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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
* JZ4740 Watchdog driver
*/
#include <linux/mfd/ingenic-tcu.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/regmap.h>
#define DEFAULT_HEARTBEAT 5
#define MAX_HEARTBEAT 2048
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static unsigned int heartbeat = DEFAULT_HEARTBEAT;
module_param(heartbeat, uint, 0);
MODULE_PARM_DESC(heartbeat,
"Watchdog heartbeat period in seconds from 1 to "
__MODULE_STRING(MAX_HEARTBEAT) ", default "
__MODULE_STRING(DEFAULT_HEARTBEAT));
struct jz4740_wdt_drvdata {
struct watchdog_device wdt;
struct regmap *map;
struct clk *clk;
unsigned long clk_rate;
};
static int jz4740_wdt_ping(struct watchdog_device *wdt_dev)
{
struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
regmap_write(drvdata->map, TCU_REG_WDT_TCNT, 0);
return 0;
}
static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int new_timeout)
{
struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
u16 timeout_value = (u16)(drvdata->clk_rate * new_timeout);
unsigned int tcer;
regmap_read(drvdata->map, TCU_REG_WDT_TCER, &tcer);
regmap_write(drvdata->map, TCU_REG_WDT_TCER, 0);
regmap_write(drvdata->map, TCU_REG_WDT_TDR, timeout_value);
regmap_write(drvdata->map, TCU_REG_WDT_TCNT, 0);
if (tcer & TCU_WDT_TCER_TCEN)
regmap_write(drvdata->map, TCU_REG_WDT_TCER, TCU_WDT_TCER_TCEN);
wdt_dev->timeout = new_timeout;
return 0;
}
static int jz4740_wdt_start(struct watchdog_device *wdt_dev)
{
struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
unsigned int tcer;
int ret;
ret = clk_prepare_enable(drvdata->clk);
if (ret)
return ret;
regmap_read(drvdata->map, TCU_REG_WDT_TCER, &tcer);
jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
/* Start watchdog if it wasn't started already */
if (!(tcer & TCU_WDT_TCER_TCEN))
regmap_write(drvdata->map, TCU_REG_WDT_TCER, TCU_WDT_TCER_TCEN);
return 0;
}
static int jz4740_wdt_stop(struct watchdog_device *wdt_dev)
{
struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
regmap_write(drvdata->map, TCU_REG_WDT_TCER, 0);
clk_disable_unprepare(drvdata->clk);
return 0;
}
static int jz4740_wdt_restart(struct watchdog_device *wdt_dev,
unsigned long action, void *data)
{
wdt_dev->timeout = 0;
jz4740_wdt_start(wdt_dev);
return 0;
}
static const struct watchdog_info jz4740_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "jz4740 Watchdog",
};
static const struct watchdog_ops jz4740_wdt_ops = {
.owner = THIS_MODULE,
.start = jz4740_wdt_start,
.stop = jz4740_wdt_stop,
.ping = jz4740_wdt_ping,
.set_timeout = jz4740_wdt_set_timeout,
.restart = jz4740_wdt_restart,
};
#ifdef CONFIG_OF
static const struct of_device_id jz4740_wdt_of_matches[] = {
{ .compatible = "ingenic,jz4740-watchdog", },
{ .compatible = "ingenic,jz4780-watchdog", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, jz4740_wdt_of_matches);
#endif
static int jz4740_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct jz4740_wdt_drvdata *drvdata;
struct watchdog_device *jz4740_wdt;
long rate;
int ret;
drvdata = devm_kzalloc(dev, sizeof(struct jz4740_wdt_drvdata),
GFP_KERNEL);
if (!drvdata)
return -ENOMEM;
drvdata->clk = devm_clk_get(&pdev->dev, "wdt");
if (IS_ERR(drvdata->clk)) {
dev_err(&pdev->dev, "cannot find WDT clock\n");
return PTR_ERR(drvdata->clk);
}
/* Set smallest clock possible */
rate = clk_round_rate(drvdata->clk, 1);
if (rate < 0)
return rate;
ret = clk_set_rate(drvdata->clk, rate);
if (ret)
return ret;
drvdata->clk_rate = rate;
jz4740_wdt = &drvdata->wdt;
jz4740_wdt->info = &jz4740_wdt_info;
jz4740_wdt->ops = &jz4740_wdt_ops;
jz4740_wdt->min_timeout = 1;
jz4740_wdt->max_timeout = 0xffff / rate;
jz4740_wdt->timeout = clamp(heartbeat,
jz4740_wdt->min_timeout,
jz4740_wdt->max_timeout);
jz4740_wdt->parent = dev;
watchdog_set_nowayout(jz4740_wdt, nowayout);
watchdog_set_drvdata(jz4740_wdt, drvdata);
drvdata->map = device_node_to_regmap(dev->parent->of_node);
if (!drvdata->map) {
dev_err(dev, "regmap not found\n");
return -EINVAL;
}
return devm_watchdog_register_device(dev, &drvdata->wdt);
}
static struct platform_driver jz4740_wdt_driver = {
.probe = jz4740_wdt_probe,
.driver = {
.name = "jz4740-wdt",
.of_match_table = of_match_ptr(jz4740_wdt_of_matches),
},
};
module_platform_driver(jz4740_wdt_driver);
MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
MODULE_DESCRIPTION("jz4740 Watchdog Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:jz4740-wdt");
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