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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<[email protected]>
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
77struct 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
85static 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
97static 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
109static 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
120static 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
133static 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
150static 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
170static 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
180static 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 */
199static 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 */
230static 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 */
256static 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 */
286static 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
315static 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
339static 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
347static 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 config->ioaddr = devm_platform_ioremap_resource(pdev, 0);
367 if (IS_ERR(config->ioaddr))
368 return PTR_ERR(config->ioaddr);
369
370 spin_lock_init(&config->lock);
371
372 status = devm_request_irq(&pdev->dev, irq, spear_rtc_irq, 0, pdev->name,
373 config);
374 if (status) {
375 dev_err(&pdev->dev, "Alarm interrupt IRQ%d already claimed\n",
376 irq);
377 return status;
378 }
379
380 config->clk = devm_clk_get(&pdev->dev, NULL);
381 if (IS_ERR(config->clk))
382 return PTR_ERR(config->clk);
383
384 status = clk_prepare_enable(config->clk);
385 if (status < 0)
386 return status;
387
388 platform_set_drvdata(pdev, config);
389
390 config->rtc->ops = &spear_rtc_ops;
391 config->rtc->range_min = RTC_TIMESTAMP_BEGIN_0000;
392 config->rtc->range_max = RTC_TIMESTAMP_END_9999;
393
394 status = devm_rtc_register_device(config->rtc);
395 if (status)
396 goto err_disable_clock;
397
398 if (!device_can_wakeup(&pdev->dev))
399 device_init_wakeup(&pdev->dev, true);
400
401 return 0;
402
403err_disable_clock:
404 clk_disable_unprepare(config->clk);
405
406 return status;
407}
408
409static void spear_rtc_remove(struct platform_device *pdev)
410{
411 struct spear_rtc_config *config = platform_get_drvdata(pdev);
412
413 spear_rtc_disable_interrupt(config);
414 clk_disable_unprepare(config->clk);
415 device_init_wakeup(&pdev->dev, false);
416}
417
418#ifdef CONFIG_PM_SLEEP
419static int spear_rtc_suspend(struct device *dev)
420{
421 struct platform_device *pdev = to_platform_device(dev);
422 struct spear_rtc_config *config = platform_get_drvdata(pdev);
423 int irq;
424
425 irq = platform_get_irq(pdev, 0);
426 if (device_may_wakeup(&pdev->dev)) {
427 if (!enable_irq_wake(irq))
428 config->irq_wake = 1;
429 } else {
430 spear_rtc_disable_interrupt(config);
431 clk_disable(config->clk);
432 }
433
434 return 0;
435}
436
437static int spear_rtc_resume(struct device *dev)
438{
439 struct platform_device *pdev = to_platform_device(dev);
440 struct spear_rtc_config *config = platform_get_drvdata(pdev);
441 int irq;
442
443 irq = platform_get_irq(pdev, 0);
444
445 if (device_may_wakeup(&pdev->dev)) {
446 if (config->irq_wake) {
447 disable_irq_wake(irq);
448 config->irq_wake = 0;
449 }
450 } else {
451 clk_enable(config->clk);
452 spear_rtc_enable_interrupt(config);
453 }
454
455 return 0;
456}
457#endif
458
459static SIMPLE_DEV_PM_OPS(spear_rtc_pm_ops, spear_rtc_suspend, spear_rtc_resume);
460
461static void spear_rtc_shutdown(struct platform_device *pdev)
462{
463 struct spear_rtc_config *config = platform_get_drvdata(pdev);
464
465 spear_rtc_disable_interrupt(config);
466 clk_disable(config->clk);
467}
468
469#ifdef CONFIG_OF
470static const struct of_device_id spear_rtc_id_table[] = {
471 { .compatible = "st,spear600-rtc" },
472 {}
473};
474MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
475#endif
476
477static struct platform_driver spear_rtc_driver = {
478 .probe = spear_rtc_probe,
479 .remove = spear_rtc_remove,
480 .shutdown = spear_rtc_shutdown,
481 .driver = {
482 .name = "rtc-spear",
483 .pm = &spear_rtc_pm_ops,
484 .of_match_table = of_match_ptr(spear_rtc_id_table),
485 },
486};
487
488module_platform_driver(spear_rtc_driver);
489
490MODULE_ALIAS("platform:rtc-spear");
491MODULE_AUTHOR("Rajeev Kumar <[email protected]>");
492MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
493MODULE_LICENSE("GPL");