treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / drivers / rtc / rtc-pcf8563.c
blob3c322f3079b0c5ddefe346c28e7b0c68ea7e11f3
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * An I2C driver for the Philips PCF8563 RTC
4 * Copyright 2005-06 Tower Technologies
6 * Author: Alessandro Zummo <a.zummo@towertech.it>
7 * Maintainers: http://www.nslu2-linux.org/
9 * based on the other drivers in this same directory.
11 * http://www.semiconductors.philips.com/acrobat/datasheets/PCF8563-04.pdf
14 #include <linux/clk-provider.h>
15 #include <linux/i2c.h>
16 #include <linux/bcd.h>
17 #include <linux/rtc.h>
18 #include <linux/slab.h>
19 #include <linux/module.h>
20 #include <linux/of.h>
21 #include <linux/err.h>
23 #define PCF8563_REG_ST1 0x00 /* status */
24 #define PCF8563_REG_ST2 0x01
25 #define PCF8563_BIT_AIE (1 << 1)
26 #define PCF8563_BIT_AF (1 << 3)
27 #define PCF8563_BITS_ST2_N (7 << 5)
29 #define PCF8563_REG_SC 0x02 /* datetime */
30 #define PCF8563_REG_MN 0x03
31 #define PCF8563_REG_HR 0x04
32 #define PCF8563_REG_DM 0x05
33 #define PCF8563_REG_DW 0x06
34 #define PCF8563_REG_MO 0x07
35 #define PCF8563_REG_YR 0x08
37 #define PCF8563_REG_AMN 0x09 /* alarm */
39 #define PCF8563_REG_CLKO 0x0D /* clock out */
40 #define PCF8563_REG_CLKO_FE 0x80 /* clock out enabled */
41 #define PCF8563_REG_CLKO_F_MASK 0x03 /* frequenc mask */
42 #define PCF8563_REG_CLKO_F_32768HZ 0x00
43 #define PCF8563_REG_CLKO_F_1024HZ 0x01
44 #define PCF8563_REG_CLKO_F_32HZ 0x02
45 #define PCF8563_REG_CLKO_F_1HZ 0x03
47 #define PCF8563_REG_TMRC 0x0E /* timer control */
48 #define PCF8563_TMRC_ENABLE BIT(7)
49 #define PCF8563_TMRC_4096 0
50 #define PCF8563_TMRC_64 1
51 #define PCF8563_TMRC_1 2
52 #define PCF8563_TMRC_1_60 3
53 #define PCF8563_TMRC_MASK 3
55 #define PCF8563_REG_TMR 0x0F /* timer */
57 #define PCF8563_SC_LV 0x80 /* low voltage */
58 #define PCF8563_MO_C 0x80 /* century */
60 static struct i2c_driver pcf8563_driver;
62 struct pcf8563 {
63 struct rtc_device *rtc;
65 * The meaning of MO_C bit varies by the chip type.
66 * From PCF8563 datasheet: this bit is toggled when the years
67 * register overflows from 99 to 00
68 * 0 indicates the century is 20xx
69 * 1 indicates the century is 19xx
70 * From RTC8564 datasheet: this bit indicates change of
71 * century. When the year digit data overflows from 99 to 00,
72 * this bit is set. By presetting it to 0 while still in the
73 * 20th century, it will be set in year 2000, ...
74 * There seems no reliable way to know how the system use this
75 * bit. So let's do it heuristically, assuming we are live in
76 * 1970...2069.
