[linux-block.git] / drivers / rtc / rtc-st-lpc.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * rtc-st-lpc.c - ST's LPC RTC, powered by the Low Power Timer
 *
 * Copyright (C) 2014 STMicroelectronics Limited
 *
 * Author: David Paris <david.paris@st.com> for STMicroelectronics
 *         Lee Jones <lee.jones@linaro.org> for STMicroelectronics
 *
 * Based on the original driver written by Stuart Menefy.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>

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

/* Low Power Timer */
#define LPC_LPT_LSB_OFF		0x400
#define LPC_LPT_MSB_OFF		0x404
#define LPC_LPT_START_OFF	0x408

/* Low Power Alarm */
#define LPC_LPA_LSB_OFF		0x410
#define LPC_LPA_MSB_OFF		0x414
#define LPC_LPA_START_OFF	0x418

/* LPC as WDT */
#define LPC_WDT_OFF		0x510
#define LPC_WDT_FLAG_OFF	0x514

struct st_rtc {
	struct rtc_device *rtc_dev;
	struct rtc_wkalrm alarm;
	struct clk *clk;
	unsigned long clkrate;
	void __iomem *ioaddr;
	bool irq_enabled:1;
	spinlock_t lock;
	short irq;
};

static void st_rtc_set_hw_alarm(struct st_rtc *rtc,
				unsigned long msb, unsigned long  lsb)
{
	unsigned long flags;

	spin_lock_irqsave(&rtc->lock, flags);

	writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);

	writel_relaxed(msb, rtc->ioaddr + LPC_LPA_MSB_OFF);
	writel_relaxed(lsb, rtc->ioaddr + LPC_LPA_LSB_OFF);
	writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF);

	writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);

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

static irqreturn_t st_rtc_handler(int this_irq, void *data)
{
	struct st_rtc *rtc = (struct st_rtc *)data;

	rtc_update_irq(rtc->rtc_dev, 1, RTC_AF);

	return IRQ_HANDLED;
}

static int st_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct st_rtc *rtc = dev_get_drvdata(dev);
	unsigned long lpt_lsb, lpt_msb;
	unsigned long long lpt;
	unsigned long flags;

	spin_lock_irqsave(&rtc->lock, flags);

	do {
		lpt_msb = readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF);
		lpt_lsb = readl_relaxed(rtc->ioaddr + LPC_LPT_LSB_OFF);
	} while (readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF) != lpt_msb);

	spin_unlock_irqrestore(&rtc->lock, flags);

	lpt = ((unsigned long long)lpt_msb << 32) | lpt_lsb;
	do_div(lpt, rtc->clkrate);
	rtc_time64_to_tm(lpt, tm);

	return 0;
}

static int st_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct st_rtc *rtc = dev_get_drvdata(dev);
	unsigned long long lpt, secs;
	unsigned long flags;

	secs = rtc_tm_to_time64(tm);

	lpt = (unsigned long long)secs * rtc->clkrate;

	spin_lock_irqsave(&rtc->lock, flags);

	writel_relaxed(lpt >> 32, rtc->ioaddr + LPC_LPT_MSB_OFF);
	writel_relaxed(lpt, rtc->ioaddr + LPC_LPT_LSB_OFF);
	writel_relaxed(1, rtc->ioaddr + LPC_LPT_START_OFF);

	spin_unlock_irqrestore(&rtc->lock, flags);

	return 0;
}

static int st_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
{
	struct st_rtc *rtc = dev_get_drvdata(dev);
	unsigned long flags;

	spin_lock_irqsave(&rtc->lock, flags);

	memcpy(wkalrm, &rtc->alarm, sizeof(struct rtc_wkalrm));

	spin_unlock_irqrestore(&rtc->lock, flags);

	return 0;
}

static int st_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
	struct st_rtc *rtc = dev_get_drvdata(dev);

	if (enabled && !rtc->irq_enabled) {
		enable_irq(rtc->irq);
		rtc->irq_enabled = true;
	} else if (!enabled && rtc->irq_enabled) {
		disable_irq(rtc->irq);
		rtc->irq_enabled = false;
	}

	return 0;
}

static int st_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
{
	struct st_rtc *rtc = dev_get_drvdata(dev);
	struct rtc_time now;
	unsigned long long now_secs;
	unsigned long long alarm_secs;
	unsigned long long lpa;

	st_rtc_read_time(dev, &now);
	now_secs = rtc_tm_to_time64(&now);
	alarm_secs = rtc_tm_to_time64(&t->time);

	memcpy(&rtc->alarm, t, sizeof(struct rtc_wkalrm));

