[WATCHDOG] Add support for the WM8350 watchdog
authorMark Brown <broonie@opensource.wolfsonmicro.com>
Thu, 6 Nov 2008 10:56:21 +0000 (10:56 +0000)
committerWim Van Sebroeck <wim@iguana.be>
Wed, 31 Dec 2008 16:12:54 +0000 (16:12 +0000)
This driver implements support for the watchdog functionality provided
by the Wolfson Microelectronics WM8350, a multi-function audio and
power management subsystem intended for use in embedded systems. It is
based on a driver originally written by Graeme Gregory, though it has
been extensively modified since then.

Use of a GPIO to kick the watchdog is not yet supported.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
drivers/watchdog/Kconfig
drivers/watchdog/Makefile
drivers/watchdog/wm8350_wdt.c [new file with mode: 0644]

index 81f7021b38163161ad353212055b51705d735be7..ec68c741b5645eddd206df2a02b492b3ee783650 100644 (file)
@@ -55,6 +55,13 @@ config SOFT_WATCHDOG
          To compile this driver as a module, choose M here: the
          module will be called softdog.
 
+config WM8350_WATCHDOG
+       tristate "WM8350 watchdog"
+       depends on MFD_WM8350
+       help
+         Support for the watchdog in the WM8350 AudioPlus PMIC.  When
+         the watchdog triggers the system will be reset.
+
 # ALPHA Architecture
 
 # ARM Architecture
index 0cd47867b194dd5820c6e92344a3e624c11623a4..c19b866f5ed1d6a8e73cc627f494baadf0468af1 100644 (file)
@@ -134,4 +134,5 @@ obj-$(CONFIG_WATCHDOG_CP1XXX)               += cpwd.o
 # XTENSA Architecture
 
