xref: /openbmc/linux/drivers/rtc/rtc-spear.c (revision 05bcf503) 
1 /*
2  * drivers/rtc/rtc-spear.c
3  *
4  * Copyright (C) 2010 ST Microelectronics
5  * Rajeev Kumar<rajeev-dlh.kumar@st.com>
6  *
7  * This file is licensed under the terms of the GNU General Public
8  * License version 2. This program is licensed "as is" without any
9  * warranty of any kind, whether express or implied.
10  */
11 
12 #include <linux/bcd.h>
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/module.h>
19 #include <linux/of.h>
20 #include <linux/platform_device.h>
21 #include <linux/rtc.h>
22 #include <linux/slab.h>
23 #include <linux/spinlock.h>
24 
25 /* RTC registers */
26 #define TIME_REG		0x00
27 #define DATE_REG		0x04
28 #define ALARM_TIME_REG		0x08
29 #define ALARM_DATE_REG		0x0C
30 #define CTRL_REG		0x10
31 #define STATUS_REG		0x14
32 
33 /* TIME_REG & ALARM_TIME_REG */
34 #define SECONDS_UNITS		(0xf<<0)	/* seconds units position */
35 #define SECONDS_TENS		(0x7<<4)	/* seconds tens position */
36 #define MINUTES_UNITS		(0xf<<8)	/* minutes units position */
37 #define MINUTES_TENS		(0x7<<12)	/* minutes tens position */
38 #define HOURS_UNITS		(0xf<<16)	/* hours units position */
39 #define HOURS_TENS		(0x3<<20)	/* hours tens position */
40 
41 /* DATE_REG & ALARM_DATE_REG */
42 #define DAYS_UNITS		(0xf<<0)	/* days units position */
43 #define DAYS_TENS		(0x3<<4)	/* days tens position */
44 #define MONTHS_UNITS		(0xf<<8)	/* months units position */
45 #define MONTHS_TENS		(0x1<<12)	/* months tens position */
46 #define YEARS_UNITS		(0xf<<16)	/* years units position */
47 #define YEARS_TENS		(0xf<<20)	/* years tens position */
48 #define YEARS_HUNDREDS		(0xf<<24)	/* years hundereds position */
49 #define YEARS_MILLENIUMS	(0xf<<28)	/* years millenium position */
50 
51 /* MASK SHIFT TIME_REG & ALARM_TIME_REG*/
52 #define SECOND_SHIFT		0x00		/* seconds units */
53 #define MINUTE_SHIFT		0x08		/* minutes units position */
54 #define HOUR_SHIFT		0x10		/* hours units position */
55 #define MDAY_SHIFT		0x00		/* Month day shift */
56 #define MONTH_SHIFT		0x08		/* Month shift */
57 #define YEAR_SHIFT		0x10		/* Year shift */
58 
59 #define SECOND_MASK		0x7F
60 #define MIN_MASK		0x7F
61 #define HOUR_MASK		0x3F
62 #define DAY_MASK		0x3F
63 #define MONTH_MASK		0x7F
64 #define YEAR_MASK		0xFFFF
65 
66 /* date reg equal to time reg, for debug only */
67 #define TIME_BYP		(1<<9)
68 #define INT_ENABLE		(1<<31)		/* interrupt enable */
69 
70 /* STATUS_REG */
71 #define CLK_UNCONNECTED		(1<<0)
72 #define PEND_WR_TIME		(1<<2)
73 #define PEND_WR_DATE		(1<<3)
74 #define LOST_WR_TIME		(1<<4)
75 #define LOST_WR_DATE		(1<<5)
76 #define RTC_INT_MASK		(1<<31)
77 #define STATUS_BUSY		(PEND_WR_TIME | PEND_WR_DATE)
78 #define STATUS_FAIL		(LOST_WR_TIME | LOST_WR_DATE)
79 
80 struct spear_rtc_config {
81 	struct rtc_device *rtc;
82 	struct clk *clk;
83 	spinlock_t lock;
84 	void __iomem *ioaddr;
85 	unsigned int irq_wake;
86 };
87 
88 static inline void spear_rtc_clear_interrupt(struct spear_rtc_config *config)
89 {
90 	unsigned int val;
91 	unsigned long flags;
92 
93 	spin_lock_irqsave(&config->lock, flags);