	/* Now many secs to fire */
	alarm_secs -= now_secs;
	lpa = (unsigned long long)alarm_secs * rtc->clkrate;

	st_rtc_set_hw_alarm(rtc, lpa >> 32, lpa);
	st_rtc_alarm_irq_enable(dev, t->enabled);

	return 0;
}

static const struct rtc_class_ops st_rtc_ops = {
	.read_time		= st_rtc_read_time,
	.set_time		= st_rtc_set_time,
	.read_alarm		= st_rtc_read_alarm,
	.set_alarm		= st_rtc_set_alarm,
	.alarm_irq_enable	= st_rtc_alarm_irq_enable,
};

static int st_rtc_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct st_rtc *rtc;
	uint32_t mode;
	int ret = 0;

	ret = of_property_read_u32(np, "st,lpc-mode", &mode);
	if (ret) {
		dev_err(&pdev->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_RTC)
		return -ENODEV;

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

	rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
	if (IS_ERR(rtc->rtc_dev))
		return PTR_ERR(rtc->rtc_dev);

	spin_lock_init(&rtc->lock);

	rtc->ioaddr = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(rtc->ioaddr))
		return PTR_ERR(rtc->ioaddr);

	rtc->irq = irq_of_parse_and_map(np, 0);
	if (!rtc->irq) {
		dev_err(&pdev->dev, "IRQ missing or invalid\n");
		return -EINVAL;
	}

	ret = devm_request_irq(&pdev->dev, rtc->irq, st_rtc_handler, 0,
			       pdev->name, rtc);
	if (ret) {
		dev_err(&pdev->dev, "Failed to request irq %i\n", rtc->irq);
		return ret;
	}

	enable_irq_wake(rtc->irq);
	disable_irq(rtc->irq);

	rtc->clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(rtc->clk)) {
		dev_err(&pdev->dev, "Unable to request clock\n");
		return PTR_ERR(rtc->clk);
	}

	clk_prepare_enable(rtc->clk);

	rtc->clkrate = clk_get_rate(rtc->clk);
	if (!rtc->clkrate) {
		clk_disable_unprepare(rtc->clk);
		dev_err(&pdev->dev, "Unable to fetch clock rate\n");
		return -EINVAL;
	}

	device_set_wakeup_capable(&pdev->dev, 1);

	platform_set_drvdata(pdev, rtc);

	rtc->rtc_dev->ops = &st_rtc_ops;
	rtc->rtc_dev->range_max = U64_MAX;
	do_div(rtc->rtc_dev->range_max, rtc->clkrate);

	ret = devm_rtc_register_device(rtc->rtc_dev);
	if (ret) {
		clk_disable_unprepare(rtc->clk);
		return ret;
	}

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int st_rtc_suspend(struct device *dev)
{
	struct st_rtc *rtc = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
		return 0;

	writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
	writel_relaxed(0, rtc->ioaddr + LPC_LPA_START_OFF);
	writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);

	return 0;
}

static int st_rtc_resume(struct device *dev)
{
	struct st_rtc *rtc = dev_get_drvdata(dev);

	rtc_alarm_irq_enable(rtc->rtc_dev, 0);

	/*
	 * clean 'rtc->alarm' to allow a new
	 * .set_alarm to the upper RTC layer
	 */
	memset(&rtc->alarm, 0, sizeof(struct rtc_wkalrm));

	writel_relaxed(0, rtc->ioaddr + LPC_LPA_MSB_OFF);
	writel_relaxed(0, rtc->ioaddr + LPC_LPA_LSB_OFF);
	writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
	writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF);
	writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);

	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(st_rtc_pm_ops, st_rtc_suspend, st_rtc_resume);

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

static struct platform_driver st_rtc_platform_driver = {
	.driver = {
		.name = "st-lpc-rtc",
		.pm = &st_rtc_pm_ops,
		.of_match_table = st_rtc_match,
	},
	.probe = st_rtc_probe,
};

module_platform_driver(st_rtc_platform_driver);

