1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * drivers/rtc/rtc-spear.c
4 *
5 * Copyright (C) 2010 ST Microelectronics
6 * Rajeev Kumar<rajeev-dlh.kumar@st.com>
7 */
8
9#include <linux/bcd.h>
10#include <linux/clk.h>
11#include <linux/delay.h>
12#include <linux/init.h>
13#include <linux/io.h>
14#include <linux/irq.h>
15#include <linux/module.h>
16#include <linux/of.h>
17#include <linux/platform_device.h>
18#include <linux/rtc.h>
19#include <linux/slab.h>
20#include <linux/spinlock.h>
21
22/* RTC registers */
23#define TIME_REG		0x00
24#define DATE_REG		0x04
25#define ALARM_TIME_REG		0x08
26#define ALARM_DATE_REG		0x0C
27#define CTRL_REG		0x10
28#define STATUS_REG		0x14
29
30/* TIME_REG & ALARM_TIME_REG */
31#define SECONDS_UNITS		(0xf<<0)	/* seconds units position */
32#define SECONDS_TENS		(0x7<<4)	/* seconds tens position */
33#define MINUTES_UNITS		(0xf<<8)	/* minutes units position */
34#define MINUTES_TENS		(0x7<<12)	/* minutes tens position */
35#define HOURS_UNITS		(0xf<<16)	/* hours units position */
36#define HOURS_TENS		(0x3<<20)	/* hours tens position */
37
38/* DATE_REG & ALARM_DATE_REG */
39#define DAYS_UNITS		(0xf<<0)	/* days units position */
40#define DAYS_TENS		(0x3<<4)	/* days tens position */
41#define MONTHS_UNITS		(0xf<<8)	/* months units position */
42#define MONTHS_TENS		(0x1<<12)	/* months tens position */
43#define YEARS_UNITS		(0xf<<16)	/* years units position */
44#define YEARS_TENS		(0xf<<20)	/* years tens position */
45#define YEARS_HUNDREDS		(0xf<<24)	/* years hundereds position */
46#define YEARS_MILLENIUMS	(0xf<<28)	/* years millenium position */
47
48/* MASK SHIFT TIME_REG & ALARM_TIME_REG*/
49#define SECOND_SHIFT		0x00		/* seconds units */
50#define MINUTE_SHIFT		0x08		/* minutes units position */
51#define HOUR_SHIFT		0x10		/* hours units position */
52#define MDAY_SHIFT		0x00		/* Month day shift */
53#define MONTH_SHIFT		0x08		/* Month shift */
54#define YEAR_SHIFT		0x10		/* Year shift */
55
56#define SECOND_MASK		0x7F
57#define MIN_MASK		0x7F
58#define HOUR_MASK		0x3F
59#define DAY_MASK		0x3F
60#define MONTH_MASK		0x7F
61#define YEAR_MASK		0xFFFF
62
63/* date reg equal to time reg, for debug only */
64#define TIME_BYP		(1<<9)
65#define INT_ENABLE		(1<<31)		/* interrupt enable */
66
67/* STATUS_REG */
68#define CLK_UNCONNECTED		(1<<0)
69#define PEND_WR_TIME		(1<<2)
70#define PEND_WR_DATE		(1<<3)
71#define LOST_WR_TIME		(1<<4)
72#define LOST_WR_DATE		(1<<5)
73#define RTC_INT_MASK		(1<<31)
74#define STATUS_BUSY		(PEND_WR_TIME | PEND_WR_DATE)
75#define STATUS_FAIL		(LOST_WR_TIME | LOST_WR_DATE)
76
77struct spear_rtc_config {
78	struct rtc_device *rtc;
79	struct clk *clk;
80	spinlock_t lock;
81	void __iomem *ioaddr;
82	unsigned int irq_wake;
83};
84
85static inline void spear_rtc_clear_interrupt(struct spear_rtc_config *config)
86{
87	unsigned int val;
88	unsigned long flags;
89
90	spin_lock_irqsave(&config->lock, flags);
91	val = readl(config->ioaddr + STATUS_REG);
92	val |= RTC_INT_MASK;
93	writel(val, config->ioaddr + STATUS_REG);
94	spin_unlock_irqrestore(&config->lock, flags);
95}
96
97static inline void spear_rtc_enable_interrupt(struct spear_rtc_config *config)
98{
99	unsigned int val;
100
101	val = readl(config->ioaddr + CTRL_REG);
102	if (!(val & INT_ENABLE)) {
103		spear_rtc_clear_interrupt(config);
104		val |= INT_ENABLE;
105		writel(val, config->ioaddr + CTRL_REG);
106	}
107}
108
109static inline void spear_rtc_disable_interrupt(struct spear_rtc_config *config)