94 	val = readl(config->ioaddr + STATUS_REG);
95 	val |= RTC_INT_MASK;
96 	writel(val, config->ioaddr + STATUS_REG);
97 	spin_unlock_irqrestore(&config->lock, flags);
98 }
99 
100 static inline void spear_rtc_enable_interrupt(struct spear_rtc_config *config)
101 {
102 	unsigned int val;
103 
104 	val = readl(config->ioaddr + CTRL_REG);
105 	if (!(val & INT_ENABLE)) {
106 		spear_rtc_clear_interrupt(config);
107 		val |= INT_ENABLE;
108 		writel(val, config->ioaddr + CTRL_REG);
109 	}
110 }
111 
112 static inline void spear_rtc_disable_interrupt(struct spear_rtc_config *config)
113 {
114 	unsigned int val;
115 
116 	val = readl(config->ioaddr + CTRL_REG);
117 	if (val & INT_ENABLE) {
118 		val &= ~INT_ENABLE;
119 		writel(val, config->ioaddr + CTRL_REG);
120 	}
121 }
122 
123 static inline int is_write_complete(struct spear_rtc_config *config)
124 {
125 	int ret = 0;
126 	unsigned long flags;
127 
128 	spin_lock_irqsave(&config->lock, flags);
129 	if ((readl(config->ioaddr + STATUS_REG)) & STATUS_FAIL)
130 		ret = -EIO;
131 	spin_unlock_irqrestore(&config->lock, flags);
132 
133 	return ret;
134 }
135 
136 static void rtc_wait_not_busy(struct spear_rtc_config *config)
137 {
138 	int status, count = 0;
139 	unsigned long flags;
140 
141 	/* Assuming BUSY may stay active for 80 msec) */
142 	for (count = 0; count < 80; count++) {
143 		spin_lock_irqsave(&config->lock, flags);
144 		status = readl(config->ioaddr + STATUS_REG);
145 		spin_unlock_irqrestore(&config->lock, flags);
146 		if ((status & STATUS_BUSY) == 0)
147 			break;
148 		/* check status busy, after each msec */
149 		msleep(1);
150 	}
151 }
152 
153 static irqreturn_t spear_rtc_irq(int irq, void *dev_id)
154 {
155 	struct spear_rtc_config *config = dev_id;
156 	unsigned long flags, events = 0;
157 	unsigned int irq_data;
158 
159 	spin_lock_irqsave(&config->lock, flags);
160 	irq_data = readl(config->ioaddr + STATUS_REG);
161 	spin_unlock_irqrestore(&config->lock, flags);
162 
163 	if ((irq_data & RTC_INT_MASK)) {
164 		spear_rtc_clear_interrupt(config);
165 		events = RTC_IRQF | RTC_AF;
166 		rtc_update_irq(config->rtc, 1, events);
167 		return IRQ_HANDLED;
168 	} else
169 		return IRQ_NONE;
170 
171 }
172 
173 static int tm2bcd(struct rtc_time *tm)
174 {
175 	if (rtc_valid_tm(tm) != 0)
176 		return -EINVAL;
177 	tm->tm_sec = bin2bcd(tm->tm_sec);
178 	tm->tm_min = bin2bcd(tm->tm_min);
179 	tm->tm_hour = bin2bcd(tm->tm_hour);
180 	tm->tm_mday = bin2bcd(tm->tm_mday);
181 	tm->tm_mon = bin2bcd(tm->tm_mon + 1);
182 	tm->tm_year = bin2bcd(tm->tm_year);
183 
184 	return 0;
185 }
186 
187 static void bcd2tm(struct rtc_time *tm)
188 {
189 	tm->tm_sec = bcd2bin(tm->tm_sec);
190 	tm->tm_min = bcd2bin(tm->tm_min);
191 	tm->tm_hour = bcd2bin(tm->tm_hour);
192 	tm->tm_mday = bcd2bin(tm->tm_mday);
193 	tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
194 	/* epoch == 1900 */
195 	tm->tm_year = bcd2bin(tm->tm_year);
196 }
197 
198 /*
199  * spear_rtc_read_time - set the time
200  * @dev: rtc device in use
201  * @tm: holds date and time
202  *
203  * This function read time and date. On success it will return 0
204  * otherwise -ve error is returned.
