[linux-2.6-block.git] / drivers / watchdog / moxart_wdt.c

/*
 * MOXA ART SoCs watchdog driver.
 *
 * Copyright (C) 2013 Jonas Jensen
 *
 * Jonas Jensen <jonas.jensen@gmail.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2.  This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

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

#define REG_COUNT			0x4
#define REG_MODE			0x8
#define REG_ENABLE			0xC

struct moxart_wdt_dev {
	struct watchdog_device dev;
	void __iomem *base;
	unsigned int clock_frequency;
};

static int heartbeat;

static int moxart_wdt_restart(struct watchdog_device *wdt_dev,
			      unsigned long action, void *data)
{
	struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);

	writel(1, moxart_wdt->base + REG_COUNT);
	writel(0x5ab9, moxart_wdt->base + REG_MODE);
	writel(0x03, moxart_wdt->base + REG_ENABLE);

	return 0;
}

static int moxart_wdt_stop(struct watchdog_device *wdt_dev)
{
	struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);

	writel(0, moxart_wdt->base + REG_ENABLE);

	return 0;
}

static int moxart_wdt_start(struct watchdog_device *wdt_dev)
{
	struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);

	writel(moxart_wdt->clock_frequency * wdt_dev->timeout,
	       moxart_wdt->base + REG_COUNT);
	writel(0x5ab9, moxart_wdt->base + REG_MODE);
	writel(0x03, moxart_wdt->base + REG_ENABLE);

	return 0;
}

static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev,
				  unsigned int timeout)
{
	wdt_dev->timeout = timeout;

	return 0;
}

static const struct watchdog_info moxart_wdt_info = {
	.identity       = "moxart-wdt",
	.options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
			  WDIOF_MAGICCLOSE,
};

static const struct watchdog_ops moxart_wdt_ops = {
	.owner          = THIS_MODULE,
	.start          = moxart_wdt_start,
	.stop           = moxart_wdt_stop,
	.set_timeout    = moxart_wdt_set_timeout,
	.restart        = moxart_wdt_restart,
};

static int moxart_wdt_probe(struct platform_device *pdev)
{
	struct moxart_wdt_dev *moxart_wdt;
	struct device *dev = &pdev->dev;
	struct clk *clk;
	int err;
	unsigned int max_timeout;
	bool nowayout = WATCHDOG_NOWAYOUT;

	moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL);
	if (!moxart_wdt)
		return -ENOMEM;

	platform_set_drvdata(pdev, moxart_wdt);

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

	clk = devm_clk_get(dev, NULL);
	if (IS_ERR(clk)) {
		pr_err("%s: of_clk_get failed\n", __func__);
		return PTR_ERR(clk);
	}

	moxart_wdt->clock_frequency = clk_get_rate(clk);
	if (moxart_wdt->clock_frequency == 0) {
		pr_err("%s: incorrect clock frequency\n", __func__);
		return -EINVAL;
	}

	max_timeout = UINT_MAX / moxart_wdt->clock_frequency;

	moxart_wdt->dev.info = &moxart_wdt_info;
	moxart_wdt->dev.ops = &moxart_wdt_ops;
	moxart_wdt->dev.timeout = max_timeout;
	moxart_wdt->dev.min_timeout = 1;
	moxart_wdt->dev.max_timeout = max_timeout;
	moxart_wdt->dev.parent = dev;

	watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev);
	watchdog_set_nowayout(&moxart_wdt->dev, nowayout);
	watchdog_set_restart_priority(&moxart_wdt->dev, 128);

	watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt);

	watchdog_stop_on_unregister(&moxart_wdt->dev);
	err = devm_watchdog_register_device(dev, &moxart_wdt->dev);
	if (err)
		return err;

	dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n",
		moxart_wdt->dev.timeout, nowayout);

	return 0;
}

static const struct of_device_id moxart_watchdog_match[] = {
	{ .compatible = "moxa,moxart-watchdog" },
	{ },
};
MODULE_DEVICE_TABLE(of, moxart_watchdog_match);

static struct platform_driver moxart_wdt_driver = {
	.probe      = moxart_wdt_probe,
	.driver     = {
		.name		= "moxart-watchdog",
		.of_match_table	= moxart_watchdog_match,
	},
};
module_platform_driver(moxart_wdt_driver);

