1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Real-time clock driver for MPC5121
4 *
5 * Copyright 2007, Domen Puncer <domen.puncer@telargo.com>
6 * Copyright 2008, Freescale Semiconductor, Inc. All rights reserved.
7 * Copyright 2011, Dmitry Eremin-Solenikov
8 */
9
10#include <linux/init.h>
11#include <linux/module.h>
12#include <linux/rtc.h>
13#include <linux/of.h>
14#include <linux/of_irq.h>
15#include <linux/platform_device.h>
16#include <linux/io.h>
17#include <linux/slab.h>
18
19struct mpc5121_rtc_regs {
20	u8 set_time;		/* RTC + 0x00 */
21	u8 hour_set;		/* RTC + 0x01 */
22	u8 minute_set;		/* RTC + 0x02 */
23	u8 second_set;		/* RTC + 0x03 */
24
25	u8 set_date;		/* RTC + 0x04 */
26	u8 month_set;		/* RTC + 0x05 */
27	u8 weekday_set;		/* RTC + 0x06 */
28	u8 date_set;		/* RTC + 0x07 */
29
30	u8 write_sw;		/* RTC + 0x08 */
31	u8 sw_set;		/* RTC + 0x09 */
32	u16 year_set;		/* RTC + 0x0a */
33
34	u8 alm_enable;		/* RTC + 0x0c */
35	u8 alm_hour_set;	/* RTC + 0x0d */
36	u8 alm_min_set;		/* RTC + 0x0e */
37	u8 int_enable;		/* RTC + 0x0f */
38
39	u8 reserved1;
40	u8 hour;		/* RTC + 0x11 */
41	u8 minute;		/* RTC + 0x12 */
42	u8 second;		/* RTC + 0x13 */
43
44	u8 month;		/* RTC + 0x14 */
45	u8 wday_mday;		/* RTC + 0x15 */
46	u16 year;		/* RTC + 0x16 */
47
48	u8 int_alm;		/* RTC + 0x18 */
49	u8 int_sw;		/* RTC + 0x19 */
50	u8 alm_status;		/* RTC + 0x1a */
51	u8 sw_minute;		/* RTC + 0x1b */
52
53	u8 bus_error_1;		/* RTC + 0x1c */
54	u8 int_day;		/* RTC + 0x1d */
55	u8 int_min;		/* RTC + 0x1e */
56	u8 int_sec;		/* RTC + 0x1f */
57
58	/*
59	 * target_time:
60	 *	intended to be used for hibernation but hibernation
61	 *	does not work on silicon rev 1.5 so use it for non-volatile
62	 *	storage of offset between the actual_time register and linux
63	 *	time
64	 */
65	u32 target_time;	/* RTC + 0x20 */
66	/*
67	 * actual_time:
68	 *	readonly time since VBAT_RTC was last connected
69	 */
70	u32 actual_time;	/* RTC + 0x24 */
71	u32 keep_alive;		/* RTC + 0x28 */
72};
73
74struct mpc5121_rtc_data {
75	unsigned irq;
76	unsigned irq_periodic;
77	struct mpc5121_rtc_regs __iomem *regs;
78	struct rtc_device *rtc;
79	struct rtc_wkalrm wkalarm;
80};
81
82/*
83 * Update second/minute/hour registers.
84 *
85 * This is just so alarm will work.
86 */
87static void mpc5121_rtc_update_smh(struct mpc5121_rtc_regs __iomem *regs,
88				   struct rtc_time *tm)
89{
90	out_8(&regs->second_set, tm->tm_sec);
91	out_8(&regs->minute_set, tm->tm_min);
92	out_8(&regs->hour_set, tm->tm_hour);
93
94	/* set time sequence */
95	out_8(&regs->set_time, 0x1);
96	out_8(&regs->set_time, 0x3);
97	out_8(&regs->set_time, 0x1);
98	out_8(&regs->set_time, 0x0);
99}
100
101static int mpc5121_rtc_read_time(struct device *dev, struct rtc_time *tm)
102{
103	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
104	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
105	unsigned long now;
106
107	/*
108	 * linux time is actual_time plus the offset saved in target_time
109	 */
110	now = in_be32(&regs->actual_time) + in_be32(&regs->target_time);
111
112	rtc_time64_to_tm(now, tm);
113
114	/*
115	 * update second minute hour registers
116	 * so alarms will work
117	 */
118	mpc5121_rtc_update_smh(regs, tm);
119
120	return 0;
121}
122
123static int mpc5121_rtc_set_time(struct device *dev, struct rtc_time *tm)
124{
125	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
126	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
127	unsigned long now;
128
129	/*
130	 * The actual_time register is read only so we write the offset
131	 * between it and linux time to the target_time register.
