1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * pm8xxx RTC driver
4 *
5 * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
6 * Copyright (c) 2023, Linaro Limited
7 */
8 #include <linux/of.h>
9 #include <linux/module.h>
10 #include <linux/nvmem-consumer.h>
11 #include <linux/init.h>
12 #include <linux/rtc.h>
13 #include <linux/platform_device.h>
14 #include <linux/pm.h>
15 #include <linux/pm_wakeirq.h>
16 #include <linux/regmap.h>
17 #include <linux/slab.h>
18 #include <linux/spinlock.h>
19
20 #include <linux/unaligned.h>
21
22 /* RTC_CTRL register bit fields */
23 #define PM8xxx_RTC_ENABLE BIT(7)
24 #define PM8xxx_RTC_ALARM_CLEAR BIT(0)
25 #define PM8xxx_RTC_ALARM_ENABLE BIT(7)
26
27 #define NUM_8_BIT_RTC_REGS 0x4
28
29 /**
30 * struct pm8xxx_rtc_regs - describe RTC registers per PMIC versions
31 * @ctrl: address of control register
32 * @write: base address of write registers
33 * @read: base address of read registers
34 * @alarm_ctrl: address of alarm control register
35 * @alarm_ctrl2: address of alarm control2 register
36 * @alarm_rw: base address of alarm read-write registers
37 * @alarm_en: alarm enable mask
38 */
39 struct pm8xxx_rtc_regs {
40 unsigned int ctrl;
41 unsigned int write;
42 unsigned int read;
43 unsigned int alarm_ctrl;
44 unsigned int alarm_ctrl2;
45 unsigned int alarm_rw;
46 unsigned int alarm_en;
47 };
48
49 /**
50 * struct pm8xxx_rtc - RTC driver internal structure
51 * @rtc: RTC device
52 * @regmap: regmap used to access registers
53 * @allow_set_time: whether the time can be set
54 * @alarm_irq: alarm irq number
55 * @regs: register description
56 * @dev: device structure
57 * @nvmem_cell: nvmem cell for offset
58 * @offset: offset from epoch in seconds
59 */
60 struct pm8xxx_rtc {
61 struct rtc_device *rtc;
62 struct regmap *regmap;
63 bool allow_set_time;
64 int alarm_irq;
65 const struct pm8xxx_rtc_regs *regs;
66 struct device *dev;
67 struct nvmem_cell *nvmem_cell;
68 u32 offset;
69 };
70
pm8xxx_rtc_read_nvmem_offset(struct pm8xxx_rtc * rtc_dd)71 static int pm8xxx_rtc_read_nvmem_offset(struct pm8xxx_rtc *rtc_dd)
72 {
73 size_t len;
74 void *buf;
75 int rc;
76
77 buf = nvmem_cell_read(rtc_dd->nvmem_cell, &len);
78 if (IS_ERR(buf)) {
79 rc = PTR_ERR(buf);
80 dev_dbg(rtc_dd->dev, "failed to read nvmem offset: %d\n", rc);
81 return rc;
82 }
83
84 if (len != sizeof(u32)) {
85 dev_dbg(rtc_dd->dev, "unexpected nvmem cell size %zu\n", len);
86 kfree(buf);
87 return -EINVAL;
88 }
89
90 rtc_dd->offset = get_unaligned_le32(buf);
91
92 kfree(buf);
93
94 return 0;
95 }
96
pm8xxx_rtc_write_nvmem_offset(struct pm8xxx_rtc * rtc_dd,u32 offset)97 static int pm8xxx_rtc_write_nvmem_offset(struct pm8xxx_rtc *rtc_dd, u32 offset)
98 {
99 u8 buf[sizeof(u32)];
100 int rc;
101
102 put_unaligned_le32(offset, buf);
103
104 rc = nvmem_cell_write(rtc_dd->nvmem_cell, buf, sizeof(buf));
105 if (rc < 0) {
106 dev_dbg(rtc_dd->dev, "failed to write nvmem offset: %d\n", rc);
107 return rc;
108 }
109
110 return 0;
111 }
112
pm8xxx_rtc_read_offset(struct pm8xxx_rtc * rtc_dd)113 static int pm8xxx_rtc_read_offset(struct pm8xxx_rtc *rtc_dd)
114 {
115 if (!rtc_dd->nvmem_cell)
116 return 0;
117
118 return pm8xxx_rtc_read_nvmem_offset(rtc_dd);
119 }
120
pm8xxx_rtc_read_raw(struct pm8xxx_rtc * rtc_dd,u32 * secs)121 static int pm8xxx_rtc_read_raw(struct pm8xxx_rtc *rtc_dd, u32 *secs)
122 {
123 const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
124 u8 value[NUM_8_BIT_RTC_REGS];
125 unsigned int reg;
126 int rc;
127
128 rc = regmap_bulk_read(rtc_dd->regmap, regs->read, value, sizeof(value));
129 if (rc)
130 return rc;
131
132 /*
133 * Read the LSB again and check if there has been a carry over.