205  */
206 static int spear_rtc_read_time(struct device *dev, struct rtc_time *tm)
207 {
208 	struct spear_rtc_config *config = dev_get_drvdata(dev);
209 	unsigned int time, date;
210 
211 	/* we don't report wday/yday/isdst ... */
212 	rtc_wait_not_busy(config);
213 
214 	time = readl(config->ioaddr + TIME_REG);
215 	date = readl(config->ioaddr + DATE_REG);
216 	tm->tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
217 	tm->tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
218 	tm->tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
219 	tm->tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
220 	tm->tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
221 	tm->tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
222 
223 	bcd2tm(tm);
224 	return 0;
225 }
226 
227 /*
228  * spear_rtc_set_time - set the time
229  * @dev: rtc device in use
230  * @tm: holds date and time
231  *
232  * This function set time and date. On success it will return 0
233  * otherwise -ve error is returned.
234  */
235 static int spear_rtc_set_time(struct device *dev, struct rtc_time *tm)
236 {
237 	struct spear_rtc_config *config = dev_get_drvdata(dev);
238 	unsigned int time, date;
239 
240 	if (tm2bcd(tm) < 0)
241 		return -EINVAL;
242 
243 	rtc_wait_not_busy(config);
244 	time = (tm->tm_sec << SECOND_SHIFT) | (tm->tm_min << MINUTE_SHIFT) |
245 		(tm->tm_hour << HOUR_SHIFT);
246 	date = (tm->tm_mday << MDAY_SHIFT) | (tm->tm_mon << MONTH_SHIFT) |
247 		(tm->tm_year << YEAR_SHIFT);
248 	writel(time, config->ioaddr + TIME_REG);
249 	writel(date, config->ioaddr + DATE_REG);
250 
251 	return is_write_complete(config);
252 }
253 
254 /*
255  * spear_rtc_read_alarm - read the alarm time
256  * @dev: rtc device in use
257  * @alm: holds alarm date and time
258  *
259  * This function read alarm time and date. On success it will return 0
260  * otherwise -ve error is returned.
261  */
262 static int spear_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
263 {
264 	struct spear_rtc_config *config = dev_get_drvdata(dev);
265 	unsigned int time, date;
266 
267 	rtc_wait_not_busy(config);
268 
269 	time = readl(config->ioaddr + ALARM_TIME_REG);
270 	date = readl(config->ioaddr + ALARM_DATE_REG);
271 	alm->time.tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
272 	alm->time.tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
273 	alm->time.tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
274 	alm->time.tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
275 	alm->time.tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
276 	alm->time.tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
277 
278 	bcd2tm(&alm->time);
279 	alm->enabled = readl(config->ioaddr + CTRL_REG) & INT_ENABLE;
280 
281 	return 0;
282 }
283 
284 /*
285  * spear_rtc_set_alarm - set the alarm time
286  * @dev: rtc device in use
287  * @alm: holds alarm date and time
288  *
289  * This function set alarm time and date. On success it will return 0
290  * otherwise -ve error is returned.
