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/*
* Realtek RTD129x watchdog
*
* Copyright (c) 2017 Andreas Färber
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#define RTD119X_TCWCR 0x0
#define RTD119X_TCWTR 0x4
#define RTD119X_TCWOV 0xc
#define RTD119X_TCWCR_WDEN_DISABLED 0xa5
#define RTD119X_TCWCR_WDEN_ENABLED 0xff
#define RTD119X_TCWCR_WDEN_MASK 0xff
#define RTD119X_TCWTR_WDCLR BIT(0)
struct rtd119x_watchdog_device {
struct watchdog_device wdt_dev;
void __iomem *base;
struct clk *clk;
};
static int rtd119x_wdt_start(struct watchdog_device *wdev)
{
struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
u32 val;
val = readl_relaxed(data->base + RTD119X_TCWCR);
val &= ~RTD119X_TCWCR_WDEN_MASK;
val |= RTD119X_TCWCR_WDEN_ENABLED;
writel(val, data->base + RTD119X_TCWCR);
return 0;
}
static int rtd119x_wdt_stop(struct watchdog_device *wdev)
{
struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
u32 val;
val = readl_relaxed(data->base + RTD119X_TCWCR);
val &= ~RTD119X_TCWCR_WDEN_MASK;
val |= RTD119X_TCWCR_WDEN_DISABLED;
writel(val, data->base + RTD119X_TCWCR);
return 0;
}
static int rtd119x_wdt_ping(struct watchdog_device *wdev)
{
struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
writel_relaxed(RTD119X_TCWTR_WDCLR, data->base + RTD119X_TCWTR);
return rtd119x_wdt_start(wdev);
}
static int rtd119x_wdt_set_timeout(struct watchdog_device *wdev, unsigned int val)
{
struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
writel(val * clk_get_rate(data->clk), data->base + RTD119X_TCWOV);
data->wdt_dev.timeout = val;
return 0;
}
static const struct watchdog_ops rtd119x_wdt_ops = {
.owner = THIS_MODULE,
.start = rtd119x_wdt_start,
.stop = rtd119x_wdt_stop,
.ping = rtd119x_wdt_ping,
.set_timeout = rtd119x_wdt_set_timeout,
};
static const struct watchdog_info rtd119x_wdt_info = {
.identity = "rtd119x-wdt",
.options = 0,
};
static const struct of_device_id rtd119x_wdt_dt_ids[] = {
{ .compatible = "realtek,rtd1295-watchdog" },
{ }
};
static void rtd119x_clk_disable_unprepare(void *data)
{
clk_disable_unprepare(data);
}
static int rtd119x_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct rtd119x_watchdog_device *data;
int ret;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(data->base))
return PTR_ERR(data->base);
data->clk = devm_clk_get(dev, NULL);
if (IS_ERR(data->clk))
return PTR_ERR(data->clk);
ret = clk_prepare_enable(data->clk);
if (ret)
return ret;
ret = devm_add_action_or_reset(dev, rtd119x_clk_disable_unprepare,
data->clk);
if (ret)
return ret;
data->wdt_dev.info = &rtd119x_wdt_info;
data->wdt_dev.ops = &rtd119x_wdt_ops;
data->wdt_dev.timeout = 120;
data->wdt_dev.max_timeout = 0xffffffff / clk_get_rate(data->clk);
data->wdt_dev.min_timeout = 1;
data->wdt_dev.parent = dev;
watchdog_stop_on_reboot(&data->wdt_dev);
watchdog_set_drvdata(&data->wdt_dev, data);
platform_set_drvdata(pdev, data);
writel_relaxed(RTD119X_TCWTR_WDCLR, data->base + RTD119X_TCWTR);
rtd119x_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout);
rtd119x_wdt_stop(&data->wdt_dev);
return devm_watchdog_register_device(dev, &data->wdt_dev);
}
static struct platform_driver rtd119x_wdt_driver = {
.probe = rtd119x_wdt_probe,
.driver = {
.name = "rtd1295-watchdog",
.of_match_table = rtd119x_wdt_dt_ids,
},
};
builtin_platform_driver(rtd119x_wdt_driver);
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