1/*
2 * Haoyu HYM8563 RTC driver
3 *
4 * Copyright (C) 2013 MundoReader S.L.
5 * Author: Heiko Stuebner <heiko@sntech.de>
6 *
7 * based on rtc-HYM8563
8 * Copyright (C) 2010 ROCKCHIP, Inc.
9 *
10 * This software is licensed under the terms of the GNU General Public
11 * License version 2, as published by the Free Software Foundation, and
12 * may be copied, distributed, and modified under those terms.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 * GNU General Public License for more details.
18 */
19
20#include <linux/module.h>
21#include <linux/clk-provider.h>
22#include <linux/i2c.h>
23#include <linux/bcd.h>
24#include <linux/rtc.h>
25
26#define HYM8563_CTL1		0x00
27#define HYM8563_CTL1_TEST	BIT(7)
28#define HYM8563_CTL1_STOP	BIT(5)
29#define HYM8563_CTL1_TESTC	BIT(3)
30
31#define HYM8563_CTL2		0x01
32#define HYM8563_CTL2_TI_TP	BIT(4)
33#define HYM8563_CTL2_AF		BIT(3)
34#define HYM8563_CTL2_TF		BIT(2)
35#define HYM8563_CTL2_AIE	BIT(1)
36#define HYM8563_CTL2_TIE	BIT(0)
37
38#define HYM8563_SEC		0x02
39#define HYM8563_SEC_VL		BIT(7)
40#define HYM8563_SEC_MASK	0x7f
41
42#define HYM8563_MIN		0x03
43#define HYM8563_MIN_MASK	0x7f
44
45#define HYM8563_HOUR		0x04
46#define HYM8563_HOUR_MASK	0x3f
47
48#define HYM8563_DAY		0x05
49#define HYM8563_DAY_MASK	0x3f
50
51#define HYM8563_WEEKDAY		0x06
52#define HYM8563_WEEKDAY_MASK	0x07
53
54#define HYM8563_MONTH		0x07
55#define HYM8563_MONTH_CENTURY	BIT(7)
56#define HYM8563_MONTH_MASK	0x1f
57
58#define HYM8563_YEAR		0x08
59
60#define HYM8563_ALM_MIN		0x09
61#define HYM8563_ALM_HOUR	0x0a
62#define HYM8563_ALM_DAY		0x0b
63#define HYM8563_ALM_WEEK	0x0c
64
65/* Each alarm check can be disabled by setting this bit in the register */
66#define HYM8563_ALM_BIT_DISABLE	BIT(7)
67
68#define HYM8563_CLKOUT		0x0d
69#define HYM8563_CLKOUT_DISABLE	BIT(7)
70#define HYM8563_CLKOUT_32768	0
71#define HYM8563_CLKOUT_1024	1
72#define HYM8563_CLKOUT_32	2
73#define HYM8563_CLKOUT_1	3
74#define HYM8563_CLKOUT_MASK	3
75
76#define HYM8563_TMR_CTL		0x0e
77#define HYM8563_TMR_CTL_ENABLE	BIT(7)
78#define HYM8563_TMR_CTL_4096	0
79#define HYM8563_TMR_CTL_64	1
80#define HYM8563_TMR_CTL_1	2
81#define HYM8563_TMR_CTL_1_60	3
82#define HYM8563_TMR_CTL_MASK	3
83
84#define HYM8563_TMR_CNT		0x0f
85
86struct hym8563 {
87	struct i2c_client	*client;
88	struct rtc_device	*rtc;
89	bool			valid;
90#ifdef CONFIG_COMMON_CLK
91	struct clk_hw		clkout_hw;
92#endif
93};
94
95/*
96 * RTC handling
97 */
98
99static int hym8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
100{
101	struct i2c_client *client = to_i2c_client(dev);
102	struct hym8563 *hym8563 = i2c_get_clientdata(client);
103	u8 buf[7];
104	int ret;
105
106	if (!hym8563->valid) {
107		dev_warn(&client->dev, "no valid clock/calendar values available\n");
108		return -EPERM;
109	}
110
111	ret = i2c_smbus_read_i2c_block_data(client, HYM8563_SEC, 7, buf);
112
113	tm->tm_sec = bcd2bin(buf[0] & HYM8563_SEC_MASK);
114	tm->tm_min = bcd2bin(buf[1] & HYM8563_MIN_MASK);
115	tm->tm_hour = bcd2bin(buf[2] & HYM8563_HOUR_MASK);
116	tm->tm_mday = bcd2bin(buf[3] & HYM8563_DAY_MASK);
117	tm->tm_wday = bcd2bin(buf[4] & HYM8563_WEEKDAY_MASK); /* 0 = Sun */
118	tm->tm_mon = bcd2bin(buf[5] & HYM8563_MONTH_MASK) - 1; /* 0 = Jan */
119	tm->tm_year = bcd2bin(buf[6]) + 100;
120
121	return 0;
122}
123
124static int hym8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
125{
126	struct i2c_client *client = to_i2c_client(dev);
127	struct hym8563 *hym8563 = i2c_get_clientdata(client);
128	u8 buf[7];
129	int ret;
130
131	/* Years >= 2100 are to far in the future, 19XX is to early */
132	if (tm->tm_year < 100 || tm->tm_year >= 200)
133		return -EINVAL;
134
135	buf[0] = bin2bcd(tm->tm_sec);
136	buf[1] = bin2bcd(tm->tm_min);
137	buf[2] = bin2bcd(tm->tm_hour);
138	buf[3] = bin2bcd(tm->tm_mday);
139	buf[4] = bin2bcd(tm->tm_wday);
140	buf[5] = bin2bcd(tm->tm_mon + 1);
141
142	/*
143	 * While the HYM8563 has a century flag in the month register,
144	 * it does not seem to carry it over a subsequent write/read.
