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10#include <linux/clk.h>
11#include <linux/interrupt.h>
12#include <linux/ioctl.h>
13#include <linux/io.h>
14#include <linux/kernel.h>
15#include <linux/mfd/syscon.h>
16#include <linux/module.h>
17#include <linux/of.h>
18#include <linux/platform_device.h>
19#include <linux/regmap.h>
20#include <linux/rtc.h>
21#include <linux/slab.h>
22#include <linux/suspend.h>
23#include <linux/time.h>
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45
46#define AT91_RTT_MR 0x00
47#define AT91_RTT_RTPRES (0xffff << 0)
48#define AT91_RTT_ALMIEN BIT(16)
49#define AT91_RTT_RTTINCIEN BIT(17)
50#define AT91_RTT_RTTRST BIT(18)
51
52#define AT91_RTT_AR 0x04
53#define AT91_RTT_ALMV (0xffffffff)
54
55#define AT91_RTT_VR 0x08
56#define AT91_RTT_CRTV (0xffffffff)
57
58#define AT91_RTT_SR 0x0c
59#define AT91_RTT_ALMS BIT(0)
60#define AT91_RTT_RTTINC BIT(1)
61
62
63
64
65
66#define ALARM_DISABLED ((u32)~0)
67
68struct sam9_rtc {
69 void __iomem *rtt;
70 struct rtc_device *rtcdev;
71 u32 imr;
72 struct regmap *gpbr;
73 unsigned int gpbr_offset;
74 int irq;
75 struct clk *sclk;
76 bool suspended;
77 unsigned long events;
78 spinlock_t lock;
79};
80
81#define rtt_readl(rtc, field) \
82 readl((rtc)->rtt + AT91_RTT_ ## field)
83#define rtt_writel(rtc, field, val) \
84 writel((val), (rtc)->rtt + AT91_RTT_ ## field)
85
86static inline unsigned int gpbr_readl(struct sam9_rtc *rtc)
87{
88 unsigned int val;
89
90 regmap_read(rtc->gpbr, rtc->gpbr_offset, &val);
91
92 return val;
93}
94
95static inline void gpbr_writel(struct sam9_rtc *rtc, unsigned int val)
96{
97 regmap_write(rtc->gpbr, rtc->gpbr_offset, val);
98}
99
100
101
102
103static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
104{
105 struct sam9_rtc *rtc = dev_get_drvdata(dev);
106 u32 secs, secs2;
107 u32 offset;
108
109
110 offset = gpbr_readl(rtc);
111 if (offset == 0)
112 return -EILSEQ;
113
114
115 secs = rtt_readl(rtc, VR);
116 secs2 = rtt_readl(rtc, VR);
117 if (secs != secs2)
118 secs = rtt_readl(rtc, VR);
119
120 rtc_time64_to_tm(offset + secs, tm);
121
122 dev_dbg(dev, "%s: %ptR\n", __func__, tm);
123
124 return 0;
125}
126
127
128
129
130static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
131{
132 struct sam9_rtc *rtc = dev_get_drvdata(dev);
133 u32 offset, alarm, mr;
134 unsigned long secs;
135
136 dev_dbg(dev, "%s: %ptR\n", __func__, tm);
137
138 secs = rtc_tm_to_time64(tm);
139
140 mr = rtt_readl(rtc, MR);
141
142
143 rtt_writel(rtc, MR, mr & ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN));
144
145
146 offset = gpbr_readl(rtc);
147
148
149 secs += 1;
150 gpbr_writel(rtc, secs);
151
152
153 alarm = rtt_readl(rtc, AR);
154 if (alarm != ALARM_DISABLED) {
155 if (offset > secs) {
156
157 alarm += (offset - secs);
158 } else if ((alarm + offset) > secs) {
159
160 alarm -= (secs - offset);
161 } else {
162
163 alarm = ALARM_DISABLED;
164 mr &= ~AT91_RTT_ALMIEN;
165 }
