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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>
299 lines
6.5 KiB
C
299 lines
6.5 KiB
C
/* Watchdog timer for machines with the CS5535/CS5536 companion chip
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*
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* Copyright (C) 2006-2007, Advanced Micro Devices, Inc.
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* Copyright (C) 2009 Andres Salomon <dilinger@collabora.co.uk>
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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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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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/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/fs.h>
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#include <linux/platform_device.h>
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#include <linux/reboot.h>
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#include <linux/uaccess.h>
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#include <linux/cs5535.h>
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#define GEODEWDT_HZ 500
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#define GEODEWDT_SCALE 6
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#define GEODEWDT_MAX_SECONDS 131
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#define WDT_FLAGS_OPEN 1
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#define WDT_FLAGS_ORPHAN 2
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#define DRV_NAME "geodewdt"
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#define WATCHDOG_NAME "Geode GX/LX WDT"
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#define WATCHDOG_TIMEOUT 60
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static int timeout = WATCHDOG_TIMEOUT;
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module_param(timeout, int, 0);
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MODULE_PARM_DESC(timeout,
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"Watchdog timeout in seconds. 1<= timeout <=131, default="
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__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
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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,
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"Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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static struct platform_device *geodewdt_platform_device;
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static unsigned long wdt_flags;
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static struct cs5535_mfgpt_timer *wdt_timer;
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static int safe_close;
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static void geodewdt_ping(void)
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{
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/* Stop the counter */
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cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
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/* Reset the counter */
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cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
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/* Enable the counter */
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cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
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}
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static void geodewdt_disable(void)
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{
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cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
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cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
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}
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static int geodewdt_set_heartbeat(int val)
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{
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if (val < 1 || val > GEODEWDT_MAX_SECONDS)
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return -EINVAL;
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cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
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cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ);
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cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
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cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
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timeout = val;
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return 0;
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}
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static int geodewdt_open(struct inode *inode, struct file *file)
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{
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if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags))
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return -EBUSY;
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if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
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__module_get(THIS_MODULE);
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geodewdt_ping();
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return nonseekable_open(inode, file);
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}
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static int geodewdt_release(struct inode *inode, struct file *file)
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{
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if (safe_close) {
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geodewdt_disable();
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module_put(THIS_MODULE);
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} else {
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pr_crit("Unexpected close - watchdog is not stopping\n");
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geodewdt_ping();
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set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
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}
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clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
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safe_close = 0;
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return 0;
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}
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static ssize_t geodewdt_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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safe_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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safe_close = 1;
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}
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}
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geodewdt_ping();
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}
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return len;
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}
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static long geodewdt_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 = argp;
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int interval;
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static const struct watchdog_info ident = {
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
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| WDIOF_MAGICCLOSE,
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.firmware_version = 1,
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.identity = WATCHDOG_NAME,
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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, &ident,
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sizeof(ident)) ? -EFAULT : 0;
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break;
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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_SETOPTIONS:
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{
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int options, ret = -EINVAL;
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if (get_user(options, p))
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return -EFAULT;
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if (options & WDIOS_DISABLECARD) {
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geodewdt_disable();
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ret = 0;
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}
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if (options & WDIOS_ENABLECARD) {
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geodewdt_ping();
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ret = 0;
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}
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return ret;
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}
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case WDIOC_KEEPALIVE:
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geodewdt_ping();
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return 0;
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case WDIOC_SETTIMEOUT:
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if (get_user(interval, p))
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return -EFAULT;
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if (geodewdt_set_heartbeat(interval))
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return -EINVAL;
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/* Fall through */
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case WDIOC_GETTIMEOUT:
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return put_user(timeout, 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 const struct file_operations geodewdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = geodewdt_write,
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.unlocked_ioctl = geodewdt_ioctl,
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.open = geodewdt_open,
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.release = geodewdt_release,
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};
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static struct miscdevice geodewdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &geodewdt_fops,
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};
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static int geodewdt_probe(struct platform_device *dev)
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{
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int ret;
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wdt_timer = cs5535_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);
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if (!wdt_timer) {
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pr_err("No timers were available\n");
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return -ENODEV;
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}
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/* Set up the timer */
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cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
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GEODEWDT_SCALE | (3 << 8));
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/* Set up comparator 2 to reset when the event fires */
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cs5535_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);
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/* Set up the initial timeout */
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cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
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timeout * GEODEWDT_HZ);
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ret = misc_register(&geodewdt_miscdev);
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return ret;
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}
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static int geodewdt_remove(struct platform_device *dev)
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{
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misc_deregister(&geodewdt_miscdev);
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return 0;
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}
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static void geodewdt_shutdown(struct platform_device *dev)
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{
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geodewdt_disable();
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}
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static struct platform_driver geodewdt_driver = {
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.probe = geodewdt_probe,
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.remove = geodewdt_remove,
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.shutdown = geodewdt_shutdown,
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.driver = {
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.owner = THIS_MODULE,
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.name = DRV_NAME,
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},
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};
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static int __init geodewdt_init(void)
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{
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int ret;
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ret = platform_driver_register(&geodewdt_driver);
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if (ret)
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return ret;
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geodewdt_platform_device = platform_device_register_simple(DRV_NAME,
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-1, NULL, 0);
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if (IS_ERR(geodewdt_platform_device)) {
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ret = PTR_ERR(geodewdt_platform_device);
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goto err;
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}
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return 0;
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err:
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platform_driver_unregister(&geodewdt_driver);
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return ret;
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}
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static void __exit geodewdt_exit(void)
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{
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platform_device_unregister(geodewdt_platform_device);
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platform_driver_unregister(&geodewdt_driver);
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}
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module_init(geodewdt_init);
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module_exit(geodewdt_exit);
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MODULE_AUTHOR("Advanced Micro Devices, Inc");
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MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
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MODULE_LICENSE("GPL");
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