xref: /openbmc/linux/drivers/rtc/rtc-spear.c (revision 56c6eed1) 
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 void tm2bcd(struct rtc_time *tm)
174 {
175 	tm->tm_sec = bin2bcd(tm->tm_sec);
176 	tm->tm_min = bin2bcd(tm->tm_min);
177 	tm->tm_hour = bin2bcd(tm->tm_hour);
178 	tm->tm_mday = bin2bcd(tm->tm_mday);
179 	tm->tm_mon = bin2bcd(tm->tm_mon + 1);
180 	tm->tm_year = bin2bcd(tm->tm_year);
181 }
182 
183 static void bcd2tm(struct rtc_time *tm)
184 {
185 	tm->tm_sec = bcd2bin(tm->tm_sec);
186 	tm->tm_min = bcd2bin(tm->tm_min);
187 	tm->tm_hour = bcd2bin(tm->tm_hour);
188 	tm->tm_mday = bcd2bin(tm->tm_mday);
189 	tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
190 	/* epoch == 1900 */
191 	tm->tm_year = bcd2bin(tm->tm_year);
192 }
193 
194 /*
195  * spear_rtc_read_time - set the time
196  * @dev: rtc device in use
197  * @tm: holds date and time
198  *
199  * This function read time and date. On success it will return 0
200  * otherwise -ve error is returned.
201  */
202 static int spear_rtc_read_time(struct device *dev, struct rtc_time *tm)
203 {
204 	struct spear_rtc_config *config = dev_get_drvdata(dev);
205 	unsigned int time, date;
206 
207 	/* we don't report wday/yday/isdst ... */
208 	rtc_wait_not_busy(config);
209 
210 	time = readl(config->ioaddr + TIME_REG);
211 	date = readl(config->ioaddr + DATE_REG);
212 	tm->tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
213 	tm->tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
214 	tm->tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
215 	tm->tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
216 	tm->tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
217 	tm->tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
218 
219 	bcd2tm(tm);
220 	return 0;
221 }
222 
223 /*
224  * spear_rtc_set_time - set the time
225  * @dev: rtc device in use
226  * @tm: holds date and time
227  *
228  * This function set time and date. On success it will return 0
229  * otherwise -ve error is returned.
230  */
231 static int spear_rtc_set_time(struct device *dev, struct rtc_time *tm)
232 {
233 	struct spear_rtc_config *config = dev_get_drvdata(dev);
234 	unsigned int time, date;
235 
236 	tm2bcd(tm);
237 
238 	rtc_wait_not_busy(config);
239 	time = (tm->tm_sec << SECOND_SHIFT) | (tm->tm_min << MINUTE_SHIFT) |
240 		(tm->tm_hour << HOUR_SHIFT);
241 	date = (tm->tm_mday << MDAY_SHIFT) | (tm->tm_mon << MONTH_SHIFT) |
242 		(tm->tm_year << YEAR_SHIFT);
243 	writel(time, config->ioaddr + TIME_REG);
244 	writel(date, config->ioaddr + DATE_REG);
245 
246 	return is_write_complete(config);
247 }
248 
249 /*
250  * spear_rtc_read_alarm - read the alarm time
251  * @dev: rtc device in use
252  * @alm: holds alarm date and time
253  *
254  * This function read alarm time and date. On success it will return 0
255  * otherwise -ve error is returned.
256  */
257 static int spear_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
258 {
259 	struct spear_rtc_config *config = dev_get_drvdata(dev);
260 	unsigned int time, date;
261 
262 	rtc_wait_not_busy(config);
263 
264 	time = readl(config->ioaddr + ALARM_TIME_REG);
265 	date = readl(config->ioaddr + ALARM_DATE_REG);
266 	alm->time.tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
267 	alm->time.tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
268 	alm->time.tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
269 	alm->time.tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
270 	alm->time.tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
271 	alm->time.tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
272 
273 	bcd2tm(&alm->time);
274 	alm->enabled = readl(config->ioaddr + CTRL_REG) & INT_ENABLE;
275 
276 	return 0;
277 }
278 
279 /*
280  * spear_rtc_set_alarm - set the alarm time
281  * @dev: rtc device in use
282  * @alm: holds alarm date and time
283  *
284  * This function set alarm time and date. On success it will return 0
285  * otherwise -ve error is returned.
