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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>
310 lines
7.2 KiB
C
310 lines
7.2 KiB
C
/*
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* Copyright (c) 2009 Nuvoton technology corporation.
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*
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* Wan ZongShun <mcuos.com@gmail.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;version 2 of the License.
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*
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*/
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#include <linux/bitops.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/clk.h>
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#include <linux/kernel.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/interrupt.h>
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#include <linux/types.h>
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#include <linux/watchdog.h>
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#include <linux/uaccess.h>
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#define REG_WTCR 0x1c
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#define WTCLK (0x01 << 10)
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#define WTE (0x01 << 7) /*wdt enable*/
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#define WTIS (0x03 << 4)
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#define WTIF (0x01 << 3)
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#define WTRF (0x01 << 2)
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#define WTRE (0x01 << 1)
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#define WTR (0x01 << 0)
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/*
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* The watchdog time interval can be calculated via following formula:
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* WTIS real time interval (formula)
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* 0x00 ((2^ 14 ) * ((external crystal freq) / 256))seconds
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* 0x01 ((2^ 16 ) * ((external crystal freq) / 256))seconds
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* 0x02 ((2^ 18 ) * ((external crystal freq) / 256))seconds
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* 0x03 ((2^ 20 ) * ((external crystal freq) / 256))seconds
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*
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* The external crystal freq is 15Mhz in the nuc900 evaluation board.
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* So 0x00 = +-0.28 seconds, 0x01 = +-1.12 seconds, 0x02 = +-4.48 seconds,
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* 0x03 = +- 16.92 seconds..
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*/
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#define WDT_HW_TIMEOUT 0x02
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#define WDT_TIMEOUT (HZ/2)
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#define WDT_HEARTBEAT 15
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static int heartbeat = WDT_HEARTBEAT;
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module_param(heartbeat, int, 0);
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MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
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"(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
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static bool nowayout = WATCHDOG_NOWAYOUT;
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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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"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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struct nuc900_wdt {
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struct clk *wdt_clock;
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struct platform_device *pdev;
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void __iomem *wdt_base;
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char expect_close;
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struct timer_list timer;
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spinlock_t wdt_lock;
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unsigned long next_heartbeat;
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};
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static unsigned long nuc900wdt_busy;
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static struct nuc900_wdt *nuc900_wdt;
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static inline void nuc900_wdt_keepalive(void)
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{
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unsigned int val;
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spin_lock(&nuc900_wdt->wdt_lock);
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val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);
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val |= (WTR | WTIF);
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__raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);
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spin_unlock(&nuc900_wdt->wdt_lock);
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}
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static inline void nuc900_wdt_start(void)
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{
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unsigned int val;
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spin_lock(&nuc900_wdt->wdt_lock);
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val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);
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val |= (WTRE | WTE | WTR | WTCLK | WTIF);
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val &= ~WTIS;
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val |= (WDT_HW_TIMEOUT << 0x04);
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__raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);
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spin_unlock(&nuc900_wdt->wdt_lock);
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nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ;
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mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT);
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}
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static inline void nuc900_wdt_stop(void)
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{
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unsigned int val;
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del_timer(&nuc900_wdt->timer);
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spin_lock(&nuc900_wdt->wdt_lock);
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val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);
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val &= ~WTE;
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__raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);
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spin_unlock(&nuc900_wdt->wdt_lock);
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}
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static inline void nuc900_wdt_ping(void)
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{
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nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ;
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}
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static int nuc900_wdt_open(struct inode *inode, struct file *file)
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{
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if (test_and_set_bit(0, &nuc900wdt_busy))
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return -EBUSY;
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nuc900_wdt_start();
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return nonseekable_open(inode, file);
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}
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static int nuc900_wdt_close(struct inode *inode, struct file *file)
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{
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if (nuc900_wdt->expect_close == 42)
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nuc900_wdt_stop();
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else {
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dev_crit(&nuc900_wdt->pdev->dev,