78 int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
79 int voltage_low; /* incicates if a low_voltage was detected */
81 struct i2c_client *client;
82 #ifdef CONFIG_COMMON_CLK
83 struct clk_hw clkout_hw;
84 #endif
87 static int pcf8563_read_block_data(struct i2c_client *client, unsigned char reg,
88 unsigned char length, unsigned char *buf)
90 struct i2c_msg msgs[] = {
91 {/* setup read ptr */
92 .addr = client->addr,
93 .len = 1,
94 .buf = &reg,
97 .addr = client->addr,
98 .flags = I2C_M_RD,
99 .len = length,
100 .buf = buf
104 if ((i2c_transfer(client->adapter, msgs, 2)) != 2) {
105 dev_err(&client->dev, "%s: read error\n", __func__);
106 return -EIO;
109 return 0;
112 static int pcf8563_write_block_data(struct i2c_client *client,
113 unsigned char reg, unsigned char length,
114 unsigned char *buf)
116 int i, err;
118 for (i = 0; i < length; i++) {
119 unsigned char data[2] = { reg + i, buf[i] };
121 err = i2c_master_send(client, data, sizeof(data));
122 if (err != sizeof(data)) {
123 dev_err(&client->dev,
124 "%s: err=%d addr=%02x, data=%02x\n",
125 __func__, err, data[0], data[1]);
126 return -EIO;
130 return 0;
133 static int pcf8563_set_alarm_mode(struct i2c_client *client, bool on)
135 unsigned char buf;
136 int err;
138 err = pcf8563_read_block_data(client, PCF8563_REG_ST2, 1, &buf);
139 if (err < 0)
140 return err;
142 if (on)
143 buf |= PCF8563_BIT_AIE;
144 else
145 buf &= ~PCF8563_BIT_AIE;
147 buf &= ~(PCF8563_BIT_AF | PCF8563_BITS_ST2_N);
149 err = pcf8563_write_block_data(client, PCF8563_REG_ST2, 1, &buf);
150 if (err < 0) {
151 dev_err(&client->dev, "%s: write error\n", __func__);
152 return -EIO;
155 return 0;
158 static int pcf8563_get_alarm_mode(struct i2c_client *client, unsigned char *en,
159 unsigned char *pen)
161 unsigned char buf;
162 int err;
164 err = pcf8563_read_block_data(client, PCF8563_REG_ST2, 1, &buf);
165 if (err)
166 return err;
168 if (en)
169 *en = !!(buf & PCF8563_BIT_AIE);
170 if (pen)
171 *pen = !!(buf & PCF8563_BIT_AF);
173 return 0;
176 static irqreturn_t pcf8563_irq(int irq, void *dev_id)
178 struct pcf8563 *pcf8563 = i2c_get_clientdata(dev_id);
179 int err;
180 char pending;
182 err = pcf8563_get_alarm_mode(pcf8563->client, NULL, &pending);
183 if (err)
184 return IRQ_NONE;
186 if (pending) {
187 rtc_update_irq(pcf8563->rtc, 1, RTC_IRQF | RTC_AF);
188 pcf8563_set_alarm_mode(pcf8563->client, 1);
189 return IRQ_HANDLED;
192 return IRQ_NONE;
196 * In the routines that deal directly with the pcf8563 hardware, we use
197 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
199 static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
201 struct i2c_client *client = to_i2c_client(dev);
202 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
203 unsigned char buf[9];
204 int err;
206 err = pcf8563_read_block_data(client, PCF8563_REG_ST1, 9, buf);
207 if (err)
208 return err;
210 if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) {
211 pcf8563->voltage_low = 1;
212 dev_err(&client->dev,
213 "low voltage detected, date/time is not reliable.\n");
214 return -EINVAL;
217 dev_dbg(&client->dev,
218 "%s: raw data is st1=%02x, st2=%02x, sec=%02x, min=%02x, hr=%02x, "
219 "mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
220 __func__,
221 buf[0], buf[1], buf[2], buf[3],
222 buf[4], buf[5], buf[6], buf[7],
223 buf[8]);
226 tm->tm_sec = bcd2bin(buf[PCF8563_REG_SC] & 0x7F);
227 tm->tm_min = bcd2bin(buf[PCF8563_REG_MN] & 0x7F);
228 tm->tm_hour = bcd2bin(buf[PCF8563_REG_HR] & 0x3F); /* rtc hr 0-23 */
229 tm->tm_mday = bcd2bin(buf[PCF8563_REG_DM] & 0x3F);
230 tm->tm_wday = buf[PCF8563_REG_DW] & 0x07;
231 tm->tm_mon = bcd2bin(buf[PCF8563_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
232 tm->tm_year = bcd2bin(buf[PCF8563_REG_YR]) + 100;
233 /* detect the polarity heuristically. see note above. */
234 pcf8563->c_polarity = (buf[PCF8563_REG_MO] & PCF8563_MO_C) ?
