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

// SPDX-License-Identifier: GPL-2.0+
/*
 * ST's LPC Watchdog
 *
 * Copyright (C) 2014 STMicroelectronics -- All Rights Reserved
 *
 * Author: David Paris <david.paris@st.com> for STMicroelectronics
 *         Lee Jones <lee.jones@linaro.org> for STMicroelectronics
 */

#include <linux/clk.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/watchdog.h>

#include <dt-bindings/mfd/st-lpc.h>

/* Low Power Alarm */
#define LPC_LPA_LSB_OFF			0x410
#define LPC_LPA_START_OFF		0x418

/* LPC as WDT */
#define LPC_WDT_OFF			0x510

static struct watchdog_device st_wdog_dev;

struct st_wdog_syscfg {
	unsigned int reset_type_reg;
	unsigned int reset_type_mask;
	unsigned int enable_reg;
	unsigned int enable_mask;
};

struct st_wdog {
	void __iomem *base;
	struct device *dev;
	struct regmap *regmap;
	struct st_wdog_syscfg *syscfg;
	struct clk *clk;
	unsigned long clkrate;
	bool warm_reset;
};

static struct st_wdog_syscfg stih407_syscfg = {
	.enable_reg		= 0x204,
	.enable_mask		= BIT(19),
};

static const struct of_device_id st_wdog_match[] = {
	{
		.compatible = "st,stih407-lpc",
		.data = &stih407_syscfg,
	},
	{},
};
MODULE_DEVICE_TABLE(of, st_wdog_match);

static void st_wdog_setup(struct st_wdog *st_wdog, bool enable)
{
	/* Type of watchdog reset - 0: Cold 1: Warm */
	if (st_wdog->syscfg->reset_type_reg)
		regmap_update_bits(st_wdog->regmap,
				   st_wdog->syscfg->reset_type_reg,
				   st_wdog->syscfg->reset_type_mask,
				   st_wdog->warm_reset);

	/* Mask/unmask watchdog reset */
	regmap_update_bits(st_wdog->regmap,
			   st_wdog->syscfg->enable_reg,
			   st_wdog->syscfg->enable_mask,
			   enable ? 0 : st_wdog->syscfg->enable_mask);
}

static void st_wdog_load_timer(struct st_wdog *st_wdog, unsigned int timeout)
{
	unsigned long clkrate = st_wdog->clkrate;

	writel_relaxed(timeout * clkrate, st_wdog->base + LPC_LPA_LSB_OFF);
	writel_relaxed(1, st_wdog->base + LPC_LPA_START_OFF);
}

static int st_wdog_start(struct watchdog_device *wdd)
{
	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);

	writel_relaxed(1, st_wdog->base + LPC_WDT_OFF);

	return 0;
}

static int st_wdog_stop(struct watchdog_device *wdd)
{
	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);

	writel_relaxed(0, st_wdog->base + LPC_WDT_OFF);

	return 0;
}

static int st_wdog_set_timeout(struct watchdog_device *wdd,
			       unsigned int timeout)
{
	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);

	wdd->timeout = timeout;
	st_wdog_load_timer(st_wdog, timeout);

	return 0;
}

static int st_wdog_keepalive(struct watchdog_device *wdd)
{
	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);

	st_wdog_load_timer(st_wdog, wdd->timeout);

	return 0;
}

static const struct watchdog_info st_wdog_info = {
	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
	.identity = "ST LPC WDT",
};

static const struct watchdog_ops st_wdog_ops = {
	.owner		= THIS_MODULE,
	.start		= st_wdog_start,
	.stop		= st_wdog_stop,
	.ping		= st_wdog_keepalive,
	.set_timeout	= st_wdog_set_timeout,
};

static struct watchdog_device st_wdog_dev = {
	.info		= &st_wdog_info,
	.ops		= &st_wdog_ops,
};

static void st_clk_disable_unprepare(void *data)
{
	clk_disable_unprepare(data);
}

static int st_wdog_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	const struct of_device_id *match;
	struct device_node *np = dev->of_node;
	struct st_wdog *st_wdog;
	struct regmap *regmap;
	struct clk *clk;
	void __iomem *base;
	uint32_t mode;
	int ret;

	ret = of_property_read_u32(np, "st,lpc-mode", &mode);
	if (ret) {
		dev_err(dev, "An LPC mode must be provided\n");
		return -EINVAL;
	}