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"Unexpected close, not stopping watchdog!\n");
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nuc900_wdt_ping();
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}
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nuc900_wdt->expect_close = 0;
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clear_bit(0, &nuc900wdt_busy);
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return 0;
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}
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static const struct watchdog_info nuc900_wdt_info = {
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.identity = "nuc900 watchdog",
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
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WDIOF_MAGICCLOSE,
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};
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static long nuc900_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_value;
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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return copy_to_user(argp, &nuc900_wdt_info,
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sizeof(nuc900_wdt_info)) ? -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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nuc900_wdt_ping();
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return 0;
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case WDIOC_SETTIMEOUT:
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if (get_user(new_value, p))
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return -EFAULT;
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heartbeat = new_value;
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nuc900_wdt_ping();
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return put_user(new_value, p);
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case WDIOC_GETTIMEOUT:
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return put_user(heartbeat, p);
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default:
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return -ENOTTY;
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}
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}
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static ssize_t nuc900_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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return 0;
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/* Scan for magic character */
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if (!nowayout) {
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size_t i;
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nuc900_wdt->expect_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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nuc900_wdt->expect_close = 42;
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break;
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}
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}
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}
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nuc900_wdt_ping();
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return len;
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}
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static void nuc900_wdt_timer_ping(unsigned long data)
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{
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if (time_before(jiffies, nuc900_wdt->next_heartbeat)) {
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nuc900_wdt_keepalive();
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mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT);
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} else
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dev_warn(&nuc900_wdt->pdev->dev, "Will reset the machine !\n");
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}
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static const struct file_operations nuc900wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.unlocked_ioctl = nuc900_wdt_ioctl,
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.open = nuc900_wdt_open,
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.release = nuc900_wdt_close,
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.write = nuc900_wdt_write,
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};
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static struct miscdevice nuc900wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &nuc900wdt_fops,
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};
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static int nuc900wdt_probe(struct platform_device *pdev)
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{
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struct resource *res;
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int ret = 0;
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nuc900_wdt = devm_kzalloc(&pdev->dev, sizeof(*nuc900_wdt),
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GFP_KERNEL);
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if (!nuc900_wdt)
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return -ENOMEM;
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nuc900_wdt->pdev = pdev;
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spin_lock_init(&nuc900_wdt->wdt_lock);
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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nuc900_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(nuc900_wdt->wdt_base))
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return PTR_ERR(nuc900_wdt->wdt_base);
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nuc900_wdt->wdt_clock = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(nuc900_wdt->wdt_clock)) {
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dev_err(&pdev->dev, "failed to find watchdog clock source\n");
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return PTR_ERR(nuc900_wdt->wdt_clock);
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}
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clk_enable(nuc900_wdt->wdt_clock);
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setup_timer(&nuc900_wdt->timer, nuc900_wdt_timer_ping, 0);
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ret = misc_register(&nuc900wdt_miscdev);
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if (ret) {
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dev_err(&pdev->dev, "err register miscdev on minor=%d (%d)\n",
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WATCHDOG_MINOR, ret);
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goto err_clk;
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}
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return 0;
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err_clk:
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clk_disable(nuc900_wdt->wdt_clock);
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return ret;
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}
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static int nuc900wdt_remove(struct platform_device *pdev)
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{
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misc_deregister(&nuc900wdt_miscdev);
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clk_disable(nuc900_wdt->wdt_clock);
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return 0;
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}
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static struct platform_driver nuc900wdt_driver = {
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.probe = nuc900wdt_probe,
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.remove = nuc900wdt_remove,
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.driver = {
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.name = "nuc900-wdt",
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.owner = THIS_MODULE,
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},
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};
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module_platform_driver(nuc900wdt_driver);
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MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
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MODULE_DESCRIPTION("Watchdog driver for NUC900");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:nuc900-wdt");
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