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

MODULE_DESCRIPTION("MOXART watchdog driver");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
Commit	Line	Data
e14538e0 JJ	1	/*
	2	* MOXA ART SoCs watchdog driver.
	3	*
	4	* Copyright (C) 2013 Jonas Jensen
	5	*
	6	* Jonas Jensen <jonas.jensen@gmail.com>
	7	*
	8	* This file is licensed under the terms of the GNU General Public
	9	* License version 2. This program is licensed "as is" without any
	10	* warranty of any kind, whether express or implied.
	11	*/
	12
	13	#include <linux/clk.h>
	14	#include <linux/io.h>
	15	#include <linux/module.h>
ac316725	16	#include <linux/mod_devicetable.h>
e14538e0 JJ	17	#include <linux/err.h>
	18	#include <linux/kernel.h>
	19	#include <linux/platform_device.h>
	20	#include <linux/watchdog.h>
	21	#include <linux/moduleparam.h>
	22
	23	#define REG_COUNT 0x4
	24	#define REG_MODE 0x8
	25	#define REG_ENABLE 0xC
	26
	27	struct moxart_wdt_dev {
	28	struct watchdog_device dev;
	29	void __iomem *base;
	30	unsigned int clock_frequency;
	31	};
	32
	33	static int heartbeat;
	34
4d8b229d GR	35	static int moxart_wdt_restart(struct watchdog_device *wdt_dev,
4d8b229d GR	36	unsigned long action, void *data)
8773926d	37	{
46c17f0f DR	38	struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
46c17f0f DR	39
ad0e0e68 GR	40	writel(1, moxart_wdt->base + REG_COUNT);
	41	writel(0x5ab9, moxart_wdt->base + REG_MODE);
	42	writel(0x03, moxart_wdt->base + REG_ENABLE);
	43
46c17f0f	44	return 0;
8773926d JJ	45	}
8773926d JJ	46
e14538e0 JJ	47	static int moxart_wdt_stop(struct watchdog_device *wdt_dev)
	48	{
	49	struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
	50
	51	writel(0, moxart_wdt->base + REG_ENABLE);
	52
	53	return 0;
	54	}
	55
	56	static int moxart_wdt_start(struct watchdog_device *wdt_dev)
	57	{
	58	struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
	59
	60	writel(moxart_wdt->clock_frequency * wdt_dev->timeout,
	61	moxart_wdt->base + REG_COUNT);
	62	writel(0x5ab9, moxart_wdt->base + REG_MODE);
	63	writel(0x03, moxart_wdt->base + REG_ENABLE);
	64
	65	return 0;
	66	}
	67
	68	static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev,
	69	unsigned int timeout)
	70	{
	71	wdt_dev->timeout = timeout;
	72
	73	return 0;
	74	}
	75
	76	static const struct watchdog_info moxart_wdt_info = {
	77	.identity = "moxart-wdt",
	78	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \|
	79	WDIOF_MAGICCLOSE,
	80	};
	81
	82	static const struct watchdog_ops moxart_wdt_ops = {
	83	.owner = THIS_MODULE,
	84	.start = moxart_wdt_start,
	85	.stop = moxart_wdt_stop,
	86	.set_timeout = moxart_wdt_set_timeout,
46c17f0f	87	.restart = moxart_wdt_restart,
e14538e0 JJ	88	};
	89
	90	static int moxart_wdt_probe(struct platform_device *pdev)
	91	{
	92	struct moxart_wdt_dev *moxart_wdt;
	93	struct device *dev = &pdev->dev;
e14538e0 JJ	94	struct clk *clk;
	95	int err;
	96	unsigned int max_timeout;
	97	bool nowayout = WATCHDOG_NOWAYOUT;
	98
	99	moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL);
	100	if (!moxart_wdt)
	101	return -ENOMEM;
	102
	103	platform_set_drvdata(pdev, moxart_wdt);
	104
0f0a6a28	105	moxart_wdt->base = devm_platform_ioremap_resource(pdev, 0);
e14538e0 JJ	106	if (IS_ERR(moxart_wdt->base))
	107	return PTR_ERR(moxart_wdt->base);
	108
615e40ad	109	clk = devm_clk_get(dev, NULL);
e14538e0 JJ	110	if (IS_ERR(clk)) {
	111	pr_err("%s: of_clk_get failed\n", __func__);
	112	return PTR_ERR(clk);
	113	}
	114
	115	moxart_wdt->clock_frequency = clk_get_rate(clk);
	116	if (moxart_wdt->clock_frequency == 0) {
	117	pr_err("%s: incorrect clock frequency\n", __func__);
	118	return -EINVAL;
	119	}
	120
	121	max_timeout = UINT_MAX / moxart_wdt->clock_frequency;
	122
	123	moxart_wdt->dev.info = &moxart_wdt_info;
	124	moxart_wdt->dev.ops = &moxart_wdt_ops;
	125	moxart_wdt->dev.timeout = max_timeout;
	126	moxart_wdt->dev.min_timeout = 1;
	127	moxart_wdt->dev.max_timeout = max_timeout;
	128	moxart_wdt->dev.parent = dev;
	129
	130	watchdog_init_timeout(&moxart_wdt->dev, heartbeat, dev);
	131	watchdog_set_nowayout(&moxart_wdt->dev, nowayout);
46c17f0f	132	watchdog_set_restart_priority(&moxart_wdt->dev, 128);
e14538e0 JJ	133
	134	watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt);
	135
615e40ad GR	136	watchdog_stop_on_unregister(&moxart_wdt->dev);
615e40ad GR	137	err = devm_watchdog_register_device(dev, &moxart_wdt->dev);
e14538e0 JJ	138	if (err)
	139	return err;
	140
	141	dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n",
	142	moxart_wdt->dev.timeout, nowayout);
	143
	144	return 0;
	145	}
	146
e14538e0 JJ	147	static const struct of_device_id moxart_watchdog_match[] = {
	148	{ .compatible = "moxa,moxart-watchdog" },
	149	{ },
	150	};
c73318f4	151	MODULE_DEVICE_TABLE(of, moxart_watchdog_match);
e14538e0 JJ	152
	153	static struct platform_driver moxart_wdt_driver = {
	154	.probe = moxart_wdt_probe,
e14538e0 JJ	155	.driver = {
e14538e0 JJ	156	.name = "moxart-watchdog",
e14538e0 JJ	157	.of_match_table = moxart_watchdog_match,
	158	},
	159	};
	160	module_platform_driver(moxart_wdt_driver);
	161
	162	module_param(heartbeat, int, 0);
	163	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds");
	164
	165	MODULE_DESCRIPTION("MOXART watchdog driver");
	166	MODULE_LICENSE("GPL");
	167	MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");