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
80struct 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
88static 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
100static 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
112static 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
123static 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
136static 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
153static 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
173static 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
183static 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 */
202static 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 */
231static 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 */
257static 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 */
287static 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
316static 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
340static 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
348static int spear_rtc_probe(struct platform_device *pdev)
349{
350	struct spear_rtc_config *config;
351	int status = 0;
352	int irq;
353
354	config = devm_kzalloc(&pdev->dev, sizeof(*config), GFP_KERNEL);
355	if (!config)
356		return -ENOMEM;
357
358	/* alarm irqs */
359	irq = platform_get_irq(pdev, 0);
360	if (irq < 0)
361		return irq;
362
363	status = devm_request_irq(&pdev->dev, irq, spear_rtc_irq, 0, pdev->name,
364			config);
365	if (status) {
366		dev_err(&pdev->dev, "Alarm interrupt IRQ%d already claimed\n",
367				irq);
368		return status;
369	}
370
371	config->ioaddr = devm_platform_ioremap_resource(pdev, 0);
372	if (IS_ERR(config->ioaddr))
373		return PTR_ERR(config->ioaddr);
374
375	config->clk = devm_clk_get(&pdev->dev, NULL);
376	if (IS_ERR(config->clk))
377		return PTR_ERR(config->clk);
378
379	status = clk_prepare_enable(config->clk);
380	if (status < 0)
381		return status;
382
383	spin_lock_init(&config->lock);
384	platform_set_drvdata(pdev, config);
385
386	config->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
387					&spear_rtc_ops, THIS_MODULE);
388	if (IS_ERR(config->rtc)) {
389		dev_err(&pdev->dev, "can't register RTC device, err %ld\n",
390				PTR_ERR(config->rtc));
391		status = PTR_ERR(config->rtc);
392		goto err_disable_clock;
393	}
394
395	config->rtc->uie_unsupported = 1;
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 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
420static 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
438static 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
460static SIMPLE_DEV_PM_OPS(spear_rtc_pm_ops, spear_rtc_suspend, spear_rtc_resume);
461
462static 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
471static const struct of_device_id spear_rtc_id_table[] = {
472	{ .compatible = "st,spear600-rtc" },
473	{}
474};
475MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
476#endif
477
478static 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
489module_platform_driver(spear_rtc_driver);
490
491MODULE_ALIAS("platform:rtc-spear");
492MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
493MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
494MODULE_LICENSE("GPL");
495