xref: /linux/drivers/rtc/rtc-ti-k3.c (revision 3c4fc7bf4c9e66fe71abcbf93f62f4ddb89b7f15)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Texas Instruments K3 RTC driver
4  *
5  * Copyright (C) 2021-2022 Texas Instruments Incorporated - https://www.ti.com/
6  */
7 
8 #include <linux/clk.h>
9 #include <linux/delay.h>
10 #include <linux/mod_devicetable.h>
11 #include <linux/module.h>
12 #include <linux/of_device.h>
13 #include <linux/platform_device.h>
14 #include <linux/property.h>
15 #include <linux/regmap.h>
16 #include <linux/rtc.h>
17 
18 /* Registers */
19 #define REG_K3RTC_S_CNT_LSW		0x08
20 #define REG_K3RTC_S_CNT_MSW		0x0c
21 #define REG_K3RTC_COMP			0x10
22 #define REG_K3RTC_ON_OFF_S_CNT_LSW	0x20
23 #define REG_K3RTC_ON_OFF_S_CNT_MSW	0x24
24 #define REG_K3RTC_SCRATCH0		0x30
25 #define REG_K3RTC_SCRATCH7		0x4c
26 #define REG_K3RTC_GENERAL_CTL		0x50
27 #define REG_K3RTC_IRQSTATUS_RAW_SYS	0x54
28 #define REG_K3RTC_IRQSTATUS_SYS		0x58
29 #define REG_K3RTC_IRQENABLE_SET_SYS	0x5c
30 #define REG_K3RTC_IRQENABLE_CLR_SYS	0x60
31 #define REG_K3RTC_SYNCPEND		0x68
32 #define REG_K3RTC_KICK0			0x70
33 #define REG_K3RTC_KICK1			0x74
34 
35 /* Freeze when lsw is read and unfreeze when msw is read */
36 #define K3RTC_CNT_FMODE_S_CNT_VALUE	(0x2 << 24)
37 
38 /* Magic values for lock/unlock */
39 #define K3RTC_KICK0_UNLOCK_VALUE	0x83e70b13
40 #define K3RTC_KICK1_UNLOCK_VALUE	0x95a4f1e0
41 
42 /* Multiplier for ppb conversions */
43 #define K3RTC_PPB_MULT			(1000000000LL)
44 /* Min and max values supported with 'offset' interface (swapped sign) */
45 #define K3RTC_MIN_OFFSET		(-277761)
46 #define K3RTC_MAX_OFFSET		(277778)
47 
48 /**
49  * struct ti_k3_rtc_soc_data - Private of compatible data for ti-k3-rtc
50  * @unlock_irq_erratum:	Has erratum for unlock infinite IRQs (erratum i2327)
51  */
52 struct ti_k3_rtc_soc_data {
53 	const bool unlock_irq_erratum;
54 };
55 
56 static const struct regmap_config ti_k3_rtc_regmap_config = {
57 	.name = "peripheral-registers",
58 	.reg_bits = 32,
59 	.val_bits = 32,
60 	.reg_stride = 4,
61 	.max_register = REG_K3RTC_KICK1,
62 };
63 
64 enum ti_k3_rtc_fields {
65 	K3RTC_KICK0,
66 	K3RTC_KICK1,
67 	K3RTC_S_CNT_LSW,
68 	K3RTC_S_CNT_MSW,
69 	K3RTC_O32K_OSC_DEP_EN,
70 	K3RTC_UNLOCK,
71 	K3RTC_CNT_FMODE,
72 	K3RTC_PEND,
73 	K3RTC_RELOAD_FROM_BBD,
74 	K3RTC_COMP,
75 
76 	K3RTC_ALM_S_CNT_LSW,
77 	K3RTC_ALM_S_CNT_MSW,
78 	K3RTC_IRQ_STATUS_RAW,
79 	K3RTC_IRQ_STATUS,
80 	K3RTC_IRQ_ENABLE_SET,
81 	K3RTC_IRQ_ENABLE_CLR,
82 
83 	K3RTC_IRQ_STATUS_ALT,
84 	K3RTC_IRQ_ENABLE_CLR_ALT,
85 
86 	K3_RTC_MAX_FIELDS
87 };
88 
89 static const struct reg_field ti_rtc_reg_fields[] = {
90 	[K3RTC_KICK0] = REG_FIELD(REG_K3RTC_KICK0, 0, 31),
91 	[K3RTC_KICK1] = REG_FIELD(REG_K3RTC_KICK1, 0, 31),
92 	[K3RTC_S_CNT_LSW] = REG_FIELD(REG_K3RTC_S_CNT_LSW, 0, 31),
93 	[K3RTC_S_CNT_MSW] = REG_FIELD(REG_K3RTC_S_CNT_MSW, 0, 15),
94 	[K3RTC_O32K_OSC_DEP_EN] = REG_FIELD(REG_K3RTC_GENERAL_CTL, 21, 21),
95 	[K3RTC_UNLOCK] = REG_FIELD(REG_K3RTC_GENERAL_CTL, 23, 23),
96 	[K3RTC_CNT_FMODE] = REG_FIELD(REG_K3RTC_GENERAL_CTL, 24, 25),
97 	[K3RTC_PEND] = REG_FIELD(REG_K3RTC_SYNCPEND, 0, 1),
