276 lines
6.5 KiB
C
276 lines
6.5 KiB
C
/*
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* Copyright (C) Nokia Corporation
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*
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* Written by Timo Kokkonen <timo.t.kokkonen at nokia.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/watchdog.h>
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#include <linux/platform_device.h>
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#include <linux/miscdevice.h>
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#include <linux/uaccess.h>
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#include <linux/i2c/twl.h>
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#define TWL4030_WATCHDOG_CFG_REG_OFFS 0x3
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#define TWL4030_WDT_STATE_OPEN 0x1
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#define TWL4030_WDT_STATE_ACTIVE 0x8
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static struct platform_device *twl4030_wdt_dev;
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struct twl4030_wdt {
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struct miscdevice miscdev;
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int timer_margin;
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unsigned long state;
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};
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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, "Watchdog cannot be stopped once started "
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"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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static int twl4030_wdt_write(unsigned char val)
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{
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return twl_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, val,
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TWL4030_WATCHDOG_CFG_REG_OFFS);
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}
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static int twl4030_wdt_enable(struct twl4030_wdt *wdt)
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{
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return twl4030_wdt_write(wdt->timer_margin + 1);
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}
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static int twl4030_wdt_disable(struct twl4030_wdt *wdt)
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{
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return twl4030_wdt_write(0);
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}
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static int twl4030_wdt_set_timeout(struct twl4030_wdt *wdt, int timeout)
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{
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if (timeout < 0 || timeout > 30) {
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dev_warn(wdt->miscdev.parent,
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"Timeout can only be in the range [0-30] seconds");
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return -EINVAL;
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}
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wdt->timer_margin = timeout;
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return twl4030_wdt_enable(wdt);
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}
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static ssize_t twl4030_wdt_write_fop(struct file *file,
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const char __user *data, size_t len, loff_t *ppos)
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{
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struct twl4030_wdt *wdt = file->private_data;
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if (len)
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twl4030_wdt_enable(wdt);
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return len;
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}
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static long twl4030_wdt_ioctl(struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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void __user *argp = (void __user *)arg;
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int __user *p = argp;
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int new_margin;
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struct twl4030_wdt *wdt = file->private_data;
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static const struct watchdog_info twl4030_wd_ident = {
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.identity = "TWL4030 Watchdog",
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.options = WDIOF_SETTIMEOUT,
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.firmware_version = 0,
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};
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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return copy_to_user(argp, &twl4030_wd_ident,
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sizeof(twl4030_wd_ident)) ? -EFAULT : 0;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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return put_user(0, p);
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case WDIOC_KEEPALIVE:
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twl4030_wdt_enable(wdt);
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break;
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case WDIOC_SETTIMEOUT:
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if (get_user(new_margin, p))
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return -EFAULT;
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if (twl4030_wdt_set_timeout(wdt, new_margin))
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return -EINVAL;
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return put_user(wdt->timer_margin, p);
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case WDIOC_GETTIMEOUT:
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return put_user(wdt->timer_margin, p);
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default:
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return -ENOTTY;
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}
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return 0;
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}
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static int twl4030_wdt_open(struct inode *inode, struct file *file)
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{
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struct twl4030_wdt *wdt = platform_get_drvdata(twl4030_wdt_dev);
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/* /dev/watchdog can only be opened once */
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if (test_and_set_bit(0, &wdt->state))
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return -EBUSY;
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wdt->state |= TWL4030_WDT_STATE_ACTIVE;
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file->private_data = (void *) wdt;
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twl4030_wdt_enable(wdt);
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return nonseekable_open(inode, file);
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}
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static int twl4030_wdt_release(struct inode *inode, struct file *file)
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{
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struct twl4030_wdt *wdt = file->private_data;
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if (nowayout) {
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dev_alert(wdt->miscdev.parent,
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"Unexpected close, watchdog still running!\n");
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twl4030_wdt_enable(wdt);
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} else {
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if (twl4030_wdt_disable(wdt))
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return -EFAULT;
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wdt->state &= ~TWL4030_WDT_STATE_ACTIVE;
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}
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clear_bit(0, &wdt->state);
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return 0;
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}
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static const struct file_operations twl4030_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.open = twl4030_wdt_open,
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.release = twl4030_wdt_release,
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.unlocked_ioctl = twl4030_wdt_ioctl,
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.write = twl4030_wdt_write_fop,
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};
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static int __devinit twl4030_wdt_probe(struct platform_device *pdev)
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{
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int ret = 0;
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struct twl4030_wdt *wdt;
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wdt = kzalloc(sizeof(struct twl4030_wdt), GFP_KERNEL);
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if (!wdt)
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return -ENOMEM;
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wdt->state = 0;
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wdt->timer_margin = 30;
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wdt->miscdev.parent = &pdev->dev;
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wdt->miscdev.fops = &twl4030_wdt_fops;
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wdt->miscdev.minor = WATCHDOG_MINOR;
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wdt->miscdev.name = "watchdog";
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platform_set_drvdata(pdev, wdt);
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twl4030_wdt_dev = pdev;
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twl4030_wdt_disable(wdt);
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ret = misc_register(&wdt->miscdev);
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if (ret) {
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dev_err(wdt->miscdev.parent,
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"Failed to register misc device\n");
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platform_set_drvdata(pdev, NULL);
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kfree(wdt);
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twl4030_wdt_dev = NULL;
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return ret;
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}
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return 0;
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}
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static int __devexit twl4030_wdt_remove(struct platform_device *pdev)
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{
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struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
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if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
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if (twl4030_wdt_disable(wdt))
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return -EFAULT;
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wdt->state &= ~TWL4030_WDT_STATE_ACTIVE;
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misc_deregister(&wdt->miscdev);
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platform_set_drvdata(pdev, NULL);
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kfree(wdt);
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twl4030_wdt_dev = NULL;
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return 0;
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}
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#ifdef CONFIG_PM
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static int twl4030_wdt_suspend(struct platform_device *pdev, pm_message_t state)
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{
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struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
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if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
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return twl4030_wdt_disable(wdt);
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return 0;
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}
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static int twl4030_wdt_resume(struct platform_device *pdev)
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{
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struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
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if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
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return twl4030_wdt_enable(wdt);
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return 0;
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}
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#else
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#define twl4030_wdt_suspend NULL
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#define twl4030_wdt_resume NULL
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#endif
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static struct platform_driver twl4030_wdt_driver = {
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.probe = twl4030_wdt_probe,
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.remove = __devexit_p(twl4030_wdt_remove),
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.suspend = twl4030_wdt_suspend,
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.resume = twl4030_wdt_resume,
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.driver = {
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.owner = THIS_MODULE,
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.name = "twl4030_wdt",
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},
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};
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static int __devinit twl4030_wdt_init(void)
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{
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return platform_driver_register(&twl4030_wdt_driver);
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}
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module_init(twl4030_wdt_init);
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static void __devexit twl4030_wdt_exit(void)
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{
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platform_driver_unregister(&twl4030_wdt_driver);
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}
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module_exit(twl4030_wdt_exit);
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MODULE_AUTHOR("Nokia Corporation");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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MODULE_ALIAS("platform:twl4030_wdt");
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