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 | |
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(addr: config->ioaddr + STATUS_REG); |
92 | val |= RTC_INT_MASK; |
93 | writel(val, addr: config->ioaddr + STATUS_REG); |
94 | spin_unlock_irqrestore(lock: &config->lock, flags); |
95 | } |
96 | |
97 | static inline void spear_rtc_enable_interrupt(struct spear_rtc_config *config) |
98 | { |
99 | unsigned int val; |
100 | |
101 | val = readl(addr: config->ioaddr + CTRL_REG); |
102 | if (!(val & INT_ENABLE)) { |
103 | spear_rtc_clear_interrupt(config); |
104 | val |= INT_ENABLE; |
105 | writel(val, addr: config->ioaddr + CTRL_REG); |
106 | } |
107 | } |
108 | |
109 | static inline void spear_rtc_disable_interrupt(struct spear_rtc_config *config) |
110 | { |
111 | unsigned int val; |
112 | |
113 | val = readl(addr: config->ioaddr + CTRL_REG); |
114 | if (val & INT_ENABLE) { |
115 | val &= ~INT_ENABLE; |
116 | writel(val, addr: config->ioaddr + CTRL_REG); |
117 | } |
118 | } |
119 | |
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(addr: config->ioaddr + STATUS_REG)) & STATUS_FAIL) |
127 | ret = -EIO; |
128 | spin_unlock_irqrestore(lock: &config->lock, flags); |
129 | |
130 | return ret; |
131 | } |
132 | |
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(addr: config->ioaddr + STATUS_REG); |
142 | spin_unlock_irqrestore(lock: &config->lock, flags); |
143 | if ((status & STATUS_BUSY) == 0) |
144 | break; |
145 | /* check status busy, after each msec */ |
146 | msleep(msecs: 1); |
147 | } |
148 | } |
149 | |
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(lock: &config->lock); |
157 | irq_data = readl(addr: config->ioaddr + STATUS_REG); |
158 | spin_unlock(lock: &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(rtc: config->rtc, num: 1, events); |
164 | return IRQ_HANDLED; |
165 | } else |
166 | return IRQ_NONE; |
167 | |
168 | } |
169 | |
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 | |
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 | */ |
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(addr: config->ioaddr + TIME_REG); |
209 | date = readl(addr: config->ioaddr + DATE_REG); |
210 | } while (time == readl(addr: 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 | */ |
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(val: time, addr: config->ioaddr + TIME_REG); |
243 | writel(val: date, addr: 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 | */ |
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(addr: config->ioaddr + ALARM_TIME_REG); |
264 | date = readl(addr: 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(tm: &alm->time); |
273 | alm->enabled = readl(addr: 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 | */ |
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(tm: &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(val: time, addr: config->ioaddr + ALARM_TIME_REG); |
302 | writel(val: date, addr: 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 | |
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 | |
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(dev: &pdev->dev, size: sizeof(*config), GFP_KERNEL); |
354 | if (!config) |
355 | return -ENOMEM; |
356 | |
357 | config->rtc = devm_rtc_allocate_device(dev: &pdev->dev); |
358 | if (IS_ERR(ptr: config->rtc)) |
359 | return PTR_ERR(ptr: 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(dev: &pdev->dev, irq, handler: spear_rtc_irq, irqflags: 0, devname: pdev->name, |
367 | dev_id: 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, index: 0); |
375 | if (IS_ERR(ptr: config->ioaddr)) |
376 | return PTR_ERR(ptr: config->ioaddr); |
377 | |
378 | config->clk = devm_clk_get(dev: &pdev->dev, NULL); |
379 | if (IS_ERR(ptr: config->clk)) |
380 | return PTR_ERR(ptr: config->clk); |
381 | |
382 | status = clk_prepare_enable(clk: config->clk); |
383 | if (status < 0) |
384 | return status; |
385 | |
386 | spin_lock_init(&config->lock); |
387 | platform_set_drvdata(pdev, data: 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(dev: &pdev->dev)) |
398 | device_init_wakeup(dev: &pdev->dev, enable: 1); |
399 | |
400 | return 0; |
401 | |
402 | err_disable_clock: |
403 | clk_disable_unprepare(clk: config->clk); |
404 | |
405 | return status; |
406 | } |
407 | |
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(clk: config->clk); |
414 | device_init_wakeup(dev: &pdev->dev, enable: 0); |
415 | } |
416 | |
417 | #ifdef CONFIG_PM_SLEEP |
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(dev: &pdev->dev)) { |
426 | if (!enable_irq_wake(irq)) |
427 | config->irq_wake = 1; |
428 | } else { |
429 | spear_rtc_disable_interrupt(config); |
430 | clk_disable(clk: config->clk); |
431 | } |
432 | |
433 | return 0; |
434 | } |
435 | |
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(dev: &pdev->dev)) { |
445 | if (config->irq_wake) { |
446 | disable_irq_wake(irq); |
447 | config->irq_wake = 0; |
448 | } |
449 | } else { |
450 | clk_enable(clk: 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 | |
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(clk: 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_new = 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 | |