	/* LPC can either run as a Clocksource or in RTC or WDT mode */
	if (mode != ST_LPC_MODE_WDT)
		return -ENODEV;

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

	match = of_match_device(st_wdog_match, dev);
	if (!match) {
		dev_err(dev, "Couldn't match device\n");
		return -ENODEV;
	}
	st_wdog->syscfg	= (struct st_wdog_syscfg *)match->data;

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

	regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
	if (IS_ERR(regmap)) {
		dev_err(dev, "No syscfg phandle specified\n");
		return PTR_ERR(regmap);
	}

	clk = devm_clk_get(dev, NULL);
	if (IS_ERR(clk)) {
		dev_err(dev, "Unable to request clock\n");
		return PTR_ERR(clk);
	}

	st_wdog->dev		= dev;
	st_wdog->base		= base;
	st_wdog->clk		= clk;
	st_wdog->regmap		= regmap;
	st_wdog->warm_reset	= of_property_read_bool(np, "st,warm_reset");
	st_wdog->clkrate	= clk_get_rate(st_wdog->clk);

	if (!st_wdog->clkrate) {
		dev_err(dev, "Unable to fetch clock rate\n");
		return -EINVAL;
	}
	st_wdog_dev.max_timeout = 0xFFFFFFFF / st_wdog->clkrate;
	st_wdog_dev.parent = dev;

	ret = clk_prepare_enable(clk);
	if (ret) {
		dev_err(dev, "Unable to enable clock\n");
		return ret;
	}
	ret = devm_add_action_or_reset(dev, st_clk_disable_unprepare, clk);
	if (ret)
		return ret;

	watchdog_set_drvdata(&st_wdog_dev, st_wdog);
	watchdog_set_nowayout(&st_wdog_dev, WATCHDOG_NOWAYOUT);

	/* Init Watchdog timeout with value in DT */
	ret = watchdog_init_timeout(&st_wdog_dev, 0, dev);
	if (ret)
		return ret;

	ret = devm_watchdog_register_device(dev, &st_wdog_dev);
	if (ret)
		return ret;

	st_wdog_setup(st_wdog, true);

	dev_info(dev, "LPC Watchdog driver registered, reset type is %s",
		 st_wdog->warm_reset ? "warm" : "cold");

	return ret;
}

static int st_wdog_remove(struct platform_device *pdev)
{
	struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);

	st_wdog_setup(st_wdog, false);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int st_wdog_suspend(struct device *dev)
{
	struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);

	if (watchdog_active(&st_wdog_dev))
		st_wdog_stop(&st_wdog_dev);

	st_wdog_setup(st_wdog, false);

	clk_disable(st_wdog->clk);

	return 0;
}

static int st_wdog_resume(struct device *dev)
{
	struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
	int ret;

	ret = clk_enable(st_wdog->clk);
	if (ret) {
		dev_err(dev, "Unable to re-enable clock\n");
		watchdog_unregister_device(&st_wdog_dev);
		clk_unprepare(st_wdog->clk);
		return ret;
	}

	st_wdog_setup(st_wdog, true);

	if (watchdog_active(&st_wdog_dev)) {
		st_wdog_load_timer(st_wdog, st_wdog_dev.timeout);
		st_wdog_start(&st_wdog_dev);
	}

	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(st_wdog_pm_ops,
			 st_wdog_suspend,
			 st_wdog_resume);

static struct platform_driver st_wdog_driver = {
	.driver	= {
		.name = "st-lpc-wdt",
		.pm = &st_wdog_pm_ops,
		.of_match_table = st_wdog_match,
	},
	.probe = st_wdog_probe,
	.remove = st_wdog_remove,
};
module_platform_driver(st_wdog_driver);