134 * If there has, redo the read operation.
135 */
136 rc = regmap_read(rtc_dd->regmap, regs->read, ®);
137 if (rc < 0)
138 return rc;
139
140 if (reg < value[0]) {
141 rc = regmap_bulk_read(rtc_dd->regmap, regs->read, value,
142 sizeof(value));
143 if (rc)
144 return rc;
145 }
146
147 *secs = get_unaligned_le32(value);
148
149 return 0;
150 }
151
pm8xxx_rtc_update_offset(struct pm8xxx_rtc * rtc_dd,u32 secs)152 static int pm8xxx_rtc_update_offset(struct pm8xxx_rtc *rtc_dd, u32 secs)
153 {
154 u32 raw_secs;
155 u32 offset;
156 int rc;
157
158 if (!rtc_dd->nvmem_cell)
159 return -ENODEV;
160
161 rc = pm8xxx_rtc_read_raw(rtc_dd, &raw_secs);
162 if (rc)
163 return rc;
164
165 offset = secs - raw_secs;
166
167 if (offset == rtc_dd->offset)
168 return 0;
169
170 rc = pm8xxx_rtc_write_nvmem_offset(rtc_dd, offset);
171 if (rc)
172 return rc;
173
174 rtc_dd->offset = offset;
175
176 return 0;
177 }
178
179 /*
180 * Steps to write the RTC registers.
181 * 1. Disable alarm if enabled.
182 * 2. Disable rtc if enabled.
183 * 3. Write 0x00 to LSB.
184 * 4. Write Byte[1], Byte[2], Byte[3] then Byte[0].
185 * 5. Enable rtc if disabled in step 2.
186 * 6. Enable alarm if disabled in step 1.
187 */
__pm8xxx_rtc_set_time(struct pm8xxx_rtc * rtc_dd,u32 secs)188 static int __pm8xxx_rtc_set_time(struct pm8xxx_rtc *rtc_dd, u32 secs)
189 {
190 const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
191 u8 value[NUM_8_BIT_RTC_REGS];
192 bool alarm_enabled;
193 int rc;
194
195 put_unaligned_le32(secs, value);
196
197 rc = regmap_update_bits_check(rtc_dd->regmap, regs->alarm_ctrl,
198 regs->alarm_en, 0, &alarm_enabled);
199 if (rc)
200 return rc;
201
202 /* Disable RTC */
203 rc = regmap_update_bits(rtc_dd->regmap, regs->ctrl, PM8xxx_RTC_ENABLE, 0);
204 if (rc)
205 return rc;
206
207 /* Write 0 to Byte[0] */
208 rc = regmap_write(rtc_dd->regmap, regs->write, 0);
209 if (rc)
210 return rc;
211
212 /* Write Byte[1], Byte[2], Byte[3] */
213 rc = regmap_bulk_write(rtc_dd->regmap, regs->write + 1,
214 &value[1], sizeof(value) - 1);
215 if (rc)
216 return rc;
217
218 /* Write Byte[0] */
219 rc = regmap_write(rtc_dd->regmap, regs->write, value[0]);
220 if (rc)
221 return rc;
222
223 /* Enable RTC */
224 rc = regmap_update_bits(rtc_dd->regmap, regs->ctrl, PM8xxx_RTC_ENABLE,
225 PM8xxx_RTC_ENABLE);
226 if (rc)
227 return rc;
228
229 if (alarm_enabled) {
230 rc = regmap_update_bits(rtc_dd->regmap, regs->alarm_ctrl,
231 regs->alarm_en, regs->alarm_en);
232 if (rc)
233 return rc;
234 }
235
236 return 0;
237 }
238
pm8xxx_rtc_set_time(struct device * dev,struct rtc_time * tm)239 static int pm8xxx_rtc_set_time(struct device *dev, struct rtc_time *tm)
240 {
241 struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
242 u32 secs;
243 int rc;
244
245 secs = rtc_tm_to_time64(tm);
