linux/drivers/watchdog/twl4030_wdt.c
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   1/*
   2 * Copyright (C) Nokia Corporation
   3 *
   4 * Written by Timo Kokkonen <timo.t.kokkonen at nokia.com>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  19 */
  20
  21#include <linux/module.h>
  22#include <linux/types.h>
  23#include <linux/slab.h>
  24#include <linux/kernel.h>
  25#include <linux/fs.h>
  26#include <linux/watchdog.h>
  27#include <linux/platform_device.h>
  28#include <linux/miscdevice.h>
  29#include <linux/uaccess.h>
  30#include <linux/i2c/twl.h>
  31
  32#define TWL4030_WATCHDOG_CFG_REG_OFFS   0x3
  33
  34#define TWL4030_WDT_STATE_OPEN          0x1
  35#define TWL4030_WDT_STATE_ACTIVE        0x8
  36
  37static struct platform_device *twl4030_wdt_dev;
  38
  39struct twl4030_wdt {
  40        struct miscdevice       miscdev;
  41        int                     timer_margin;
  42        unsigned long           state;
  43};
  44
  45static bool nowayout = WATCHDOG_NOWAYOUT;
  46module_param(nowayout, bool, 0);
  47MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
  48        "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  49
  50static int twl4030_wdt_write(unsigned char val)
  51{
  52        return twl_i2c_write_u8(TWL4030_MODULE_PM_RECEIVER, val,
  53                                        TWL4030_WATCHDOG_CFG_REG_OFFS);
  54}
  55
  56static int twl4030_wdt_enable(struct twl4030_wdt *wdt)
  57{
  58        return twl4030_wdt_write(wdt->timer_margin + 1);
  59}
  60
  61static int twl4030_wdt_disable(struct twl4030_wdt *wdt)
  62{
  63        return twl4030_wdt_write(0);
  64}
  65
  66static int twl4030_wdt_set_timeout(struct twl4030_wdt *wdt, int timeout)
  67{
  68        if (timeout < 0 || timeout > 30) {
  69                dev_warn(wdt->miscdev.parent,
  70                        "Timeout can only be in the range [0-30] seconds");
  71                return -EINVAL;
  72        }
  73        wdt->timer_margin = timeout;
  74        return twl4030_wdt_enable(wdt);
  75}
  76
  77static ssize_t twl4030_wdt_write_fop(struct file *file,
  78                const char __user *data, size_t len, loff_t *ppos)
  79{
  80        struct twl4030_wdt *wdt = file->private_data;
  81
  82        if (len)
  83                twl4030_wdt_enable(wdt);
  84
  85        return len;
  86}
  87
  88static long twl4030_wdt_ioctl(struct file *file,
  89                unsigned int cmd, unsigned long arg)
  90{
  91        void __user *argp = (void __user *)arg;
  92        int __user *p = argp;
  93        int new_margin;
  94        struct twl4030_wdt *wdt = file->private_data;
  95
  96        static const struct watchdog_info twl4030_wd_ident = {
  97                .identity = "TWL4030 Watchdog",
  98                .options = WDIOF_SETTIMEOUT,
  99                .firmware_version = 0,
 100        };
 101
 102        switch (cmd) {
 103        case WDIOC_GETSUPPORT:
 104                return copy_to_user(argp, &twl4030_wd_ident,
 105                                sizeof(twl4030_wd_ident)) ? -EFAULT : 0;
 106
 107        case WDIOC_GETSTATUS:
 108        case WDIOC_GETBOOTSTATUS:
 109                return put_user(0, p);
 110
 111        case WDIOC_KEEPALIVE:
 112                twl4030_wdt_enable(wdt);
 113                break;
 114
 115        case WDIOC_SETTIMEOUT:
 116                if (get_user(new_margin, p))
 117                        return -EFAULT;
 118                if (twl4030_wdt_set_timeout(wdt, new_margin))
 119                        return -EINVAL;
 120                return put_user(wdt->timer_margin, p);
 121
 122        case WDIOC_GETTIMEOUT:
 123                return put_user(wdt->timer_margin, p);
 124
 125        default:
 126                return -ENOTTY;
 127        }
 128
 129        return 0;
 130}
 131
 132static int twl4030_wdt_open(struct inode *inode, struct file *file)
 133{
 134        struct twl4030_wdt *wdt = platform_get_drvdata(twl4030_wdt_dev);
 135
 136        /* /dev/watchdog can only be opened once */
 137        if (test_and_set_bit(0, &wdt->state))
 138                return -EBUSY;
 139
 140        wdt->state |= TWL4030_WDT_STATE_ACTIVE;