98 	[K3RTC_RELOAD_FROM_BBD] = REG_FIELD(REG_K3RTC_SYNCPEND, 31, 31),
99 	[K3RTC_COMP] = REG_FIELD(REG_K3RTC_COMP, 0, 31),
100 
101 	/* We use on to off as alarm trigger */
102 	[K3RTC_ALM_S_CNT_LSW] = REG_FIELD(REG_K3RTC_ON_OFF_S_CNT_LSW, 0, 31),
103 	[K3RTC_ALM_S_CNT_MSW] = REG_FIELD(REG_K3RTC_ON_OFF_S_CNT_MSW, 0, 15),
104 	[K3RTC_IRQ_STATUS_RAW] = REG_FIELD(REG_K3RTC_IRQSTATUS_RAW_SYS, 0, 0),
105 	[K3RTC_IRQ_STATUS] = REG_FIELD(REG_K3RTC_IRQSTATUS_SYS, 0, 0),
106 	[K3RTC_IRQ_ENABLE_SET] = REG_FIELD(REG_K3RTC_IRQENABLE_SET_SYS, 0, 0),
107 	[K3RTC_IRQ_ENABLE_CLR] = REG_FIELD(REG_K3RTC_IRQENABLE_CLR_SYS, 0, 0),
108 	/* Off to on is alternate */
109 	[K3RTC_IRQ_STATUS_ALT] = REG_FIELD(REG_K3RTC_IRQSTATUS_SYS, 1, 1),
110 	[K3RTC_IRQ_ENABLE_CLR_ALT] = REG_FIELD(REG_K3RTC_IRQENABLE_CLR_SYS, 1, 1),
111 };
112 
113 /**
114  * struct ti_k3_rtc - Private data for ti-k3-rtc
115  * @irq:		IRQ
116  * @sync_timeout_us:	data sync timeout period in uSec
117  * @rate_32k:		32k clock rate in Hz
118  * @rtc_dev:		rtc device
119  * @regmap:		rtc mmio regmap
120  * @r_fields:		rtc register fields
121  * @soc:		SoC compatible match data
122  */
123 struct ti_k3_rtc {
124 	unsigned int irq;
125 	u32 sync_timeout_us;
126 	unsigned long rate_32k;
127 	struct rtc_device *rtc_dev;
128 	struct regmap *regmap;
129 	struct regmap_field *r_fields[K3_RTC_MAX_FIELDS];
130 	const struct ti_k3_rtc_soc_data *soc;
131 };
132 
133 static int k3rtc_field_read(struct ti_k3_rtc *priv, enum ti_k3_rtc_fields f)
134 {
135 	int ret;
136 	int val;
137 
138 	ret = regmap_field_read(priv->r_fields[f], &val);
139 	/*
140 	 * We shouldn't be seeing regmap fail on us for mmio reads
141 	 * This is possible if clock context fails, but that isn't the case for us
142 	 */
143 	if (WARN_ON_ONCE(ret))
144 		return ret;
145 	return val;
146 }
147 
148 static void k3rtc_field_write(struct ti_k3_rtc *priv, enum ti_k3_rtc_fields f, u32 val)
149 {
150 	regmap_field_write(priv->r_fields[f], val);
151 }
152 
153 /**
154  * k3rtc_fence  - Ensure a register sync took place between the two domains
155  * @priv:      pointer to priv data
156  *
157  * Return: 0 if the sync took place, else returns -ETIMEDOUT
158  */
159 static int k3rtc_fence(struct ti_k3_rtc *priv)
160 {
161 	int ret;
162 
163 	ret = regmap_field_read_poll_timeout(priv->r_fields[K3RTC_PEND], ret,
164 					     !ret, 2, priv->sync_timeout_us);
165 
166 	return ret;
167 }
168 
169 static inline int k3rtc_check_unlocked(struct ti_k3_rtc *priv)
170 {
171 	int ret;
172 
173 	ret = k3rtc_field_read(priv, K3RTC_UNLOCK);
174 	if (ret < 0)
175 		return ret;
176 
177 	return (ret) ? 0 : 1;
178 }
179 
180 static int k3rtc_unlock_rtc(struct ti_k3_rtc *priv)
181 {
182 	int ret;
183 
184 	ret = k3rtc_check_unlocked(priv);
185 	if (!ret)
186 		return ret;
187 
188 	k3rtc_field_write(priv, K3RTC_KICK0, K3RTC_KICK0_UNLOCK_VALUE);
189 	k3rtc_field_write(priv, K3RTC_KICK1, K3RTC_KICK1_UNLOCK_VALUE);
190 
191 	/* Skip fence since we are going to check the unlock bit as fence */
192 	ret = regmap_field_read_poll_timeout(priv->r_fields[K3RTC_UNLOCK], ret,