235 (tm->tm_year >= 100) : (tm->tm_year < 100);
237 dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
238 "mday=%d, mon=%d, year=%d, wday=%d\n",
239 __func__,
240 tm->tm_sec, tm->tm_min, tm->tm_hour,
241 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
243 return 0;
246 static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
248 struct i2c_client *client = to_i2c_client(dev);
249 struct pcf8563 *pcf8563 = i2c_get_clientdata(client);
250 unsigned char buf[9];
252 dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
253 "mday=%d, mon=%d, year=%d, wday=%d\n",
254 __func__,
255 tm->tm_sec, tm->tm_min, tm->tm_hour,
256 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
258 /* hours, minutes and seconds */
259 buf[PCF8563_REG_SC] = bin2bcd(tm->tm_sec);
260 buf[PCF8563_REG_MN] = bin2bcd(tm->tm_min);
261 buf[PCF8563_REG_HR] = bin2bcd(tm->tm_hour);
263 buf[PCF8563_REG_DM] = bin2bcd(tm->tm_mday);
265 /* month, 1 - 12 */
266 buf[PCF8563_REG_MO] = bin2bcd(tm->tm_mon + 1);
268 /* year and century */
269 buf[PCF8563_REG_YR] = bin2bcd(tm->tm_year - 100);
270 if (pcf8563->c_polarity ? (tm->tm_year >= 100) : (tm->tm_year < 100))
271 buf[PCF8563_REG_MO] |= PCF8563_MO_C;
273 buf[PCF8563_REG_DW] = tm->tm_wday & 0x07;
275 return pcf8563_write_block_data(client, PCF8563_REG_SC,
276 9 - PCF8563_REG_SC, buf + PCF8563_REG_SC);
279 #ifdef CONFIG_RTC_INTF_DEV
280 static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
282 struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev));
283 struct rtc_time tm;
285 switch (cmd) {
286 case RTC_VL_READ:
287 if (pcf8563->voltage_low)
288 dev_info(dev, "low voltage detected, date/time is not reliable.\n");
290 if (copy_to_user((void __user *)arg, &pcf8563->voltage_low,
291 sizeof(int)))
292 return -EFAULT;
293 return 0;
294 case RTC_VL_CLR:
296 * Clear the VL bit in the seconds register in case
297 * the time has not been set already (which would
298 * have cleared it). This does not really matter
299 * because of the cached voltage_low value but do it
300 * anyway for consistency.
302 if (pcf8563_rtc_read_time(dev, &tm))
303 pcf8563_rtc_set_time(dev, &tm);
305 /* Clear the cached value. */
306 pcf8563->voltage_low = 0;
308 return 0;
309 default:
310 return -ENOIOCTLCMD;
313 #else
314 #define pcf8563_rtc_ioctl NULL
315 #endif
317 static int pcf8563_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
319 struct i2c_client *client = to_i2c_client(dev);
320 unsigned char buf[4];
321 int err;
323 err = pcf8563_read_block_data(client, PCF8563_REG_AMN, 4, buf);
324 if (err)
325 return err;
327 dev_dbg(&client->dev,
328 "%s: raw data is min=%02x, hr=%02x, mday=%02x, wday=%02x\n",
329 __func__, buf[0], buf[1], buf[2], buf[3]);
331 tm->time.tm_sec = 0;
332 tm->time.tm_min = bcd2bin(buf[0] & 0x7F);
333 tm->time.tm_hour = bcd2bin(buf[1] & 0x3F);
334 tm->time.tm_mday = bcd2bin(buf[2] & 0x3F);
335 tm->time.tm_wday = bcd2bin(buf[3] & 0x7);
337 err = pcf8563_get_alarm_mode(client, &tm->enabled, &tm->pending);
338 if (err < 0)
339 return err;
341 dev_dbg(&client->dev, "%s: tm is mins=%d, hours=%d, mday=%d, wday=%d,"
342 " enabled=%d, pending=%d\n", __func__, tm->time.tm_min,
343 tm->time.tm_hour, tm->time.tm_mday, tm->time.tm_wday,
344 tm->enabled, tm->pending);
346 return 0;
349 static int pcf8563_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm)
351 struct i2c_client *client = to_i2c_client(dev);
352 unsigned char buf[4];
353 int err;
355 /* The alarm has no seconds, round up to nearest minute */
356 if (tm->time.tm_sec) {
357 time64_t alarm_time = rtc_tm_to_time64(&tm->time);
359 alarm_time += 60 - tm->time.tm_sec;
360 rtc_time64_to_tm(alarm_time, &tm->time);
363 dev_dbg(dev, "%s, min=%d hour=%d wday=%d mday=%d "
