[deliverable/linux.git] / drivers / watchdog / digicolor_wdt.c

/*
 * Watchdog driver for Conexant Digicolor
 *
 * Copyright (C) 2015 Paradox Innovation Ltd.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 */

#include <linux/types.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/of_address.h>

#define TIMER_A_CONTROL		0
#define TIMER_A_COUNT		4

#define TIMER_A_ENABLE_COUNT	BIT(0)
#define TIMER_A_ENABLE_WATCHDOG	BIT(1)

struct dc_wdt {
	void __iomem		*base;
	struct clk		*clk;
	spinlock_t		lock;
};

static unsigned timeout;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");

static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks)
{
	unsigned long flags;

	spin_lock_irqsave(&wdt->lock, flags);

	writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
	writel_relaxed(ticks, wdt->base + TIMER_A_COUNT);
	writel_relaxed(TIMER_A_ENABLE_COUNT | TIMER_A_ENABLE_WATCHDOG,
		       wdt->base + TIMER_A_CONTROL);

	spin_unlock_irqrestore(&wdt->lock, flags);
}

static int dc_wdt_restart(struct watchdog_device *wdog)
{
	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);

	dc_wdt_set(wdt, 1);
	/* wait for reset to assert... */
	mdelay(500);

	return 0;
}

static int dc_wdt_start(struct watchdog_device *wdog)
{
	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);

	dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk));

	return 0;
}

static int dc_wdt_stop(struct watchdog_device *wdog)
{
	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);

	writel_relaxed(0, wdt->base + TIMER_A_CONTROL);

	return 0;
}

static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
{
	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);

	dc_wdt_set(wdt, t * clk_get_rate(wdt->clk));
	wdog->timeout = t;

	return 0;
}

static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog)
{
	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
	uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT);

	return count / clk_get_rate(wdt->clk);
}

static struct watchdog_ops dc_wdt_ops = {
	.owner		= THIS_MODULE,
	.start		= dc_wdt_start,
	.stop		= dc_wdt_stop,
	.set_timeout	= dc_wdt_set_timeout,
	.get_timeleft	= dc_wdt_get_timeleft,
	.restart        = dc_wdt_restart,
};

static struct watchdog_info dc_wdt_info = {
	.options	= WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE
			| WDIOF_KEEPALIVEPING,
	.identity	= "Conexant Digicolor Watchdog",
};

static struct watchdog_device dc_wdt_wdd = {
	.info		= &dc_wdt_info,
	.ops		= &dc_wdt_ops,
	.min_timeout	= 1,
};

static int dc_wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	struct dc_wdt *wdt;
	int ret;

	wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL);
	if (!wdt)
		return -ENOMEM;
	platform_set_drvdata(pdev, wdt);

	wdt->base = of_iomap(np, 0);
	if (!wdt->base) {
		dev_err(dev, "Failed to remap watchdog regs");
		return -ENODEV;
	}

	wdt->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(wdt->clk)) {
		ret = PTR_ERR(wdt->clk);
		goto err_iounmap;
	}
	dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk);
	dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout;
	dc_wdt_wdd.parent = &pdev->dev;

	spin_lock_init(&wdt->lock);

	watchdog_set_drvdata(&dc_wdt_wdd, wdt);
	watchdog_set_restart_priority(&dc_wdt_wdd, 128);
	watchdog_init_timeout(&dc_wdt_wdd, timeout, dev);
	ret = watchdog_register_device(&dc_wdt_wdd);
	if (ret) {
		dev_err(dev, "Failed to register watchdog device");
		goto err_iounmap;
	}

	return 0;

err_iounmap:
	iounmap(wdt->base);
	return ret;
}

static int dc_wdt_remove(struct platform_device *pdev)
{
	struct dc_wdt *wdt = platform_get_drvdata(pdev);

	watchdog_unregister_device(&dc_wdt_wdd);
	iounmap(wdt->base);

	return 0;
}

static void dc_wdt_shutdown(struct platform_device *pdev)
{
	dc_wdt_stop(&dc_wdt_wdd);
}

static const struct of_device_id dc_wdt_of_match[] = {
	{ .compatible = "cnxt,cx92755-wdt", },
	{},
};
MODULE_DEVICE_TABLE(of, dc_wdt_of_match);

static struct platform_driver dc_wdt_driver = {
	.probe		= dc_wdt_probe,
	.remove		= dc_wdt_remove,
	.shutdown	= dc_wdt_shutdown,
	.driver = {
		.name =		"digicolor-wdt",
		.of_match_table = dc_wdt_of_match,
	},
};
module_platform_driver(dc_wdt_driver);

MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer");
MODULE_LICENSE("GPL");
Commit	Line	Data
336694a0 BS	1	/*
	2	* Watchdog driver for Conexant Digicolor
	3	*
	4	* Copyright (C) 2015 Paradox Innovation Ltd.
	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms of the GNU General Public License as published by the
	8	* Free Software Foundation; either version 2 of the License, or (at your
	9	* option) any later version.
	10	*/
	11
	12	#include <linux/types.h>
	13	#include <linux/module.h>
	14	#include <linux/io.h>
	15	#include <linux/delay.h>
	16	#include <linux/clk.h>
	17	#include <linux/watchdog.h>
336694a0 BS	18	#include <linux/platform_device.h>
	19	#include <linux/of_address.h>
	20
	21	#define TIMER_A_CONTROL 0
	22	#define TIMER_A_COUNT 4
	23
	24	#define TIMER_A_ENABLE_COUNT BIT(0)
	25	#define TIMER_A_ENABLE_WATCHDOG BIT(1)
	26
	27	struct dc_wdt {
	28	void __iomem *base;
	29	struct clk *clk;
336694a0 BS	30	spinlock_t lock;
	31	};
	32
	33	static unsigned timeout;
	34	module_param(timeout, uint, 0);
	35	MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
	36
	37	static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks)
	38	{
	39	unsigned long flags;
	40
	41	spin_lock_irqsave(&wdt->lock, flags);
	42
	43	writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
	44	writel_relaxed(ticks, wdt->base + TIMER_A_COUNT);
	45	writel_relaxed(TIMER_A_ENABLE_COUNT \| TIMER_A_ENABLE_WATCHDOG,
	46	wdt->base + TIMER_A_CONTROL);
	47
	48	spin_unlock_irqrestore(&wdt->lock, flags);
	49	}
	50
d3b08185	51	static int dc_wdt_restart(struct watchdog_device *wdog)
336694a0	52	{
d3b08185	53	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
336694a0 BS	54
	55	dc_wdt_set(wdt, 1);
	56	/* wait for reset to assert... */
	57	mdelay(500);
	58
d3b08185	59	return 0;
336694a0 BS	60	}
	61
	62	static int dc_wdt_start(struct watchdog_device *wdog)
	63	{
	64	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
	65
	66	dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk));
	67
	68	return 0;
	69	}
	70
	71	static int dc_wdt_stop(struct watchdog_device *wdog)
	72	{
	73	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
	74
	75	writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
	76
	77	return 0;
	78	}
	79
	80	static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
	81	{
	82	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
	83
	84	dc_wdt_set(wdt, t * clk_get_rate(wdt->clk));
	85	wdog->timeout = t;
	86
	87	return 0;
	88	}
	89
	90	static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog)
	91	{
	92	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
	93	uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT);
	94
	95	return count / clk_get_rate(wdt->clk);
	96	}
	97
	98	static struct watchdog_ops dc_wdt_ops = {
	99	.owner = THIS_MODULE,
	100	.start = dc_wdt_start,
	101	.stop = dc_wdt_stop,
	102	.set_timeout = dc_wdt_set_timeout,
	103	.get_timeleft = dc_wdt_get_timeleft,
d3b08185	104	.restart = dc_wdt_restart,
336694a0 BS	105	};
	106
	107	static struct watchdog_info dc_wdt_info = {
	108	.options = WDIOF_SETTIMEOUT \| WDIOF_MAGICCLOSE
	109	\| WDIOF_KEEPALIVEPING,
	110	.identity = "Conexant Digicolor Watchdog",
	111	};
	112
	113	static struct watchdog_device dc_wdt_wdd = {
	114	.info = &dc_wdt_info,
	115	.ops = &dc_wdt_ops,
	116	.min_timeout = 1,
	117	};
	118
	119	static int dc_wdt_probe(struct platform_device *pdev)
	120	{
	121	struct device *dev = &pdev->dev;
	122	struct device_node *np = dev->of_node;
	123	struct dc_wdt *wdt;
	124	int ret;
	125
	126	wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL);
	127	if (!wdt)
	128	return -ENOMEM;
	129	platform_set_drvdata(pdev, wdt);
	130
	131	wdt->base = of_iomap(np, 0);
	132	if (!wdt->base) {
	133	dev_err(dev, "Failed to remap watchdog regs");
	134	return -ENODEV;
	135	}
	136
	137	wdt->clk = devm_clk_get(&pdev->dev, NULL);
	138	if (IS_ERR(wdt->clk)) {
	139	ret = PTR_ERR(wdt->clk);
	140	goto err_iounmap;
	141	}
	142	dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk);
	143	dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout;
6551881c	144	dc_wdt_wdd.parent = &pdev->dev;
336694a0 BS	145
	146	spin_lock_init(&wdt->lock);
	147
	148	watchdog_set_drvdata(&dc_wdt_wdd, wdt);
d3b08185	149	watchdog_set_restart_priority(&dc_wdt_wdd, 128);
336694a0 BS	150	watchdog_init_timeout(&dc_wdt_wdd, timeout, dev);
	151	ret = watchdog_register_device(&dc_wdt_wdd);
	152	if (ret) {
	153	dev_err(dev, "Failed to register watchdog device");
	154	goto err_iounmap;
	155	}
	156
336694a0 BS	157	return 0;
	158
	159	err_iounmap:
	160	iounmap(wdt->base);
	161	return ret;
	162	}
	163
	164	static int dc_wdt_remove(struct platform_device *pdev)
	165	{
	166	struct dc_wdt *wdt = platform_get_drvdata(pdev);
	167
336694a0 BS	168	watchdog_unregister_device(&dc_wdt_wdd);
	169	iounmap(wdt->base);
	170
	171	return 0;
	172	}
	173
	174	static void dc_wdt_shutdown(struct platform_device *pdev)
	175	{
	176	dc_wdt_stop(&dc_wdt_wdd);
	177	}
	178
	179	static const struct of_device_id dc_wdt_of_match[] = {
	180	{ .compatible = "cnxt,cx92755-wdt", },
	181	{},
	182	};
	183	MODULE_DEVICE_TABLE(of, dc_wdt_of_match);
	184
	185	static struct platform_driver dc_wdt_driver = {
	186	.probe = dc_wdt_probe,
	187	.remove = dc_wdt_remove,
	188	.shutdown = dc_wdt_shutdown,
	189	.driver = {
	190	.name = "digicolor-wdt",
	191	.of_match_table = dc_wdt_of_match,
	192	},
	193	};
	194	module_platform_driver(dc_wdt_driver);
	195
	196	MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
	197	MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer");
	198	MODULE_LICENSE("GPL");