MODULE_DESCRIPTION("STMicroelectronics LPC RTC driver");
MODULE_AUTHOR("David Paris <david.paris@st.com>");
MODULE_LICENSE("GPL");
Commit	Line	Data
b4d0d230	1	// SPDX-License-Identifier: GPL-2.0-or-later
b5b2bdfc LJ	2	/*
	3	* rtc-st-lpc.c - ST's LPC RTC, powered by the Low Power Timer
	4	*
	5	* Copyright (C) 2014 STMicroelectronics Limited
	6	*
	7	* Author: David Paris <david.paris@st.com> for STMicroelectronics
	8	* Lee Jones <lee.jones@linaro.org> for STMicroelectronics
	9	*
	10	* Based on the original driver written by Stuart Menefy.
b5b2bdfc LJ	11	*/
	12
	13	#include <linux/clk.h>
	14	#include <linux/delay.h>
	15	#include <linux/init.h>
	16	#include <linux/io.h>
	17	#include <linux/irq.h>
	18	#include <linux/kernel.h>
	19	#include <linux/module.h>
	20	#include <linux/of.h>
	21	#include <linux/of_irq.h>
	22	#include <linux/platform_device.h>
	23	#include <linux/rtc.h>
	24
	25	#include <dt-bindings/mfd/st-lpc.h>
	26
	27	/* Low Power Timer */
	28	#define LPC_LPT_LSB_OFF 0x400
	29	#define LPC_LPT_MSB_OFF 0x404
	30	#define LPC_LPT_START_OFF 0x408
	31
	32	/* Low Power Alarm */
	33	#define LPC_LPA_LSB_OFF 0x410
	34	#define LPC_LPA_MSB_OFF 0x414
	35	#define LPC_LPA_START_OFF 0x418
	36
	37	/* LPC as WDT */
	38	#define LPC_WDT_OFF 0x510
	39	#define LPC_WDT_FLAG_OFF 0x514
	40
	41	struct st_rtc {
	42	struct rtc_device *rtc_dev;
	43	struct rtc_wkalrm alarm;
b5b2bdfc LJ	44	struct clk *clk;
	45	unsigned long clkrate;
	46	void __iomem *ioaddr;
	47	bool irq_enabled:1;
	48	spinlock_t lock;
	49	short irq;
	50	};
	51
	52	static void st_rtc_set_hw_alarm(struct st_rtc *rtc,
	53	unsigned long msb, unsigned long lsb)
	54	{
	55	unsigned long flags;
	56
	57	spin_lock_irqsave(&rtc->lock, flags);
	58
	59	writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
	60
	61	writel_relaxed(msb, rtc->ioaddr + LPC_LPA_MSB_OFF);
	62	writel_relaxed(lsb, rtc->ioaddr + LPC_LPA_LSB_OFF);
	63	writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF);
	64
	65	writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
	66
	67	spin_unlock_irqrestore(&rtc->lock, flags);
	68	}
	69
	70	static irqreturn_t st_rtc_handler(int this_irq, void *data)
	71	{
	72	struct st_rtc rtc = (struct st_rtc )data;
	73
	74	rtc_update_irq(rtc->rtc_dev, 1, RTC_AF);
	75
	76	return IRQ_HANDLED;
	77	}
	78
	79	static int st_rtc_read_time(struct device dev, struct rtc_time tm)
	80	{
	81	struct st_rtc *rtc = dev_get_drvdata(dev);
	82	unsigned long lpt_lsb, lpt_msb;
	83	unsigned long long lpt;
	84	unsigned long flags;
	85
	86	spin_lock_irqsave(&rtc->lock, flags);
	87
	88	do {
	89	lpt_msb = readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF);
	90	lpt_lsb = readl_relaxed(rtc->ioaddr + LPC_LPT_LSB_OFF);
	91	} while (readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF) != lpt_msb);
	92
	93	spin_unlock_irqrestore(&rtc->lock, flags);
	94
	95	lpt = ((unsigned long long)lpt_msb << 32) \| lpt_lsb;
	96	do_div(lpt, rtc->clkrate);
f4b82d39	97	rtc_time64_to_tm(lpt, tm);
b5b2bdfc LJ	98
	99	return 0;
	100	}
	101
	102	static int st_rtc_set_time(struct device dev, struct rtc_time tm)
	103	{
	104	struct st_rtc *rtc = dev_get_drvdata(dev);
f4b82d39 BG	105	unsigned long long lpt, secs;
