u-boot/drivers/watchdog/sl28cpld-wdt.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* Watchdog driver for the sl28cpld
*
* Copyright (c) 2021 Michael Walle <michael@walle.cc>
*/
#include <common.h>
#include <dm.h>
#include <wdt.h>
#include <sl28cpld.h>
#include <div64.h>
#define SL28CPLD_WDT_CTRL 0x00
#define WDT_CTRL_EN0 BIT(0)
#define WDT_CTRL_EN1 BIT(1)
#define WDT_CTRL_EN_MASK GENMASK(1, 0)
#define WDT_CTRL_LOCK BIT(2)
#define WDT_CTRL_ASSERT_SYS_RESET BIT(6)
#define WDT_CTRL_ASSERT_WDT_TIMEOUT BIT(7)
#define SL28CPLD_WDT_TIMEOUT 0x01
#define SL28CPLD_WDT_KICK 0x02
#define WDT_KICK_VALUE 0x6b
static int sl28cpld_wdt_reset(struct udevice *dev)
{
return sl28cpld_write(dev, SL28CPLD_WDT_KICK, WDT_KICK_VALUE);
}
static int sl28cpld_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
{
int ret, val;
val = sl28cpld_read(dev, SL28CPLD_WDT_CTRL);
if (val < 0)
return val;
/* (1) disable watchdog */
val &= ~WDT_CTRL_EN_MASK;
ret = sl28cpld_write(dev, SL28CPLD_WDT_CTRL, val);
if (ret)
return ret;
/* (2) set timeout */
ret = sl28cpld_write(dev, SL28CPLD_WDT_TIMEOUT, lldiv(timeout, 1000));
if (ret)
return ret;
/* (3) kick it, will reset timer to the timeout value */
ret = sl28cpld_wdt_reset(dev);
if (ret)
return ret;
/* (4) enable either recovery or normal one */
if (flags & BIT(0))
val |= WDT_CTRL_EN1;
else
val |= WDT_CTRL_EN0;
if (flags & BIT(1))
val |= WDT_CTRL_LOCK;
if (flags & BIT(2))
val &= ~WDT_CTRL_ASSERT_SYS_RESET;
else
val |= WDT_CTRL_ASSERT_SYS_RESET;
if (flags & BIT(3))
val |= WDT_CTRL_ASSERT_WDT_TIMEOUT;
else
val &= ~WDT_CTRL_ASSERT_WDT_TIMEOUT;
return sl28cpld_write(dev, SL28CPLD_WDT_CTRL, val);
}
static int sl28cpld_wdt_stop(struct udevice *dev)
{
int val;
val = sl28cpld_read(dev, SL28CPLD_WDT_CTRL);
if (val < 0)
return val;
return sl28cpld_write(dev, SL28CPLD_WDT_CTRL, val & ~WDT_CTRL_EN_MASK);
}
static int sl28cpld_wdt_expire_now(struct udevice *dev, ulong flags)
{
return sl28cpld_wdt_start(dev, 0, flags);
}
static const struct wdt_ops sl28cpld_wdt_ops = {
.start = sl28cpld_wdt_start,
.reset = sl28cpld_wdt_reset,
.stop = sl28cpld_wdt_stop,
.expire_now = sl28cpld_wdt_expire_now,
};
static const struct udevice_id sl28cpld_wdt_ids[] = {
{ .compatible = "kontron,sl28cpld-wdt", },
{}
};
U_BOOT_DRIVER(sl28cpld_wdt) = {
.name = "sl28cpld-wdt",
.id = UCLASS_WDT,
.of_match = sl28cpld_wdt_ids,
.ops = &sl28cpld_wdt_ops,
};