291  */
292 static int spear_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
293 {
294 	struct spear_rtc_config *config = dev_get_drvdata(dev);
295 	unsigned int time, date;
296 	int err;
297 
298 	if (tm2bcd(&alm->time) < 0)
299 		return -EINVAL;
300 
301 	rtc_wait_not_busy(config);
302 
303 	time = (alm->time.tm_sec << SECOND_SHIFT) | (alm->time.tm_min <<
304 			MINUTE_SHIFT) |	(alm->time.tm_hour << HOUR_SHIFT);
305 	date = (alm->time.tm_mday << MDAY_SHIFT) | (alm->time.tm_mon <<
306 			MONTH_SHIFT) | (alm->time.tm_year << YEAR_SHIFT);
307 
308 	writel(time, config->ioaddr + ALARM_TIME_REG);
309 	writel(date, config->ioaddr + ALARM_DATE_REG);
310 	err = is_write_complete(config);
311 	if (err < 0)
312 		return err;
313 
314 	if (alm->enabled)
315 		spear_rtc_enable_interrupt(config);
316 	else
317 		spear_rtc_disable_interrupt(config);
318 
319 	return 0;
320 }
321 
322 static int spear_alarm_irq_enable(struct device *dev, unsigned int enabled)
323 {
324 	struct spear_rtc_config *config = dev_get_drvdata(dev);
325 	int ret = 0;
326 
327 	spear_rtc_clear_interrupt(config);
328 
329 	switch (enabled) {
330 	case 0:
331 		/* alarm off */
332 		spear_rtc_disable_interrupt(config);
333 		break;
334 	case 1:
335 		/* alarm on */
336 		spear_rtc_enable_interrupt(config);
337 		break;
338 	default:
339 		ret = -EINVAL;
340 		break;
341 	}
342 
343 	return ret;
344 }
345 
346 static struct rtc_class_ops spear_rtc_ops = {
347 	.read_time = spear_rtc_read_time,
348 	.set_time = spear_rtc_set_time,
349 	.read_alarm = spear_rtc_read_alarm,
350 	.set_alarm = spear_rtc_set_alarm,
351 	.alarm_irq_enable = spear_alarm_irq_enable,
352 };
353 
354 static int __devinit spear_rtc_probe(struct platform_device *pdev)
355 {
356 	struct resource *res;
357 	struct spear_rtc_config *config;
358 	int status = 0;
359 	int irq;
360 
361 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
362 	if (!res) {
363 		dev_err(&pdev->dev, "no resource defined\n");
364 		return -EBUSY;
365 	}
366 	if (!request_mem_region(res->start, resource_size(res), pdev->name)) {
367 		dev_err(&pdev->dev, "rtc region already claimed\n");
368 		return -EBUSY;
369 	}
370 
371 	config = kzalloc(sizeof(*config), GFP_KERNEL);
372 	if (!config) {
373 		dev_err(&pdev->dev, "out of memory\n");
374 		status = -ENOMEM;
375 		goto err_release_region;
376 	}
377 
378 	config->clk = clk_get(&pdev->dev, NULL);
379 	if (IS_ERR(config->clk)) {
380 		status = PTR_ERR(config->clk);
381 		goto err_kfree;
382 	}
383 
384 	status = clk_enable(config->clk);
385 	if (status < 0)
386 		goto err_clk_put;
387 
388 	config->ioaddr = ioremap(res->start, resource_size(res));
389 	if (!config->ioaddr) {
390 		dev_err(&pdev->dev, "ioremap fail\n");
391 		status = -ENOMEM;
392 		goto err_disable_clock;
393 	}
394 
395 	spin_lock_init(&config->lock);
396 	platform_set_drvdata(pdev, config);
397 
398 	config->rtc = rtc_device_register(pdev->name, &pdev->dev,
399 			&spear_rtc_ops, THIS_MODULE);
400 	if (IS_ERR(config->rtc)) {
401 		dev_err(&pdev->dev, "can't register RTC device, err %ld\n",
402 				PTR_ERR(config->rtc));
403 		status = PTR_ERR(config->rtc);
404 		goto err_iounmap;
405 	}
406 
407 	/* alarm irqs */
408 	irq = platform_get_irq(pdev, 0);
409 	if (irq < 0) {
410 		dev_err(&pdev->dev, "no update irq?\n");
411 		status = irq;
412 		goto err_clear_platdata;
413 	}
414 
415 	status = request_irq(irq, spear_rtc_irq, 0, pdev->name, config);
416 	if (status) {