 141        file->private_data = (void *) wdt;
 142
 143        twl4030_wdt_enable(wdt);
 144        return nonseekable_open(inode, file);
 145}
 146
 147static int twl4030_wdt_release(struct inode *inode, struct file *file)
 148{
 149        struct twl4030_wdt *wdt = file->private_data;
 150        if (nowayout) {
 151                dev_alert(wdt->miscdev.parent,
 152                       "Unexpected close, watchdog still running!\n");
 153                twl4030_wdt_enable(wdt);
 154        } else {
 155                if (twl4030_wdt_disable(wdt))
 156                        return -EFAULT;
 157                wdt->state &= ~TWL4030_WDT_STATE_ACTIVE;
 158        }
 159
 160        clear_bit(0, &wdt->state);
 161        return 0;
 162}
 163
 164static const struct file_operations twl4030_wdt_fops = {
 165        .owner          = THIS_MODULE,
 166        .llseek         = no_llseek,
 167        .open           = twl4030_wdt_open,
 168        .release        = twl4030_wdt_release,
 169        .unlocked_ioctl = twl4030_wdt_ioctl,
 170        .write          = twl4030_wdt_write_fop,
 171};
 172
 173static int __devinit twl4030_wdt_probe(struct platform_device *pdev)
 174{
 175        int ret = 0;
 176        struct twl4030_wdt *wdt;
 177
 178        wdt = kzalloc(sizeof(struct twl4030_wdt), GFP_KERNEL);
 179        if (!wdt)
 180                return -ENOMEM;
 181
 182        wdt->state              = 0;
 183        wdt->timer_margin       = 30;
 184        wdt->miscdev.parent     = &pdev->dev;
 185        wdt->miscdev.fops       = &twl4030_wdt_fops;
 186        wdt->miscdev.minor      = WATCHDOG_MINOR;
 187        wdt->miscdev.name       = "watchdog";
 188
 189        platform_set_drvdata(pdev, wdt);
 190
 191        twl4030_wdt_dev = pdev;
 192
 193        twl4030_wdt_disable(wdt);
 194
 195        ret = misc_register(&wdt->miscdev);
 196        if (ret) {
 197                dev_err(wdt->miscdev.parent,
 198                        "Failed to register misc device\n");
 199                platform_set_drvdata(pdev, NULL);
 200                kfree(wdt);
 201                twl4030_wdt_dev = NULL;
 202                return ret;
 203        }
 204        return 0;
 205}
 206
 207static int __devexit twl4030_wdt_remove(struct platform_device *pdev)
 208{
 209        struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
 210
 211        if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
 212                if (twl4030_wdt_disable(wdt))
 213                        return -EFAULT;
 214
 215        wdt->state &= ~TWL4030_WDT_STATE_ACTIVE;
 216        misc_deregister(&wdt->miscdev);
 217
 218        platform_set_drvdata(pdev, NULL);
 219        kfree(wdt);
 220        twl4030_wdt_dev = NULL;
 221
 222        return 0;
 223}
 224
 225#ifdef CONFIG_PM
 226static int twl4030_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 227{
 228        struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
 229        if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
 230                return twl4030_wdt_disable(wdt);
 231
 232        return 0;
 233}
 234
 235static int twl4030_wdt_resume(struct platform_device *pdev)
 236{
 237        struct twl4030_wdt *wdt = platform_get_drvdata(pdev);
 238        if (wdt->state & TWL4030_WDT_STATE_ACTIVE)
 239                return twl4030_wdt_enable(wdt);
 240
 241        return 0;
 242}
 243#else
 244#define twl4030_wdt_suspend        NULL
 245#define twl4030_wdt_resume         NULL
 246#endif
 247
 248static struct platform_driver twl4030_wdt_driver = {
 249        .probe          = twl4030_wdt_probe,
 250        .remove         = __devexit_p(twl4030_wdt_remove),
 251        .suspend        = twl4030_wdt_suspend,
 252        .resume         = twl4030_wdt_resume,
 253        .driver         = {
 254                .owner  = THIS_MODULE,
 255                .name   = "twl4030_wdt",
 256        },
 257};
 258
 259module_platform_driver(twl4030_wdt_driver);
 260
 261MODULE_AUTHOR("Nokia Corporation");
 262MODULE_LICENSE("GPL");
 263MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 264MODULE_ALIAS("platform:twl4030_wdt");
 265
 266
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