[WATCHDOG] Add support for WM831x watchdog
The WM831x series of devices provide a watchdog with configurable
behaviour on timer expiry.
Currently this driver support refreshes via a register or GPIO line and
autonomous refreshes from a hardware source (eg, a clock).
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/watchdog/wm831x_wdt.c b/drivers/watchdog/wm831x_wdt.c
new file mode 100644
index 0000000..775bcd8
--- /dev/null
+++ b/drivers/watchdog/wm831x_wdt.c
@@ -0,0 +1,441 @@
+/*
+ * Watchdog driver for the wm831x PMICs
+ *
+ * Copyright (C) 2009 Wolfson Microelectronics
+ *
+ * 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/gpio.h>
+
+#include <linux/mfd/wm831x/core.h>
+#include <linux/mfd/wm831x/pdata.h>
+#include <linux/mfd/wm831x/watchdog.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 wm831x_wdt_users;
+static struct miscdevice wm831x_wdt_miscdev;
+static int wm831x_wdt_expect_close;
+static DEFINE_MUTEX(wdt_mutex);
+static struct wm831x *wm831x;
+static unsigned int update_gpio;
+static unsigned int update_state;
+
+/* We can't use the sub-second values here but they're included
+ * for completeness. */
+static struct {
+ int time; /* Seconds */
+ u16 val; /* WDOG_TO value */
+} wm831x_wdt_cfgs[] = {
+ { 1, 2 },
+ { 2, 3 },
+ { 4, 4 },
+ { 8, 5 },
+ { 16, 6 },
+ { 32, 7 },
+ { 33, 7 }, /* Actually 32.768s so include both, others round down */
+};
+
+static int wm831x_wdt_set_timeout(struct wm831x *wm831x, u16 value)
+{
+ int ret;
+
+ mutex_lock(&wdt_mutex);
+
+ ret = wm831x_reg_unlock(wm831x);
+ if (ret == 0) {
+ ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
+ WM831X_WDOG_TO_MASK, value);
+ wm831x_reg_lock(wm831x);
+ } else {
+ dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
+ ret);
+ }
+
+ mutex_unlock(&wdt_mutex);
+
+ return ret;
+}
+
+static int wm831x_wdt_start(struct wm831x *wm831x)
+{
+ int ret;
+
+ mutex_lock(&wdt_mutex);
+
+ ret = wm831x_reg_unlock(wm831x);
+ if (ret == 0) {
+ ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
+ WM831X_WDOG_ENA, WM831X_WDOG_ENA);
+ wm831x_reg_lock(wm831x);
+ } else {
+ dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
+ ret);
+ }
+
+ mutex_unlock(&wdt_mutex);
+
+ return ret;
+}
+
+static int wm831x_wdt_stop(struct wm831x *wm831x)
+{
+ int ret;
+
+ mutex_lock(&wdt_mutex);
+
+ ret = wm831x_reg_unlock(wm831x);
+ if (ret == 0) {
+ ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
+ WM831X_WDOG_ENA, 0);
+ wm831x_reg_lock(wm831x);
+ } else {
+ dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
+ ret);
+ }
+
+ mutex_unlock(&wdt_mutex);
+
+ return ret;
+}
+
+static int wm831x_wdt_kick(struct wm831x *wm831x)
+{
+ int ret;
+ u16 reg;
+
+ mutex_lock(&wdt_mutex);
+
+ if (update_gpio) {
+ gpio_set_value_cansleep(update_gpio, update_state);
+ update_state = !update_state;
+ ret = 0;
+ goto out;
+ }
+
+
+ reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
+
+ if (!(reg & WM831X_WDOG_RST_SRC)) {
+ dev_err(wm831x->dev, "Hardware watchdog update unsupported\n");
+ ret = -EINVAL;
+ goto out;
+ }
+
+ reg |= WM831X_WDOG_RESET;
+
+ ret = wm831x_reg_unlock(wm831x);
+ if (ret == 0) {
+ ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
+ wm831x_reg_lock(wm831x);
+ } else {
+ dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
+ ret);
+ }
+
+out:
+ mutex_unlock(&wdt_mutex);
+
+ return ret;
+}
+
+static int wm831x_wdt_open(struct inode *inode, struct file *file)
+{
+ int ret;
+
+ if (!wm831x)
+ return -ENODEV;
+
+ if (test_and_set_bit(0, &wm831x_wdt_users))
+ return -EBUSY;
+
+ ret = wm831x_wdt_start(wm831x);
+ if (ret != 0)
+ return ret;
+
+ return nonseekable_open(inode, file);
+}
+
+static int wm831x_wdt_release(struct inode *inode, struct file *file)
+{
+ if (wm831x_wdt_expect_close)
+ wm831x_wdt_stop(wm831x);
+ else {
+ dev_warn(wm831x->dev, "Watchdog device closed uncleanly\n");
+ wm831x_wdt_kick(wm831x);
+ }
+
+ clear_bit(0, &wm831x_wdt_users);
+
+ return 0;
+}
+
+static ssize_t wm831x_wdt_write(struct file *file,
+ const char __user *data, size_t count,
+ loff_t *ppos)
+{
+ size_t i;
+
+ if (count) {
+ wm831x_wdt_kick(wm831x);
+
+ if (!nowayout) {
+ /* In case it was set long ago */
+ wm831x_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')
+ wm831x_wdt_expect_close = 42;
+ }
+ }
+ }
+ return count;
+}
+
+static struct watchdog_info ident = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+ .identity = "WM831x Watchdog",