364 "enabled=%d pending=%d\n", __func__,
365 tm->time.tm_min, tm->time.tm_hour, tm->time.tm_wday,
366 tm->time.tm_mday, tm->enabled, tm->pending);
368 buf[0] = bin2bcd(tm->time.tm_min);
369 buf[1] = bin2bcd(tm->time.tm_hour);
370 buf[2] = bin2bcd(tm->time.tm_mday);
371 buf[3] = tm->time.tm_wday & 0x07;
373 err = pcf8563_write_block_data(client, PCF8563_REG_AMN, 4, buf);
374 if (err)
375 return err;
377 return pcf8563_set_alarm_mode(client, !!tm->enabled);
380 static int pcf8563_irq_enable(struct device *dev, unsigned int enabled)
382 dev_dbg(dev, "%s: en=%d\n", __func__, enabled);
383 return pcf8563_set_alarm_mode(to_i2c_client(dev), !!enabled);
386 #ifdef CONFIG_COMMON_CLK
388 * Handling of the clkout
391 #define clkout_hw_to_pcf8563(_hw) container_of(_hw, struct pcf8563, clkout_hw)
393 static const int clkout_rates[] = {
394 32768,
395 1024,
400 static unsigned long pcf8563_clkout_recalc_rate(struct clk_hw *hw,
401 unsigned long parent_rate)
403 struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
404 struct i2c_client *client = pcf8563->client;
405 unsigned char buf;
406 int ret = pcf8563_read_block_data(client, PCF8563_REG_CLKO, 1, &buf);
408 if (ret < 0)
409 return 0;
411 buf &= PCF8563_REG_CLKO_F_MASK;
412 return clkout_rates[buf];
415 static long pcf8563_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
416 unsigned long *prate)
418 int i;
420 for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
421 if (clkout_rates[i] <= rate)
422 return clkout_rates[i];
424 return 0;
427 static int pcf8563_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
428 unsigned long parent_rate)
430 struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
431 struct i2c_client *client = pcf8563->client;
432 unsigned char buf;
433 int ret = pcf8563_read_block_data(client, PCF8563_REG_CLKO, 1, &buf);
434 int i;
436 if (ret < 0)
437 return ret;
439 for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
440 if (clkout_rates[i] == rate) {
441 buf &= ~PCF8563_REG_CLKO_F_MASK;
442 buf |= i;
443 ret = pcf8563_write_block_data(client,
444 PCF8563_REG_CLKO, 1,
445 &buf);
446 return ret;
449 return -EINVAL;
452 static int pcf8563_clkout_control(struct clk_hw *hw, bool enable)
454 struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
455 struct i2c_client *client = pcf8563->client;
456 unsigned char buf;
457 int ret = pcf8563_read_block_data(client, PCF8563_REG_CLKO, 1, &buf);
459 if (ret < 0)
460 return ret;
462 if (enable)
463 buf |= PCF8563_REG_CLKO_FE;
464 else
465 buf &= ~PCF8563_REG_CLKO_FE;
467 ret = pcf8563_write_block_data(client, PCF8563_REG_CLKO, 1, &buf);
468 return ret;
471 static int pcf8563_clkout_prepare(struct clk_hw *hw)
473 return pcf8563_clkout_control(hw, 1);
476 static void pcf8563_clkout_unprepare(struct clk_hw *hw)
478 pcf8563_clkout_control(hw, 0);
481 static int pcf8563_clkout_is_prepared(struct clk_hw *hw)
483 struct pcf8563 *pcf8563 = clkout_hw_to_pcf8563(hw);
484 struct i2c_client *client = pcf8563->client;
485 unsigned char buf;
486 int ret = pcf8563_read_block_data(client, PCF8563_REG_CLKO, 1, &buf);
488 if (ret < 0)
489 return ret;
491 return !!(buf & PCF8563_REG_CLKO_FE);
494 static const struct clk_ops pcf8563_clkout_ops = {
495 .prepare = pcf8563_clkout_prepare,
496 .unprepare = pcf8563_clkout_unprepare,
497 .is_prepared = pcf8563_clkout_is_prepared,
498 .recalc_rate = pcf8563_clkout_recalc_rate,
499 .round_rate = pcf8563_clkout_round_rate,
500 .set_rate = pcf8563_clkout_set_rate,
503 static struct clk *pcf8563_clkout_register_clk(struct pcf8563 *pcf8563)
505 struct i2c_client *client = pcf8563->client;
506 struct device_node *node = client->dev.of_node;
507 struct clk *clk;
508 struct clk_init_data init;
509 int ret;