193 					     !ret, 2, priv->sync_timeout_us);
194 
195 	return ret;
196 }
197 
198 static int k3rtc_configure(struct device *dev)
199 {
200 	int ret;
201 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
202 
203 	/*
204 	 * HWBUG: The compare state machine is broken if the RTC module
205 	 * is NOT unlocked in under one second of boot - which is pretty long
206 	 * time from the perspective of Linux driver (module load, u-boot
207 	 * shell all can take much longer than this.
208 	 *
209 	 * In such occurrence, it is assumed that the RTC module is unusable
210 	 */
211 	if (priv->soc->unlock_irq_erratum) {
212 		ret = k3rtc_check_unlocked(priv);
213 		/* If there is an error OR if we are locked, return error */
214 		if (ret) {
215 			dev_err(dev,
216 				HW_ERR "Erratum i2327 unlock QUIRK! Cannot operate!!\n");
217 			return -EFAULT;
218 		}
219 	} else {
220 		/* May need to explicitly unlock first time */
221 		ret = k3rtc_unlock_rtc(priv);
222 		if (ret) {
223 			dev_err(dev, "Failed to unlock(%d)!\n", ret);
224 			return ret;
225 		}
226 	}
227 
228 	/* Enable Shadow register sync on 32k clock boundary */
229 	k3rtc_field_write(priv, K3RTC_O32K_OSC_DEP_EN, 0x1);
230 
231 	/*
232 	 * Wait at least clock sync time before proceeding further programming.
233 	 * This ensures that the 32k based sync is active.
234 	 */
235 	usleep_range(priv->sync_timeout_us, priv->sync_timeout_us + 5);
236 
237 	/* We need to ensure fence here to make sure sync here */
238 	ret = k3rtc_fence(priv);
239 	if (ret) {
240 		dev_err(dev,
241 			"Failed fence osc_dep enable(%d) - is 32k clk working?!\n", ret);
242 		return ret;
243 	}
244 
245 	/*
246 	 * FMODE setting: Reading lower seconds will freeze value on higher
247 	 * seconds. This also implies that we must *ALWAYS* read lower seconds
248 	 * prior to reading higher seconds
249 	 */
250 	k3rtc_field_write(priv, K3RTC_CNT_FMODE, K3RTC_CNT_FMODE_S_CNT_VALUE);
251 
252 	/* Clear any spurious IRQ sources if any */
253 	k3rtc_field_write(priv, K3RTC_IRQ_STATUS_ALT, 0x1);
254 	k3rtc_field_write(priv, K3RTC_IRQ_STATUS, 0x1);
255 	/* Disable all IRQs */
256 	k3rtc_field_write(priv, K3RTC_IRQ_ENABLE_CLR_ALT, 0x1);
257 	k3rtc_field_write(priv, K3RTC_IRQ_ENABLE_CLR, 0x1);
258 
259 	/* And.. Let us Sync the writes in */
260 	return k3rtc_fence(priv);
261 }
262 
263 static int ti_k3_rtc_read_time(struct device *dev, struct rtc_time *tm)
264 {
265 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
266 	u32 seconds_lo, seconds_hi;
267 
268 	seconds_lo = k3rtc_field_read(priv, K3RTC_S_CNT_LSW);
269 	seconds_hi = k3rtc_field_read(priv, K3RTC_S_CNT_MSW);
270 
271 	rtc_time64_to_tm((((time64_t)seconds_hi) << 32) | (time64_t)seconds_lo, tm);
272 
273 	return 0;
274 }
275 
276 static int ti_k3_rtc_set_time(struct device *dev, struct rtc_time *tm)
277 {
278 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
279 	time64_t seconds;
280 
281 	seconds = rtc_tm_to_time64(tm);
282 
283 	/*
284 	 * Read operation on LSW will freeze the RTC, so to update
285 	 * the time, we cannot use field operations. Just write since the
286 	 * reserved bits are ignored.
