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

/*
 *  Copyright (C) 2015 Mans Rullgard <mans@mansr.com>
 *  SMP86xx/SMP87xx Watchdog driver
 *
 *  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/bitops.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>

#define DEFAULT_TIMEOUT 30

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
		 "Watchdog cannot be stopped once started (default="
		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

static unsigned int timeout;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout");

/*
 * Counter counts down from programmed value.  Reset asserts when
 * the counter reaches 1.
 */
#define WD_COUNTER		0

#define WD_CONFIG		4
#define WD_CONFIG_XTAL_IN	BIT(0)
#define WD_CONFIG_DISABLE	BIT(31)

struct tangox_wdt_device {
	struct watchdog_device wdt;
	void __iomem *base;
	unsigned long clk_rate;
	struct clk *clk;
};

static int tangox_wdt_set_timeout(struct watchdog_device *wdt,
				  unsigned int new_timeout)
{
	wdt->timeout = new_timeout;

	return 0;
}

static int tangox_wdt_start(struct watchdog_device *wdt)
{
	struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
	u32 ticks;

	ticks = 1 + wdt->timeout * dev->clk_rate;
	writel(ticks, dev->base + WD_COUNTER);

	return 0;
}

static int tangox_wdt_stop(struct watchdog_device *wdt)
{
	struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);

	writel(0, dev->base + WD_COUNTER);

	return 0;
}

static unsigned int tangox_wdt_get_timeleft(struct watchdog_device *wdt)
{
	struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
	u32 count;

	count = readl(dev->base + WD_COUNTER);

	if (!count)
		return 0;

	return (count - 1) / dev->clk_rate;
}

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

static int tangox_wdt_restart(struct watchdog_device *wdt,
			      unsigned long action, void *data)
{
	struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);

	writel(1, dev->base + WD_COUNTER);

	return 0;
}

static const struct watchdog_ops tangox_wdt_ops = {
	.start		= tangox_wdt_start,
	.stop		= tangox_wdt_stop,
	.set_timeout	= tangox_wdt_set_timeout,
	.get_timeleft	= tangox_wdt_get_timeleft,
	.restart	= tangox_wdt_restart,
};

static int tangox_wdt_probe(struct platform_device *pdev)
{
	struct tangox_wdt_device *dev;
	struct resource *res;
	u32 config;
	int err;

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

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

	dev->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(dev->clk))
		return PTR_ERR(dev->clk);

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

	dev->clk_rate = clk_get_rate(dev->clk);
	if (!dev->clk_rate) {
		err = -EINVAL;
		goto err;
	}

	dev->wdt.parent = &pdev->dev;
	dev->wdt.info = &tangox_wdt_info;
	dev->wdt.ops = &tangox_wdt_ops;
	dev->wdt.timeout = DEFAULT_TIMEOUT;
	dev->wdt.min_timeout = 1;
	dev->wdt.max_hw_heartbeat_ms = (U32_MAX - 1) / dev->clk_rate;

	watchdog_init_timeout(&dev->wdt, timeout, &pdev->dev);
	watchdog_set_nowayout(&dev->wdt, nowayout);
	watchdog_set_drvdata(&dev->wdt, dev);

	/*
	 * Deactivate counter if disable bit is set to avoid
	 * accidental reset.
	 */
	config = readl(dev->base + WD_CONFIG);
	if (config & WD_CONFIG_DISABLE)
		writel(0, dev->base + WD_COUNTER);

	writel(WD_CONFIG_XTAL_IN, dev->base + WD_CONFIG);

	/*
	 * Mark as active and restart with configured timeout if
	 * already running.
	 */
	if (readl(dev->base + WD_COUNTER)) {
		set_bit(WDOG_HW_RUNNING, &dev->wdt.status);
		tangox_wdt_start(&dev->wdt);
	}

	watchdog_set_restart_priority(&dev->wdt, 128);

	err = watchdog_register_device(&dev->wdt);
	if (err)
		goto err;

	platform_set_drvdata(pdev, dev);

	dev_info(&pdev->dev, "SMP86xx/SMP87xx watchdog registered\n");

	return 0;

 err:
	clk_disable_unprepare(dev->clk);
	return err;
}

static int tangox_wdt_remove(struct platform_device *pdev)
{
	struct tangox_wdt_device *dev = platform_get_drvdata(pdev);

	tangox_wdt_stop(&dev->wdt);
	clk_disable_unprepare(dev->clk);

	watchdog_unregister_device(&dev->wdt);

	return 0;
}

static const struct of_device_id tangox_wdt_dt_ids[] = {
	{ .compatible = "sigma,smp8642-wdt" },
	{ .compatible = "sigma,smp8759-wdt" },
	{ }
};
MODULE_DEVICE_TABLE(of, tangox_wdt_dt_ids);

static struct platform_driver tangox_wdt_driver = {
	.probe	= tangox_wdt_probe,
	.remove	= tangox_wdt_remove,
	.driver	= {
		.name		= "tangox-wdt",
		.of_match_table	= tangox_wdt_dt_ids,
	},
};

module_platform_driver(tangox_wdt_driver);

