[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/err.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/moduleparam.h>

#include <asm/system_misc.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 struct moxart_wdt_dev *moxart_restart_ctx;

static int heartbeat;

static void moxart_wdt_restart(enum reboot_mode reboot_mode, const char *cmd)
{
	writel(1, moxart_restart_ctx->base + REG_COUNT);
	writel(0x5ab9, moxart_restart_ctx->base + REG_MODE);
	writel(0x03, moxart_restart_ctx->base + REG_ENABLE);
}

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,
};

static int moxart_wdt_probe(struct platform_device *pdev)
{
	struct moxart_wdt_dev *moxart_wdt;
	struct device *dev = &pdev->dev;
	struct device_node *node = dev->of_node;
	struct resource *res;
	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);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	moxart_wdt->base = devm_ioremap_resource(dev, res);
	if (IS_ERR(moxart_wdt->base))
		return PTR_ERR(moxart_wdt->base);

	clk = of_clk_get(node, 0);
	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_drvdata(&moxart_wdt->dev, moxart_wdt);

	err = watchdog_register_device(&moxart_wdt->dev);
	if (err)
		return err;

	moxart_restart_ctx = moxart_wdt;
	arm_pm_restart = moxart_wdt_restart;

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

	return 0;
}

static int moxart_wdt_remove(struct platform_device *pdev)
{
	struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev);

	arm_pm_restart = NULL;
	moxart_wdt_stop(&moxart_wdt->dev);
	watchdog_unregister_device(&moxart_wdt->dev);

	return 0;
}

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

static struct platform_driver moxart_wdt_driver = {
	.probe      = moxart_wdt_probe,
	.remove     = moxart_wdt_remove,
	.driver     = {
		.name		= "moxart-watchdog",
		.owner		= THIS_MODULE,
		.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>
	16	#include <linux/err.h>
	17	#include <linux/kernel.h>
	18	#include <linux/platform_device.h>
	19	#include <linux/watchdog.h>
	20	#include <linux/moduleparam.h>
	21
8773926d JJ	22	#include <asm/system_misc.h>
8773926d JJ	23
e14538e0 JJ	24	#define REG_COUNT 0x4
	25	#define REG_MODE 0x8
	26	#define REG_ENABLE 0xC
	27
	28	struct moxart_wdt_dev {
	29	struct watchdog_device dev;
	30	void __iomem *base;
	31	unsigned int clock_frequency;
	32	};
	33
8773926d JJ	34	static struct moxart_wdt_dev *moxart_restart_ctx;
8773926d JJ	35
e14538e0 JJ	36	static int heartbeat;
e14538e0 JJ	37
8773926d JJ	38	static void moxart_wdt_restart(enum reboot_mode reboot_mode, const char *cmd)
	39	{
	40	writel(1, moxart_restart_ctx->base + REG_COUNT);
	41	writel(0x5ab9, moxart_restart_ctx->base + REG_MODE);
	42	writel(0x03, moxart_restart_ctx->base + REG_ENABLE);
	43	}
	44
e14538e0 JJ	45	static 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
	54	static 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
	66	static 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
	74	static const struct watchdog_info moxart_wdt_info = {
	75	.identity = "moxart-wdt",
	76	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \|
	77	WDIOF_MAGICCLOSE,
	78	};
	79
	80	static 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	};
	86
	87	static int moxart_wdt_probe(struct platform_device *pdev)
	88	{
	89	struct moxart_wdt_dev *moxart_wdt;
	90	struct device *dev = &pdev->dev;
	91	struct device_node *node = dev->of_node;
	92	struct resource *res;
	93	struct clk *clk;
	94	int err;
	95	unsigned int max_timeout;
	96	bool nowayout = WATCHDOG_NOWAYOUT;
	97
	98	moxart_wdt = devm_kzalloc(dev, sizeof(*moxart_wdt), GFP_KERNEL);
	99	if (!moxart_wdt)
	100	return -ENOMEM;
	101
	102	platform_set_drvdata(pdev, moxart_wdt);
	103
	104	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	105	moxart_wdt->base = devm_ioremap_resource(dev, res);
	106	if (IS_ERR(moxart_wdt->base))
	107	return PTR_ERR(moxart_wdt->base);
	108
109	clk = of_clk_get(node, 0);
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);
132
133	watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt);
134
135	err = watchdog_register_device(&moxart_wdt->dev);
136	if (err)
137	return err;
138
8773926d JJ	139	moxart_restart_ctx = moxart_wdt;
	140	arm_pm_restart = moxart_wdt_restart;
	141
e14538e0 JJ	142	dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n",
	143	moxart_wdt->dev.timeout, nowayout);
	144
	145	return 0;
	146	}
	147
	148	static int moxart_wdt_remove(struct platform_device *pdev)
	149	{
	150	struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev);
	151
8773926d	152	arm_pm_restart = NULL;
e14538e0 JJ	153	moxart_wdt_stop(&moxart_wdt->dev);
	154	watchdog_unregister_device(&moxart_wdt->dev);
	155
	156	return 0;
	157	}
	158
	159	static const struct of_device_id moxart_watchdog_match[] = {
	160	{ .compatible = "moxa,moxart-watchdog" },
	161	{ },
	162	};
	163
	164	static struct platform_driver moxart_wdt_driver = {
	165	.probe = moxart_wdt_probe,
	166	.remove = moxart_wdt_remove,
	167	.driver = {
	168	.name = "moxart-watchdog",
	169	.owner = THIS_MODULE,
	170	.of_match_table = moxart_watchdog_match,
	171	},
	172	};
	173	module_platform_driver(moxart_wdt_driver);
	174
	175	module_param(heartbeat, int, 0);
	176	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds");
	177
	178	MODULE_DESCRIPTION("MOXART watchdog driver");
	179	MODULE_LICENSE("GPL");
	180	MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");