summaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/msc313e_wdt.c
blob: 90171431fc59433317fc8123e4b28c9b47578383 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
// SPDX-License-Identifier: GPL-2.0
/*
 * MStar WDT driver
 *
 * Copyright (C) 2019 - 2021 Daniel Palmer
 * Copyright (C) 2021 Romain Perier
 *
 */

#include <linux/clk.h>
#include <linux/io.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>

#define REG_WDT_CLR			0x0
#define REG_WDT_MAX_PRD_L		0x10
#define REG_WDT_MAX_PRD_H		0x14

#define MSC313E_WDT_MIN_TIMEOUT		1
#define MSC313E_WDT_DEFAULT_TIMEOUT	30

static unsigned int timeout;

module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");

struct msc313e_wdt_priv {
	void __iomem *base;
	struct watchdog_device wdev;
	struct clk *clk;
};

static int msc313e_wdt_start(struct watchdog_device *wdev)
{
	struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev);
	u32 timeout;
	int err;

	err = clk_prepare_enable(priv->clk);
	if (err)
		return err;

	timeout = wdev->timeout * clk_get_rate(priv->clk);
	writew(timeout & 0xffff, priv->base + REG_WDT_MAX_PRD_L);
	writew((timeout >> 16) & 0xffff, priv->base + REG_WDT_MAX_PRD_H);
	writew(1, priv->base + REG_WDT_CLR);
	return 0;
}

static int msc313e_wdt_ping(struct watchdog_device *wdev)
{
	struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev);

	writew(1, priv->base + REG_WDT_CLR);
	return 0;
}

static int msc313e_wdt_stop(struct watchdog_device *wdev)
{
	struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev);

	writew(0, priv->base + REG_WDT_MAX_PRD_L);
	writew(0, priv->base + REG_WDT_MAX_PRD_H);
	writew(0, priv->base + REG_WDT_CLR);
	clk_disable_unprepare(priv->clk);
	return 0;
}

static int msc313e_wdt_settimeout(struct watchdog_device *wdev, unsigned int new_time)
{
	wdev->timeout = new_time;

	return msc313e_wdt_start(wdev);
}

static const struct watchdog_info msc313e_wdt_ident = {
	.identity = "MSC313e watchdog",
	.options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
};

static const struct watchdog_ops msc313e_wdt_ops = {
	.owner = THIS_MODULE,
	.start = msc313e_wdt_start,
	.stop = msc313e_wdt_stop,
	.ping = msc313e_wdt_ping,
	.set_timeout = msc313e_wdt_settimeout,
};

static const struct of_device_id msc313e_wdt_of_match[] = {
	{ .compatible = "mstar,msc313e-wdt", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, msc313e_wdt_of_match);

static int msc313e_wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct msc313e_wdt_priv *priv;

	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(priv->base))
		return PTR_ERR(priv->base);

	priv->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(priv->clk)) {
		dev_err(dev, "No input clock\n");
		return PTR_ERR(priv->clk);
	}

	priv->wdev.info = &msc313e_wdt_ident,
	priv->wdev.ops = &msc313e_wdt_ops,
	priv->wdev.parent = dev;
	priv->wdev.min_timeout = MSC313E_WDT_MIN_TIMEOUT;
	priv->wdev.max_timeout = U32_MAX / clk_get_rate(priv->clk);
	priv->wdev.timeout = MSC313E_WDT_DEFAULT_TIMEOUT;

	/* If the period is non-zero the WDT is running */
	if (readw(priv->base + REG_WDT_MAX_PRD_L) | (readw(priv->base + REG_WDT_MAX_PRD_H) << 16))
		set_bit(WDOG_HW_RUNNING, &priv->wdev.status);

	watchdog_set_drvdata(&priv->wdev, priv);

	watchdog_init_timeout(&priv->wdev, timeout, dev);
	watchdog_stop_on_reboot(&priv->wdev);
	watchdog_stop_on_unregister(&priv->wdev);

	return devm_watchdog_register_device(dev, &priv->wdev);
}

static int __maybe_unused msc313e_wdt_suspend(struct device *dev)
{
	struct msc313e_wdt_priv *priv = dev_get_drvdata(dev);

	if (watchdog_active(&priv->wdev))
		msc313e_wdt_stop(&priv->wdev);

	return 0;
}

static int __maybe_unused msc313e_wdt_resume(struct device *dev)
{
	struct msc313e_wdt_priv *priv = dev_get_drvdata(dev);

	if (watchdog_active(&priv->wdev))
		msc313e_wdt_start(&priv->wdev);

	return 0;
}

static SIMPLE_DEV_PM_OPS(msc313e_wdt_pm_ops, msc313e_wdt_suspend, msc313e_wdt_resume);

static struct platform_driver msc313e_wdt_driver = {
	.driver = {
		.name = "msc313e-wdt",
		.of_match_table = msc313e_wdt_of_match,
		.pm = &msc313e_wdt_pm_ops,
	},
	.probe = msc313e_wdt_probe,
};
module_platform_driver(msc313e_wdt_driver);

MODULE_AUTHOR("Daniel Palmer <daniel@thingy.jp>");
MODULE_DESCRIPTION("Watchdog driver for MStar MSC313e");
MODULE_LICENSE("GPL v2");