246
247 if (rtc_dd->allow_set_time)
248 rc = __pm8xxx_rtc_set_time(rtc_dd, secs);
249 else
250 rc = pm8xxx_rtc_update_offset(rtc_dd, secs);
251
252 if (rc)
253 return rc;
254
255 dev_dbg(dev, "set time: %ptRd %ptRt (%u + %u)\n", tm, tm,
256 secs - rtc_dd->offset, rtc_dd->offset);
257 return 0;
258 }
259
pm8xxx_rtc_read_time(struct device * dev,struct rtc_time * tm)260 static int pm8xxx_rtc_read_time(struct device *dev, struct rtc_time *tm)
261 {
262 struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
263 u32 secs;
264 int rc;
265
266 rc = pm8xxx_rtc_read_raw(rtc_dd, &secs);
267 if (rc)
268 return rc;
269
270 secs += rtc_dd->offset;
271 rtc_time64_to_tm(secs, tm);
272
273 dev_dbg(dev, "read time: %ptRd %ptRt (%u + %u)\n", tm, tm,
274 secs - rtc_dd->offset, rtc_dd->offset);
275 return 0;
276 }
277
pm8xxx_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alarm)278 static int pm8xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
279 {
280 struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
281 const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
282 u8 value[NUM_8_BIT_RTC_REGS];
283 u32 secs;
284 int rc;
285
286 secs = rtc_tm_to_time64(&alarm->time);
287 secs -= rtc_dd->offset;
288 put_unaligned_le32(secs, value);
289
290 rc = regmap_update_bits(rtc_dd->regmap, regs->alarm_ctrl,
291 regs->alarm_en, 0);
292 if (rc)
293 return rc;
294
295 rc = regmap_bulk_write(rtc_dd->regmap, regs->alarm_rw, value,
296 sizeof(value));
297 if (rc)
298 return rc;
299
300 if (alarm->enabled) {
301 rc = regmap_update_bits(rtc_dd->regmap, regs->alarm_ctrl,
302 regs->alarm_en, regs->alarm_en);
303 if (rc)
304 return rc;
305 }
306
307 dev_dbg(dev, "set alarm: %ptRd %ptRt\n", &alarm->time, &alarm->time);
308
309 return 0;
310 }
311
pm8xxx_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alarm)312 static int pm8xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
313 {
314 struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
315 const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
316 u8 value[NUM_8_BIT_RTC_REGS];
317 unsigned int ctrl_reg;
318 u32 secs;
319 int rc;
320
321 rc = regmap_bulk_read(rtc_dd->regmap, regs->alarm_rw, value,
322 sizeof(value));
323 if (rc)
324 return rc;
325
326 secs = get_unaligned_le32(value);
327 secs += rtc_dd->offset;
328 rtc_time64_to_tm(secs, &alarm->time);
329
330 rc = regmap_read(rtc_dd->regmap, regs->alarm_ctrl, &ctrl_reg);
331 if (rc)
332 return rc;
333
334 alarm->enabled = !!(ctrl_reg & PM8xxx_RTC_ALARM_ENABLE);
335
336 dev_dbg(dev, "read alarm: %ptRd %ptRt\n", &alarm->time, &alarm->time);
337
338 return 0;
339 }
340
pm8xxx_rtc_alarm_irq_enable(struct device * dev,unsigned int enable)341 static int pm8xxx_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
342 {