166 rtt_writel(rtc, AR, alarm);
167 }
168
169
170 rtt_writel(rtc, MR, mr | AT91_RTT_RTTRST);
171
172 return 0;
173}
174
175static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
176{
177 struct sam9_rtc *rtc = dev_get_drvdata(dev);
178 struct rtc_time *tm = &alrm->time;
179 u32 alarm = rtt_readl(rtc, AR);
180 u32 offset;
181
182 offset = gpbr_readl(rtc);
183 if (offset == 0)
184 return -EILSEQ;
185
186 memset(alrm, 0, sizeof(*alrm));
187 if (alarm != ALARM_DISABLED && offset != 0) {
188 rtc_time64_to_tm(offset + alarm, tm);
189
190 dev_dbg(dev, "%s: %ptR\n", __func__, tm);
191
192 if (rtt_readl(rtc, MR) & AT91_RTT_ALMIEN)
193 alrm->enabled = 1;
194 }
195
196 return 0;
197}
198
199static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
200{
201 struct sam9_rtc *rtc = dev_get_drvdata(dev);
202 struct rtc_time *tm = &alrm->time;
203 unsigned long secs;
204 u32 offset;
205 u32 mr;
206
207 secs = rtc_tm_to_time64(tm);
208
209 offset = gpbr_readl(rtc);
210 if (offset == 0) {
211
212 return -EILSEQ;
213 }
214 mr = rtt_readl(rtc, MR);
215 rtt_writel(rtc, MR, mr & ~AT91_RTT_ALMIEN);
216
217
218 if (secs <= offset) {
219 rtt_writel(rtc, AR, ALARM_DISABLED);
220 return 0;
221 }
222
223
224 rtt_writel(rtc, AR, secs - offset);
225 if (alrm->enabled)
226 rtt_writel(rtc, MR, mr | AT91_RTT_ALMIEN);
227
228 dev_dbg(dev, "%s: %ptR\n", __func__, tm);
229
230 return 0;
231}
232
233static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
234{
235 struct sam9_rtc *rtc = dev_get_drvdata(dev);
236 u32 mr = rtt_readl(rtc, MR);
237
238 dev_dbg(dev, "alarm_irq_enable: enabled=%08x, mr %08x\n", enabled, mr);
239 if (enabled)
240 rtt_writel(rtc, MR, mr | AT91_RTT_ALMIEN);
241 else
242 rtt_writel(rtc, MR, mr & ~AT91_RTT_ALMIEN);
243 return 0;
244}
245
246
247
248
249static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
250{
251 struct sam9_rtc *rtc = dev_get_drvdata(dev);
252 u32 mr = rtt_readl(rtc, MR);
253
254 seq_printf(seq, "update_IRQ\t: %s\n",
255 (mr & AT91_RTT_RTTINCIEN) ? "yes" : "no");
256 return 0;
257}
258
259static irqreturn_t at91_rtc_cache_events(struct sam9_rtc *rtc)
260{
261 u32 sr, mr;
262
263
264
265
266 mr = rtt_readl(rtc, MR) & (AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN);
267 sr = rtt_readl(rtc, SR) & (mr >> 16);
268 if (!sr)
269 return IRQ_NONE;
270
271
272 if (sr & AT91_RTT_ALMS)
273 rtc->events |= (RTC_AF | RTC_IRQF);
274
275
276 if (sr & AT91_RTT_RTTINC)
277 rtc->events |= (RTC_UF | RTC_IRQF);
278
279 return IRQ_HANDLED;
280}
281
282static void at91_rtc_flush_events(struct sam9_rtc *rtc)
283{
284 if (!rtc->events)
285 return;
286
287 rtc_update_irq(rtc->rtcdev, 1, rtc->events);
288 rtc->events = 0;
289
290 pr_debug("%s: num=%ld, events=0x%02lx\n", __func__,
291 rtc->events >> 8, rtc->events & 0x000000FF);
292}
293
294
295
296
297static irqreturn_t at91_rtc_interrupt(int irq, void *_rtc)
298{
299 struct sam9_rtc *rtc = _rtc;
300 int ret;
301
