442 lines
9.1 KiB
C
442 lines
9.1 KiB
C
/*
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* Watchdog driver for the wm831x PMICs
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*
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* Copyright (C) 2009 Wolfson Microelectronics
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/miscdevice.h>
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#include <linux/platform_device.h>
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#include <linux/watchdog.h>
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#include <linux/uaccess.h>
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#include <linux/gpio.h>
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#include <linux/mfd/wm831x/core.h>
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#include <linux/mfd/wm831x/pdata.h>
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#include <linux/mfd/wm831x/watchdog.h>
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static int nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, int, 0);
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MODULE_PARM_DESC(nowayout,
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"Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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static unsigned long wm831x_wdt_users;
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static struct miscdevice wm831x_wdt_miscdev;
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static int wm831x_wdt_expect_close;
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static DEFINE_MUTEX(wdt_mutex);
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static struct wm831x *wm831x;
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static unsigned int update_gpio;
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static unsigned int update_state;
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/* We can't use the sub-second values here but they're included
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* for completeness. */
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static struct {
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int time; /* Seconds */
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u16 val; /* WDOG_TO value */
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} wm831x_wdt_cfgs[] = {
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{ 1, 2 },
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{ 2, 3 },
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{ 4, 4 },
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{ 8, 5 },
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{ 16, 6 },
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{ 32, 7 },
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{ 33, 7 }, /* Actually 32.768s so include both, others round down */
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};
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static int wm831x_wdt_set_timeout(struct wm831x *wm831x, u16 value)
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{
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int ret;
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mutex_lock(&wdt_mutex);
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ret = wm831x_reg_unlock(wm831x);
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if (ret == 0) {
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ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
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WM831X_WDOG_TO_MASK, value);
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wm831x_reg_lock(wm831x);
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} else {
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dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
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ret);
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}
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mutex_unlock(&wdt_mutex);
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return ret;
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}
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static int wm831x_wdt_start(struct wm831x *wm831x)
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{
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int ret;
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mutex_lock(&wdt_mutex);
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ret = wm831x_reg_unlock(wm831x);
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if (ret == 0) {
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ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
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WM831X_WDOG_ENA, WM831X_WDOG_ENA);
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wm831x_reg_lock(wm831x);
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} else {
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dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
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ret);
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}
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mutex_unlock(&wdt_mutex);
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return ret;
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}
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static int wm831x_wdt_stop(struct wm831x *wm831x)
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{
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int ret;
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mutex_lock(&wdt_mutex);
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ret = wm831x_reg_unlock(wm831x);
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if (ret == 0) {
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ret = wm831x_set_bits(wm831x, WM831X_WATCHDOG,
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WM831X_WDOG_ENA, 0);
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wm831x_reg_lock(wm831x);
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} else {
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dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
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ret);
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}
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mutex_unlock(&wdt_mutex);
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return ret;
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}
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static int wm831x_wdt_kick(struct wm831x *wm831x)
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{
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int ret;
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u16 reg;
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mutex_lock(&wdt_mutex);
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if (update_gpio) {
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gpio_set_value_cansleep(update_gpio, update_state);
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update_state = !update_state;
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ret = 0;
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goto out;
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}
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reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
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if (!(reg & WM831X_WDOG_RST_SRC)) {
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dev_err(wm831x->dev, "Hardware watchdog update unsupported\n");
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ret = -EINVAL;
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goto out;
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}
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reg |= WM831X_WDOG_RESET;
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ret = wm831x_reg_unlock(wm831x);
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if (ret == 0) {
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ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
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wm831x_reg_lock(wm831x);
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} else {
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dev_err(wm831x->dev, "Failed to unlock security key: %d\n",
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ret);
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}
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out:
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mutex_unlock(&wdt_mutex);
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return ret;
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}
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static int wm831x_wdt_open(struct inode *inode, struct file *file)
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{
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int ret;
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if (!wm831x)
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return -ENODEV;
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if (test_and_set_bit(0, &wm831x_wdt_users))
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return -EBUSY;
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ret = wm831x_wdt_start(wm831x);
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if (ret != 0)
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return ret;
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return nonseekable_open(inode, file);
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}
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static int wm831x_wdt_release(struct inode *inode, struct file *file)
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{
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if (wm831x_wdt_expect_close)
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wm831x_wdt_stop(wm831x);
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else {
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dev_warn(wm831x->dev, "Watchdog device closed uncleanly\n");
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wm831x_wdt_kick(wm831x);
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}
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clear_bit(0, &wm831x_wdt_users);
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return 0;
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}
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static ssize_t wm831x_wdt_write(struct file *file,
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const char __user *data, size_t count,
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loff_t *ppos)
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{
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size_t i;
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if (count) {
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wm831x_wdt_kick(wm831x);
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if (!nowayout) {
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/* In case it was set long ago */
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wm831x_wdt_expect_close = 0;
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/* scan to see whether or not we got the magic
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character */
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for (i = 0; i != count; i++) {
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char c;
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if (get_user(c, data + i))
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return -EFAULT;
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if (c == 'V')
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wm831x_wdt_expect_close = 42;
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}
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}
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}
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return count;
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}
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static const struct watchdog_info ident = {
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
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.identity = "WM831x Watchdog",
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};
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static long wm831x_wdt_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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int ret = -ENOTTY, time, i;
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void __user *argp = (void __user *)arg;