MODULE_AUTHOR("Mans Rullgard <mans@mansr.com>");
MODULE_DESCRIPTION("SMP86xx/SMP87xx Watchdog driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
dca536c4 MR	1	/*
	2	* Copyright (C) 2015 Mans Rullgard <mans@mansr.com>
	3	* SMP86xx/SMP87xx Watchdog driver
	4	*
	5	* This program is free software; you can redistribute it and/or modify it
	6	* under the terms of the GNU General Public License as published by the
	7	* Free Software Foundation; either version 2 of the License, or (at your
	8	* option) any later version.
	9	*/
	10
	11	#include <linux/bitops.h>
	12	#include <linux/clk.h>
	13	#include <linux/delay.h>
	14	#include <linux/io.h>
	15	#include <linux/kernel.h>
	16	#include <linux/module.h>
	17	#include <linux/moduleparam.h>
dca536c4	18	#include <linux/platform_device.h>
dca536c4 MR	19	#include <linux/watchdog.h>
	20
	21	#define DEFAULT_TIMEOUT 30
	22
	23	static bool nowayout = WATCHDOG_NOWAYOUT;
	24	module_param(nowayout, bool, 0);
	25	MODULE_PARM_DESC(nowayout,
	26	"Watchdog cannot be stopped once started (default="
	27	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	28
	29	static unsigned int timeout;
	30	module_param(timeout, int, 0);
	31	MODULE_PARM_DESC(timeout, "Watchdog timeout");
	32
	33	/*
	34	* Counter counts down from programmed value. Reset asserts when
	35	* the counter reaches 1.
	36	*/
	37	#define WD_COUNTER 0
	38
	39	#define WD_CONFIG 4
	40	#define WD_CONFIG_XTAL_IN BIT(0)
	41	#define WD_CONFIG_DISABLE BIT(31)
	42
	43	struct tangox_wdt_device {
	44	struct watchdog_device wdt;
	45	void __iomem *base;
	46	unsigned long clk_rate;
	47	struct clk *clk;
dca536c4 MR	48	};
	49
	50	static int tangox_wdt_set_timeout(struct watchdog_device *wdt,
	51	unsigned int new_timeout)
	52	{
	53	wdt->timeout = new_timeout;
	54
	55	return 0;
	56	}
	57
	58	static int tangox_wdt_start(struct watchdog_device *wdt)
	59	{
	60	struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
	61	u32 ticks;
	62
	63	ticks = 1 + wdt->timeout * dev->clk_rate;
	64	writel(ticks, dev->base + WD_COUNTER);
	65
	66	return 0;
	67	}
	68
	69	static int tangox_wdt_stop(struct watchdog_device *wdt)
	70	{
	71	struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
	72
	73	writel(0, dev->base + WD_COUNTER);
	74
	75	return 0;
	76	}
	77
	78	static unsigned int tangox_wdt_get_timeleft(struct watchdog_device *wdt)
	79	{
	80	struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
	81	u32 count;
	82
	83	count = readl(dev->base + WD_COUNTER);
	84
	85	if (!count)
	86	return 0;
	87
	88	return (count - 1) / dev->clk_rate;
	89	}
	90
	91	static const struct watchdog_info tangox_wdt_info = {
	92	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
	93	.identity = "tangox watchdog",
	94	};
	95
0397c5db GR	96	static int tangox_wdt_restart(struct watchdog_device *wdt,
	97	unsigned long action, void *data)
	98	{
	99	struct tangox_wdt_device *dev = watchdog_get_drvdata(wdt);
	100
	101	writel(1, dev->base + WD_COUNTER);
	102
	103	return 0;
	104	}
	105
dca536c4 MR	106	static const struct watchdog_ops tangox_wdt_ops = {
	107	.start = tangox_wdt_start,
	108	.stop = tangox_wdt_stop,
	109	.set_timeout = tangox_wdt_set_timeout,
	110	.get_timeleft = tangox_wdt_get_timeleft,
0397c5db	111	.restart = tangox_wdt_restart,