302 spin_lock(&rtc->lock);
303
304 ret = at91_rtc_cache_events(rtc);
305
306
307 if (rtc->suspended) {
308
309 rtt_writel(rtc, MR,
310 rtt_readl(rtc, MR) &
311 ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN));
312
313 pm_system_wakeup();
314 } else {
315 at91_rtc_flush_events(rtc);
316 }
317
318 spin_unlock(&rtc->lock);
319
320 return ret;
321}
322
323static const struct rtc_class_ops at91_rtc_ops = {
324 .read_time = at91_rtc_readtime,
325 .set_time = at91_rtc_settime,
326 .read_alarm = at91_rtc_readalarm,
327 .set_alarm = at91_rtc_setalarm,
328 .proc = at91_rtc_proc,
329 .alarm_irq_enable = at91_rtc_alarm_irq_enable,
330};
331
332
333
334
335static int at91_rtc_probe(struct platform_device *pdev)
336{
337 struct resource *r;
338 struct sam9_rtc *rtc;
339 int ret, irq;
340 u32 mr;
341 unsigned int sclk_rate;
342 struct of_phandle_args args;
343
344 irq = platform_get_irq(pdev, 0);
345 if (irq < 0) {
346 dev_err(&pdev->dev, "failed to get interrupt resource\n");
347 return irq;
348 }
349
350 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
351 if (!rtc)
352 return -ENOMEM;
353
354 spin_lock_init(&rtc->lock);
355 rtc->irq = irq;
356
357
358 if (!device_can_wakeup(&pdev->dev))
359 device_init_wakeup(&pdev->dev, 1);
360
361 platform_set_drvdata(pdev, rtc);
362
363 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
364 rtc->rtt = devm_ioremap_resource(&pdev->dev, r);
365 if (IS_ERR(rtc->rtt))
366 return PTR_ERR(rtc->rtt);
367
368 ret = of_parse_phandle_with_fixed_args(pdev->dev.of_node,
369 "atmel,rtt-rtc-time-reg", 1, 0,
370 &args);
371 if (ret)
372 return ret;
373
374 rtc->gpbr = syscon_node_to_regmap(args.np);
375 rtc->gpbr_offset = args.args[0];
376 if (IS_ERR(rtc->gpbr)) {
377 dev_err(&pdev->dev, "failed to retrieve gpbr regmap, aborting.\n");
378 return -ENOMEM;
379 }
380
381 rtc->sclk = devm_clk_get(&pdev->dev, NULL);
382 if (IS_ERR(rtc->sclk))
383 return PTR_ERR(rtc->sclk);
384
385 ret = clk_prepare_enable(rtc->sclk);
386 if (ret) {
387 dev_err(&pdev->dev, "Could not enable slow clock\n");
388 return ret;
389 }
390
391 sclk_rate = clk_get_rate(rtc->sclk);
392 if (!sclk_rate || sclk_rate > AT91_RTT_RTPRES) {
393 dev_err(&pdev->dev, "Invalid slow clock rate\n");
394 ret = -EINVAL;
395 goto err_clk;
396 }
397
398 mr = rtt_readl(rtc, MR);
399
400
401 if ((mr & AT91_RTT_RTPRES) != sclk_rate) {
402 mr = AT91_RTT_RTTRST | (sclk_rate & AT91_RTT_RTPRES);
403 gpbr_writel(rtc, 0);
404 }
405
406
407 mr &= ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN);
408 rtt_writel(rtc, MR, mr);
409
410 rtc->rtcdev = devm_rtc_allocate_device(&pdev->dev);
411 if (IS_ERR(rtc->rtcdev)) {
412 ret = PTR_ERR(rtc->rtcdev);
413 goto err_clk;
414 }
415
416 rtc->rtcdev->ops = &at91_rtc_ops;
417 rtc->rtcdev->range_max = U32_MAX;
418
419
420 ret = devm_request_irq(&pdev->dev, rtc->irq, at91_rtc_interrupt,
421 IRQF_SHARED | IRQF_COND_SUSPEND,
422 dev_name(&rtc->rtcdev->dev), rtc);
423 if (ret) {