343 struct pm8xxx_rtc *rtc_dd = dev_get_drvdata(dev);
344 const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
345 u8 value[NUM_8_BIT_RTC_REGS] = {0};
346 unsigned int val;
347 int rc;
348
349 if (enable)
350 val = regs->alarm_en;
351 else
352 val = 0;
353
354 rc = regmap_update_bits(rtc_dd->regmap, regs->alarm_ctrl,
355 regs->alarm_en, val);
356 if (rc)
357 return rc;
358
359 /* Clear alarm register */
360 if (!enable) {
361 rc = regmap_bulk_write(rtc_dd->regmap, regs->alarm_rw, value,
362 sizeof(value));
363 if (rc)
364 return rc;
365 }
366
367 return 0;
368 }
369
370 static const struct rtc_class_ops pm8xxx_rtc_ops = {
371 .read_time = pm8xxx_rtc_read_time,
372 .set_time = pm8xxx_rtc_set_time,
373 .set_alarm = pm8xxx_rtc_set_alarm,
374 .read_alarm = pm8xxx_rtc_read_alarm,
375 .alarm_irq_enable = pm8xxx_rtc_alarm_irq_enable,
376 };
377
pm8xxx_alarm_trigger(int irq,void * dev_id)378 static irqreturn_t pm8xxx_alarm_trigger(int irq, void *dev_id)
379 {
380 struct pm8xxx_rtc *rtc_dd = dev_id;
381 const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
382 int rc;
383
384 rtc_update_irq(rtc_dd->rtc, 1, RTC_IRQF | RTC_AF);
385
386 /* Disable alarm */
387 rc = regmap_update_bits(rtc_dd->regmap, regs->alarm_ctrl,
388 regs->alarm_en, 0);
389 if (rc)
390 return IRQ_NONE;
391
392 /* Clear alarm status */
393 rc = regmap_update_bits(rtc_dd->regmap, regs->alarm_ctrl2,
394 PM8xxx_RTC_ALARM_CLEAR, 0);
395 if (rc)
396 return IRQ_NONE;
397
398 return IRQ_HANDLED;
399 }
400
pm8xxx_rtc_enable(struct pm8xxx_rtc * rtc_dd)401 static int pm8xxx_rtc_enable(struct pm8xxx_rtc *rtc_dd)
402 {
403 const struct pm8xxx_rtc_regs *regs = rtc_dd->regs;
404
405 return regmap_update_bits(rtc_dd->regmap, regs->ctrl, PM8xxx_RTC_ENABLE,
406 PM8xxx_RTC_ENABLE);
407 }
408
409 static const struct pm8xxx_rtc_regs pm8921_regs = {
410 .ctrl = 0x11d,
411 .write = 0x11f,
412 .read = 0x123,
413 .alarm_rw = 0x127,
414 .alarm_ctrl = 0x11d,
415 .alarm_ctrl2 = 0x11e,
416 .alarm_en = BIT(1),
417 };
418
419 static const struct pm8xxx_rtc_regs pm8058_regs = {
420 .ctrl = 0x1e8,
421 .write = 0x1ea,
422 .read = 0x1ee,
423 .alarm_rw = 0x1f2,
424 .alarm_ctrl = 0x1e8,
425 .alarm_ctrl2 = 0x1e9,
426 .alarm_en = BIT(1),
427 };
428
429 static const struct pm8xxx_rtc_regs pm8941_regs = {
430 .ctrl = 0x6046,
431 .write = 0x6040,
432 .read = 0x6048,
433 .alarm_rw = 0x6140,
434 .alarm_ctrl = 0x6146,
435 .alarm_ctrl2 = 0x6148,
436 .alarm_en = BIT(7),
437 };
438
439 static const struct pm8xxx_rtc_regs pmk8350_regs = {
440 .ctrl = 0x6146,
441 .write = 0x6140,
442 .read = 0x6148,
443 .alarm_rw = 0x6240,
444 .alarm_ctrl = 0x6246,
445 .alarm_ctrl2 = 0x6248,
446 .alarm_en = BIT(7),
447 };
448
449 static const struct of_device_id pm8xxx_id_table[] = {
450 { .compatible = "qcom,pm8921-rtc", .data = &pm8921_regs },