145	 * So we'll limit ourself to 100 years, starting at 2000 for now.
146	 */
147	buf[6] = tm->tm_year - 100;
148
149	/*
150	 * CTL1 only contains TEST-mode bits apart from stop,
151	 * so no need to read the value first
152	 */
153	ret = i2c_smbus_write_byte_data(client, HYM8563_CTL1,
154						HYM8563_CTL1_STOP);
155	if (ret < 0)
156		return ret;
157
158	ret = i2c_smbus_write_i2c_block_data(client, HYM8563_SEC, 7, buf);
159	if (ret < 0)
160		return ret;
161
162	ret = i2c_smbus_write_byte_data(client, HYM8563_CTL1, 0);
163	if (ret < 0)
164		return ret;
165
166	hym8563->valid = true;
167
168	return 0;
169}
170
171static int hym8563_rtc_alarm_irq_enable(struct device *dev,
172					unsigned int enabled)
173{
174	struct i2c_client *client = to_i2c_client(dev);
175	int data;
176
177	data = i2c_smbus_read_byte_data(client, HYM8563_CTL2);
178	if (data < 0)
179		return data;
180
181	if (enabled)
182		data |= HYM8563_CTL2_AIE;
183	else
184		data &= ~HYM8563_CTL2_AIE;
185
186	return i2c_smbus_write_byte_data(client, HYM8563_CTL2, data);
187};
188
189static int hym8563_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
190{
191	struct i2c_client *client = to_i2c_client(dev);
192	struct rtc_time *alm_tm = &alm->time;
193	u8 buf[4];
194	int ret;
195
196	ret = i2c_smbus_read_i2c_block_data(client, HYM8563_ALM_MIN, 4, buf);
197	if (ret < 0)
198		return ret;
199
200	/* The alarm only has a minute accuracy */
201	alm_tm->tm_sec = -1;
202
203	alm_tm->tm_min = (buf[0] & HYM8563_ALM_BIT_DISABLE) ?
204					-1 :
205					bcd2bin(buf[0] & HYM8563_MIN_MASK);
206	alm_tm->tm_hour = (buf[1] & HYM8563_ALM_BIT_DISABLE) ?
207					-1 :
208					bcd2bin(buf[1] & HYM8563_HOUR_MASK);
209	alm_tm->tm_mday = (buf[2] & HYM8563_ALM_BIT_DISABLE) ?
210					-1 :
211					bcd2bin(buf[2] & HYM8563_DAY_MASK);
212	alm_tm->tm_wday = (buf[3] & HYM8563_ALM_BIT_DISABLE) ?