MODULE_AUTHOR("David Paris <david.paris@st.com>");
MODULE_DESCRIPTION("ST LPC Watchdog Driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
2e62c498	1	// SPDX-License-Identifier: GPL-2.0+
f27925a6 LJ	2	/*
	3	* ST's LPC Watchdog
	4	*
	5	* Copyright (C) 2014 STMicroelectronics -- All Rights Reserved
	6	*
	7	* Author: David Paris <david.paris@st.com> for STMicroelectronics
	8	* Lee Jones <lee.jones@linaro.org> for STMicroelectronics
f27925a6 LJ	9	*/
	10
	11	#include <linux/clk.h>
	12	#include <linux/init.h>
	13	#include <linux/io.h>
	14	#include <linux/kernel.h>
	15	#include <linux/mfd/syscon.h>
	16	#include <linux/module.h>
	17	#include <linux/of.h>
	18	#include <linux/of_platform.h>
	19	#include <linux/platform_device.h>
	20	#include <linux/regmap.h>
	21	#include <linux/watchdog.h>
	22
	23	#include <dt-bindings/mfd/st-lpc.h>
	24
	25	/* Low Power Alarm */
	26	#define LPC_LPA_LSB_OFF 0x410
	27	#define LPC_LPA_START_OFF 0x418
	28
	29	/* LPC as WDT */
	30	#define LPC_WDT_OFF 0x510
	31
	32	static struct watchdog_device st_wdog_dev;
	33
	34	struct st_wdog_syscfg {
	35	unsigned int reset_type_reg;
	36	unsigned int reset_type_mask;
	37	unsigned int enable_reg;
	38	unsigned int enable_mask;
	39	};
	40
	41	struct st_wdog {
	42	void __iomem *base;
	43	struct device *dev;
	44	struct regmap *regmap;
	45	struct st_wdog_syscfg *syscfg;
	46	struct clk *clk;
	47	unsigned long clkrate;
	48	bool warm_reset;
	49	};
	50
f27925a6 LJ	51	static struct st_wdog_syscfg stih407_syscfg = {
	52	.enable_reg = 0x204,
	53	.enable_mask = BIT(19),
	54	};
	55
	56	static const struct of_device_id st_wdog_match[] = {
	57	{
	58	.compatible = "st,stih407-lpc",
	59	.data = &stih407_syscfg,
	60	},
f27925a6 LJ	61	{},
	62	};
	63	MODULE_DEVICE_TABLE(of, st_wdog_match);
	64
	65	static void st_wdog_setup(struct st_wdog *st_wdog, bool enable)
	66	{
	67	/* Type of watchdog reset - 0: Cold 1: Warm */
	68	if (st_wdog->syscfg->reset_type_reg)
	69	regmap_update_bits(st_wdog->regmap,
	70	st_wdog->syscfg->reset_type_reg,
	71	st_wdog->syscfg->reset_type_mask,
	72	st_wdog->warm_reset);
	73
	74	/* Mask/unmask watchdog reset */
	75	regmap_update_bits(st_wdog->regmap,
	76	st_wdog->syscfg->enable_reg,
	77	st_wdog->syscfg->enable_mask,
	78	enable ? 0 : st_wdog->syscfg->enable_mask);
	79	}
	80
	81	static void st_wdog_load_timer(struct st_wdog *st_wdog, unsigned int timeout)
	82	{
	83	unsigned long clkrate = st_wdog->clkrate;
	84
	85	writel_relaxed(timeout * clkrate, st_wdog->base + LPC_LPA_LSB_OFF);
	86	writel_relaxed(1, st_wdog->base + LPC_LPA_START_OFF);
	87	}
	88
	89	static int st_wdog_start(struct watchdog_device *wdd)
	90	{
	91	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
	92
	93	writel_relaxed(1, st_wdog->base + LPC_WDT_OFF);
	94
	95	return 0;
	96	}
	97
	98	static int st_wdog_stop(struct watchdog_device *wdd)
	99	{
	100	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
	101
