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Date: Thu, 6 Nov 2008 10:56:21 +0000
From: Mark Brown <broonie@...nsource.wolfsonmicro.com>
To: Wim Van Sebroeck <wim@...ana.be>
Cc: linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>,
Mark Brown <broonie@...nsource.wolfsonmicro.com>
Subject: [PATCH] watchdog: Add support for the WM8350 watchdog
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@...nsource.wolfsonmicro.com>
---
Since last submission the driver has been changed to use bit zero rather
than bit 1 when using test_and_set_bit() to ensure that we only have
one user.
drivers/watchdog/Kconfig | 7 +
drivers/watchdog/Makefile | 1 +
drivers/watchdog/wm8350_wdt.c | 329 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 337 insertions(+), 0 deletions(-)
create mode 100644 drivers/watchdog/wm8350_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 4fd3fa5..d5bc085 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -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
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index e352bbb..c3b8db3 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -134,3 +134,4 @@ obj-$(CONFIG_WATCHDOG_CP1XXX) += cpwd.o
# Architecture Independant
obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
+obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
diff --git a/drivers/watchdog/wm8350_wdt.c b/drivers/watchdog/wm8350_wdt.c
new file mode 100644
index 0000000..d7b8ad4
--- /dev/null
+++ b/drivers/watchdog/wm8350_wdt.c
@@ -0,0 +1,329 @@
+/*
+ * Watchdog driver for the wm8350
+ *
+ * Copyright (C) 2007, 2008 Wolfson Microelectronics <linux@...fsonmicro.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_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);
+ break;
+
+ case WDIOC_KEEPALIVE:
+ ret = wm8350_wdt_kick(wm8350);
+ 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);
+ }
+
+ }
+
+ 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");
--
1.5.6.5
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