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 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
187static 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 */
206static 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 */
235static 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 */
262static 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 */
292static 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
322static 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
346static 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
354static int 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
367	config = devm_kzalloc(&pdev->dev, sizeof(*config), GFP_KERNEL);
368	if (!config)
369		return -ENOMEM;
370
371	/* alarm irqs */
372	irq = platform_get_irq(pdev, 0);
373	if (irq < 0) {
374		dev_err(&pdev->dev, "no update irq?\n");
375		return irq;
376	}
377
378	status = devm_request_irq(&pdev->dev, irq, spear_rtc_irq, 0, pdev->name,
379			config);
380	if (status) {
381		dev_err(&pdev->dev, "Alarm interrupt IRQ%d already claimed\n",
382				irq);
383		return status;
384	}
385
386	config->ioaddr = devm_ioremap_resource(&pdev->dev, res);
387	if (IS_ERR(config->ioaddr))
388		return PTR_ERR(config->ioaddr);
389
390	config->clk = devm_clk_get(&pdev->dev, NULL);
391	if (IS_ERR(config->clk))
392		return PTR_ERR(config->clk);
393
394	status = clk_prepare_enable(config->clk);
395	if (status < 0)
396		return status;
397
398	spin_lock_init(&config->lock);
399	platform_set_drvdata(pdev, config);
400
401	config->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
402					&spear_rtc_ops, THIS_MODULE);
403	if (IS_ERR(config->rtc)) {
404		dev_err(&pdev->dev, "can't register RTC device, err %ld\n",
405				PTR_ERR(config->rtc));
406		status = PTR_ERR(config->rtc);
407		goto err_disable_clock;
408	}
409
410	config->rtc->uie_unsupported = 1;
411
412	if (!device_can_wakeup(&pdev->dev))
413		device_init_wakeup(&pdev->dev, 1);
414
415	return 0;
416
417err_disable_clock:
418	clk_disable_unprepare(config->clk);
419
420	return status;
421}
422
423static int spear_rtc_remove(struct platform_device *pdev)
424{
425	struct spear_rtc_config *config = platform_get_drvdata(pdev);
426
427	spear_rtc_disable_interrupt(config);
428	clk_disable_unprepare(config->clk);
429	device_init_wakeup(&pdev->dev, 0);
430
431	return 0;
432}
433
434#ifdef CONFIG_PM_SLEEP
435static int spear_rtc_suspend(struct device *dev)
436{
437	struct platform_device *pdev = to_platform_device(dev);
438	struct spear_rtc_config *config = platform_get_drvdata(pdev);
439	int irq;
440
441	irq = platform_get_irq(pdev, 0);
442	if (device_may_wakeup(&pdev->dev)) {
443		if (!enable_irq_wake(irq))
444			config->irq_wake = 1;
445	} else {
446		spear_rtc_disable_interrupt(config);
447		clk_disable(config->clk);
448	}
449
450	return 0;
451}
452
453static int spear_rtc_resume(struct device *dev)
454{
455	struct platform_device *pdev = to_platform_device(dev);
456	struct spear_rtc_config *config = platform_get_drvdata(pdev);
457	int irq;
458
459	irq = platform_get_irq(pdev, 0);
460
461	if (device_may_wakeup(&pdev->dev)) {
462		if (config->irq_wake) {
463			disable_irq_wake(irq);
464			config->irq_wake = 0;
465		}
466	} else {
467		clk_enable(config->clk);
468		spear_rtc_enable_interrupt(config);
469	}
470
471	return 0;
472}
473#endif
474
475static SIMPLE_DEV_PM_OPS(spear_rtc_pm_ops, spear_rtc_suspend, spear_rtc_resume);
476
477static void spear_rtc_shutdown(struct platform_device *pdev)
478{
479	struct spear_rtc_config *config = platform_get_drvdata(pdev);
480
481	spear_rtc_disable_interrupt(config);
482	clk_disable(config->clk);
483}
484
485#ifdef CONFIG_OF
486static const struct of_device_id spear_rtc_id_table[] = {
487	{ .compatible = "st,spear600-rtc" },
488	{}
489};
490MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
491#endif
492
493static struct platform_driver spear_rtc_driver = {
494	.probe = spear_rtc_probe,
495	.remove = spear_rtc_remove,
496	.shutdown = spear_rtc_shutdown,
497	.driver = {
498		.name = "rtc-spear",
499		.pm = &spear_rtc_pm_ops,
500		.of_match_table = of_match_ptr(spear_rtc_id_table),
501	},
502};
503
504module_platform_driver(spear_rtc_driver);
505
506MODULE_ALIAS("platform:rtc-spear");
507MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
508MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
509MODULE_LICENSE("GPL");
510