1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Realtek RTD129x watchdog
  4 *
  5 * Copyright (c) 2017 Andreas Färber
  6 *
  7 */
  8
  9#include <linux/bitops.h>
 10#include <linux/clk.h>
 11#include <linux/io.h>
 12#include <linux/of.h>
 13#include <linux/of_address.h>
 14#include <linux/platform_device.h>
 15#include <linux/watchdog.h>
 16
 17#define RTD119X_TCWCR		0x0
 18#define RTD119X_TCWTR		0x4
 19#define RTD119X_TCWOV		0xc
 20
 21#define RTD119X_TCWCR_WDEN_DISABLED		0xa5
 22#define RTD119X_TCWCR_WDEN_ENABLED		0xff
 23#define RTD119X_TCWCR_WDEN_MASK			0xff
 24
 25#define RTD119X_TCWTR_WDCLR			BIT(0)
 26
 27struct rtd119x_watchdog_device {
 28	struct watchdog_device wdt_dev;
 29	void __iomem *base;
 30	struct clk *clk;
 31};
 32
 33static int rtd119x_wdt_start(struct watchdog_device *wdev)
 34{
 35	struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
 36	u32 val;
 37
 38	val = readl_relaxed(data->base + RTD119X_TCWCR);
 39	val &= ~RTD119X_TCWCR_WDEN_MASK;
 40	val |= RTD119X_TCWCR_WDEN_ENABLED;
 41	writel(val, data->base + RTD119X_TCWCR);
 42
 43	return 0;
 44}
 45
 46static int rtd119x_wdt_stop(struct watchdog_device *wdev)
 47{
 48	struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
 49	u32 val;
 50
 51	val = readl_relaxed(data->base + RTD119X_TCWCR);
 52	val &= ~RTD119X_TCWCR_WDEN_MASK;
 53	val |= RTD119X_TCWCR_WDEN_DISABLED;
 54	writel(val, data->base + RTD119X_TCWCR);
 55
 56	return 0;
 57}
 58
 59static int rtd119x_wdt_ping(struct watchdog_device *wdev)
 60{
 61	struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
 62
 63	writel_relaxed(RTD119X_TCWTR_WDCLR, data->base + RTD119X_TCWTR);
 64
 65	return rtd119x_wdt_start(wdev);
 66}
 67
 68static int rtd119x_wdt_set_timeout(struct watchdog_device *wdev, unsigned int val)
 69{
 70	struct rtd119x_watchdog_device *data = watchdog_get_drvdata(wdev);
 71
 72	writel(val * clk_get_rate(data->clk), data->base + RTD119X_TCWOV);
 73
 74	data->wdt_dev.timeout = val;
 75
 76	return 0;
 77}
 78
 79static const struct watchdog_ops rtd119x_wdt_ops = {
 80	.owner = THIS_MODULE,
 81	.start		= rtd119x_wdt_start,
 82	.stop		= rtd119x_wdt_stop,
 83	.ping		= rtd119x_wdt_ping,
 84	.set_timeout	= rtd119x_wdt_set_timeout,
 85};
 86
 87static const struct watchdog_info rtd119x_wdt_info = {
 88	.identity = "rtd119x-wdt",
 89	.options = 0,
 90};
 91
 92static const struct of_device_id rtd119x_wdt_dt_ids[] = {
 93	 { .compatible = "realtek,rtd1295-watchdog" },
 94	 { }
 95};
 96
 97static int rtd119x_wdt_probe(struct platform_device *pdev)
 98{
 99	struct device *dev = &pdev->dev;
100	struct rtd119x_watchdog_device *data;
101
102	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
103	if (!data)
104		return -ENOMEM;
105
106	data->base = devm_platform_ioremap_resource(pdev, 0);
107	if (IS_ERR(data->base))
108		return PTR_ERR(data->base);
109
110	data->clk = devm_clk_get_enabled(dev, NULL);
111	if (IS_ERR(data->clk))
112		return PTR_ERR(data->clk);
113
114	data->wdt_dev.info = &rtd119x_wdt_info;
115	data->wdt_dev.ops = &rtd119x_wdt_ops;
116	data->wdt_dev.timeout = 120;
117	data->wdt_dev.max_timeout = 0xffffffff / clk_get_rate(data->clk);
118	data->wdt_dev.min_timeout = 1;
119	data->wdt_dev.parent = dev;
120
121	watchdog_stop_on_reboot(&data->wdt_dev);
122	watchdog_set_drvdata(&data->wdt_dev, data);
123	platform_set_drvdata(pdev, data);
124
125	writel_relaxed(RTD119X_TCWTR_WDCLR, data->base + RTD119X_TCWTR);
126	rtd119x_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout);
127	rtd119x_wdt_stop(&data->wdt_dev);
128
129	return devm_watchdog_register_device(dev, &data->wdt_dev);
130}
131
132static struct platform_driver rtd119x_wdt_driver = {
133	.probe = rtd119x_wdt_probe,
134	.driver = {
135		.name = "rtd1295-watchdog",
136		.of_match_table	= rtd119x_wdt_dt_ids,
137	},
138};
139builtin_platform_driver(rtd119x_wdt_driver);