dca536c4 MR	112	};
dca536c4 MR	113
dca536c4 MR	114	static int tangox_wdt_probe(struct platform_device *pdev)
	115	{
	116	struct tangox_wdt_device *dev;
	117	struct resource *res;
	118	u32 config;
	119	int err;
	120
	121	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
	122	if (!dev)
	123	return -ENOMEM;
	124
	125	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	126	dev->base = devm_ioremap_resource(&pdev->dev, res);
	127	if (IS_ERR(dev->base))
	128	return PTR_ERR(dev->base);
	129
	130	dev->clk = devm_clk_get(&pdev->dev, NULL);
	131	if (IS_ERR(dev->clk))
	132	return PTR_ERR(dev->clk);
	133
	134	err = clk_prepare_enable(dev->clk);
	135	if (err)
	136	return err;
	137
	138	dev->clk_rate = clk_get_rate(dev->clk);
84b84bcf WS	139	if (!dev->clk_rate) {
	140	err = -EINVAL;
	141	goto err;
	142	}
dca536c4 MR	143
	144	dev->wdt.parent = &pdev->dev;
	145	dev->wdt.info = &tangox_wdt_info;
	146	dev->wdt.ops = &tangox_wdt_ops;
	147	dev->wdt.timeout = DEFAULT_TIMEOUT;
	148	dev->wdt.min_timeout = 1;
c7ef68c3	149	dev->wdt.max_hw_heartbeat_ms = (U32_MAX - 1) / dev->clk_rate;
dca536c4 MR	150
	151	watchdog_init_timeout(&dev->wdt, timeout, &pdev->dev);
	152	watchdog_set_nowayout(&dev->wdt, nowayout);
	153	watchdog_set_drvdata(&dev->wdt, dev);
	154
	155	/*
	156	* Deactivate counter if disable bit is set to avoid
	157	* accidental reset.
	158	*/
	159	config = readl(dev->base + WD_CONFIG);
	160	if (config & WD_CONFIG_DISABLE)
	161	writel(0, dev->base + WD_COUNTER);
	162
	163	writel(WD_CONFIG_XTAL_IN, dev->base + WD_CONFIG);
	164
	165	/*
	166	* Mark as active and restart with configured timeout if
	167	* already running.
	168	*/
	169	if (readl(dev->base + WD_COUNTER)) {
a3e376d2	170	set_bit(WDOG_HW_RUNNING, &dev->wdt.status);
dca536c4 MR	171	tangox_wdt_start(&dev->wdt);
	172	}
	173
0397c5db GR	174	watchdog_set_restart_priority(&dev->wdt, 128);
0397c5db GR	175
dca536c4	176	err = watchdog_register_device(&dev->wdt);
84b84bcf WS	177	if (err)
84b84bcf WS	178	goto err;
dca536c4 MR	179
	180	platform_set_drvdata(pdev, dev);
	181
3d29f808	182	dev_info(&pdev->dev, "SMP86xx/SMP87xx watchdog registered\n");
dca536c4 MR	183
dca536c4 MR	184	return 0;
84b84bcf WS	185
	186	err:
	187	clk_disable_unprepare(dev->clk);
	188	return err;
dca536c4 MR	189	}
	190
	191	static int tangox_wdt_remove(struct platform_device *pdev)
	192	{
	193	struct tangox_wdt_device *dev = platform_get_drvdata(pdev);
	194
	195	tangox_wdt_stop(&dev->wdt);
	196	clk_disable_unprepare(dev->clk);
	197
dca536c4 MR	198	watchdog_unregister_device(&dev->wdt);
	199
	200	return 0;
	201	}
	202
	203	static const struct of_device_id tangox_wdt_dt_ids[] = {
	204	{ .compatible = "sigma,smp8642-wdt" },
	205	{ .compatible = "sigma,smp8759-wdt" },
	206	{ }
	207	};
	208	MODULE_DEVICE_TABLE(of, tangox_wdt_dt_ids);
	209
	210	static struct platform_driver tangox_wdt_driver = {
	211	.probe = tangox_wdt_probe,
	212	.remove = tangox_wdt_remove,
	213	.driver = {
	214	.name = "tangox-wdt",
	215	.of_match_table = tangox_wdt_dt_ids,
	216	},
	217	};
	218
	219	module_platform_driver(tangox_wdt_driver);
	220
	221	MODULE_AUTHOR("Mans Rullgard <mans@mansr.com>");
	222	MODULE_DESCRIPTION("SMP86xx/SMP87xx Watchdog driver");
	223	MODULE_LICENSE("GPL");