287 	 */
288 	regmap_write(priv->regmap, REG_K3RTC_S_CNT_LSW, seconds);
289 	regmap_write(priv->regmap, REG_K3RTC_S_CNT_MSW, seconds >> 32);
290 
291 	return k3rtc_fence(priv);
292 }
293 
294 static int ti_k3_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
295 {
296 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
297 	u32 reg;
298 	u32 offset = enabled ? K3RTC_IRQ_ENABLE_SET : K3RTC_IRQ_ENABLE_CLR;
299 
300 	reg = k3rtc_field_read(priv, K3RTC_IRQ_ENABLE_SET);
301 	if ((enabled && reg) || (!enabled && !reg))
302 		return 0;
303 
304 	k3rtc_field_write(priv, offset, 0x1);
305 
306 	/*
307 	 * Ensure the write sync is through - NOTE: it should be OK to have
308 	 * ISR to fire as we are checking sync (which should be done in a 32k
309 	 * cycle or so).
310 	 */
311 	return k3rtc_fence(priv);
312 }
313 
314 static int ti_k3_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
315 {
316 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
317 	u32 seconds_lo, seconds_hi;
318 
319 	seconds_lo = k3rtc_field_read(priv, K3RTC_ALM_S_CNT_LSW);
320 	seconds_hi = k3rtc_field_read(priv, K3RTC_ALM_S_CNT_MSW);
321 
322 	rtc_time64_to_tm((((time64_t)seconds_hi) << 32) | (time64_t)seconds_lo, &alarm->time);
323 
324 	alarm->enabled = k3rtc_field_read(priv, K3RTC_IRQ_ENABLE_SET);
325 
326 	return 0;
327 }
328 
329 static int ti_k3_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
330 {
331 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
332 	time64_t seconds;
333 	int ret;
334 
335 	seconds = rtc_tm_to_time64(&alarm->time);
336 
337 	k3rtc_field_write(priv, K3RTC_ALM_S_CNT_LSW, seconds);
338 	k3rtc_field_write(priv, K3RTC_ALM_S_CNT_MSW, (seconds >> 32));
339 
340 	/* Make sure the alarm time is synced in */
341 	ret = k3rtc_fence(priv);
342 	if (ret) {
343 		dev_err(dev, "Failed to fence(%d)! Potential config issue?\n", ret);
344 		return ret;
345 	}
346 
347 	/* Alarm IRQ enable will do a sync */
348 	return ti_k3_rtc_alarm_irq_enable(dev, alarm->enabled);
349 }
350 
351 static int ti_k3_rtc_read_offset(struct device *dev, long *offset)
352 {
353 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
354 	u32 ticks_per_hr = priv->rate_32k * 3600;
355 	int comp;
356 	s64 tmp;
357 
358 	comp = k3rtc_field_read(priv, K3RTC_COMP);
359 
360 	/* Convert from RTC calibration register format to ppb format */
361 	tmp = comp * (s64)K3RTC_PPB_MULT;
362 	if (tmp < 0)
363 		tmp -= ticks_per_hr / 2LL;
364 	else
365 		tmp += ticks_per_hr / 2LL;
366 	tmp = div_s64(tmp, ticks_per_hr);
367 