451 { .compatible = "qcom,pm8058-rtc", .data = &pm8058_regs },
452 { .compatible = "qcom,pm8941-rtc", .data = &pm8941_regs },
453 { .compatible = "qcom,pmk8350-rtc", .data = &pmk8350_regs },
454 { },
455 };
456 MODULE_DEVICE_TABLE(of, pm8xxx_id_table);
457
pm8xxx_rtc_probe(struct platform_device * pdev)458 static int pm8xxx_rtc_probe(struct platform_device *pdev)
459 {
460 const struct of_device_id *match;
461 struct pm8xxx_rtc *rtc_dd;
462 int rc;
463
464 match = of_match_node(pm8xxx_id_table, pdev->dev.of_node);
465 if (!match)
466 return -ENXIO;
467
468 rtc_dd = devm_kzalloc(&pdev->dev, sizeof(*rtc_dd), GFP_KERNEL);
469 if (rtc_dd == NULL)
470 return -ENOMEM;
471
472 rtc_dd->regmap = dev_get_regmap(pdev->dev.parent, NULL);
473 if (!rtc_dd->regmap)
474 return -ENXIO;
475
476 rtc_dd->alarm_irq = platform_get_irq(pdev, 0);
477 if (rtc_dd->alarm_irq < 0)
478 return -ENXIO;
479
480 rtc_dd->allow_set_time = of_property_read_bool(pdev->dev.of_node,
481 "allow-set-time");
482
483 rtc_dd->nvmem_cell = devm_nvmem_cell_get(&pdev->dev, "offset");
484 if (IS_ERR(rtc_dd->nvmem_cell)) {
485 rc = PTR_ERR(rtc_dd->nvmem_cell);
486 if (rc != -ENOENT)
487 return rc;
488 rtc_dd->nvmem_cell = NULL;
489 }
490
491 rtc_dd->regs = match->data;
492 rtc_dd->dev = &pdev->dev;
493
494 if (!rtc_dd->allow_set_time) {
495 rc = pm8xxx_rtc_read_offset(rtc_dd);
496 if (rc)
497 return rc;
498 }
499
500 rc = pm8xxx_rtc_enable(rtc_dd);
501 if (rc)
502 return rc;
503
504 platform_set_drvdata(pdev, rtc_dd);
505
506 device_init_wakeup(&pdev->dev, 1);
507
508 rtc_dd->rtc = devm_rtc_allocate_device(&pdev->dev);
509 if (IS_ERR(rtc_dd->rtc))
510 return PTR_ERR(rtc_dd->rtc);
511
512 rtc_dd->rtc->ops = &pm8xxx_rtc_ops;
513 rtc_dd->rtc->range_max = U32_MAX;
514
515 rc = devm_request_any_context_irq(&pdev->dev, rtc_dd->alarm_irq,
516 pm8xxx_alarm_trigger,
517 IRQF_TRIGGER_RISING,
518 "pm8xxx_rtc_alarm", rtc_dd);
519 if (rc < 0)
520 return rc;
521
522 rc = devm_rtc_register_device(rtc_dd->rtc);
523 if (rc)
524 return rc;
525
526 rc = dev_pm_set_wake_irq(&pdev->dev, rtc_dd->alarm_irq);
527 if (rc)
528 return rc;
529
530 return 0;
531 }
532
pm8xxx_remove(struct platform_device * pdev)533 static void pm8xxx_remove(struct platform_device *pdev)
534 {
535 dev_pm_clear_wake_irq(&pdev->dev);
536 }
537
538 static struct platform_driver pm8xxx_rtc_driver = {
539 .probe = pm8xxx_rtc_probe,
540 .remove_new = pm8xxx_remove,
541 .driver = {
542 .name = "rtc-pm8xxx",
543 .of_match_table = pm8xxx_id_table,
544 },
545 };
546
547 module_platform_driver(pm8xxx_rtc_driver);
548
549 MODULE_ALIAS("platform:rtc-pm8xxx");
550 MODULE_DESCRIPTION("PMIC8xxx RTC driver");
551 MODULE_LICENSE("GPL v2");
552 MODULE_AUTHOR("Anirudh Ghayal <aghayal@codeaurora.org>");
553 MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
554