110{
111	unsigned int val;
112
113	val = readl(config->ioaddr + CTRL_REG);
114	if (val & INT_ENABLE) {
115		val &= ~INT_ENABLE;
116		writel(val, config->ioaddr + CTRL_REG);
117	}
118}
119
120static inline int is_write_complete(struct spear_rtc_config *config)
121{
122	int ret = 0;
123	unsigned long flags;
124
125	spin_lock_irqsave(&config->lock, flags);
126	if ((readl(config->ioaddr + STATUS_REG)) & STATUS_FAIL)
127		ret = -EIO;
128	spin_unlock_irqrestore(&config->lock, flags);
129
130	return ret;
131}
132
133static void rtc_wait_not_busy(struct spear_rtc_config *config)
134{
135	int status, count = 0;
136	unsigned long flags;
137
138	/* Assuming BUSY may stay active for 80 msec) */
139	for (count = 0; count < 80; count++) {
140		spin_lock_irqsave(&config->lock, flags);
141		status = readl(config->ioaddr + STATUS_REG);
142		spin_unlock_irqrestore(&config->lock, flags);
143		if ((status & STATUS_BUSY) == 0)
144			break;
145		/* check status busy, after each msec */
146		msleep(1);
147	}
148}
149
150static irqreturn_t spear_rtc_irq(int irq, void *dev_id)
151{
152	struct spear_rtc_config *config = dev_id;
153	unsigned long events = 0;
154	unsigned int irq_data;
155
156	spin_lock(&config->lock);
157	irq_data = readl(config->ioaddr + STATUS_REG);
158	spin_unlock(&config->lock);
159
160	if ((irq_data & RTC_INT_MASK)) {
161		spear_rtc_clear_interrupt(config);
162		events = RTC_IRQF | RTC_AF;
163		rtc_update_irq(config->rtc, 1, events);
164		return IRQ_HANDLED;
165	} else
166		return IRQ_NONE;
167
168}
169
170static void tm2bcd(struct rtc_time *tm)
171{
172	tm->tm_sec = bin2bcd(tm->tm_sec);
173	tm->tm_min = bin2bcd(tm->tm_min);
174	tm->tm_hour = bin2bcd(tm->tm_hour);
175	tm->tm_mday = bin2bcd(tm->tm_mday);
176	tm->tm_mon = bin2bcd(tm->tm_mon + 1);
177	tm->tm_year = bin2bcd(tm->tm_year);
178}
179
180static void bcd2tm(struct rtc_time *tm)
181{
182	tm->tm_sec = bcd2bin(tm->tm_sec);
183	tm->tm_min = bcd2bin(tm->tm_min);
184	tm->tm_hour = bcd2bin(tm->tm_hour);
185	tm->tm_mday = bcd2bin(tm->tm_mday);
186	tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
187	/* epoch == 1900 */
188	tm->tm_year = bcd2bin(tm->tm_year);
189}
190
191/*
192 * spear_rtc_read_time - set the time
193 * @dev: rtc device in use
194 * @tm: holds date and time
195 *
196 * This function read time and date. On success it will return 0
197 * otherwise -ve error is returned.
198 */
199static int spear_rtc_read_time(struct device *dev, struct rtc_time *tm)
200{
201	struct spear_rtc_config *config = dev_get_drvdata(dev);
202	unsigned int time, date;
203
204	/* we don't report wday/yday/isdst ... */
205	rtc_wait_not_busy(config);
206
207	do {
208		time = readl(config->ioaddr + TIME_REG);
209		date = readl(config->ioaddr + DATE_REG);
210	} while (time == readl(config->ioaddr + TIME_REG));
211	tm->tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
212	tm->tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
213	tm->tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
214	tm->tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
215	tm->tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
216	tm->tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
217
218	bcd2tm(tm);
219	return 0;
220}
221
222/*
223 * spear_rtc_set_time - set the time
224 * @dev: rtc device in use
225 * @tm: holds date and time
226 *
227 * This function set time and date. On success it will return 0
228 * otherwise -ve error is returned.
