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/*
* Moschip MCS814x Watchdog driver
*
* Copyright (C) 2012, Florian Fainelli <florian@openwrt.org>
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/of.h>
#define WDT_COUNT 0x00
#define WDT_CTRL 0x04
#define WDT_CTRL_EN 0x1
/* watchdog frequency */
#define WDT_MAX_VALUE (0xffffffff)
struct mcs814x_wdt {
void __iomem *regs;
spinlock_t lock;
struct watchdog_device wdt_dev;
struct clk *clk;
};
static int mcs814x_wdt_start(struct watchdog_device *dev)
{
struct mcs814x_wdt *wdt = watchdog_get_drvdata(dev);
u32 reg;
spin_lock(&wdt->lock);
reg = readl_relaxed(wdt->regs + WDT_CTRL);
reg |= WDT_CTRL_EN;
writel_relaxed(reg, wdt->regs + WDT_CTRL);
spin_unlock(&wdt->lock);
return 0;
}
static int mcs814x_wdt_stop(struct watchdog_device *dev)
{
struct mcs814x_wdt *wdt = watchdog_get_drvdata(dev);
u32 reg;
spin_lock(&wdt->lock);
reg = readl_relaxed(wdt->regs + WDT_CTRL);
reg &= ~WDT_CTRL_EN;
writel_relaxed(reg, wdt->regs + WDT_CTRL);
spin_unlock(&wdt->lock);
return 0;
}
static int mcs814x_wdt_set_timeout(struct watchdog_device *dev,
unsigned int new_timeout)
{
struct mcs814x_wdt *wdt = watchdog_get_drvdata(dev);
spin_lock(&wdt->lock);
/* watchdog counts upward and rollover (0xfffffff -> 0)
* triggers the reboot
*/
writel_relaxed(WDT_MAX_VALUE - (new_timeout * clk_get_rate(wdt->clk)),
wdt->regs + WDT_COUNT);
spin_unlock(&wdt->lock);
return 0;
}
static int mcs814x_wdt_ping(struct watchdog_device *dev)
{
/* restart the watchdog */
mcs814x_wdt_stop(dev);
mcs814x_wdt_set_timeout(dev, dev->timeout);
mcs814x_wdt_start(dev);
return 0;
}
static const struct watchdog_info mcs814x_wdt_ident = {
.options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
.identity = "MCS814x Watchdog",
};
static struct watchdog_ops mcs814x_wdt_ops = {
.owner = THIS_MODULE,
.start = mcs814x_wdt_start,
.stop = mcs814x_wdt_stop,
.set_timeout = mcs814x_wdt_set_timeout,
.ping = mcs814x_wdt_ping,
};
static int __devinit mcs814x_wdt_probe(struct platform_device *pdev)
{
struct resource *res;
struct mcs814x_wdt *wdt;
int ret;
struct clk *clk;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENODEV;
clk = clk_get(NULL, "wdt");
if (IS_ERR_OR_NULL(clk)) {
dev_err(&pdev->dev, "failed to get watchdog clock\n");
return PTR_ERR(clk);
}
wdt = kzalloc(sizeof(*wdt), GFP_KERNEL);
if (!wdt) {
ret = -ENOMEM;
goto out_clk;
}
spin_lock_init(&wdt->lock);
wdt->clk = clk;
wdt->wdt_dev.info = &mcs814x_wdt_ident;
wdt->wdt_dev.ops = &mcs814x_wdt_ops;
wdt->wdt_dev.min_timeout = 1;
/* approximately 10995 secs */
wdt->wdt_dev.max_timeout = (WDT_MAX_VALUE / clk_get_rate(clk));
platform_set_drvdata(pdev, wdt);
/* only ioremap registers, because the register is shared */
wdt->regs = devm_ioremap(&pdev->dev, res->start, resource_size(res));
if (!wdt->regs) {
ret = -ENOMEM;
goto out;
}
watchdog_set_drvdata(&wdt->wdt_dev, wdt);
ret = watchdog_register_device(&wdt->wdt_dev);
if (ret) {
dev_err(&pdev->dev, "cannot register watchdog: %d\n", ret);
goto out;
}
dev_info(&pdev->dev, "registered\n");
return 0;
out:
platform_set_drvdata(pdev, NULL);
kfree(wdt);
out_clk:
clk_put(clk);
return ret;
}
static int __devexit mcs814x_wdt_remove(struct platform_device *pdev)
{
struct mcs814x_wdt *wdt = platform_get_drvdata(pdev);
clk_put(wdt->clk);
watchdog_unregister_device(&wdt->wdt_dev);
watchdog_set_drvdata(&wdt->wdt_dev, NULL);
kfree(wdt);
platform_set_drvdata(pdev, NULL);
return 0;
}
static const struct of_device_id mcs814x_wdt_ids[] = {
{ .compatible = "moschip,mcs814x-wdt", },
{ /* sentinel */ },
};
static struct platform_driver mcs814x_wdt_driver = {
.driver = {
.name = "mcs814x-wdt",
.owner = THIS_MODULE,
.of_match_table = mcs814x_wdt_ids,
},
.probe = mcs814x_wdt_probe,
.remove = __devexit_p(mcs814x_wdt_remove),
};
module_platform_driver(mcs814x_wdt_driver);
MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
MODULE_DESCRIPTION("Moschip MCS814x Watchdog driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:mcs814x-wdt");
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