f4b82d39 BG	106	unsigned long flags;
b5b2bdfc	107
f4b82d39	108	secs = rtc_tm_to_time64(tm);
b5b2bdfc LJ	109
	110	lpt = (unsigned long long)secs * rtc->clkrate;
	111
	112	spin_lock_irqsave(&rtc->lock, flags);
	113
	114	writel_relaxed(lpt >> 32, rtc->ioaddr + LPC_LPT_MSB_OFF);
	115	writel_relaxed(lpt, rtc->ioaddr + LPC_LPT_LSB_OFF);
	116	writel_relaxed(1, rtc->ioaddr + LPC_LPT_START_OFF);
	117
	118	spin_unlock_irqrestore(&rtc->lock, flags);
	119
	120	return 0;
	121	}
	122
	123	static int st_rtc_read_alarm(struct device dev, struct rtc_wkalrm wkalrm)
	124	{
	125	struct st_rtc *rtc = dev_get_drvdata(dev);
	126	unsigned long flags;
	127
	128	spin_lock_irqsave(&rtc->lock, flags);
	129
	130	memcpy(wkalrm, &rtc->alarm, sizeof(struct rtc_wkalrm));
	131
	132	spin_unlock_irqrestore(&rtc->lock, flags);
	133
	134	return 0;
	135	}
	136
	137	static int st_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
	138	{
	139	struct st_rtc *rtc = dev_get_drvdata(dev);
	140
	141	if (enabled && !rtc->irq_enabled) {
	142	enable_irq(rtc->irq);
	143	rtc->irq_enabled = true;
	144	} else if (!enabled && rtc->irq_enabled) {
	145	disable_irq(rtc->irq);
	146	rtc->irq_enabled = false;
	147	}
	148
	149	return 0;
	150	}
	151
	152	static int st_rtc_set_alarm(struct device dev, struct rtc_wkalrm t)
	153	{
	154	struct st_rtc *rtc = dev_get_drvdata(dev);
	155	struct rtc_time now;
f4b82d39 BG	156	unsigned long long now_secs;
f4b82d39 BG	157	unsigned long long alarm_secs;
b5b2bdfc LJ	158	unsigned long long lpa;
	159
	160	st_rtc_read_time(dev, &now);
f4b82d39 BG	161	now_secs = rtc_tm_to_time64(&now);
f4b82d39 BG	162	alarm_secs = rtc_tm_to_time64(&t->time);
b5b2bdfc	163
b5b2bdfc LJ	164	memcpy(&rtc->alarm, t, sizeof(struct rtc_wkalrm));
	165
	166	/* Now many secs to fire */
	167	alarm_secs -= now_secs;
	168	lpa = (unsigned long long)alarm_secs * rtc->clkrate;
	169
	170	st_rtc_set_hw_alarm(rtc, lpa >> 32, lpa);
	171	st_rtc_alarm_irq_enable(dev, t->enabled);
	172
	173	return 0;
	174	}
	175
d0a3b650	176	static const struct rtc_class_ops st_rtc_ops = {
b5b2bdfc LJ	177	.read_time = st_rtc_read_time,
	178	.set_time = st_rtc_set_time,
	179	.read_alarm = st_rtc_read_alarm,
	180	.set_alarm = st_rtc_set_alarm,
	181	.alarm_irq_enable = st_rtc_alarm_irq_enable,
	182	};
	183
	184	static int st_rtc_probe(struct platform_device *pdev)
	185	{
	186	struct device_node *np = pdev->dev.of_node;
	187	struct st_rtc *rtc;
b5b2bdfc LJ	188	uint32_t mode;
	189	int ret = 0;
	190
	191	ret = of_property_read_u32(np, "st,lpc-mode", &mode);
	192	if (ret) {
	193	dev_err(&pdev->dev, "An LPC mode must be provided\n");
	194	return -EINVAL;
	195	}
	196
742e4097	197	/* LPC can either run as a Clocksource or in RTC or WDT mode */
b5b2bdfc LJ	198	if (mode != ST_LPC_MODE_RTC)
	199	return -ENODEV;
	200
	201	rtc = devm_kzalloc(&pdev->dev, sizeof(struct st_rtc), GFP_KERNEL);
	202	if (!rtc)
	203	return -ENOMEM;
	204
d482510f AB	205	rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
	206	if (IS_ERR(rtc->rtc_dev))
	207	return PTR_ERR(rtc->rtc_dev);
	208
b5b2bdfc LJ	209	spin_lock_init(&rtc->lock);
b5b2bdfc LJ	210
09ef18bc	211	rtc->ioaddr = devm_platform_ioremap_resource(pdev, 0);
