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fa21a580de
A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
246 lines
5.7 KiB
C
246 lines
5.7 KiB
C
/*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation.
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*
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* Copyright (C) 2010 John Crispin <blogic@openwrt.org>
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* Based on EP93xx wdt driver
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/of_platform.h>
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#include <linux/uaccess.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <lantiq_soc.h>
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/*
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* Section 3.4 of the datasheet
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* The password sequence protects the WDT control register from unintended
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* write actions, which might cause malfunction of the WDT.
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*
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* essentially the following two magic passwords need to be written to allow
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* IO access to the WDT core
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*/
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#define LTQ_WDT_PW1 0x00BE0000
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#define LTQ_WDT_PW2 0x00DC0000
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#define LTQ_WDT_CR 0x0 /* watchdog control register */
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#define LTQ_WDT_SR 0x8 /* watchdog status register */
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#define LTQ_WDT_SR_EN (0x1 << 31) /* enable bit */
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#define LTQ_WDT_SR_PWD (0x3 << 26) /* turn on power */
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#define LTQ_WDT_SR_CLKDIV (0x3 << 24) /* turn on clock and set */
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/* divider to 0x40000 */
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#define LTQ_WDT_DIVIDER 0x40000
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#define LTQ_MAX_TIMEOUT ((1 << 16) - 1) /* the reload field is 16 bit */
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static bool nowayout = WATCHDOG_NOWAYOUT;
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static void __iomem *ltq_wdt_membase;
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static unsigned long ltq_io_region_clk_rate;
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static unsigned long ltq_wdt_bootstatus;
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static unsigned long ltq_wdt_in_use;
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static int ltq_wdt_timeout = 30;
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static int ltq_wdt_ok_to_close;
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static void
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ltq_wdt_enable(void)
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{
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unsigned long int timeout = ltq_wdt_timeout *
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(ltq_io_region_clk_rate / LTQ_WDT_DIVIDER) + 0x1000;
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if (timeout > LTQ_MAX_TIMEOUT)
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timeout = LTQ_MAX_TIMEOUT;
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/* write the first password magic */
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ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR);
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/* write the second magic plus the configuration and new timeout */
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ltq_w32(LTQ_WDT_SR_EN | LTQ_WDT_SR_PWD | LTQ_WDT_SR_CLKDIV |
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LTQ_WDT_PW2 | timeout, ltq_wdt_membase + LTQ_WDT_CR);
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}
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static void
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ltq_wdt_disable(void)
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{
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/* write the first password magic */
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ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR);
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/*
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* write the second password magic with no config
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* this turns the watchdog off
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*/
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ltq_w32(LTQ_WDT_PW2, ltq_wdt_membase + LTQ_WDT_CR);
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}
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static ssize_t
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ltq_wdt_write(struct file *file, const char __user *data,
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size_t len, loff_t *ppos)
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{
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if (len) {
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if (!nowayout) {
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size_t i;
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ltq_wdt_ok_to_close = 0;
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for (i = 0; i != len; 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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ltq_wdt_ok_to_close = 1;
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else
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ltq_wdt_ok_to_close = 0;
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}
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}
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ltq_wdt_enable();
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}
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return len;
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}
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static struct watchdog_info ident = {
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.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
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WDIOF_CARDRESET,
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.identity = "ltq_wdt",
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};
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static long
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ltq_wdt_ioctl(struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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int ret = -ENOTTY;
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
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sizeof(ident)) ? -EFAULT : 0;
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break;
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case WDIOC_GETBOOTSTATUS:
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ret = put_user(ltq_wdt_bootstatus, (int __user *)arg);
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break;
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case WDIOC_GETSTATUS:
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ret = put_user(0, (int __user *)arg);
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break;
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case WDIOC_SETTIMEOUT:
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ret = get_user(ltq_wdt_timeout, (int __user *)arg);
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if (!ret)
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ltq_wdt_enable();
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/* intentional drop through */
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case WDIOC_GETTIMEOUT:
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ret = put_user(ltq_wdt_timeout, (int __user *)arg);
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break;
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case WDIOC_KEEPALIVE:
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ltq_wdt_enable();
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ret = 0;
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break;
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}
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return ret;
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}
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static int
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ltq_wdt_open(struct inode *inode, struct file *file)
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{
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if (test_and_set_bit(0, <q_wdt_in_use))
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return -EBUSY;
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ltq_wdt_in_use = 1;
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ltq_wdt_enable();
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return nonseekable_open(inode, file);
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}
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static int
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ltq_wdt_release(struct inode *inode, struct file *file)
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{
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if (ltq_wdt_ok_to_close)
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ltq_wdt_disable();
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else
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pr_err("watchdog closed without warning\n");
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ltq_wdt_ok_to_close = 0;
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clear_bit(0, <q_wdt_in_use);
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return 0;
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}
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static const struct file_operations ltq_wdt_fops = {
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.owner = THIS_MODULE,
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.write = ltq_wdt_write,
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.unlocked_ioctl = ltq_wdt_ioctl,
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.open = ltq_wdt_open,
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.release = ltq_wdt_release,
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.llseek = no_llseek,
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};
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static struct miscdevice ltq_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = <q_wdt_fops,
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};
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static int
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ltq_wdt_probe(struct platform_device *pdev)
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{
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struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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struct clk *clk;
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ltq_wdt_membase = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(ltq_wdt_membase))
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return PTR_ERR(ltq_wdt_membase);
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/* we do not need to enable the clock as it is always running */
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clk = clk_get_io();
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if (IS_ERR(clk)) {
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dev_err(&pdev->dev, "Failed to get clock\n");
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return -ENOENT;
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}
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ltq_io_region_clk_rate = clk_get_rate(clk);
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clk_put(clk);
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/* find out if the watchdog caused the last reboot */
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if (ltq_reset_cause() == LTQ_RST_CAUSE_WDTRST)
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ltq_wdt_bootstatus = WDIOF_CARDRESET;
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dev_info(&pdev->dev, "Init done\n");
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return misc_register(<q_wdt_miscdev);
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}
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static int
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ltq_wdt_remove(struct platform_device *pdev)
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{
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misc_deregister(<q_wdt_miscdev);
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return 0;
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}
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static const struct of_device_id ltq_wdt_match[] = {
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{ .compatible = "lantiq,wdt" },
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{},
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};
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MODULE_DEVICE_TABLE(of, ltq_wdt_match);
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static struct platform_driver ltq_wdt_driver = {
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.probe = ltq_wdt_probe,
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.remove = ltq_wdt_remove,
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.driver = {
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.name = "wdt",
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.of_match_table = ltq_wdt_match,
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},
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};
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module_platform_driver(ltq_wdt_driver);
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
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MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
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MODULE_DESCRIPTION("Lantiq SoC Watchdog");
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MODULE_LICENSE("GPL");
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