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248 lines
5.8 KiB
248 lines
5.8 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* Driver for the MTX-1 Watchdog. |
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* |
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* (C) Copyright 2005 4G Systems <[email protected]>, |
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* All Rights Reserved. |
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* http://www.4g-systems.biz |
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* |
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* (C) Copyright 2007 OpenWrt.org, Florian Fainelli <[email protected]> |
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* (c) Copyright 2005 4G Systems <[email protected]> |
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* |
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* Release 0.01. |
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* Author: Michael Stickel [email protected] |
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* |
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* Release 0.02. |
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* Author: Florian Fainelli [email protected] |
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* use the Linux watchdog/timer APIs |
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* |
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* The Watchdog is configured to reset the MTX-1 |
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* if it is not triggered for 100 seconds. |
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* It should not be triggered more often than 1.6 seconds. |
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* |
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* A timer triggers the watchdog every 5 seconds, until |
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* it is opened for the first time. After the first open |
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* it MUST be triggered every 2..95 seconds. |
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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/errno.h> |
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#include <linux/miscdevice.h> |
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#include <linux/fs.h> |
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#include <linux/ioport.h> |
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#include <linux/timer.h> |
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#include <linux/completion.h> |
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#include <linux/jiffies.h> |
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#include <linux/watchdog.h> |
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#include <linux/platform_device.h> |
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#include <linux/io.h> |
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#include <linux/uaccess.h> |
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#include <linux/gpio/consumer.h> |
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#define MTX1_WDT_INTERVAL (5 * HZ) |
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static int ticks = 100 * HZ; |
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static struct { |
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struct completion stop; |
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spinlock_t lock; |
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int running; |
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struct timer_list timer; |
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int queue; |
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int default_ticks; |
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unsigned long inuse; |
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struct gpio_desc *gpiod; |
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unsigned int gstate; |
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} mtx1_wdt_device; |
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static void mtx1_wdt_trigger(struct timer_list *unused) |
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{ |
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spin_lock(&mtx1_wdt_device.lock); |
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if (mtx1_wdt_device.running) |
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ticks--; |
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/* toggle wdt gpio */ |
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mtx1_wdt_device.gstate = !mtx1_wdt_device.gstate; |
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gpiod_set_value(mtx1_wdt_device.gpiod, mtx1_wdt_device.gstate); |
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if (mtx1_wdt_device.queue && ticks) |
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mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL); |
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else |
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complete(&mtx1_wdt_device.stop); |
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spin_unlock(&mtx1_wdt_device.lock); |
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} |
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static void mtx1_wdt_reset(void) |
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{ |
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ticks = mtx1_wdt_device.default_ticks; |
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} |
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static void mtx1_wdt_start(void) |
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{ |
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unsigned long flags; |
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spin_lock_irqsave(&mtx1_wdt_device.lock, flags); |
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if (!mtx1_wdt_device.queue) { |
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mtx1_wdt_device.queue = 1; |
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mtx1_wdt_device.gstate = 1; |
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gpiod_set_value(mtx1_wdt_device.gpiod, 1); |
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mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL); |
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} |
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mtx1_wdt_device.running++; |
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spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags); |
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} |
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static int mtx1_wdt_stop(void) |
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{ |
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unsigned long flags; |
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spin_lock_irqsave(&mtx1_wdt_device.lock, flags); |
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if (mtx1_wdt_device.queue) { |
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mtx1_wdt_device.queue = 0; |
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mtx1_wdt_device.gstate = 0; |
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gpiod_set_value(mtx1_wdt_device.gpiod, 0); |
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} |
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ticks = mtx1_wdt_device.default_ticks; |
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spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags); |
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return 0; |
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} |
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/* Filesystem functions */ |
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static int mtx1_wdt_open(struct inode *inode, struct file *file) |
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{ |
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if (test_and_set_bit(0, &mtx1_wdt_device.inuse)) |
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return -EBUSY; |
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return stream_open(inode, file); |
