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    Subject[PATCH 22/22] [WATCHDOG] Add support for WM831x watchdog
    Date
    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>
    Cc: Wim Van Sebroeck <wim@iguana.be>
    ---
    drivers/watchdog/Kconfig | 7 +
    drivers/watchdog/Makefile | 1 +
    drivers/watchdog/wm831x_wdt.c | 441 +++++++++++++++++++++++++++++++++++
    include/linux/mfd/wm831x/watchdog.h | 52 ++++
    4 files changed, 501 insertions(+), 0 deletions(-)
    create mode 100644 drivers/watchdog/wm831x_wdt.c
    create mode 100644 include/linux/mfd/wm831x/watchdog.h

    diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
    index b1ccc04..2d22ab6 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 WM831X_WATCHDOG
    + tristate "WM831x watchdog"
    + depends on MFD_WM831X
    + help
    + Support for the watchdog in the WM831x AudioPlus PMICs. When
    + the watchdog triggers the system will be reset.
    +
    config WM8350_WATCHDOG
    tristate "WM8350 watchdog"
    depends on MFD_WM8350
    diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
    index 3d77429..244be98 100644
    --- a/drivers/watchdog/Makefile
    +++ b/drivers/watchdog/Makefile
    @@ -139,5 +139,6 @@ obj-$(CONFIG_WATCHDOG_CP1XXX) += cpwd.o
    # XTENSA Architecture

    # Architecture Independant
    +obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
    obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
    obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
    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");
    diff --git a/include/linux/mfd/wm831x/watchdog.h b/include/linux/mfd/wm831x/watchdog.h
    new file mode 100644
    index 0000000..97a99b5
    --- /dev/null
    +++ b/include/linux/mfd/wm831x/watchdog.h
    @@ -0,0 +1,52 @@
    +/*
    + * include/linux/mfd/wm831x/watchdog.h -- Watchdog for WM831x
    + *
    + * Copyright 2009 Wolfson Microelectronics PLC.
    + *
    + * Author: Mark Brown <broonie@opensource.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; either version 2 of the License, or (at your
    + * option) any later version.
    + *
    + */
    +
    +#ifndef __MFD_WM831X_WATCHDOG_H__
    +#define __MFD_WM831X_WATCHDOG_H__
    +
    +
    +/*
    + * R16388 (0x4004) - Watchdog
    + */
    +#define WM831X_WDOG_ENA 0x8000 /* WDOG_ENA */
    +#define WM831X_WDOG_ENA_MASK 0x8000 /* WDOG_ENA */
    +#define WM831X_WDOG_ENA_SHIFT 15 /* WDOG_ENA */
    +#define WM831X_WDOG_ENA_WIDTH 1 /* WDOG_ENA */
    +#define WM831X_WDOG_DEBUG 0x4000 /* WDOG_DEBUG */
    +#define WM831X_WDOG_DEBUG_MASK 0x4000 /* WDOG_DEBUG */
    +#define WM831X_WDOG_DEBUG_SHIFT 14 /* WDOG_DEBUG */
    +#define WM831X_WDOG_DEBUG_WIDTH 1 /* WDOG_DEBUG */
    +#define WM831X_WDOG_RST_SRC 0x2000 /* WDOG_RST_SRC */
    +#define WM831X_WDOG_RST_SRC_MASK 0x2000 /* WDOG_RST_SRC */
    +#define WM831X_WDOG_RST_SRC_SHIFT 13 /* WDOG_RST_SRC */
    +#define WM831X_WDOG_RST_SRC_WIDTH 1 /* WDOG_RST_SRC */
    +#define WM831X_WDOG_SLPENA 0x1000 /* WDOG_SLPENA */
    +#define WM831X_WDOG_SLPENA_MASK 0x1000 /* WDOG_SLPENA */
    +#define WM831X_WDOG_SLPENA_SHIFT 12 /* WDOG_SLPENA */
    +#define WM831X_WDOG_SLPENA_WIDTH 1 /* WDOG_SLPENA */
    +#define WM831X_WDOG_RESET 0x0800 /* WDOG_RESET */
    +#define WM831X_WDOG_RESET_MASK 0x0800 /* WDOG_RESET */
    +#define WM831X_WDOG_RESET_SHIFT 11 /* WDOG_RESET */
    +#define WM831X_WDOG_RESET_WIDTH 1 /* WDOG_RESET */
    +#define WM831X_WDOG_SECACT_MASK 0x0300 /* WDOG_SECACT - [9:8] */
    +#define WM831X_WDOG_SECACT_SHIFT 8 /* WDOG_SECACT - [9:8] */
    +#define WM831X_WDOG_SECACT_WIDTH 2 /* WDOG_SECACT - [9:8] */
    +#define WM831X_WDOG_PRIMACT_MASK 0x0030 /* WDOG_PRIMACT - [5:4] */
    +#define WM831X_WDOG_PRIMACT_SHIFT 4 /* WDOG_PRIMACT - [5:4] */
    +#define WM831X_WDOG_PRIMACT_WIDTH 2 /* WDOG_PRIMACT - [5:4] */
    +#define WM831X_WDOG_TO_MASK 0x0007 /* WDOG_TO - [2:0] */
    +#define WM831X_WDOG_TO_SHIFT 0 /* WDOG_TO - [2:0] */
    +#define WM831X_WDOG_TO_WIDTH 3 /* WDOG_TO - [2:0] */
    +
    +#endif
    --
    1.6.3.3


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