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/*
* Watchdog driver for Conexant Digicolor
*
* Copyright (C) 2015 Paradox Innovation Ltd.
*
* 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.
*/
#include <linux/types.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/of_address.h>
#define TIMER_A_CONTROL 0
#define TIMER_A_COUNT 4
#define TIMER_A_ENABLE_COUNT BIT(0)
#define TIMER_A_ENABLE_WATCHDOG BIT(1)
struct dc_wdt {
void __iomem *base;
struct clk *clk;
spinlock_t lock;
};
static unsigned timeout;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks)
{
unsigned long flags;
spin_lock_irqsave(&wdt->lock, flags);
writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
writel_relaxed(ticks, wdt->base + TIMER_A_COUNT);
writel_relaxed(TIMER_A_ENABLE_COUNT | TIMER_A_ENABLE_WATCHDOG,
wdt->base + TIMER_A_CONTROL);
spin_unlock_irqrestore(&wdt->lock, flags);
}
static int dc_wdt_restart(struct watchdog_device *wdog, unsigned long action,
void *data)
{
struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
dc_wdt_set(wdt, 1);
/* wait for reset to assert... */
mdelay(500);
return 0;
}
static int dc_wdt_start(struct watchdog_device *wdog)
{
struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk));
return 0;
}
static int dc_wdt_stop(struct watchdog_device *wdog)
{
struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
return 0;
}
static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
{
struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
dc_wdt_set(wdt, t * clk_get_rate(wdt->clk));
wdog->timeout = t;
return 0;
}
static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog)
{
struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT);
return count / clk_get_rate(wdt->clk);
}
static struct watchdog_ops dc_wdt_ops = {
.owner = THIS_MODULE,
.start = dc_wdt_start,
.stop = dc_wdt_stop,
.set_timeout = dc_wdt_set_timeout,
.get_timeleft = dc_wdt_get_timeleft,
.restart = dc_wdt_restart,
};
static struct watchdog_info dc_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE
| WDIOF_KEEPALIVEPING,
.identity = "Conexant Digicolor Watchdog",
};
static struct watchdog_device dc_wdt_wdd = {
.info = &dc_wdt_info,
.ops = &dc_wdt_ops,
.min_timeout = 1,
};
static int dc_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct dc_wdt *wdt;
int ret;
wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
platform_set_drvdata(pdev, wdt);
wdt->base = of_iomap(np, 0);
if (!wdt->base) {
dev_err(dev, "Failed to remap watchdog regs");
return -ENODEV;
}
wdt->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(wdt->clk)) {
ret = PTR_ERR(wdt->clk);
goto err_iounmap;
}
dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk);
dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout;
dc_wdt_wdd.parent = &pdev->dev;
spin_lock_init(&wdt->lock);
watchdog_set_drvdata(&dc_wdt_wdd, wdt);
watchdog_set_restart_priority(&dc_wdt_wdd, 128);
watchdog_init_timeout(&dc_wdt_wdd, timeout, dev);
ret = watchdog_register_device(&dc_wdt_wdd);
if (ret) {
dev_err(dev, "Failed to register watchdog device");
goto err_iounmap;
}
return 0;
err_iounmap:
iounmap(wdt->base);
return ret;
}
static int dc_wdt_remove(struct platform_device *pdev)
{
struct dc_wdt *wdt = platform_get_drvdata(pdev);
watchdog_unregister_device(&dc_wdt_wdd);
iounmap(wdt->base);
return 0;
}
static void dc_wdt_shutdown(struct platform_device *pdev)
{
dc_wdt_stop(&dc_wdt_wdd);
}
static const struct of_device_id dc_wdt_of_match[] = {
{ .compatible = "cnxt,cx92755-wdt", },
{},
};
MODULE_DEVICE_TABLE(of, dc_wdt_of_match);
static struct platform_driver dc_wdt_driver = {
.probe = dc_wdt_probe,
.remove = dc_wdt_remove,
.shutdown = dc_wdt_shutdown,
.driver = {
.name = "digicolor-wdt",
.of_match_table = dc_wdt_of_match,
},
};
module_platform_driver(dc_wdt_driver);
MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer");
MODULE_LICENSE("GPL");
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