex);
        return ret;
 }
+#endif
 
 static irqreturn_t ds1374_irq(int irq, void *dev_id)
 {
@@ -307,6 +325,7 @@ 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);
@@ -331,15 +350,260 @@ 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)
 {
@@ -378,12 +642,33 @@ static int ds1374_probe(struct i2c_client *client,
                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);