330 lines
6.8 KiB
C
330 lines
6.8 KiB
C
/*
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* Watchdog driver for the wm8350
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*
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* Copyright (C) 2007, 2008 Wolfson Microelectronics <linux@wolfsonmicro.com>
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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/mfd/wm8350/core.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 wm8350_wdt_users;
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static struct miscdevice wm8350_wdt_miscdev;
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static int wm8350_wdt_expect_close;
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static DEFINE_MUTEX(wdt_mutex);
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static struct {
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int time; /* Seconds */
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u16 val; /* To be set in WM8350_SYSTEM_CONTROL_2 */
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} wm8350_wdt_cfgs[] = {
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{ 1, 0x02 },
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{ 2, 0x04 },
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{ 4, 0x05 },
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};
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static struct wm8350 *get_wm8350(void)
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{
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return dev_get_drvdata(wm8350_wdt_miscdev.parent);
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}
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static int wm8350_wdt_set_timeout(struct wm8350 *wm8350, u16 value)
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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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wm8350_reg_unlock(wm8350);
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reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
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reg &= ~WM8350_WDOG_TO_MASK;
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reg |= value;
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ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
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wm8350_reg_lock(wm8350);
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mutex_unlock(&wdt_mutex);
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return ret;
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}
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static int wm8350_wdt_start(struct wm8350 *wm8350)
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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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wm8350_reg_unlock(wm8350);
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reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
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reg &= ~WM8350_WDOG_MODE_MASK;
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reg |= 0x20;
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ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
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wm8350_reg_lock(wm8350);
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mutex_unlock(&wdt_mutex);
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return ret;
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}
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static int wm8350_wdt_stop(struct wm8350 *wm8350)
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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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wm8350_reg_unlock(wm8350);
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reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
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reg &= ~WM8350_WDOG_MODE_MASK;
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ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
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wm8350_reg_lock(wm8350);
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mutex_unlock(&wdt_mutex);
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return ret;
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}
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static int wm8350_wdt_kick(struct wm8350 *wm8350)
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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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reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
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ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg);
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mutex_unlock(&wdt_mutex);
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return ret;
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}
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static int wm8350_wdt_open(struct inode *inode, struct file *file)
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{
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struct wm8350 *wm8350 = get_wm8350();
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int ret;
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if (!wm8350)
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return -ENODEV;
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if (test_and_set_bit(0, &wm8350_wdt_users))
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return -EBUSY;
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ret = wm8350_wdt_start(wm8350);
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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 wm8350_wdt_release(struct inode *inode, struct file *file)
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{
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struct wm8350 *wm8350 = get_wm8350();
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if (wm8350_wdt_expect_close)
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wm8350_wdt_stop(wm8350);
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else {
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dev_warn(wm8350->dev, "Watchdog device closed uncleanly\n");
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wm8350_wdt_kick(wm8350);
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}
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clear_bit(0, &wm8350_wdt_users);
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return 0;
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}
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static ssize_t wm8350_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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struct wm8350 *wm8350 = get_wm8350();
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size_t i;
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if (count) {
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wm8350_wdt_kick(wm8350);
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if (!nowayout) {
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/* In case it was set long ago */
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wm8350_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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wm8350_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 = "WM8350 Watchdog",
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};
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static long wm8350_wdt_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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struct wm8350 *wm8350 = get_wm8350();
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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 = wm8350_wdt_start(wm8350);
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if (options == WDIOS_ENABLECARD)
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ret = wm8350_wdt_stop(wm8350);
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break;
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}
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case WDIOC_KEEPALIVE:
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ret = wm8350_wdt_kick(wm8350);
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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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wm8350_wdt_stop(wm8350);
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break;
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}
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for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
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if (wm8350_wdt_cfgs[i].time == time)
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break;
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if (i == ARRAY_SIZE(wm8350_wdt_cfgs))
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ret = -EINVAL;
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else
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ret = wm8350_wdt_set_timeout(wm8350,
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wm8350_wdt_cfgs[i].val);
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break;
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case WDIOC_GETTIMEOUT:
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reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2);
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reg &= WM8350_WDOG_TO_MASK;
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for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++)
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if (wm8350_wdt_cfgs[i].val == reg)
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break;
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if (i == ARRAY_SIZE(wm8350_wdt_cfgs)) {
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dev_warn(wm8350->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(wm8350_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 wm8350_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = wm8350_wdt_write,
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.unlocked_ioctl = wm8350_wdt_ioctl,
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.open = wm8350_wdt_open,
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.release = wm8350_wdt_release,
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};
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static struct miscdevice wm8350_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &wm8350_wdt_fops,
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};
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static int __devinit wm8350_wdt_probe(struct platform_device *pdev)
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{
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struct wm8350 *wm8350 = platform_get_drvdata(pdev);
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if (!wm8350) {
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pr_err("No driver data supplied\n");
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return -ENODEV;
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}
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/* Default to 4s timeout */
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wm8350_wdt_set_timeout(wm8350, 0x05);
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wm8350_wdt_miscdev.parent = &pdev->dev;
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return misc_register(&wm8350_wdt_miscdev);
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}
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static int __devexit wm8350_wdt_remove(struct platform_device *pdev)
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{
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misc_deregister(&wm8350_wdt_miscdev);
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return 0;
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}
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static struct platform_driver wm8350_wdt_driver = {
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.probe = wm8350_wdt_probe,
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.remove = __devexit_p(wm8350_wdt_remove),
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.driver = {
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.name = "wm8350-wdt",
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},
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};
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static int __init wm8350_wdt_init(void)
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{
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return platform_driver_register(&wm8350_wdt_driver);
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}
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module_init(wm8350_wdt_init);
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static void __exit wm8350_wdt_exit(void)
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{
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platform_driver_unregister(&wm8350_wdt_driver);
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}
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module_exit(wm8350_wdt_exit);
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MODULE_AUTHOR("Mark Brown");
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MODULE_DESCRIPTION("WM8350 Watchdog");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:wm8350-wdt");
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