	102	writel_relaxed(0, st_wdog->base + LPC_WDT_OFF);
	103
	104	return 0;
	105	}
	106
	107	static int st_wdog_set_timeout(struct watchdog_device *wdd,
	108	unsigned int timeout)
	109	{
	110	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
	111
	112	wdd->timeout = timeout;
	113	st_wdog_load_timer(st_wdog, timeout);
	114
	115	return 0;
	116	}
	117
	118	static int st_wdog_keepalive(struct watchdog_device *wdd)
	119	{
	120	struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
	121
	122	st_wdog_load_timer(st_wdog, wdd->timeout);
	123
	124	return 0;
125	}
126
127	static const struct watchdog_info st_wdog_info = {
128	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
129	.identity = "ST LPC WDT",
130	};
131
132	static const struct watchdog_ops st_wdog_ops = {
133	.owner = THIS_MODULE,
134	.start = st_wdog_start,
135	.stop = st_wdog_stop,
136	.ping = st_wdog_keepalive,
137	.set_timeout = st_wdog_set_timeout,
138	};
139
140	static struct watchdog_device st_wdog_dev = {
141	.info = &st_wdog_info,
142	.ops = &st_wdog_ops,
143	};
144
cfe9ee3a GR	145	static void st_clk_disable_unprepare(void *data)
	146	{
	147	clk_disable_unprepare(data);
	148	}
	149
f27925a6 LJ	150	static int st_wdog_probe(struct platform_device *pdev)
f27925a6 LJ	151	{
cfe9ee3a	152	struct device *dev = &pdev->dev;
f27925a6	153	const struct of_device_id *match;
cfe9ee3a	154	struct device_node *np = dev->of_node;
f27925a6 LJ	155	struct st_wdog *st_wdog;
f27925a6 LJ	156	struct regmap *regmap;
f27925a6 LJ	157	struct clk *clk;
	158	void __iomem *base;
	159	uint32_t mode;
	160	int ret;
	161
	162	ret = of_property_read_u32(np, "st,lpc-mode", &mode);
	163	if (ret) {
cfe9ee3a	164	dev_err(dev, "An LPC mode must be provided\n");
f27925a6 LJ	165	return -EINVAL;
	166	}
	167
79cb0976	168	/* LPC can either run as a Clocksource or in RTC or WDT mode */
f27925a6 LJ	169	if (mode != ST_LPC_MODE_WDT)
	170	return -ENODEV;
	171
cfe9ee3a	172	st_wdog = devm_kzalloc(dev, sizeof(*st_wdog), GFP_KERNEL);
f27925a6 LJ	173	if (!st_wdog)
	174	return -ENOMEM;
	175
cfe9ee3a	176	match = of_match_device(st_wdog_match, dev);
f27925a6	177	if (!match) {
cfe9ee3a	178	dev_err(dev, "Couldn't match device\n");
f27925a6 LJ	179	return -ENODEV;
	180	}
	181	st_wdog->syscfg = (struct st_wdog_syscfg *)match->data;
	182
0f0a6a28	183	base = devm_platform_ioremap_resource(pdev, 0);
f27925a6 LJ	184	if (IS_ERR(base))
	185	return PTR_ERR(base);
	186
	187	regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
	188	if (IS_ERR(regmap)) {
cfe9ee3a	189	dev_err(dev, "No syscfg phandle specified\n");
f27925a6 LJ	190	return PTR_ERR(regmap);
	191	}
	192
cfe9ee3a	193	clk = devm_clk_get(dev, NULL);
f27925a6	194	if (IS_ERR(clk)) {
cfe9ee3a	195	dev_err(dev, "Unable to request clock\n");
f27925a6 LJ	196	return PTR_ERR(clk);
	197	}
	198
cfe9ee3a	199	st_wdog->dev = dev;
f27925a6 LJ	200	st_wdog->base = base;
	201	st_wdog->clk = clk;
	202	st_wdog->regmap = regmap;