368 	/* Offset value operates in negative way, so swap sign */
369 	*offset = (long)-tmp;
370 
371 	return 0;
372 }
373 
374 static int ti_k3_rtc_set_offset(struct device *dev, long offset)
375 {
376 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
377 	u32 ticks_per_hr = priv->rate_32k * 3600;
378 	int comp;
379 	s64 tmp;
380 
381 	/* Make sure offset value is within supported range */
382 	if (offset < K3RTC_MIN_OFFSET || offset > K3RTC_MAX_OFFSET)
383 		return -ERANGE;
384 
385 	/* Convert from ppb format to RTC calibration register format */
386 	tmp = offset * (s64)ticks_per_hr;
387 	if (tmp < 0)
388 		tmp -= K3RTC_PPB_MULT / 2LL;
389 	else
390 		tmp += K3RTC_PPB_MULT / 2LL;
391 	tmp = div_s64(tmp, K3RTC_PPB_MULT);
392 
393 	/* Offset value operates in negative way, so swap sign */
394 	comp = (int)-tmp;
395 
396 	k3rtc_field_write(priv, K3RTC_COMP, comp);
397 
398 	return k3rtc_fence(priv);
399 }
400 
401 static irqreturn_t ti_k3_rtc_interrupt(s32 irq, void *dev_id)
402 {
403 	struct device *dev = dev_id;
404 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
405 	u32 reg;
406 	int ret;
407 
408 	/*
409 	 * IRQ assertion can be very fast, however, the IRQ Status clear
410 	 * de-assert depends on 32k clock edge in the 32k domain
411 	 * If we clear the status prior to the first 32k clock edge,
412 	 * the status bit is cleared, but the IRQ stays re-asserted.
413 	 *
414 	 * To prevent this condition, we need to wait for clock sync time.
415 	 * We can either do that by polling the 32k observability signal for
416 	 * a toggle OR we could just sleep and let the processor do other
417 	 * stuff.
418 	 */
419 	usleep_range(priv->sync_timeout_us, priv->sync_timeout_us + 2);
420 
421 	/* Lets make sure that this is a valid interrupt */
422 	reg = k3rtc_field_read(priv, K3RTC_IRQ_STATUS);
423 
424 	if (!reg) {
425 		u32 raw = k3rtc_field_read(priv, K3RTC_IRQ_STATUS_RAW);
426 
427 		dev_err(dev,
428 			HW_ERR
429 			"Erratum i2327/IRQ trig: status: 0x%08x / 0x%08x\n", reg, raw);
430 		return IRQ_NONE;
431 	}
432 
433 	/*
434 	 * Write 1 to clear status reg
435 	 * We cannot use a field operation here due to a potential race between
436 	 * 32k domain and vbus domain.
437 	 */
438 	regmap_write(priv->regmap, REG_K3RTC_IRQSTATUS_SYS, 0x1);
439 
440 	/* Sync the write in */
441 	ret = k3rtc_fence(priv);
442 	if (ret) {
443 		dev_err(dev, "Failed to fence irq status clr(%d)!\n", ret);
444 		return IRQ_NONE;
445 	}
446 
447 	/*
448 	 * Force the 32k status to be reloaded back in to ensure status is
449 	 * reflected back correctly.