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} |
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static int mtx1_wdt_release(struct inode *inode, struct file *file) |
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{ |
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clear_bit(0, &mtx1_wdt_device.inuse); |
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return 0; |
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} |
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static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd, |
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unsigned long arg) |
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{ |
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void __user *argp = (void __user *)arg; |
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int __user *p = (int __user *)argp; |
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unsigned int value; |
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static const struct watchdog_info ident = { |
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.options = WDIOF_CARDRESET, |
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.identity = "MTX-1 WDT", |
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}; |
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switch (cmd) { |
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case WDIOC_GETSUPPORT: |
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if (copy_to_user(argp, &ident, sizeof(ident))) |
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return -EFAULT; |
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break; |
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case WDIOC_GETSTATUS: |
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case WDIOC_GETBOOTSTATUS: |
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put_user(0, p); |
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break; |
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case WDIOC_SETOPTIONS: |
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if (get_user(value, p)) |
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return -EFAULT; |
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if (value & WDIOS_ENABLECARD) |
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mtx1_wdt_start(); |
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else if (value & WDIOS_DISABLECARD) |
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mtx1_wdt_stop(); |
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else |
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return -EINVAL; |
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return 0; |
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case WDIOC_KEEPALIVE: |
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mtx1_wdt_reset(); |
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break; |
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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 ssize_t mtx1_wdt_write(struct file *file, const char *buf, |
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size_t count, loff_t *ppos) |
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{ |
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if (!count) |
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return -EIO; |
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mtx1_wdt_reset(); |
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return count; |
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} |
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static const struct file_operations mtx1_wdt_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.unlocked_ioctl = mtx1_wdt_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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.open = mtx1_wdt_open, |
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.write = mtx1_wdt_write, |
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.release = mtx1_wdt_release, |
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}; |
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static struct miscdevice mtx1_wdt_misc = { |
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.minor = WATCHDOG_MINOR, |
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.name = "watchdog", |
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.fops = &mtx1_wdt_fops, |
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}; |
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static int mtx1_wdt_probe(struct platform_device *pdev) |
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{ |
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int ret; |
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mtx1_wdt_device.gpiod = devm_gpiod_get(&pdev->dev, |
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NULL, GPIOD_OUT_HIGH); |
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if (IS_ERR(mtx1_wdt_device.gpiod)) { |
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dev_err(&pdev->dev, "failed to request gpio"); |
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return PTR_ERR(mtx1_wdt_device.gpiod); |
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} |
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spin_lock_init(&mtx1_wdt_device.lock); |
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init_completion(&mtx1_wdt_device.stop); |
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mtx1_wdt_device.queue = 0; |
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clear_bit(0, &mtx1_wdt_device.inuse); |
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timer_setup(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0); |
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mtx1_wdt_device.default_ticks = ticks; |
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ret = misc_register(&mtx1_wdt_misc); |
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if (ret < 0) { |
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dev_err(&pdev->dev, "failed to register\n"); |
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return ret; |
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} |
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mtx1_wdt_start(); |
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dev_info(&pdev->dev, "MTX-1 Watchdog driver\n"); |
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return 0; |
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} |
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static int mtx1_wdt_remove(struct platform_device *pdev) |
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{ |
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/* FIXME: do we need to lock this test ? */ |
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if (mtx1_wdt_device.queue) { |
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mtx1_wdt_device.queue = 0; |
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wait_for_completion(&mtx1_wdt_device.stop); |
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} |
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misc_deregister(&mtx1_wdt_misc); |
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return 0; |
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} |
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static struct platform_driver mtx1_wdt_driver = { |
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.probe = mtx1_wdt_probe, |
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.remove = mtx1_wdt_remove, |
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.driver.name = "mtx1-wdt", |
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.driver.owner = THIS_MODULE, |
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}; |
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module_platform_driver(mtx1_wdt_driver); |
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MODULE_AUTHOR("Michael Stickel, Florian Fainelli"); |
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MODULE_DESCRIPTION("Driver for the MTX-1 watchdog"); |
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MODULE_LICENSE("GPL"); |
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MODULE_ALIAS("platform:mtx1-wdt");
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