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![Jean Delvare](/assets/img/avatar_default.png)
I just can't find any value in MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR) and MODULE_ALIAS_MISCDEV(TEMP_MINOR) statements. Either the device is enumerated and the driver already has a module alias (e.g. PCI, USB etc.) that will get the right driver loaded automatically. Or the device is not enumerated and loading its driver will lead to more or less intrusive hardware poking. Such hardware poking should be limited to a bare minimum, so the user should really decide which drivers should be tried and in what order. Trying them all in arbitrary order can't do any good. On top of that, loading that many drivers at once bloats the kernel log. Also many drivers will stay loaded afterward, bloating the output of "lsmod" and wasting memory. Some modules (cs5535_mfgpt which gets loaded as a dependency) can't even be unloaded! If defining char-major-10-130 is needed then it should happen in user-space. Signed-off-by: Jean Delvare <jdelvare@suse.de> Acked-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be> Cc: Stephen Warren <swarren@wwwdotorg.org> Cc: Mike Frysinger <vapier.adi@gmail.com> Cc: Wan ZongShun <mcuos.com@gmail.com> Cc: Ben Dooks <ben-linux@fluff.org> Cc: Kukjin Kim <kgene.kim@samsung.com> Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk> Cc: Jim Cromie <jim.cromie@gmail.com>
260 lines
6.2 KiB
C
260 lines
6.2 KiB
C
/*
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* Driver for the MTX-1 Watchdog.
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*
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* (C) Copyright 2005 4G Systems <info@4g-systems.biz>,
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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 <florian@openwrt.org>
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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; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Neither Michael Stickel nor 4G Systems admit liability nor provide
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* warranty for any of this software. This material is provided
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* "AS-IS" and at no charge.
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*
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* (c) Copyright 2005 4G Systems <info@4g-systems.biz>
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*
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* Release 0.01.
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* Author: Michael Stickel michael.stickel@4g-systems.biz
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*
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* Release 0.02.
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* Author: Florian Fainelli florian@openwrt.org
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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/init.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.h>
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#include <asm/mach-au1x00/au1000.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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unsigned gpio;
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unsigned int gstate;
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} mtx1_wdt_device;
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static void mtx1_wdt_trigger(unsigned long 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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gpio_set_value(mtx1_wdt_device.gpio, 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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gpio_set_value(mtx1_wdt_device.gpio, 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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gpio_set_value(mtx1_wdt_device.gpio, 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 nonseekable_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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.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.gpio = pdev->resource[0].start;
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ret = devm_gpio_request_one(&pdev->dev, mtx1_wdt_device.gpio,
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GPIOF_OUT_INIT_HIGH, "mtx1-wdt");
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to request gpio");
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return ret;
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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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setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
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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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