 # Architecture Independant
+obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
 obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
diff --git a/drivers/watchdog/wm8350_wdt.c b/drivers/watchdog/wm8350_wdt.c
new file mode 100644 (file)
index 0000000..2bc0d4d
--- /dev/null
@@ -0,0 +1,329 @@
+/*
+ * Watchdog driver for the wm8350
+ *
+ * Copyright (C) 2007, 2008 Wolfson Microelectronics <linux@wolfsonmicro.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <linux/uaccess.h>
+#include <linux/mfd/wm8350/core.h>
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout,
+                "Watchdog cannot be stopped once started (default="
+                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static unsigned long wm8350_wdt_users;
+static struct miscdevice wm8350_wdt_miscdev;
+static int wm8350_wdt_expect_close;
+static DEFINE_MUTEX(wdt_mutex);
+
+static struct {
+       int time;  /* Seconds */
+       u16 val;   /* To be set in WM8350_SYSTEM_CONTROL_2 */
+} wm8350_wdt_cfgs[] = {
+       { 1, 0x02 },
+       { 2, 0x04 },
+       { 4, 0x05 },
+};
+
+static struct wm8350 *get_wm8350(void)
+{
+       return dev_get_drvdata(wm8350_wdt_miscdev.parent);
+}
+
+static int wm8350_wdt_set_timeout(struct wm8350 *wm8350, u16 value)
+{
+       int ret;
+       u16 reg;
+
+       mutex_lock(&wdt_mutex);
+       wm8350_reg_unlock(wm8350);
+
+       reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
+       reg &= ~WM8350_WDOG_TO_MASK;
+       reg |= value;
+       ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
+
+       wm8350_reg_lock(wm8350);
+       mutex_unlock(&wdt_mutex);
+
+       return ret;
+}
+
+static int wm8350_wdt_start(struct wm8350 *wm8350)
+{
+       int ret;
+       u16 reg;
+
+       mutex_lock(&wdt_mutex);
+       wm8350_reg_unlock(wm8350);
+
+       reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
+       reg &= ~WM8350_WDOG_MODE_MASK;
+       reg |= 0x20;
+       ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
+
+       wm8350_reg_lock(wm8350);
+       mutex_unlock(&wdt_mutex);
+
+       return ret;
+}
+
+static int wm8350_wdt_stop(struct wm8350 *wm8350)
+{
+       int ret;
+       u16 reg;
+
+       mutex_lock(&wdt_mutex);
+       wm8350_reg_unlock(wm8350);
+
+       reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
+       reg &= ~WM8350_WDOG_MODE_MASK;
+       ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
+
+       wm8350_reg_lock(wm8350);
+       mutex_unlock(&wdt_mutex);
+
+       return ret;
+}
+
+static int wm8350_wdt_kick(struct wm8350 *wm8350)
+{
+       int ret;
+       u16 reg;
+
+       mutex_lock(&wdt_mutex);
+
+       reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
+       ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
+
+       mutex_unlock(&wdt_mutex);
+
+       return ret;
+}
+
+static int wm8350_wdt_open(struct inode *inode, struct file *file)
+{
+       struct wm8350 *wm8350 = get_wm8350();
+       int ret;
+
+       if (!wm8350)
+               return -ENODEV;
+
+       if (test_and_set_bit(0, &wm8350_wdt_users))
+               return -EBUSY;
+
+       ret = wm8350_wdt_start(wm8350);
+       if (ret != 0)
+               return ret;
+
+       return nonseekable_open(inode, file);
+}
+
+static int wm8350_wdt_release(struct inode *inode, struct file *file)
+{
+       struct wm8350 *wm8350 = get_wm8350();
+
+       if (wm8350_wdt_expect_close)
+               wm8350_wdt_stop(wm8350);
+       else {
+               dev_warn(wm8350->dev, "Watchdog device closed uncleanly\n");
+               wm8350_wdt_kick(wm8350);
+       }
+
+       clear_bit(0, &wm8350_wdt_users);
+
+       return 0;
+}
+
+static ssize_t wm8350_wdt_write(struct file *file,
+                               const char __user *data, size_t count,
+                               loff_t *ppos)
+{
+       struct wm8350 *wm8350 = get_wm8350();
+       size_t i;
+
+       if (count) {
+               wm8350_wdt_kick(wm8350);
+
+               if (!nowayout) {
+                       /* In case it was set long ago */
+                       wm8350_wdt_expect_close = 0;
+
+                       /* scan to see whether or not we got the magic
+                          character */
+                       for (i = 0; i != count; i++) {
+                               char c;
+                               if (get_user(c, data + i))
+                                       return -EFAULT;
+                               if (c == 'V')
+                                       wm8350_wdt_expect_close = 42;
+                       }
+               }
+       }
+       return count;
+}
+
+static struct watchdog_info ident = {
+       .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+       .identity = "WM8350 Watchdog",
+};
+
+static long wm8350_wdt_ioctl(struct file *file, unsigned int cmd,
+                            unsigned long arg)
+{
+       struct wm8350 *wm8350 = get_wm8350();
+       int ret = -ENOTTY, time, i;
+       void __user *argp = (void __user *)arg;
+       int __user *p = argp;
+       u16 reg;
+
+       switch (cmd) {
+       case WDIOC_GETSUPPORT:
+               ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+               break;
+
+       case WDIOC_GETSTATUS:
+       case WDIOC_GETBOOTSTATUS:
+               ret = put_user(0, p);
+               break;
+
+       case WDIOC_SETOPTIONS:
+       {
+               int options;
+
+               if (get_user(options, p))
+                       return -EFAULT;
+
+               ret = -EINVAL;
+
+               /* Setting both simultaneously means at least one must fail */
+               if (options == WDIOS_DISABLECARD)
+                       ret = wm8350_wdt_start(wm8350);
+
+               if (options == WDIOS_ENABLECARD)
+                       ret = wm8350_wdt_stop(wm8350);
+               break;
+       }
+
+       case WDIOC_KEEPALIVE:
+               ret = wm8350_wdt_kick(wm8350);
+               break;
+
+       case WDIOC_SETTIMEOUT:
+               ret = get_user(time, p);
+               if (ret)
+                       break;
+
+               if (time == 0) {
+                       if (nowayout)
+                               ret = -EINVAL;
+                       else
+                               wm8350_wdt_stop(wm8350);
+                       break;
+               }
+
+               for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
+                       if (wm8350_wdt_cfgs[i].time == time)
+                               break;
+               if (i == ARRAY_SIZE(wm8350_wdt_cfgs))
+                       ret = -EINVAL;
+               else
+                       ret = wm8350_wdt_set_timeout(wm8350,
+                                                    wm8350_wdt_cfgs[i].val);
+               break;
+
+       case WDIOC_GETTIMEOUT:
+               reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
+               reg &= WM8350_WDOG_TO_MASK;
+               for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
+                       if (wm8350_wdt_cfgs[i].val == reg)
+                               break;
+               if (i == ARRAY_SIZE(wm8350_wdt_cfgs)) {
+                       dev_warn(wm8350->dev,
+                                "Unknown watchdog configuration: %x\n", reg);
+                       ret = -EINVAL;
+               } else
+                       ret = put_user(wm8350_wdt_cfgs[i].time, p);
+
+       }
+
+       return ret;
+}
+
+static const struct file_operations wm8350_wdt_fops = {
+       .owner = THIS_MODULE,
+       .llseek = no_llseek,
+       .write = wm8350_wdt_write,
+       .unlocked_ioctl = wm8350_wdt_ioctl,
+       .open = wm8350_wdt_open,
+       .release = wm8350_wdt_release,
+};
+
+static struct miscdevice wm8350_wdt_miscdev = {
+       .minor = WATCHDOG_MINOR,
+       .name = "watchdog",
+       .fops = &wm8350_wdt_fops,
+};
+
+static int wm8350_wdt_probe(struct platform_device *pdev)
+{
+       struct wm8350 *wm8350 = platform_get_drvdata(pdev);
+
+       if (!wm8350) {
+               dev_err(wm8350->dev, "No driver data supplied\n");
+               return -ENODEV;
+       }
+
+       /* Default to 4s timeout */
+       wm8350_wdt_set_timeout(wm8350, 0x05);
+
+       wm8350_wdt_miscdev.parent = &pdev->dev;
+
+       return misc_register(&wm8350_wdt_miscdev);
+}
+
+static int __exit wm8350_wdt_remove(struct platform_device *pdev)
+{
+       misc_deregister(&wm8350_wdt_miscdev);
+
+       return 0;
+}
+
+static struct platform_driver wm8350_wdt_driver = {
+       .probe = wm8350_wdt_probe,
+       .remove = wm8350_wdt_remove,
+       .driver = {
+               .name = "wm8350-wdt",
+       },
+};
+
+static int __init wm8350_wdt_init(void)
+{
+       return platform_driver_register(&wm8350_wdt_driver);
+}
+module_init(wm8350_wdt_init);
+
+static void __exit wm8350_wdt_exit(void)
+{
+       platform_driver_unregister(&wm8350_wdt_driver);
+}
+module_exit(wm8350_wdt_exit);
+
+MODULE_AUTHOR("Mark Brown");
+MODULE_DESCRIPTION("WM8350 Watchdog");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:wm8350-wdt");