450 	 */
451 	k3rtc_field_write(priv, K3RTC_RELOAD_FROM_BBD, 0x1);
452 
453 	/* Ensure the write sync is through */
454 	ret = k3rtc_fence(priv);
455 	if (ret) {
456 		dev_err(dev, "Failed to fence reload from bbd(%d)!\n", ret);
457 		return IRQ_NONE;
458 	}
459 
460 	/* Now we ensure that the status bit is cleared */
461 	ret = regmap_field_read_poll_timeout(priv->r_fields[K3RTC_IRQ_STATUS],
462 					     ret, !ret, 2, priv->sync_timeout_us);
463 	if (ret) {
464 		dev_err(dev, "Time out waiting for status clear\n");
465 		return IRQ_NONE;
466 	}
467 
468 	/* Notify RTC core on event */
469 	rtc_update_irq(priv->rtc_dev, 1, RTC_IRQF | RTC_AF);
470 
471 	return IRQ_HANDLED;
472 }
473 
474 static const struct rtc_class_ops ti_k3_rtc_ops = {
475 	.read_time = ti_k3_rtc_read_time,
476 	.set_time = ti_k3_rtc_set_time,
477 	.read_alarm = ti_k3_rtc_read_alarm,
478 	.set_alarm = ti_k3_rtc_set_alarm,
479 	.read_offset = ti_k3_rtc_read_offset,
480 	.set_offset = ti_k3_rtc_set_offset,
481 	.alarm_irq_enable = ti_k3_rtc_alarm_irq_enable,
482 };
483 
484 static int ti_k3_rtc_scratch_read(void *priv_data, unsigned int offset,
485 				  void *val, size_t bytes)
486 {
487 	struct ti_k3_rtc *priv = (struct ti_k3_rtc *)priv_data;
488 
489 	return regmap_bulk_read(priv->regmap, REG_K3RTC_SCRATCH0 + offset, val, bytes / 4);
490 }
491 
492 static int ti_k3_rtc_scratch_write(void *priv_data, unsigned int offset,
493 				   void *val, size_t bytes)
494 {
495 	struct ti_k3_rtc *priv = (struct ti_k3_rtc *)priv_data;
496 	int ret;
497 
498 	ret = regmap_bulk_write(priv->regmap, REG_K3RTC_SCRATCH0 + offset, val, bytes / 4);
499 	if (ret)
500 		return ret;
501 
502 	return k3rtc_fence(priv);
503 }
504 
505 static struct nvmem_config ti_k3_rtc_nvmem_config = {
506 	.name = "ti_k3_rtc_scratch",
507 	.word_size = 4,
508 	.stride = 4,
509 	.size = REG_K3RTC_SCRATCH7 - REG_K3RTC_SCRATCH0 + 4,
510 	.reg_read = ti_k3_rtc_scratch_read,
511 	.reg_write = ti_k3_rtc_scratch_write,
512 };
513 
514 static int k3rtc_get_32kclk(struct device *dev, struct ti_k3_rtc *priv)
515 {
516 	int ret;
517 	struct clk *clk;
518 
519 	clk = devm_clk_get(dev, "osc32k");
520 	if (IS_ERR(clk))
521 		return PTR_ERR(clk);
522 
523 	ret = clk_prepare_enable(clk);
524 	if (ret)
525 		return ret;
526 
527 	ret = devm_add_action_or_reset(dev, (void (*)(void *))clk_disable_unprepare, clk);
528 	if (ret)
529 		return ret;
530 
531 	priv->rate_32k = clk_get_rate(clk);
532 
533 	/* Make sure we are exact 32k clock. Else, try to compensate delay */
534 	if (priv->rate_32k != 32768)
535 		dev_warn(dev, "Clock rate %ld is not 32768! Could misbehave!\n",
536 			 priv->rate_32k);
537 
538 	/*
539 	 * Sync timeout should be two 32k clk sync cycles = ~61uS. We double
540 	 * it to comprehend intermediate bus segment and cpu frequency
541 	 * deltas
542 	 */
543 	priv->sync_timeout_us = (u32)(DIV_ROUND_UP_ULL(1000000, priv->rate_32k) * 4);
544 
545 	return ret;
546 }
547 
548 static int k3rtc_get_vbusclk(struct device *dev, struct ti_k3_rtc *priv)
549 {
550 	int ret;
551 	struct clk *clk;
552 
553 	/* Note: VBUS isn't a context clock, it is needed for hardware operation */
554 	clk = devm_clk_get(dev, "vbus");
555 	if (IS_ERR(clk))
556 		return PTR_ERR(clk);
557 
558 	ret = clk_prepare_enable(clk);
559 	if (ret)
560 		return ret;
561 
562 	return devm_add_action_or_reset(dev, (void (*)(void *))clk_disable_unprepare, clk);
