/* * Watchdog driver for the wm8350 * * Copyright (C) 2007, 2008 Wolfson Microelectronics <linux@wolfsonmicro.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation */ #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/fs.h> #include <linux/miscdevice.h> #include <linux/platform_device.h> #include <linux/watchdog.h> #include <linux/uaccess.h> #include <linux/mfd/wm8350/core.h> static int nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, int, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); static unsigned long wm8350_wdt_users; static struct miscdevice wm8350_wdt_miscdev; static int wm8350_wdt_expect_close; static DEFINE_MUTEX(wdt_mutex); static struct { int time; /* Seconds */ u16 val; /* To be set in WM8350_SYSTEM_CONTROL_2 */ } wm8350_wdt_cfgs[] = { { 1, 0x02 }, { 2, 0x04 }, { 4, 0x05 }, }; static struct wm8350 *get_wm8350(void) { return dev_get_drvdata(wm8350_wdt_miscdev.parent); } static int wm8350_wdt_set_timeout(struct wm8350 *wm8350, u16 value) { int ret; u16 reg; mutex_lock(&wdt_mutex); wm8350_reg_unlock(wm8350); reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); reg &= ~WM8350_WDOG_TO_MASK; reg |= value; ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); wm8350_reg_lock(wm8350); mutex_unlock(&wdt_mutex); return ret; } static int wm8350_wdt_start(struct wm8350 *wm8350) { int ret; u16 reg; mutex_lock(&wdt_mutex); wm8350_reg_unlock(wm8350); reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); reg &= ~WM8350_WDOG_MODE_MASK; reg |= 0x20; ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); wm8350_reg_lock(wm8350); mutex_unlock(&wdt_mutex); return ret; } static int wm8350_wdt_stop(struct wm8350 *wm8350) { int ret; u16 reg; mutex_lock(&wdt_mutex); wm8350_reg_unlock(wm8350); reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); reg &= ~WM8350_WDOG_MODE_MASK; ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); wm8350_reg_lock(wm8350); mutex_unlock(&wdt_mutex); return ret; } static int wm8350_wdt_kick(struct wm8350 *wm8350) { int ret; u16 reg; mutex_lock(&wdt_mutex); reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); ret = wm8350_reg_write(wm8350, WM8350_SYSTEM_CONTROL_2, reg); mutex_unlock(&wdt_mutex); return ret; } static int wm8350_wdt_open(struct inode *inode, struct file *file) { struct wm8350 *wm8350 = get_wm8350(); int ret; if (!wm8350) return -ENODEV; if (test_and_set_bit(0, &wm8350_wdt_users)) return -EBUSY; ret = wm8350_wdt_start(wm8350); if (ret != 0) return ret; return nonseekable_open(inode, file); } static int wm8350_wdt_release(struct inode *inode, struct file *file) { struct wm8350 *wm8350 = get_wm8350(); if (wm8350_wdt_expect_close) wm8350_wdt_stop(wm8350); else { dev_warn(wm8350->dev, "Watchdog device closed uncleanly\n"); wm8350_wdt_kick(wm8350); } clear_bit(0, &wm8350_wdt_users); return 0; } static ssize_t wm8350_wdt_write(struct file *file, const char __user *data, size_t count, loff_t *ppos) { struct wm8350 *wm8350 = get_wm8350(); size_t i; if (count) { wm8350_wdt_kick(wm8350); if (!nowayout) { /* In case it was set long ago */ wm8350_wdt_expect_close = 0; /* scan to see whether or not we got the magic character */ for (i = 0; i != count; i++) { char c; if (get_user(c, data + i)) return -EFAULT; if (c == 'V') wm8350_wdt_expect_close = 42; } } } return count; } static struct watchdog_info ident = { .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .identity = "WM8350 Watchdog", }; static long wm8350_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct wm8350 *wm8350 = get_wm8350(); int ret = -ENOTTY, time, i; void __user *argp = (void __user *)arg; int __user *p = argp; u16 reg; switch (cmd) { case WDIOC_GETSUPPORT: ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; break; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: ret = put_user(0, p); break; case WDIOC_SETOPTIONS: { int options; if (get_user(options, p)) return -EFAULT; ret = -EINVAL; /* Setting both simultaneously means at least one must fail */ if (options == WDIOS_DISABLECARD) ret = wm8350_wdt_start(wm8350); if (options == WDIOS_ENABLECARD) ret = wm8350_wdt_stop(wm8350); break; } case WDIOC_KEEPALIVE: ret = wm8350_wdt_kick(wm8350); break; case WDIOC_SETTIMEOUT: ret = get_user(time, p); if (ret) break; if (time == 0) { if (nowayout) ret = -EINVAL; else wm8350_wdt_stop(wm8350); break; } for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++) if (wm8350_wdt_cfgs[i].time == time) break; if (i == ARRAY_SIZE(wm8350_wdt_cfgs)) ret = -EINVAL; else ret = wm8350_wdt_set_timeout(wm8350, wm8350_wdt_cfgs[i].val); break; case WDIOC_GETTIMEOUT: reg = wm8350_reg_read(wm8350, WM8350_SYSTEM_CONTROL_2); reg &= WM8350_WDOG_TO_MASK; for (i = 0; i < ARRAY_SIZE(wm8350_wdt_cfgs); i++) if (wm8350_wdt_cfgs[i].val == reg) break; if (i == ARRAY_SIZE(wm8350_wdt_cfgs)) { dev_warn(wm8350->dev, "Unknown watchdog configuration: %x\n", reg); ret = -EINVAL; } else ret = put_user(wm8350_wdt_cfgs[i].time, p); } return ret; } static const struct file_operations wm8350_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = wm8350_wdt_write, .unlocked_ioctl = wm8350_wdt_ioctl, .open = wm8350_wdt_open, .release = wm8350_wdt_release, }; static struct miscdevice wm8350_wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &wm8350_wdt_fops, }; static int wm8350_wdt_probe(struct platform_device *pdev) { struct wm8350 *wm8350 = platform_get_drvdata(pdev); if (!wm8350) { dev_err(wm8350->dev, "No driver data supplied\n"); return -ENODEV; } /* Default to 4s timeout */ wm8350_wdt_set_timeout(wm8350, 0x05); wm8350_wdt_miscdev.parent = &pdev->dev; return misc_register(&wm8350_wdt_miscdev); } static int __exit wm8350_wdt_remove(struct platform_device *pdev) { misc_deregister(&wm8350_wdt_miscdev); return 0; } static struct platform_driver wm8350_wdt_driver = { .probe = wm8350_wdt_probe, .remove = wm8350_wdt_remove, .driver = { .name = "wm8350-wdt", }, }; static int __init wm8350_wdt_init(void) { return platform_driver_register(&wm8350_wdt_driver); } module_init(wm8350_wdt_init); static void __exit wm8350_wdt_exit(void) { platform_driver_unregister(&wm8350_wdt_driver); } module_exit(wm8350_wdt_exit); MODULE_AUTHOR("Mark Brown"); MODULE_DESCRIPTION("WM8350 Watchdog"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:wm8350-wdt");