1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * MOXA ART SoCs watchdog driver.
4 *
5 * Copyright (C) 2013 Jonas Jensen
6 *
7 * Jonas Jensen <jonas.jensen@gmail.com>
8 *
9 */
10
11#include <linux/clk.h>
12#include <linux/io.h>
13#include <linux/module.h>
14#include <linux/mod_devicetable.h>
15#include <linux/err.h>
16#include <linux/kernel.h>
17#include <linux/platform_device.h>
18#include <linux/watchdog.h>
19#include <linux/moduleparam.h>
20
21#define REG_COUNT			0x4
22#define REG_MODE			0x8
23#define REG_ENABLE			0xC
24
25struct moxart_wdt_dev {
26	struct watchdog_device dev;
27	void __iomem *base;
28	unsigned int clock_frequency;
29};
30
31static int heartbeat;
32
33static int moxart_wdt_restart(struct watchdog_device *wdt_dev,
34			      unsigned long action, void *data)
35{
36	struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
37
38	writel(1, moxart_wdt->base + REG_COUNT);
39	writel(0x5ab9, moxart_wdt->base + REG_MODE);
40	writel(0x03, moxart_wdt->base + REG_ENABLE);
41
42	return 0;
43}
44
45static int moxart_wdt_stop(struct watchdog_device *wdt_dev)
46{
47	struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
48
49	writel(0, moxart_wdt->base + REG_ENABLE);
50
51	return 0;
52}
53
54static int moxart_wdt_start(struct watchdog_device *wdt_dev)
55{
56	struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
57
58	writel(moxart_wdt->clock_frequency * wdt_dev->timeout,
59	       moxart_wdt->base + REG_COUNT);
60	writel(0x5ab9, moxart_wdt->base + REG_MODE);
61	writel(0x03, moxart_wdt->base + REG_ENABLE);
62
63	return 0;
64}
65
66static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev,
67				  unsigned int timeout)
68{
69	wdt_dev->timeout = timeout;
70
71	return 0;
72}
73
74static const struct watchdog_info moxart_wdt_info = {
75	.identity       = "moxart-wdt",
76	.options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
77			  WDIOF_MAGICCLOSE,
78};
79
80static const struct watchdog_ops moxart_wdt_ops = {
81	.owner          = THIS_MODULE,
82	.start          = moxart_wdt_start,
83	.stop           = moxart_wdt_stop,
84	.set_timeout    = moxart_wdt_set_timeout,
85	.restart        = moxart_wdt_restart,
86};
87
88static int moxart_wdt_probe(struct platform_device *pdev)
89{
90	struct moxart_wdt_dev *moxart_wdt;
91	struct device *dev = &pdev->dev;
92	struct clk *clk;
93	int err;
94	unsigned int max_timeout;
95	bool nowayout = WATCHDOG_NOWAYOUT;
96
97	moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL);
98	if (!moxart_wdt)
99		return -ENOMEM;
100
101	platform_set_drvdata(pdev, moxart_wdt);
102
103	moxart_wdt->base = devm_platform_ioremap_resource(pdev, 0);
104	if (IS_ERR(moxart_wdt->base))
105		return PTR_ERR(moxart_wdt->base);
106
107	clk = devm_clk_get(dev, NULL);
108	if (IS_ERR(clk)) {
109		pr_err("%s: of_clk_get failed\n", __func__);
110		return PTR_ERR(clk);
111	}
112
113	moxart_wdt->clock_frequency = clk_get_rate(clk);
114	if (moxart_wdt->clock_frequency == 0) {
115		pr_err("%s: incorrect clock frequency\n", __func__);
116		return -EINVAL;
117	}
118
119	max_timeout = UINT_MAX / moxart_wdt->clock_frequency;
120
121	moxart_wdt->dev.info = &moxart_wdt_info;
122	moxart_wdt->dev.ops = &moxart_wdt_ops;
123	moxart_wdt->dev.timeout = max_timeout;
124	moxart_wdt->dev.min_timeout = 1;
125	moxart_wdt->dev.max_timeout = max_timeout;
126	moxart_wdt->dev.parent = dev;
127
128	watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev);
129	watchdog_set_nowayout(&moxart_wdt->dev, nowayout);
130	watchdog_set_restart_priority(&moxart_wdt->dev, 128);
131
132	watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt);
133
134	watchdog_stop_on_unregister(&moxart_wdt->dev);
135	err = devm_watchdog_register_device(dev, &moxart_wdt->dev);
136	if (err)
137		return err;
138
139	dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n",
140		moxart_wdt->dev.timeout, nowayout);
141
142	return 0;
143}
144
145static const struct of_device_id moxart_watchdog_match[] = {
146	{ .compatible = "moxa,moxart-watchdog" },
147	{ },
148};
149MODULE_DEVICE_TABLE(of, moxart_watchdog_match);
150
151static struct platform_driver moxart_wdt_driver = {
152	.probe      = moxart_wdt_probe,
153	.driver     = {
154		.name		= "moxart-watchdog",
155		.of_match_table	= moxart_watchdog_match,
156	},
157};
158module_platform_driver(moxart_wdt_driver);
159
160module_param(heartbeat, int, 0);
161MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds");
162
163MODULE_DESCRIPTION("MOXART watchdog driver");
164MODULE_LICENSE("GPL");
165MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
166