213					-1 :
214					bcd2bin(buf[3] & HYM8563_WEEKDAY_MASK);
215
216	alm_tm->tm_mon = -1;
217	alm_tm->tm_year = -1;
218
219	ret = i2c_smbus_read_byte_data(client, HYM8563_CTL2);
220	if (ret < 0)
221		return ret;
222
223	if (ret & HYM8563_CTL2_AIE)
224		alm->enabled = 1;
225
226	return 0;
227}
228
229static int hym8563_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
230{
231	struct i2c_client *client = to_i2c_client(dev);
232	struct rtc_time *alm_tm = &alm->time;
233	u8 buf[4];
234	int ret;
235
236	/*
237	 * The alarm has no seconds so deal with it
238	 */
239	if (alm_tm->tm_sec) {
240		alm_tm->tm_sec = 0;
241		alm_tm->tm_min++;
242		if (alm_tm->tm_min >= 60) {
243			alm_tm->tm_min = 0;
244			alm_tm->tm_hour++;
245			if (alm_tm->tm_hour >= 24) {
246				alm_tm->tm_hour = 0;
247				alm_tm->tm_mday++;
248				if (alm_tm->tm_mday > 31)
249					alm_tm->tm_mday = 0;
250			}
251		}
252	}
253
254	ret = i2c_smbus_read_byte_data(client, HYM8563_CTL2);
255	if (ret < 0)
256		return ret;
257
258	ret &= ~HYM8563_CTL2_AIE;
259
260	ret = i2c_smbus_write_byte_data(client, HYM8563_CTL2, ret);
261	if (ret < 0)
262		return ret;
263
264	buf[0] = (alm_tm->tm_min < 60 && alm_tm->tm_min >= 0) ?
265			bin2bcd(alm_tm->tm_min) : HYM8563_ALM_BIT_DISABLE;
266
267	buf[1] = (alm_tm->tm_hour < 24 && alm_tm->tm_hour >= 0) ?
268			bin2bcd(alm_tm->tm_hour) : HYM8563_ALM_BIT_DISABLE;
269
270	buf[2] = (alm_tm->tm_mday <= 31 && alm_tm->tm_mday >= 1) ?
271			bin2bcd(alm_tm->tm_mday) : HYM8563_ALM_BIT_DISABLE;
272
273	buf[3] = (alm_tm->tm_wday < 7 && alm_tm->tm_wday >= 0) ?
274			bin2bcd(alm_tm->tm_wday) : HYM8563_ALM_BIT_DISABLE;
275
276	ret = i2c_smbus_write_i2c_block_data(client, HYM8563_ALM_MIN, 4, buf);
277	if (ret < 0)
278		return ret;
279
280	return hym8563_rtc_alarm_irq_enable(dev, alm->enabled);
281}
282
283static const struct rtc_class_ops hym8563_rtc_ops = {
284	.read_time		= hym8563_rtc_read_time,
285	.set_time		= hym8563_rtc_set_time,
286	.alarm_irq_enable	= hym8563_rtc_alarm_irq_enable,
287	.read_alarm		= hym8563_rtc_read_alarm,
288	.set_alarm		= hym8563_rtc_set_alarm,
289};
290
291/*
292 * Handling of the clkout
293 */
294
295#ifdef CONFIG_COMMON_CLK
296#define clkout_hw_to_hym8563(_hw) container_of(_hw, struct hym8563, clkout_hw)
297
298static int clkout_rates[] = {
299	32768,
300	1024,
301	32,
302	1,
303};
304
305static unsigned long hym8563_clkout_recalc_rate(struct clk_hw *hw,
306						unsigned long parent_rate)
307{
308	struct hym8563 *hym8563 = clkout_hw_to_hym8563(hw);
309	struct i2c_client *client = hym8563->client;
310	int ret = i2c_smbus_read_byte_data(client, HYM8563_CLKOUT);
311
312	if (ret < 0 || ret & HYM8563_CLKOUT_DISABLE)
313		return 0;
314
315	ret &= HYM8563_CLKOUT_MASK;
316	return clkout_rates[ret];
317}
318
319static long hym8563_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
320				      unsigned long *prate)
321{
322	int i;
323
324	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
325		if (clkout_rates[i] <= rate)
326			return clkout_rates[i];
327
328	return 0;
329}
330