229 */
230static int spear_rtc_set_time(struct device *dev, struct rtc_time *tm)
231{
232	struct spear_rtc_config *config = dev_get_drvdata(dev);
233	unsigned int time, date;
234
235	tm2bcd(tm);
236
237	rtc_wait_not_busy(config);
238	time = (tm->tm_sec << SECOND_SHIFT) | (tm->tm_min << MINUTE_SHIFT) |
239		(tm->tm_hour << HOUR_SHIFT);
240	date = (tm->tm_mday << MDAY_SHIFT) | (tm->tm_mon << MONTH_SHIFT) |
241		(tm->tm_year << YEAR_SHIFT);
242	writel(time, config->ioaddr + TIME_REG);
243	writel(date, config->ioaddr + DATE_REG);
244
245	return is_write_complete(config);
246}
247
248/*
249 * spear_rtc_read_alarm - read the alarm time
250 * @dev: rtc device in use
251 * @alm: holds alarm date and time
252 *
253 * This function read alarm time and date. On success it will return 0
254 * otherwise -ve error is returned.
255 */
256static int spear_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
257{
258	struct spear_rtc_config *config = dev_get_drvdata(dev);
259	unsigned int time, date;
260
261	rtc_wait_not_busy(config);
262
263	time = readl(config->ioaddr + ALARM_TIME_REG);
264	date = readl(config->ioaddr + ALARM_DATE_REG);
265	alm->time.tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
266	alm->time.tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
267	alm->time.tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
268	alm->time.tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
269	alm->time.tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
270	alm->time.tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
271
272	bcd2tm(&alm->time);
273	alm->enabled = readl(config->ioaddr + CTRL_REG) & INT_ENABLE;
274
275	return 0;
276}
277
278/*
279 * spear_rtc_set_alarm - set the alarm time
280 * @dev: rtc device in use
281 * @alm: holds alarm date and time
282 *
283 * This function set alarm time and date. On success it will return 0
284 * otherwise -ve error is returned.
285 */
286static int spear_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
287{
288	struct spear_rtc_config *config = dev_get_drvdata(dev);
289	unsigned int time, date;
290	int err;
291
292	tm2bcd(&alm->time);
293
294	rtc_wait_not_busy(config);
295
296	time = (alm->time.tm_sec << SECOND_SHIFT) | (alm->time.tm_min <<
297			MINUTE_SHIFT) |	(alm->time.tm_hour << HOUR_SHIFT);
298	date = (alm->time.tm_mday << MDAY_SHIFT) | (alm->time.tm_mon <<
299			MONTH_SHIFT) | (alm->time.tm_year << YEAR_SHIFT);
300
301	writel(time, config->ioaddr + ALARM_TIME_REG);
302	writel(date, config->ioaddr + ALARM_DATE_REG);
303	err = is_write_complete(config);
304	if (err < 0)
305		return err;
306
307	if (alm->enabled)
308		spear_rtc_enable_interrupt(config);
309	else
310		spear_rtc_disable_interrupt(config);
311
312	return 0;
313}
314
315static int spear_alarm_irq_enable(struct device *dev, unsigned int enabled)
316{
317	struct spear_rtc_config *config = dev_get_drvdata(dev);
318	int ret = 0;
319
320	spear_rtc_clear_interrupt(config);
321
322	switch (enabled) {
323	case 0:
324		/* alarm off */
325		spear_rtc_disable_interrupt(config);
326		break;
327	case 1:
328		/* alarm on */
329		spear_rtc_enable_interrupt(config);
330		break;
331	default:
332		ret = -EINVAL;
333		break;
334	}
335
336	return ret;
337}
338
339static const struct rtc_class_ops spear_rtc_ops = {
340	.read_time = spear_rtc_read_time,
341	.set_time = spear_rtc_set_time,
342	.read_alarm = spear_rtc_read_alarm,
343	.set_alarm = spear_rtc_set_alarm,
344	.alarm_irq_enable = spear_alarm_irq_enable,
345};
346
347static int spear_rtc_probe(struct platform_device *pdev)
348{
349	struct spear_rtc_config *config;
350	int status = 0;
351	int irq;
352
353	config = devm_kzalloc(&pdev->dev, sizeof(*config), GFP_KERNEL);