+};
+
+static long wm831x_wdt_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ 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 = wm831x_wdt_start(wm831x);
+
+ if (options == WDIOS_ENABLECARD)
+ ret = wm831x_wdt_stop(wm831x);
+ break;
+ }
+
+ case WDIOC_KEEPALIVE:
+ ret = wm831x_wdt_kick(wm831x);
+ break;
+
+ case WDIOC_SETTIMEOUT:
+ ret = get_user(time, p);
+ if (ret)
+ break;
+
+ if (time == 0) {
+ if (nowayout)
+ ret = -EINVAL;
+ else
+ wm831x_wdt_stop(wm831x);
+ break;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
+ if (wm831x_wdt_cfgs[i].time == time)
+ break;
+ if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
+ ret = -EINVAL;
+ else
+ ret = wm831x_wdt_set_timeout(wm831x,
+ wm831x_wdt_cfgs[i].val);
+ break;
+
+ case WDIOC_GETTIMEOUT:
+ reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
+ reg &= WM831X_WDOG_TO_MASK;
+ for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
+ if (wm831x_wdt_cfgs[i].val == reg)
+ break;
+ if (i == ARRAY_SIZE(wm831x_wdt_cfgs)) {
+ dev_warn(wm831x->dev,
+ "Unknown watchdog configuration: %x\n", reg);
+ ret = -EINVAL;
+ } else
+ ret = put_user(wm831x_wdt_cfgs[i].time, p);
+
+ }
+
+ return ret;
+}
+
+static const struct file_operations wm831x_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = wm831x_wdt_write,
+ .unlocked_ioctl = wm831x_wdt_ioctl,
+ .open = wm831x_wdt_open,
+ .release = wm831x_wdt_release,
+};
+
+static struct miscdevice wm831x_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &wm831x_wdt_fops,
+};
+
+static int __devinit wm831x_wdt_probe(struct platform_device *pdev)
+{
+ struct wm831x_pdata *chip_pdata;
+ struct wm831x_watchdog_pdata *pdata;
+ int reg, ret;
+
+ wm831x = dev_get_drvdata(pdev->dev.parent);
+
+ ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
+ if (ret < 0) {
+ dev_err(wm831x->dev, "Failed to read watchdog status: %d\n",
+ ret);
+ goto err;
+ }
+ reg = ret;
+
+ if (reg & WM831X_WDOG_DEBUG)
+ dev_warn(wm831x->dev, "Watchdog is paused\n");
+
+ /* Apply any configuration */
+ if (pdev->dev.parent->platform_data) {
+ chip_pdata = pdev->dev.parent->platform_data;
+ pdata = chip_pdata->watchdog;
+ } else {
+ pdata = NULL;
+ }
+
+ if (pdata) {
+ reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK |
+ WM831X_WDOG_RST_SRC);
+
+ reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT;
+ reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT;
+ reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT;
+
+ if (pdata->update_gpio) {
+ ret = gpio_request(pdata->update_gpio,
+ "Watchdog update");
+ if (ret < 0) {
+ dev_err(wm831x->dev,
+ "Failed to request update GPIO: %d\n",
+ ret);
+ goto err;
+ }
+
+ ret = gpio_direction_output(pdata->update_gpio, 0);
+ if (ret != 0) {
+ dev_err(wm831x->dev,
+ "gpio_direction_output returned: %d\n",
+ ret);
+ goto err_gpio;
+ }
+
+ update_gpio = pdata->update_gpio;
+
+ /* Make sure the watchdog takes hardware updates */
+ reg |= WM831X_WDOG_RST_SRC;
+ }
+
+ ret = wm831x_reg_unlock(wm831x);
+ if (ret == 0) {
+ ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
+ wm831x_reg_lock(wm831x);
+ } else {
+ dev_err(wm831x->dev,
+ "Failed to unlock security key: %d\n", ret);
+ goto err_gpio;
+ }
+ }
+
+ wm831x_wdt_miscdev.parent = &pdev->dev;
+
+ ret = misc_register(&wm831x_wdt_miscdev);
+ if (ret != 0) {
+ dev_err(wm831x->dev, "Failed to register miscdev: %d\n", ret);
+ goto err_gpio;
+ }
+
+ return 0;
+
+err_gpio:
+ if (update_gpio) {
+ gpio_free(update_gpio);
+ update_gpio = 0;
+ }
+err:
+ return ret;
+}
+
+static int __devexit wm831x_wdt_remove(struct platform_device *pdev)
+{
+ if (update_gpio) {
+ gpio_free(update_gpio);
+ update_gpio = 0;
+ }
+
+ misc_deregister(&wm831x_wdt_miscdev);
+
+ return 0;
+}
+
+static struct platform_driver wm831x_wdt_driver = {
+ .probe = wm831x_wdt_probe,
+ .remove = __devexit_p(wm831x_wdt_remove),
+ .driver = {
+ .name = "wm831x-watchdog",
+ },
+};
+
+static int __init wm831x_wdt_init(void)
+{
+ return platform_driver_register(&wm831x_wdt_driver);
+}
+module_init(wm831x_wdt_init);
+
+static void __exit wm831x_wdt_exit(void)
+{
+ platform_driver_unregister(&wm831x_wdt_driver);
+}
+module_exit(wm831x_wdt_exit);
+
+MODULE_AUTHOR("Mark Brown");
+MODULE_DESCRIPTION("WM831x Watchdog");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:wm831x-watchdog");