424 dev_dbg(&pdev->dev, "can't share IRQ %d?\n", rtc->irq);
425 goto err_clk;
426 }
427
428
429
430
431
432
433
434 if (gpbr_readl(rtc) == 0)
435 dev_warn(&pdev->dev, "%s: SET TIME!\n",
436 dev_name(&rtc->rtcdev->dev));
437
438 return rtc_register_device(rtc->rtcdev);
439
440err_clk:
441 clk_disable_unprepare(rtc->sclk);
442
443 return ret;
444}
445
446
447
448
449static int at91_rtc_remove(struct platform_device *pdev)
450{
451 struct sam9_rtc *rtc = platform_get_drvdata(pdev);
452 u32 mr = rtt_readl(rtc, MR);
453
454
455 rtt_writel(rtc, MR, mr & ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN));
456
457 clk_disable_unprepare(rtc->sclk);
458
459 return 0;
460}
461
462static void at91_rtc_shutdown(struct platform_device *pdev)
463{
464 struct sam9_rtc *rtc = platform_get_drvdata(pdev);
465 u32 mr = rtt_readl(rtc, MR);
466
467 rtc->imr = mr & (AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN);
468 rtt_writel(rtc, MR, mr & ~rtc->imr);
469}
470
471#ifdef CONFIG_PM_SLEEP
472
473
474
475static int at91_rtc_suspend(struct device *dev)
476{
477 struct sam9_rtc *rtc = dev_get_drvdata(dev);
478 u32 mr = rtt_readl(rtc, MR);
479
480
481
482
483
484 rtc->imr = mr & (AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN);
485 if (rtc->imr) {
486 if (device_may_wakeup(dev) && (mr & AT91_RTT_ALMIEN)) {
487 unsigned long flags;
488
489 enable_irq_wake(rtc->irq);
490 spin_lock_irqsave(&rtc->lock, flags);
491 rtc->suspended = true;
492 spin_unlock_irqrestore(&rtc->lock, flags);
493
494 if (mr & AT91_RTT_RTTINCIEN)
495 rtt_writel(rtc, MR, mr & ~AT91_RTT_RTTINCIEN);
496 } else {
497 rtt_writel(rtc, MR, mr & ~rtc->imr);
498 }
499 }
500
501 return 0;
502}
503
504static int at91_rtc_resume(struct device *dev)
505{
506 struct sam9_rtc *rtc = dev_get_drvdata(dev);
507 u32 mr;
508
509 if (rtc->imr) {
510 unsigned long flags;
511
512 if (device_may_wakeup(dev))
513 disable_irq_wake(rtc->irq);
514 mr = rtt_readl(rtc, MR);
515 rtt_writel(rtc, MR, mr | rtc->imr);
516
517 spin_lock_irqsave(&rtc->lock, flags);
518 rtc->suspended = false;
519 at91_rtc_cache_events(rtc);
520 at91_rtc_flush_events(rtc);
521 spin_unlock_irqrestore(&rtc->lock, flags);
522 }
523
524 return 0;
525}
526#endif
527
528static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
529
530static const struct of_device_id at91_rtc_dt_ids[] = {
531 { .compatible = "atmel,at91sam9260-rtt" },
532 { }
533};
534MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
535
536static struct platform_driver at91_rtc_driver = {
537 .probe = at91_rtc_probe,
538 .remove = at91_rtc_remove,
539 .shutdown = at91_rtc_shutdown,
540 .driver = {
541 .name = "rtc-at91sam9",
542 .pm = &at91_rtc_pm_ops,
543 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
544 },
545};
546
547module_platform_driver(at91_rtc_driver);
548
549MODULE_AUTHOR("Michel Benoit");
550MODULE_DESCRIPTION("RTC driver for Atmel AT91SAM9x");
551MODULE_LICENSE("GPL");
552