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int __user *p = argp;
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u16 reg;
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
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break;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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ret = put_user(0, p);
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break;
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case WDIOC_SETOPTIONS:
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{
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int options;
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if (get_user(options, p))
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return -EFAULT;
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ret = -EINVAL;
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/* Setting both simultaneously means at least one must fail */
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if (options == WDIOS_DISABLECARD)
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ret = wm831x_wdt_start(wm831x);
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if (options == WDIOS_ENABLECARD)
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ret = wm831x_wdt_stop(wm831x);
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break;
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}
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case WDIOC_KEEPALIVE:
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ret = wm831x_wdt_kick(wm831x);
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break;
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case WDIOC_SETTIMEOUT:
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ret = get_user(time, p);
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if (ret)
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break;
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if (time == 0) {
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if (nowayout)
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ret = -EINVAL;
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else
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wm831x_wdt_stop(wm831x);
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break;
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}
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for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
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if (wm831x_wdt_cfgs[i].time == time)
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break;
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if (i == ARRAY_SIZE(wm831x_wdt_cfgs))
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ret = -EINVAL;
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else
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ret = wm831x_wdt_set_timeout(wm831x,
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wm831x_wdt_cfgs[i].val);
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break;
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case WDIOC_GETTIMEOUT:
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reg = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
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reg &= WM831X_WDOG_TO_MASK;
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for (i = 0; i < ARRAY_SIZE(wm831x_wdt_cfgs); i++)
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if (wm831x_wdt_cfgs[i].val == reg)
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break;
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if (i == ARRAY_SIZE(wm831x_wdt_cfgs)) {
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dev_warn(wm831x->dev,
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"Unknown watchdog configuration: %x\n", reg);
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ret = -EINVAL;
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} else
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ret = put_user(wm831x_wdt_cfgs[i].time, p);
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}
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return ret;
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}
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static const struct file_operations wm831x_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = wm831x_wdt_write,
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.unlocked_ioctl = wm831x_wdt_ioctl,
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.open = wm831x_wdt_open,
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.release = wm831x_wdt_release,
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};
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static struct miscdevice wm831x_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &wm831x_wdt_fops,
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};
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static int __devinit wm831x_wdt_probe(struct platform_device *pdev)
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{
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struct wm831x_pdata *chip_pdata;
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struct wm831x_watchdog_pdata *pdata;
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int reg, ret;
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wm831x = dev_get_drvdata(pdev->dev.parent);
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ret = wm831x_reg_read(wm831x, WM831X_WATCHDOG);
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if (ret < 0) {
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dev_err(wm831x->dev, "Failed to read watchdog status: %d\n",
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ret);
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goto err;
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}
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reg = ret;
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if (reg & WM831X_WDOG_DEBUG)
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dev_warn(wm831x->dev, "Watchdog is paused\n");
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/* Apply any configuration */
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if (pdev->dev.parent->platform_data) {
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chip_pdata = pdev->dev.parent->platform_data;
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pdata = chip_pdata->watchdog;
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} else {
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pdata = NULL;
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}
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if (pdata) {
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reg &= ~(WM831X_WDOG_SECACT_MASK | WM831X_WDOG_PRIMACT_MASK |
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WM831X_WDOG_RST_SRC);
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reg |= pdata->primary << WM831X_WDOG_PRIMACT_SHIFT;
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reg |= pdata->secondary << WM831X_WDOG_SECACT_SHIFT;
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reg |= pdata->software << WM831X_WDOG_RST_SRC_SHIFT;
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if (pdata->update_gpio) {
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ret = gpio_request(pdata->update_gpio,
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"Watchdog update");
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if (ret < 0) {
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dev_err(wm831x->dev,
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"Failed to request update GPIO: %d\n",
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ret);
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goto err;
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}
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ret = gpio_direction_output(pdata->update_gpio, 0);
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if (ret != 0) {
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dev_err(wm831x->dev,
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"gpio_direction_output returned: %d\n",
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ret);
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goto err_gpio;
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}
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update_gpio = pdata->update_gpio;
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/* Make sure the watchdog takes hardware updates */
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reg |= WM831X_WDOG_RST_SRC;
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}
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ret = wm831x_reg_unlock(wm831x);
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if (ret == 0) {
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ret = wm831x_reg_write(wm831x, WM831X_WATCHDOG, reg);
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wm831x_reg_lock(wm831x);
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} else {
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dev_err(wm831x->dev,
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"Failed to unlock security key: %d\n", ret);
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goto err_gpio;
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}
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}
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wm831x_wdt_miscdev.parent = &pdev->dev;
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ret = misc_register(&wm831x_wdt_miscdev);
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if (ret != 0) {
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dev_err(wm831x->dev, "Failed to register miscdev: %d\n", ret);
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goto err_gpio;
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}
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return 0;
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err_gpio:
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if (update_gpio) {
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gpio_free(update_gpio);
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update_gpio = 0;
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}
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err:
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return ret;
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}
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static int __devexit wm831x_wdt_remove(struct platform_device *pdev)
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{
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if (update_gpio) {
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gpio_free(update_gpio);
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update_gpio = 0;
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}
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misc_deregister(&wm831x_wdt_miscdev);
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return 0;
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}
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static struct platform_driver wm831x_wdt_driver = {
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.probe = wm831x_wdt_probe,
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.remove = __devexit_p(wm831x_wdt_remove),
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.driver = {
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.name = "wm831x-watchdog",
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},
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};
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static int __init wm831x_wdt_init(void)
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{
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return platform_driver_register(&wm831x_wdt_driver);
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}
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module_init(wm831x_wdt_init);
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static void __exit wm831x_wdt_exit(void)
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{
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platform_driver_unregister(&wm831x_wdt_driver);
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}
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module_exit(wm831x_wdt_exit);
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MODULE_AUTHOR("Mark Brown");
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MODULE_DESCRIPTION("WM831x Watchdog");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:wm831x-watchdog");
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