563 }
564 
565 static int ti_k3_rtc_probe(struct platform_device *pdev)
566 {
567 	struct device *dev = &pdev->dev;
568 	struct ti_k3_rtc *priv;
569 	void __iomem *rtc_base;
570 	int ret;
571 
572 	priv = devm_kzalloc(dev, sizeof(struct ti_k3_rtc), GFP_KERNEL);
573 	if (!priv)
574 		return -ENOMEM;
575 
576 	rtc_base = devm_platform_ioremap_resource(pdev, 0);
577 	if (IS_ERR(rtc_base))
578 		return PTR_ERR(rtc_base);
579 
580 	priv->regmap = devm_regmap_init_mmio(dev, rtc_base, &ti_k3_rtc_regmap_config);
581 	if (IS_ERR(priv->regmap))
582 		return PTR_ERR(priv->regmap);
583 
584 	ret = devm_regmap_field_bulk_alloc(dev, priv->regmap, priv->r_fields,
585 					   ti_rtc_reg_fields, K3_RTC_MAX_FIELDS);
586 	if (ret)
587 		return ret;
588 
589 	ret = k3rtc_get_32kclk(dev, priv);
590 	if (ret)
591 		return ret;
592 	ret = k3rtc_get_vbusclk(dev, priv);
593 	if (ret)
594 		return ret;
595 
596 	ret = platform_get_irq(pdev, 0);
597 	if (ret < 0)
598 		return ret;
599 	priv->irq = (unsigned int)ret;
600 
601 	priv->rtc_dev = devm_rtc_allocate_device(dev);
602 	if (IS_ERR(priv->rtc_dev))
603 		return PTR_ERR(priv->rtc_dev);
604 
605 	priv->soc = of_device_get_match_data(dev);
606 
607 	priv->rtc_dev->ops = &ti_k3_rtc_ops;
608 	priv->rtc_dev->range_max = (1ULL << 48) - 1;	/* 48Bit seconds */
609 	ti_k3_rtc_nvmem_config.priv = priv;
610 
611 	ret = devm_request_threaded_irq(dev, priv->irq, NULL,
612 					ti_k3_rtc_interrupt,
613 					IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
614 					dev_name(dev), dev);
615 	if (ret) {
616 		dev_err(dev, "Could not request IRQ: %d\n", ret);
617 		return ret;
618 	}
619 
620 	platform_set_drvdata(pdev, priv);
621 
622 	ret = k3rtc_configure(dev);
623 	if (ret)
624 		return ret;
625 
626 	if (device_property_present(dev, "wakeup-source"))
627 		device_init_wakeup(dev, true);
628 	else
629 		device_set_wakeup_capable(dev, true);
630 
631 	ret = devm_rtc_register_device(priv->rtc_dev);
632 	if (ret)
633 		return ret;
634 
635 	return devm_rtc_nvmem_register(priv->rtc_dev, &ti_k3_rtc_nvmem_config);
636 }
637 
638 static const struct ti_k3_rtc_soc_data ti_k3_am62_data = {
639 	.unlock_irq_erratum = true,
640 };
641 
642 static const struct of_device_id ti_k3_rtc_of_match_table[] = {
643 	{.compatible = "ti,am62-rtc", .data = &ti_k3_am62_data},
644 	{}
645 };
646 MODULE_DEVICE_TABLE(of, ti_k3_rtc_of_match_table);
647 
648 static int __maybe_unused ti_k3_rtc_suspend(struct device *dev)
649 {
650 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
651 
652 	if (device_may_wakeup(dev))
653 		enable_irq_wake(priv->irq);
654 	return 0;
655 }
656 
657 static int __maybe_unused ti_k3_rtc_resume(struct device *dev)
658 {
659 	struct ti_k3_rtc *priv = dev_get_drvdata(dev);
660 
661 	if (device_may_wakeup(dev))
662 		disable_irq_wake(priv->irq);
663 	return 0;
664 }
665 
666 static SIMPLE_DEV_PM_OPS(ti_k3_rtc_pm_ops, ti_k3_rtc_suspend, ti_k3_rtc_resume);
667 
668 static struct platform_driver ti_k3_rtc_driver = {
669 	.probe = ti_k3_rtc_probe,
670 	.driver = {
671 		   .name = "rtc-ti-k3",
672 		   .of_match_table = ti_k3_rtc_of_match_table,
673 		   .pm = &ti_k3_rtc_pm_ops,
674 	},
675 };
676 module_platform_driver(ti_k3_rtc_driver);
677 
678 MODULE_LICENSE("GPL");
679 MODULE_DESCRIPTION("TI K3 RTC driver");
680 MODULE_AUTHOR("Nishanth Menon");
681