linux-imx

/*

 * drivers/char/watchdog/max63xx_wdt.c

 *

 * Driver for max63{69,70,71,72,73,74} watchdog timers

 *

 * Copyright (C) 2009 Marc Zyngier <maz@misterjones.org>

 *

 * This file is licensed under the terms of the GNU General Public

 * License version 2. This program is licensed "as is" without any

 * warranty of any kind, whether express or implied.

 *

 * This driver assumes the watchdog pins are memory mapped (as it is

 * the case for the Arcom Zeus). Should it be connected over GPIOs or

 * another interface, some abstraction will have to be introduced.

 */

​

#include <linux/err.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/mod_devicetable.h>

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/watchdog.h>

#include <linux/bitops.h>

#include <linux/platform_device.h>

#include <linux/spinlock.h>

#include <linux/io.h>

#include <linux/slab.h>

​

#define DEFAULT_HEARTBEAT 60

#define MAX_HEARTBEAT     60

​

static unsigned int heartbeat = DEFAULT_HEARTBEAT;

static bool nowayout  = WATCHDOG_NOWAYOUT;

​

/*

 * Memory mapping: a single byte, 3 first lower bits to select bit 3

 * to ping the watchdog.

 */

#define MAX6369_WDSET   (7 << 0)

#define MAX6369_WDI (1 << 3)

​

#define MAX6369_WDSET_DISABLED  3

​

static int nodelay;

​

struct max63xx_wdt {

    struct watchdog_device wdd;

    const struct max63xx_timeout *timeout;

​

    /* memory mapping */

    void __iomem *base;

    spinlock_t lock;

​

    /* WDI and WSET bits write access routines */

    void (*ping)(struct max63xx_wdt *wdt);

    void (*set)(struct max63xx_wdt *wdt, u8 set);

};

​

/*

 * The timeout values used are actually the absolute minimum the chip

 * offers. Typical values on my board are slightly over twice as long

 * (10s setting ends up with a 25s timeout), and can be up to 3 times

 * the nominal setting (according to the datasheet). So please take

 * these values with a grain of salt. Same goes for the initial delay

 * "feature". Only max6373/74 have a few settings without this initial

 * delay (selected with the "nodelay" parameter).

 *

 * I also decided to remove from the tables any timeout smaller than a

 * second, as it looked completly overkill...

 */

​

/* Timeouts in second */

struct max63xx_timeout {

    const u8 wdset;

    const u8 tdelay;

    const u8 twd;

};

​

static const struct max63xx_timeout max6369_table[] = {

    { 5,  1,  1 },

    { 6, 10, 10 },

    { 7, 60, 60 },

    { },

};

​

static const struct max63xx_timeout max6371_table[] = {

    { 6, 60,  3 },

    { 7, 60, 60 },

    { },

};

​