[mirror_ubuntu-artful-kernel.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, unsigned long action,
			  void *data)
{
	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 const 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 const 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 resource *res;
	struct device *dev = &pdev->dev;
	struct dc_wdt *wdt;
	int ret;

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

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

	wdt->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(wdt->clk))
		return PTR_ERR(wdt->clk);
	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 = 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);
	watchdog_stop_on_reboot(&dc_wdt_wdd);
	ret = devm_watchdog_register_device(dev, &dc_wdt_wdd);
	if (ret) {
		dev_err(dev, "Failed to register watchdog device");
		return ret;
	}

	return 0;
}

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,
	.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
4d8b229d GR	51	static int dc_wdt_restart(struct watchdog_device *wdog, unsigned long action,
4d8b229d GR	52	void *data)
336694a0	53	{
d3b08185	54	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
336694a0 BS	55
	56	dc_wdt_set(wdt, 1);
	57	/* wait for reset to assert... */
	58	mdelay(500);
	59
d3b08185	60	return 0;
336694a0 BS	61	}
	62
	63	static int dc_wdt_start(struct watchdog_device *wdog)
	64	{
	65	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
	66
	67	dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk));
	68
	69	return 0;
	70	}
	71
	72	static int dc_wdt_stop(struct watchdog_device *wdog)
	73	{
	74	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
	75
	76	writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
	77
	78	return 0;
	79	}
	80
	81	static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
	82	{
	83	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
	84
	85	dc_wdt_set(wdt, t * clk_get_rate(wdt->clk));
	86	wdog->timeout = t;
	87
	88	return 0;
	89	}
	90
	91	static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog)
	92	{
	93	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
	94	uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT);
	95
	96	return count / clk_get_rate(wdt->clk);
	97	}
	98
b893e344	99	static const struct watchdog_ops dc_wdt_ops = {
336694a0 BS	100	.owner = THIS_MODULE,
	101	.start = dc_wdt_start,
	102	.stop = dc_wdt_stop,
	103	.set_timeout = dc_wdt_set_timeout,
	104	.get_timeleft = dc_wdt_get_timeleft,
d3b08185	105	.restart = dc_wdt_restart,
336694a0 BS	106	};
336694a0 BS	107
6c368932	108	static const struct watchdog_info dc_wdt_info = {
336694a0 BS	109	.options = WDIOF_SETTIMEOUT \| WDIOF_MAGICCLOSE
	110	\| WDIOF_KEEPALIVEPING,
	111	.identity = "Conexant Digicolor Watchdog",
	112	};
	113
	114	static struct watchdog_device dc_wdt_wdd = {
	115	.info = &dc_wdt_info,
	116	.ops = &dc_wdt_ops,
	117	.min_timeout = 1,
	118	};
	119
	120	static int dc_wdt_probe(struct platform_device *pdev)
	121	{
dd36f6ce	122	struct resource *res;
336694a0	123	struct device *dev = &pdev->dev;
336694a0 BS	124	struct dc_wdt *wdt;
	125	int ret;
	126
	127	wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL);
	128	if (!wdt)
	129	return -ENOMEM;
336694a0	130
dd36f6ce GR	131	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	132	wdt->base = devm_ioremap_resource(dev, res);
	133	if (IS_ERR(wdt->base))
	134	return PTR_ERR(wdt->base);
336694a0	135
dd36f6ce GR	136	wdt->clk = devm_clk_get(dev, NULL);
	137	if (IS_ERR(wdt->clk))
	138	return PTR_ERR(wdt->clk);
336694a0 BS	139	dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk);
336694a0 BS	140	dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout;
dd36f6ce	141	dc_wdt_wdd.parent = dev;
336694a0 BS	142
	143	spin_lock_init(&wdt->lock);
	144
	145	watchdog_set_drvdata(&dc_wdt_wdd, wdt);
d3b08185	146	watchdog_set_restart_priority(&dc_wdt_wdd, 128);
336694a0	147	watchdog_init_timeout(&dc_wdt_wdd, timeout, dev);
dd36f6ce GR	148	watchdog_stop_on_reboot(&dc_wdt_wdd);
dd36f6ce GR	149	ret = devm_watchdog_register_device(dev, &dc_wdt_wdd);
336694a0 BS	150	if (ret) {
336694a0 BS	151	dev_err(dev, "Failed to register watchdog device");
dd36f6ce	152	return ret;
336694a0 BS	153	}
336694a0 BS	154
336694a0	155	return 0;
336694a0 BS	156	}
	157
	158	static const struct of_device_id dc_wdt_of_match[] = {
	159	{ .compatible = "cnxt,cx92755-wdt", },
	160	{},
	161	};
	162	MODULE_DEVICE_TABLE(of, dc_wdt_of_match);
	163
	164	static struct platform_driver dc_wdt_driver = {
	165	.probe = dc_wdt_probe,
336694a0 BS	166	.driver = {
	167	.name = "digicolor-wdt",
	168	.of_match_table = dc_wdt_of_match,
	169	},
	170	};
	171	module_platform_driver(dc_wdt_driver);
	172
	173	MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
	174	MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer");
	175	MODULE_LICENSE("GPL");