286  */
287 static int spear_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
288 {
289 	struct spear_rtc_config *config = dev_get_drvdata(dev);
290 	unsigned int time, date;
291 	int err;
292 
293 	tm2bcd(&alm->time);
294 
295 	rtc_wait_not_busy(config);
296 
297 	time = (alm->time.tm_sec << SECOND_SHIFT) | (alm->time.tm_min <<
298 			MINUTE_SHIFT) |	(alm->time.tm_hour << HOUR_SHIFT);
299 	date = (alm->time.tm_mday << MDAY_SHIFT) | (alm->time.tm_mon <<
300 			MONTH_SHIFT) | (alm->time.tm_year << YEAR_SHIFT);
301 
302 	writel(time, config->ioaddr + ALARM_TIME_REG);
303 	writel(date, config->ioaddr + ALARM_DATE_REG);
304 	err = is_write_complete(config);
305 	if (err < 0)
306 		return err;
307 
308 	if (alm->enabled)
309 		spear_rtc_enable_interrupt(config);
310 	else
311 		spear_rtc_disable_interrupt(config);
312 
313 	return 0;
314 }
315 
316 static int spear_alarm_irq_enable(struct device *dev, unsigned int enabled)
317 {
318 	struct spear_rtc_config *config = dev_get_drvdata(dev);
319 	int ret = 0;
320 
321 	spear_rtc_clear_interrupt(config);
322 
323 	switch (enabled) {
324 	case 0:
325 		/* alarm off */
326 		spear_rtc_disable_interrupt(config);
327 		break;
328 	case 1:
329 		/* alarm on */
330 		spear_rtc_enable_interrupt(config);
331 		break;
332 	default:
333 		ret = -EINVAL;
334 		break;
335 	}
336 
337 	return ret;
338 }
339 
340 static const struct rtc_class_ops spear_rtc_ops = {
341 	.read_time = spear_rtc_read_time,
342 	.set_time = spear_rtc_set_time,
343 	.read_alarm = spear_rtc_read_alarm,
344 	.set_alarm = spear_rtc_set_alarm,
345 	.alarm_irq_enable = spear_alarm_irq_enable,
346 };
347 
348 static int spear_rtc_probe(struct platform_device *pdev)
349 {
350 	struct resource *res;
351 	struct spear_rtc_config *config;
352 	int status = 0;
353 	int irq;
354 
355 	config = devm_kzalloc(&pdev->dev, sizeof(*config), GFP_KERNEL);
356 	if (!config)
357 		return -ENOMEM;
358 
359 	/* alarm irqs */
360 	irq = platform_get_irq(pdev, 0);
361 	if (irq < 0) {
362 		dev_err(&pdev->dev, "no update irq?\n");
363 		return irq;
364 	}
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 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
375 	config->ioaddr = devm_ioremap_resource(&pdev->dev, res);
376 	if (IS_ERR(config->ioaddr))
377 		return PTR_ERR(config->ioaddr);
378 
379 	config->clk = devm_clk_get(&pdev->dev, NULL);
380 	if (IS_ERR(config->clk))
381 		return PTR_ERR(config->clk);
382 
383 	status = clk_prepare_enable(config->clk);
384 	if (status < 0)
385 		return status;
386 
387 	spin_lock_init(&config->lock);
388 	platform_set_drvdata(pdev, config);
389 
390 	config->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
391 					&spear_rtc_ops, THIS_MODULE);
392 	if (IS_ERR(config->rtc)) {
393 		dev_err(&pdev->dev, "can't register RTC device, err %ld\n",
394 				PTR_ERR(config->rtc));
395 		status = PTR_ERR(config->rtc);
396 		goto err_disable_clock;
397 	}
398 
399 	config->rtc->uie_unsupported = 1;
400 
401 	if (!device_can_wakeup(&pdev->dev))
402 		device_init_wakeup(&pdev->dev, 1);
403 
404 	return 0;
405 
406 err_disable_clock:
407 	clk_disable_unprepare(config->clk);
408 
409 	return status;
410 }
411 
412 static int spear_rtc_remove(struct platform_device *pdev)
413 {
414 	struct spear_rtc_config *config = platform_get_drvdata(pdev);
415 
416 	spear_rtc_disable_interrupt(config);
417 	clk_disable_unprepare(config->clk);
418 	device_init_wakeup(&pdev->dev, 0);
419 
420 	return 0;
421 }
422 
423 #ifdef CONFIG_PM_SLEEP
424 static int spear_rtc_suspend(struct device *dev)
425 {
426 	struct platform_device *pdev = to_platform_device(dev);
427 	struct spear_rtc_config *config = platform_get_drvdata(pdev);
428 	int irq;
429 
430 	irq = platform_get_irq(pdev, 0);
431 	if (device_may_wakeup(&pdev->dev)) {
432 		if (!enable_irq_wake(irq))
433 			config->irq_wake = 1;
434 	} else {
435 		spear_rtc_disable_interrupt(config);
436 		clk_disable(config->clk);
437 	}
438 
439 	return 0;
440 }
441 
442 static int spear_rtc_resume(struct device *dev)
443 {
444 	struct platform_device *pdev = to_platform_device(dev);
445 	struct spear_rtc_config *config = platform_get_drvdata(pdev);
446 	int irq;
447 
448 	irq = platform_get_irq(pdev, 0);
449 
450 	if (device_may_wakeup(&pdev->dev)) {
451 		if (config->irq_wake) {
452 			disable_irq_wake(irq);
453 			config->irq_wake = 0;
454 		}
455 	} else {
456 		clk_enable(config->clk);
457 		spear_rtc_enable_interrupt(config);
458 	}
459 
460 	return 0;
461 }
462 #endif
463 
464 static SIMPLE_DEV_PM_OPS(spear_rtc_pm_ops, spear_rtc_suspend, spear_rtc_resume);
465 
466 static void spear_rtc_shutdown(struct platform_device *pdev)
467 {
468 	struct spear_rtc_config *config = platform_get_drvdata(pdev);
469 
470 	spear_rtc_disable_interrupt(config);
471 	clk_disable(config->clk);
472 }
473 
474 #ifdef CONFIG_OF
475 static const struct of_device_id spear_rtc_id_table[] = {
476 	{ .compatible = "st,spear600-rtc" },
477 	{}
478 };
479 MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
480 #endif
481 
482 static struct platform_driver spear_rtc_driver = {
483 	.probe = spear_rtc_probe,
484 	.remove = spear_rtc_remove,
485 	.shutdown = spear_rtc_shutdown,
486 	.driver = {
487 		.name = "rtc-spear",
488 		.pm = &spear_rtc_pm_ops,
489 		.of_match_table = of_match_ptr(spear_rtc_id_table),
490 	},
491 };
492 
493 module_platform_driver(spear_rtc_driver);
494 
495 MODULE_ALIAS("platform:rtc-spear");
496 MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
497 MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
498 MODULE_LICENSE("GPL");
499