b5b2bdfc LJ	212	if (IS_ERR(rtc->ioaddr))
	213	return PTR_ERR(rtc->ioaddr);
	214
	215	rtc->irq = irq_of_parse_and_map(np, 0);
	216	if (!rtc->irq) {
	217	dev_err(&pdev->dev, "IRQ missing or invalid\n");
	218	return -EINVAL;
	219	}
	220
	221	ret = devm_request_irq(&pdev->dev, rtc->irq, st_rtc_handler, 0,
	222	pdev->name, rtc);
	223	if (ret) {
	224	dev_err(&pdev->dev, "Failed to request irq %i\n", rtc->irq);
	225	return ret;
	226	}
	227
	228	enable_irq_wake(rtc->irq);
	229	disable_irq(rtc->irq);
	230
	231	rtc->clk = clk_get(&pdev->dev, NULL);
	232	if (IS_ERR(rtc->clk)) {
	233	dev_err(&pdev->dev, "Unable to request clock\n");
	234	return PTR_ERR(rtc->clk);
	235	}
	236
	237	clk_prepare_enable(rtc->clk);
	238
	239	rtc->clkrate = clk_get_rate(rtc->clk);
	240	if (!rtc->clkrate) {
5fb733d7	241	clk_disable_unprepare(rtc->clk);
b5b2bdfc LJ	242	dev_err(&pdev->dev, "Unable to fetch clock rate\n");
	243	return -EINVAL;
	244	}
	245
	246	device_set_wakeup_capable(&pdev->dev, 1);
	247
	248	platform_set_drvdata(pdev, rtc);
	249
d482510f	250	rtc->rtc_dev->ops = &st_rtc_ops;
b64c984a AB	251	rtc->rtc_dev->range_max = U64_MAX;
b64c984a AB	252	do_div(rtc->rtc_dev->range_max, rtc->clkrate);
d482510f	253
fdcfd854	254	ret = devm_rtc_register_device(rtc->rtc_dev);
d482510f	255	if (ret) {
b5b2bdfc	256	clk_disable_unprepare(rtc->clk);
d482510f	257	return ret;
b5b2bdfc LJ	258	}
	259
	260	return 0;
	261	}
	262
b5b2bdfc LJ	263	#ifdef CONFIG_PM_SLEEP
	264	static int st_rtc_suspend(struct device *dev)
	265	{
	266	struct st_rtc *rtc = dev_get_drvdata(dev);
	267
	268	if (device_may_wakeup(dev))
	269	return 0;
	270
	271	writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
	272	writel_relaxed(0, rtc->ioaddr + LPC_LPA_START_OFF);
	273	writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
	274
	275	return 0;
	276	}
	277
	278	static int st_rtc_resume(struct device *dev)
	279	{
	280	struct st_rtc *rtc = dev_get_drvdata(dev);
	281
	282	rtc_alarm_irq_enable(rtc->rtc_dev, 0);
	283
	284	/*
	285	* clean 'rtc->alarm' to allow a new
	286	* .set_alarm to the upper RTC layer
	287	*/
	288	memset(&rtc->alarm, 0, sizeof(struct rtc_wkalrm));
	289
	290	writel_relaxed(0, rtc->ioaddr + LPC_LPA_MSB_OFF);
	291	writel_relaxed(0, rtc->ioaddr + LPC_LPA_LSB_OFF);
	292	writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
	293	writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF);
	294	writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
	295
	296	return 0;
	297	}
	298	#endif
	299
	300	static SIMPLE_DEV_PM_OPS(st_rtc_pm_ops, st_rtc_suspend, st_rtc_resume);
	301
	302	static const struct of_device_id st_rtc_match[] = {
	303	{ .compatible = "st,stih407-lpc" },
	304	{}
	305	};
	306	MODULE_DEVICE_TABLE(of, st_rtc_match);
	307
	308	static struct platform_driver st_rtc_platform_driver = {
	309	.driver = {
	310	.name = "st-lpc-rtc",
	311	.pm = &st_rtc_pm_ops,
	312	.of_match_table = st_rtc_match,
	313	},
	314	.probe = st_rtc_probe,
b5b2bdfc LJ	315	};
	316
	317	module_platform_driver(st_rtc_platform_driver);
	318
	319	MODULE_DESCRIPTION("STMicroelectronics LPC RTC driver");
	320	MODULE_AUTHOR("David Paris <david.paris@st.com>");
	321	MODULE_LICENSE("GPL");