[linux-2.6-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 resource *res;
	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 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;
	struct resource *res;
	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);

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