510 unsigned char buf;
512 /* disable the clkout output */
513 buf = 0;
514 ret = pcf8563_write_block_data(client, PCF8563_REG_CLKO, 1, &buf);
515 if (ret < 0)
516 return ERR_PTR(ret);
518 init.name = "pcf8563-clkout";
519 init.ops = &pcf8563_clkout_ops;
520 init.flags = 0;
521 init.parent_names = NULL;
522 init.num_parents = 0;
523 pcf8563->clkout_hw.init = &init;
525 /* optional override of the clockname */
526 of_property_read_string(node, "clock-output-names", &init.name);
528 /* register the clock */
529 clk = devm_clk_register(&client->dev, &pcf8563->clkout_hw);
531 if (!IS_ERR(clk))
532 of_clk_add_provider(node, of_clk_src_simple_get, clk);
534 return clk;
536 #endif
538 static const struct rtc_class_ops pcf8563_rtc_ops = {
539 .ioctl = pcf8563_rtc_ioctl,
540 .read_time = pcf8563_rtc_read_time,
541 .set_time = pcf8563_rtc_set_time,
542 .read_alarm = pcf8563_rtc_read_alarm,
543 .set_alarm = pcf8563_rtc_set_alarm,
544 .alarm_irq_enable = pcf8563_irq_enable,
547 static int pcf8563_probe(struct i2c_client *client,
548 const struct i2c_device_id *id)
550 struct pcf8563 *pcf8563;
551 int err;
552 unsigned char buf;
554 dev_dbg(&client->dev, "%s\n", __func__);
556 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
557 return -ENODEV;
559 pcf8563 = devm_kzalloc(&client->dev, sizeof(struct pcf8563),
560 GFP_KERNEL);
561 if (!pcf8563)
562 return -ENOMEM;
564 i2c_set_clientdata(client, pcf8563);
565 pcf8563->client = client;
566 device_set_wakeup_capable(&client->dev, 1);
568 /* Set timer to lowest frequency to save power (ref Haoyu datasheet) */
569 buf = PCF8563_TMRC_1_60;
570 err = pcf8563_write_block_data(client, PCF8563_REG_TMRC, 1, &buf);
571 if (err < 0) {
572 dev_err(&client->dev, "%s: write error\n", __func__);
573 return err;
576 /* Clear flags and disable interrupts */
577 buf = 0;
578 err = pcf8563_write_block_data(client, PCF8563_REG_ST2, 1, &buf);
579 if (err < 0) {
580 dev_err(&client->dev, "%s: write error\n", __func__);
581 return err;
584 pcf8563->rtc = devm_rtc_allocate_device(&client->dev);
585 if (IS_ERR(pcf8563->rtc))
586 return PTR_ERR(pcf8563->rtc);
588 pcf8563->rtc->ops = &pcf8563_rtc_ops;
589 /* the pcf8563 alarm only supports a minute accuracy */
590 pcf8563->rtc->uie_unsupported = 1;
591 pcf8563->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
592 pcf8563->rtc->range_max = RTC_TIMESTAMP_END_2099;
593 pcf8563->rtc->set_start_time = true;
595 if (client->irq > 0) {
596 err = devm_request_threaded_irq(&client->dev, client->irq,
597 NULL, pcf8563_irq,
598 IRQF_SHARED | IRQF_ONESHOT | IRQF_TRIGGER_LOW,
599 pcf8563_driver.driver.name, client);
600 if (err) {
601 dev_err(&client->dev, "unable to request IRQ %d\n",
602 client->irq);
603 return err;
607 err = rtc_register_device(pcf8563->rtc);
608 if (err)
609 return err;
611 #ifdef CONFIG_COMMON_CLK
612 /* register clk in common clk framework */
613 pcf8563_clkout_register_clk(pcf8563);
614 #endif
616 return 0;
619 static const struct i2c_device_id pcf8563_id[] = {
620 { "pcf8563", 0 },
621 { "rtc8564", 0 },
624 MODULE_DEVICE_TABLE(i2c, pcf8563_id);
626 #ifdef CONFIG_OF
627 static const struct of_device_id pcf8563_of_match[] = {
628 { .compatible = "nxp,pcf8563" },
629 { .compatible = "epson,rtc8564" },
630 { .compatible = "microcrystal,rv8564" },
633 MODULE_DEVICE_TABLE(of, pcf8563_of_match);
634 #endif
636 static struct i2c_driver pcf8563_driver = {
637 .driver = {
638 .name = "rtc-pcf8563",
639 .of_match_table = of_match_ptr(pcf8563_of_match),
641 .probe = pcf8563_probe,
642 .id_table = pcf8563_id,
645 module_i2c_driver(pcf8563_driver);
647 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
648 MODULE_DESCRIPTION("Philips PCF8563/Epson RTC8564 RTC driver");
649 MODULE_LICENSE("GPL");