354	if (!config)
355		return -ENOMEM;
356
357	config->rtc = devm_rtc_allocate_device(&pdev->dev);
358	if (IS_ERR(config->rtc))
359		return PTR_ERR(config->rtc);
360
361	/* alarm irqs */
362	irq = platform_get_irq(pdev, 0);
363	if (irq < 0)
364		return irq;
365
366	status = devm_request_irq(&pdev->dev, irq, spear_rtc_irq, 0, pdev->name,
367			config);
368	if (status) {
369		dev_err(&pdev->dev, "Alarm interrupt IRQ%d already claimed\n",
370				irq);
371		return status;
372	}
373
374	config->ioaddr = devm_platform_ioremap_resource(pdev, 0);
375	if (IS_ERR(config->ioaddr))
376		return PTR_ERR(config->ioaddr);
377
378	config->clk = devm_clk_get(&pdev->dev, NULL);
379	if (IS_ERR(config->clk))
380		return PTR_ERR(config->clk);
381
382	status = clk_prepare_enable(config->clk);
383	if (status < 0)
384		return status;
385
386	spin_lock_init(&config->lock);
387	platform_set_drvdata(pdev, config);
388
389	config->rtc->ops = &spear_rtc_ops;
390	config->rtc->range_min = RTC_TIMESTAMP_BEGIN_0000;
391	config->rtc->range_max = RTC_TIMESTAMP_END_9999;
392
393	status = devm_rtc_register_device(config->rtc);
394	if (status)
395		goto err_disable_clock;
396
397	if (!device_can_wakeup(&pdev->dev))
398		device_init_wakeup(&pdev->dev, 1);
399
400	return 0;
401
402err_disable_clock:
403	clk_disable_unprepare(config->clk);
404
405	return status;
406}
407
408static void spear_rtc_remove(struct platform_device *pdev)
409{
410	struct spear_rtc_config *config = platform_get_drvdata(pdev);
411
412	spear_rtc_disable_interrupt(config);
413	clk_disable_unprepare(config->clk);
414	device_init_wakeup(&pdev->dev, 0);
415}
416
417#ifdef CONFIG_PM_SLEEP
418static int spear_rtc_suspend(struct device *dev)
419{
420	struct platform_device *pdev = to_platform_device(dev);
421	struct spear_rtc_config *config = platform_get_drvdata(pdev);
422	int irq;
423
424	irq = platform_get_irq(pdev, 0);
425	if (device_may_wakeup(&pdev->dev)) {
426		if (!enable_irq_wake(irq))
427			config->irq_wake = 1;
428	} else {
429		spear_rtc_disable_interrupt(config);
430		clk_disable(config->clk);
431	}
432
433	return 0;
434}
435
436static int spear_rtc_resume(struct device *dev)
437{
438	struct platform_device *pdev = to_platform_device(dev);
439	struct spear_rtc_config *config = platform_get_drvdata(pdev);
440	int irq;
441
442	irq = platform_get_irq(pdev, 0);
443
444	if (device_may_wakeup(&pdev->dev)) {
445		if (config->irq_wake) {
446			disable_irq_wake(irq);
447			config->irq_wake = 0;
448		}
449	} else {
450		clk_enable(config->clk);
451		spear_rtc_enable_interrupt(config);
452	}
453
454	return 0;
455}
456#endif
457
458static SIMPLE_DEV_PM_OPS(spear_rtc_pm_ops, spear_rtc_suspend, spear_rtc_resume);
459
460static void spear_rtc_shutdown(struct platform_device *pdev)
461{
462	struct spear_rtc_config *config = platform_get_drvdata(pdev);
463
464	spear_rtc_disable_interrupt(config);
465	clk_disable(config->clk);
466}
467
468#ifdef CONFIG_OF
469static const struct of_device_id spear_rtc_id_table[] = {
470	{ .compatible = "st,spear600-rtc" },
471	{}
472};
473MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
474#endif
475
476static struct platform_driver spear_rtc_driver = {
477	.probe = spear_rtc_probe,
478	.remove_new = spear_rtc_remove,
479	.shutdown = spear_rtc_shutdown,
480	.driver = {
481		.name = "rtc-spear",
482		.pm = &spear_rtc_pm_ops,
483		.of_match_table = of_match_ptr(spear_rtc_id_table),
484	},
485};
486
487module_platform_driver(spear_rtc_driver);
488
489MODULE_ALIAS("platform:rtc-spear");
490MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
491MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
492MODULE_LICENSE("GPL");
493