xref: /openbmc/linux/drivers/rtc/rtc-spear.c (revision e40573a4) 
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 
77 struct 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 
85 static 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 
97 static 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 
109 static 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 
120 static 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 
133 static 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 
150 static 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 
170 static 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 
180 static 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  */
199 static 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  */
230 static 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  */
256 static 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  */
286 static 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 
315 static 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 
339 static 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 
347 static 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 
402 err_disable_clock:
403 	clk_disable_unprepare(config->clk);
404 
405 	return status;
406 }
407 
408 static int 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 	return 0;
417 }
418 
419 #ifdef CONFIG_PM_SLEEP
420 static int spear_rtc_suspend(struct device *dev)
421 {
422 	struct platform_device *pdev = to_platform_device(dev);
423 	struct spear_rtc_config *config = platform_get_drvdata(pdev);
424 	int irq;
425 
426 	irq = platform_get_irq(pdev, 0);
427 	if (device_may_wakeup(&pdev->dev)) {
428 		if (!enable_irq_wake(irq))
429 			config->irq_wake = 1;
430 	} else {
431 		spear_rtc_disable_interrupt(config);
432 		clk_disable(config->clk);
433 	}
434 
435 	return 0;
436 }
437 
438 static int spear_rtc_resume(struct device *dev)
439 {
440 	struct platform_device *pdev = to_platform_device(dev);
441 	struct spear_rtc_config *config = platform_get_drvdata(pdev);
442 	int irq;
443 
444 	irq = platform_get_irq(pdev, 0);
445 
446 	if (device_may_wakeup(&pdev->dev)) {
447 		if (config->irq_wake) {
448 			disable_irq_wake(irq);
449 			config->irq_wake = 0;
450 		}
451 	} else {
452 		clk_enable(config->clk);
453 		spear_rtc_enable_interrupt(config);
454 	}
455 
456 	return 0;
457 }
458 #endif
459 
460 static SIMPLE_DEV_PM_OPS(spear_rtc_pm_ops, spear_rtc_suspend, spear_rtc_resume);
461 
462 static void spear_rtc_shutdown(struct platform_device *pdev)
463 {
464 	struct spear_rtc_config *config = platform_get_drvdata(pdev);
465 
466 	spear_rtc_disable_interrupt(config);
467 	clk_disable(config->clk);
468 }
469 
470 #ifdef CONFIG_OF
471 static const struct of_device_id spear_rtc_id_table[] = {
472 	{ .compatible = "st,spear600-rtc" },
473 	{}
474 };
475 MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
476 #endif
477 
478 static struct platform_driver spear_rtc_driver = {
479 	.probe = spear_rtc_probe,
480 	.remove = spear_rtc_remove,
481 	.shutdown = spear_rtc_shutdown,
482 	.driver = {
483 		.name = "rtc-spear",
484 		.pm = &spear_rtc_pm_ops,
485 		.of_match_table = of_match_ptr(spear_rtc_id_table),
486 	},
487 };
488 
489 module_platform_driver(spear_rtc_driver);
490 
491 MODULE_ALIAS("platform:rtc-spear");
492 MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
493 MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
494 MODULE_LICENSE("GPL");
495