331static int hym8563_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
332				   unsigned long parent_rate)
333{
334	struct hym8563 *hym8563 = clkout_hw_to_hym8563(hw);
335	struct i2c_client *client = hym8563->client;
336	int ret = i2c_smbus_read_byte_data(client, HYM8563_CLKOUT);
337	int i;
338
339	if (ret < 0)
340		return ret;
341
342	for (i = 0; i < ARRAY_SIZE(clkout_rates); i++)
343		if (clkout_rates[i] == rate) {
344			ret &= ~HYM8563_CLKOUT_MASK;
345			ret |= i;
346			return i2c_smbus_write_byte_data(client,
347							 HYM8563_CLKOUT, ret);
348		}
349
350	return -EINVAL;
351}
352
353static int hym8563_clkout_control(struct clk_hw *hw, bool enable)
354{
355	struct hym8563 *hym8563 = clkout_hw_to_hym8563(hw);
356	struct i2c_client *client = hym8563->client;
357	int ret = i2c_smbus_read_byte_data(client, HYM8563_CLKOUT);
358
359	if (ret < 0)
360		return ret;
361
362	if (enable)
363		ret &= ~HYM8563_CLKOUT_DISABLE;
364	else
365		ret |= HYM8563_CLKOUT_DISABLE;
366
367	return i2c_smbus_write_byte_data(client, HYM8563_CLKOUT, ret);
368}
369
370static int hym8563_clkout_prepare(struct clk_hw *hw)
371{
372	return hym8563_clkout_control(hw, 1);
373}
374
375static void hym8563_clkout_unprepare(struct clk_hw *hw)
376{
377	hym8563_clkout_control(hw, 0);
378}
379
380static int hym8563_clkout_is_prepared(struct clk_hw *hw)
381{
382	struct hym8563 *hym8563 = clkout_hw_to_hym8563(hw);
383	struct i2c_client *client = hym8563->client;
384	int ret = i2c_smbus_read_byte_data(client, HYM8563_CLKOUT);
385
386	if (ret < 0)
387		return ret;
388
389	return !(ret & HYM8563_CLKOUT_DISABLE);
390}
391
392static const struct clk_ops hym8563_clkout_ops = {
393	.prepare = hym8563_clkout_prepare,
394	.unprepare = hym8563_clkout_unprepare,
395	.is_prepared = hym8563_clkout_is_prepared,
396	.recalc_rate = hym8563_clkout_recalc_rate,
397	.round_rate = hym8563_clkout_round_rate,
398	.set_rate = hym8563_clkout_set_rate,
399};
400
401static struct clk *hym8563_clkout_register_clk(struct hym8563 *hym8563)
402{
403	struct i2c_client *client = hym8563->client;
404	struct device_node *node = client->dev.of_node;
405	struct clk *clk;
406	struct clk_init_data init;
407	int ret;
408
409	ret = i2c_smbus_write_byte_data(client, HYM8563_CLKOUT,
410						HYM8563_CLKOUT_DISABLE);
411	if (ret < 0)
412		return ERR_PTR(ret);
413
414	init.name = "hym8563-clkout";
415	init.ops = &hym8563_clkout_ops;
416	init.flags = CLK_IS_ROOT;
417	init.parent_names = NULL;
418	init.num_parents = 0;
419	hym8563->clkout_hw.init = &init;
420
421	/* optional override of the clockname */
422	of_property_read_string(node, "clock-output-names", &init.name);
423
424	/* register the clock */
425	clk = clk_register(&client->dev, &hym8563->clkout_hw);
426
427	if (!IS_ERR(clk))
428		of_clk_add_provider(node, of_clk_src_simple_get, clk);
429
430	return clk;
431}
432#endif
433
434/*
435 * The alarm interrupt is implemented as a level-low interrupt in the
436 * hym8563, while the timer interrupt uses a falling edge.
437 * We don't use the timer at all, so the interrupt is requested to
438 * use the level-low trigger.