	203	st_wdog->warm_reset = of_property_read_bool(np, "st,warm_reset");
	204	st_wdog->clkrate = clk_get_rate(st_wdog->clk);
	205
	206	if (!st_wdog->clkrate) {
cfe9ee3a	207	dev_err(dev, "Unable to fetch clock rate\n");
f27925a6 LJ	208	return -EINVAL;
	209	}
	210	st_wdog_dev.max_timeout = 0xFFFFFFFF / st_wdog->clkrate;
cfe9ee3a	211	st_wdog_dev.parent = dev;
f27925a6 LJ	212
	213	ret = clk_prepare_enable(clk);
	214	if (ret) {
cfe9ee3a	215	dev_err(dev, "Unable to enable clock\n");
f27925a6 LJ	216	return ret;
f27925a6 LJ	217	}
cfe9ee3a GR	218	ret = devm_add_action_or_reset(dev, st_clk_disable_unprepare, clk);
	219	if (ret)
	220	return ret;
f27925a6 LJ	221
	222	watchdog_set_drvdata(&st_wdog_dev, st_wdog);
	223	watchdog_set_nowayout(&st_wdog_dev, WATCHDOG_NOWAYOUT);
	224
	225	/* Init Watchdog timeout with value in DT */
cfe9ee3a	226	ret = watchdog_init_timeout(&st_wdog_dev, 0, dev);
b4214185	227	if (ret)
f27925a6	228	return ret;
f27925a6	229
cfe9ee3a	230	ret = devm_watchdog_register_device(dev, &st_wdog_dev);
7283b217	231	if (ret)
f27925a6	232	return ret;
f27925a6 LJ	233
	234	st_wdog_setup(st_wdog, true);
	235
cfe9ee3a	236	dev_info(dev, "LPC Watchdog driver registered, reset type is %s",
f27925a6 LJ	237	st_wdog->warm_reset ? "warm" : "cold");
	238
	239	return ret;
	240	}
	241
	242	static int st_wdog_remove(struct platform_device *pdev)
	243	{
	244	struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
	245
	246	st_wdog_setup(st_wdog, false);
f27925a6 LJ	247
	248	return 0;
	249	}
	250
	251	#ifdef CONFIG_PM_SLEEP
	252	static int st_wdog_suspend(struct device *dev)
	253	{
	254	struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
	255
	256	if (watchdog_active(&st_wdog_dev))
	257	st_wdog_stop(&st_wdog_dev);
	258
	259	st_wdog_setup(st_wdog, false);
	260
	261	clk_disable(st_wdog->clk);
	262
	263	return 0;
	264	}
	265
	266	static int st_wdog_resume(struct device *dev)
	267	{
	268	struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
	269	int ret;
	270
	271	ret = clk_enable(st_wdog->clk);
	272	if (ret) {
	273	dev_err(dev, "Unable to re-enable clock\n");
	274	watchdog_unregister_device(&st_wdog_dev);
	275	clk_unprepare(st_wdog->clk);
	276	return ret;
	277	}
	278
	279	st_wdog_setup(st_wdog, true);
	280
	281	if (watchdog_active(&st_wdog_dev)) {
	282	st_wdog_load_timer(st_wdog, st_wdog_dev.timeout);
	283	st_wdog_start(&st_wdog_dev);
	284	}
	285
	286	return 0;
	287	}
	288	#endif
	289
	290	static SIMPLE_DEV_PM_OPS(st_wdog_pm_ops,
	291	st_wdog_suspend,
	292	st_wdog_resume);
	293
	294	static struct platform_driver st_wdog_driver = {
	295	.driver = {
	296	.name = "st-lpc-wdt",
	297	.pm = &st_wdog_pm_ops,
	298	.of_match_table = st_wdog_match,
	299	},
	300	.probe = st_wdog_probe,
	301	.remove = st_wdog_remove,
	302	};
	303	module_platform_driver(st_wdog_driver);
	304
	305	MODULE_AUTHOR("David Paris <david.paris@st.com>");
	306	MODULE_DESCRIPTION("ST LPC Watchdog Driver");
	307	MODULE_LICENSE("GPL");