417 		dev_err(&pdev->dev, "Alarm interrupt IRQ%d already \
418 				claimed\n", irq);
419 		goto err_clear_platdata;
420 	}
421 
422 	if (!device_can_wakeup(&pdev->dev))
423 		device_init_wakeup(&pdev->dev, 1);
424 
425 	return 0;
426 
427 err_clear_platdata:
428 	platform_set_drvdata(pdev, NULL);
429 	rtc_device_unregister(config->rtc);
430 err_iounmap:
431 	iounmap(config->ioaddr);
432 err_disable_clock:
433 	clk_disable(config->clk);
434 err_clk_put:
435 	clk_put(config->clk);
436 err_kfree:
437 	kfree(config);
438 err_release_region:
439 	release_mem_region(res->start, resource_size(res));
440 
441 	return status;
442 }
443 
444 static int __devexit spear_rtc_remove(struct platform_device *pdev)
445 {
446 	struct spear_rtc_config *config = platform_get_drvdata(pdev);
447 	int irq;
448 	struct resource *res;
449 
450 	/* leave rtc running, but disable irqs */
451 	spear_rtc_disable_interrupt(config);
452 	device_init_wakeup(&pdev->dev, 0);
453 	irq = platform_get_irq(pdev, 0);
454 	if (irq)
455 		free_irq(irq, pdev);
456 	clk_disable(config->clk);
457 	clk_put(config->clk);
458 	iounmap(config->ioaddr);
459 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
460 	if (res)
461 		release_mem_region(res->start, resource_size(res));
462 	platform_set_drvdata(pdev, NULL);
463 	rtc_device_unregister(config->rtc);
464 	kfree(config);
465 
466 	return 0;
467 }
468 
469 #ifdef CONFIG_PM
470 
471 static int spear_rtc_suspend(struct platform_device *pdev, pm_message_t state)
472 {
473 	struct spear_rtc_config *config = platform_get_drvdata(pdev);
474 	int irq;
475 
476 	irq = platform_get_irq(pdev, 0);
477 	if (device_may_wakeup(&pdev->dev)) {
478 		if (!enable_irq_wake(irq))
479 			config->irq_wake = 1;
480 	} else {
481 		spear_rtc_disable_interrupt(config);
482 		clk_disable(config->clk);
483 	}
484 
485 	return 0;
486 }
487 
488 static int spear_rtc_resume(struct platform_device *pdev)
489 {
490 	struct spear_rtc_config *config = platform_get_drvdata(pdev);
491 	int irq;
492 
493 	irq = platform_get_irq(pdev, 0);
494 
495 	if (device_may_wakeup(&pdev->dev)) {
496 		if (config->irq_wake) {
497 			disable_irq_wake(irq);
498 			config->irq_wake = 0;
499 		}
500 	} else {
501 		clk_enable(config->clk);
502 		spear_rtc_enable_interrupt(config);
503 	}
504 
505 	return 0;
506 }
507 
508 #else
509 #define spear_rtc_suspend	NULL
510 #define spear_rtc_resume	NULL
511 #endif
512 
513 static void spear_rtc_shutdown(struct platform_device *pdev)
514 {
515 	struct spear_rtc_config *config = platform_get_drvdata(pdev);
516 
517 	spear_rtc_disable_interrupt(config);
518 	clk_disable(config->clk);
519 }
520 
521 #ifdef CONFIG_OF
522 static const struct of_device_id spear_rtc_id_table[] = {
523 	{ .compatible = "st,spear600-rtc" },
524 	{}
525 };
526 MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
527 #endif
528 
529 static struct platform_driver spear_rtc_driver = {
530 	.probe = spear_rtc_probe,
531 	.remove = __devexit_p(spear_rtc_remove),
532 	.suspend = spear_rtc_suspend,
533 	.resume = spear_rtc_resume,
534 	.shutdown = spear_rtc_shutdown,
535 	.driver = {
536 		.name = "rtc-spear",
537 		.of_match_table = of_match_ptr(spear_rtc_id_table),
538 	},
539 };
540 
541 module_platform_driver(spear_rtc_driver);
542 
543 MODULE_ALIAS("platform:rtc-spear");
544 MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
545 MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
546 MODULE_LICENSE("GPL");
547