439 */
440static irqreturn_t hym8563_irq(int irq, void *dev_id)
441{
442	struct hym8563 *hym8563 = (struct hym8563 *)dev_id;
443	struct i2c_client *client = hym8563->client;
444	struct mutex *lock = &hym8563->rtc->ops_lock;
445	int data, ret;
446
447	mutex_lock(lock);
448
449	/* Clear the alarm flag */
450
451	data = i2c_smbus_read_byte_data(client, HYM8563_CTL2);
452	if (data < 0) {
453		dev_err(&client->dev, "%s: error reading i2c data %d\n",
454			__func__, data);
455		goto out;
456	}
457
458	data &= ~HYM8563_CTL2_AF;
459
460	ret = i2c_smbus_write_byte_data(client, HYM8563_CTL2, data);
461	if (ret < 0) {
462		dev_err(&client->dev, "%s: error writing i2c data %d\n",
463			__func__, ret);
464	}
465
466out:
467	mutex_unlock(lock);
468	return IRQ_HANDLED;
469}
470
471static int hym8563_init_device(struct i2c_client *client)
472{
473	int ret;
474
475	/* Clear stop flag if present */
476	ret = i2c_smbus_write_byte_data(client, HYM8563_CTL1, 0);
477	if (ret < 0)
478		return ret;
479
480	ret = i2c_smbus_read_byte_data(client, HYM8563_CTL2);
481	if (ret < 0)
482		return ret;
483
484	/* Disable alarm and timer interrupts */
485	ret &= ~HYM8563_CTL2_AIE;
486	ret &= ~HYM8563_CTL2_TIE;
487
488	/* Clear any pending alarm and timer flags */
489	if (ret & HYM8563_CTL2_AF)
490		ret &= ~HYM8563_CTL2_AF;
491
492	if (ret & HYM8563_CTL2_TF)
493		ret &= ~HYM8563_CTL2_TF;
494
495	ret &= ~HYM8563_CTL2_TI_TP;
496
497	return i2c_smbus_write_byte_data(client, HYM8563_CTL2, ret);
498}
499
500#ifdef CONFIG_PM_SLEEP
501static int hym8563_suspend(struct device *dev)
502{
503	struct i2c_client *client = to_i2c_client(dev);
504	int ret;
505
506	if (device_may_wakeup(dev)) {
507		ret = enable_irq_wake(client->irq);
508		if (ret) {
509			dev_err(dev, "enable_irq_wake failed, %d\n", ret);
510			return ret;
511		}
512	}
513
514	return 0;
515}
516
517static int hym8563_resume(struct device *dev)
518{
519	struct i2c_client *client = to_i2c_client(dev);
520
521	if (device_may_wakeup(dev))
522		disable_irq_wake(client->irq);
523
524	return 0;
525}
526#endif
527
528static SIMPLE_DEV_PM_OPS(hym8563_pm_ops, hym8563_suspend, hym8563_resume);
529
530static int hym8563_probe(struct i2c_client *client,
531			 const struct i2c_device_id *id)
532{
533	struct hym8563 *hym8563;
534	int ret;
535
536	hym8563 = devm_kzalloc(&client->dev, sizeof(*hym8563), GFP_KERNEL);
537	if (!hym8563)
538		return -ENOMEM;
539
540	hym8563->client = client;
541	i2c_set_clientdata(client, hym8563);
542
543	device_set_wakeup_capable(&client->dev, true);
544
545	ret = hym8563_init_device(client);
546	if (ret) {
547		dev_err(&client->dev, "could not init device, %d\n", ret);
548		return ret;
549	}
550
551	ret = devm_request_threaded_irq(&client->dev, client->irq,
552					NULL, hym8563_irq,
553					IRQF_TRIGGER_LOW | IRQF_ONESHOT,
554					client->name, hym8563);
555	if (ret < 0) {
556		dev_err(&client->dev, "irq %d request failed, %d\n",
557			client->irq, ret);
558		return ret;
559	}
560
561	/* check state of calendar information */
562	ret = i2c_smbus_read_byte_data(client, HYM8563_SEC);
563	if (ret < 0)
564		return ret;
565
566	hym8563->valid = !(ret & HYM8563_SEC_VL);
567	dev_dbg(&client->dev, "rtc information is %s\n",
568		hym8563->valid ? "valid" : "invalid");
569
570	hym8563->rtc = devm_rtc_device_register(&client->dev, client->name,
571						&hym8563_rtc_ops, THIS_MODULE);
572	if (IS_ERR(hym8563->rtc))
573		return PTR_ERR(hym8563->rtc);
574
575	/* the hym8563 alarm only supports a minute accuracy */
576	hym8563->rtc->uie_unsupported = 1;
577
578#ifdef CONFIG_COMMON_CLK
579	hym8563_clkout_register_clk(hym8563);
580#endif
581
582	return 0;
583}
584
585static const struct i2c_device_id hym8563_id[] = {
586	{ "hym8563", 0 },
587	{},
588};
589MODULE_DEVICE_TABLE(i2c, hym8563_id);
590
591static const struct of_device_id hym8563_dt_idtable[] = {
592	{ .compatible = "haoyu,hym8563" },
593	{},
594};
595MODULE_DEVICE_TABLE(of, hym8563_dt_idtable);
596
597static struct i2c_driver hym8563_driver = {
598	.driver		= {
599		.name	= "rtc-hym8563",
600		.owner	= THIS_MODULE,
601		.pm	= &hym8563_pm_ops,
602		.of_match_table	= hym8563_dt_idtable,
603	},
604	.probe		= hym8563_probe,
605	.id_table	= hym8563_id,
606};
607
608module_i2c_driver(hym8563_driver);
609
610MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
611MODULE_DESCRIPTION("HYM8563 RTC driver");
612MODULE_LICENSE("GPL");
613