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<rajeev-dlh.kumar@st.com>
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
77 struct 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
spear_rtc_clear_interrupt(struct spear_rtc_config * config)85 static 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
spear_rtc_enable_interrupt(struct spear_rtc_config * config)97 static 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
spear_rtc_disable_interrupt(struct spear_rtc_config * config)109 static 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
is_write_complete(struct spear_rtc_config * config)120 static 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
rtc_wait_not_busy(struct spear_rtc_config * config)133 static 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
spear_rtc_irq(int irq,void * dev_id)150 static 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
tm2bcd(struct rtc_time * tm)170 static 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
bcd2tm(struct rtc_time * tm)180 static 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 */
spear_rtc_read_time(struct device * dev,struct rtc_time * tm)199 static 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 */
spear_rtc_set_time(struct device * dev,struct rtc_time * tm)230 static 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 */
spear_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alm)256 static 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 */
spear_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alm)286 static 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
spear_alarm_irq_enable(struct device * dev,unsigned int enabled)315 static 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
339 static 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
spear_rtc_probe(struct platform_device * pdev)347 static 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 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 config->ioaddr = devm_platform_ioremap_resource(pdev, 0);
375 if (IS_ERR(config->ioaddr))
376 return PTR_ERR(config->ioaddr);
377
378 config->clk = devm_clk_get(&pdev->dev, NULL);
379 if (IS_ERR(config->clk))
380 return PTR_ERR(config->clk);
381
382 status = clk_prepare_enable(config->clk);
383 if (status < 0)
384 return status;
385
386 spin_lock_init(&config->lock);
387 platform_set_drvdata(pdev, config);
388
389 config->rtc->ops = &spear_rtc_ops;
390 config->rtc->range_min = RTC_TIMESTAMP_BEGIN_0000;
391 config->rtc->range_max = RTC_TIMESTAMP_END_9999;
392
393 status = devm_rtc_register_device(config->rtc);
394 if (status)
395 goto err_disable_clock;
396
397 if (!device_can_wakeup(&pdev->dev))
398 device_init_wakeup(&pdev->dev, 1);
399
400 return 0;
401
402 err_disable_clock:
403 clk_disable_unprepare(config->clk);
404
405 return status;
406 }
407
spear_rtc_remove(struct platform_device * pdev)408 static void 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
417 #ifdef CONFIG_PM_SLEEP
spear_rtc_suspend(struct device * dev)418 static int spear_rtc_suspend(struct device *dev)
419 {
420 struct platform_device *pdev = to_platform_device(dev);
421 struct spear_rtc_config *config = platform_get_drvdata(pdev);
422 int irq;
423
424 irq = platform_get_irq(pdev, 0);
425 if (device_may_wakeup(&pdev->dev)) {
426 if (!enable_irq_wake(irq))
427 config->irq_wake = 1;
428 } else {
429 spear_rtc_disable_interrupt(config);
430 clk_disable(config->clk);
431 }
432
433 return 0;
434 }
435
spear_rtc_resume(struct device * dev)436 static int spear_rtc_resume(struct device *dev)
437 {
438 struct platform_device *pdev = to_platform_device(dev);
439 struct spear_rtc_config *config = platform_get_drvdata(pdev);
440 int irq;
441
442 irq = platform_get_irq(pdev, 0);
443
444 if (device_may_wakeup(&pdev->dev)) {
445 if (config->irq_wake) {
446 disable_irq_wake(irq);
447 config->irq_wake = 0;
448 }
449 } else {
450 clk_enable(config->clk);
451 spear_rtc_enable_interrupt(config);
452 }
453
454 return 0;
455 }
456 #endif
457
458 static SIMPLE_DEV_PM_OPS(spear_rtc_pm_ops, spear_rtc_suspend, spear_rtc_resume);
459
spear_rtc_shutdown(struct platform_device * pdev)460 static void spear_rtc_shutdown(struct platform_device *pdev)
461 {
462 struct spear_rtc_config *config = platform_get_drvdata(pdev);
463
464 spear_rtc_disable_interrupt(config);
465 clk_disable(config->clk);
466 }
467
468 #ifdef CONFIG_OF
469 static const struct of_device_id spear_rtc_id_table[] = {
470 { .compatible = "st,spear600-rtc" },
471 {}
472 };
473 MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
474 #endif
475
476 static struct platform_driver spear_rtc_driver = {
477 .probe = spear_rtc_probe,
478 .remove = spear_rtc_remove,
479 .shutdown = spear_rtc_shutdown,
480 .driver = {
481 .name = "rtc-spear",
482 .pm = &spear_rtc_pm_ops,
483 .of_match_table = of_match_ptr(spear_rtc_id_table),
484 },
485 };
486
487 module_platform_driver(spear_rtc_driver);
488
489 MODULE_ALIAS("platform:rtc-spear");
490 MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
491 MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
492 MODULE_LICENSE("GPL");
493