132	 */
133	now = rtc_tm_to_time64(tm);
134	out_be32(&regs->target_time, now - in_be32(&regs->actual_time));
135
136	/*
137	 * update second minute hour registers
138	 * so alarms will work
139	 */
140	mpc5121_rtc_update_smh(regs, tm);
141
142	return 0;
143}
144
145static int mpc5200_rtc_read_time(struct device *dev, struct rtc_time *tm)
146{
147	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
148	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
149	int tmp;
150
151	tm->tm_sec = in_8(&regs->second);
152	tm->tm_min = in_8(&regs->minute);
153
154	/* 12 hour format? */
155	if (in_8(&regs->hour) & 0x20)
156		tm->tm_hour = (in_8(&regs->hour) >> 1) +
157			(in_8(&regs->hour) & 1 ? 12 : 0);
158	else
159		tm->tm_hour = in_8(&regs->hour);
160
161	tmp = in_8(&regs->wday_mday);
162	tm->tm_mday = tmp & 0x1f;
163	tm->tm_mon = in_8(&regs->month) - 1;
164	tm->tm_year = in_be16(&regs->year) - 1900;
165	tm->tm_wday = (tmp >> 5) % 7;
166	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
167	tm->tm_isdst = 0;
168
169	return 0;
170}
171
172static int mpc5200_rtc_set_time(struct device *dev, struct rtc_time *tm)
173{
174	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
175	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
176
177	mpc5121_rtc_update_smh(regs, tm);
178
179	/* date */
180	out_8(&regs->month_set, tm->tm_mon + 1);
181	out_8(&regs->weekday_set, tm->tm_wday ? tm->tm_wday : 7);
182	out_8(&regs->date_set, tm->tm_mday);
183	out_be16(&regs->year_set, tm->tm_year + 1900);
184
185	/* set date sequence */
186	out_8(&regs->set_date, 0x1);
187	out_8(&regs->set_date, 0x3);
188	out_8(&regs->set_date, 0x1);
189	out_8(&regs->set_date, 0x0);
190
191	return 0;
192}
193
194static int mpc5121_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
195{
196	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
197	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
198
199	*alarm = rtc->wkalarm;
200
201	alarm->pending = in_8(&regs->alm_status);
202
203	return 0;
204}
205
206static int mpc5121_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
207{
208	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
209	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
210
211	alarm->time.tm_mday = -1;
212	alarm->time.tm_mon = -1;
213	alarm->time.tm_year = -1;
214
215	out_8(&regs->alm_min_set, alarm->time.tm_min);
216	out_8(&regs->alm_hour_set, alarm->time.tm_hour);
217
218	out_8(&regs->alm_enable, alarm->enabled);
219
220	rtc->wkalarm = *alarm;
221	return 0;
222}
223
224static irqreturn_t mpc5121_rtc_handler(int irq, void *dev)
225{
226	struct mpc5121_rtc_data *rtc = dev_get_drvdata((struct device *)dev);
227	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
228
229	if (in_8(&regs->int_alm)) {
230		/* acknowledge and clear status */
231		out_8(&regs->int_alm, 1);
232		out_8(&regs->alm_status, 1);
233
234		rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
235		return IRQ_HANDLED;
236	}
237
238	return IRQ_NONE;
239}
240
241static irqreturn_t mpc5121_rtc_handler_upd(int irq, void *dev)
242{
243	struct mpc5121_rtc_data *rtc = dev_get_drvdata((struct device *)dev);
244	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
245
246	if (in_8(&regs->int_sec) && (in_8(&regs->int_enable) & 0x1)) {
247		/* acknowledge */
248		out_8(&regs->int_sec, 1);
249
250		rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_UF);
251		return IRQ_HANDLED;
252	}
253
254	return IRQ_NONE;
255}
256
257static int mpc5121_rtc_alarm_irq_enable(struct device *dev,
258					unsigned int enabled)
259{
260	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
261	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
262	int val;
263
264	if (enabled)
265		val = 1;
266	else
267		val = 0;
268
269	out_8(&regs->alm_enable, val);
270	rtc->wkalarm.enabled = val;
271
272	return 0;
273}
274
275static const struct rtc_class_ops mpc5121_rtc_ops = {
276	.read_time = mpc5121_rtc_read_time,
277	.set_time = mpc5121_rtc_set_time,
278	.read_alarm = mpc5121_rtc_read_alarm,
279	.set_alarm = mpc5121_rtc_set_alarm,
280	.alarm_irq_enable = mpc5121_rtc_alarm_irq_enable,
281};
282
283static const struct rtc_class_ops mpc5200_rtc_ops = {
284	.read_time = mpc5200_rtc_read_time,
285	.set_time = mpc5200_rtc_set_time,
286	.read_alarm = mpc5121_rtc_read_alarm,
287	.set_alarm = mpc5121_rtc_set_alarm,
288	.alarm_irq_enable = mpc5121_rtc_alarm_irq_enable,
289};
290
291static int mpc5121_rtc_probe(struct platform_device *op)
292{
293	struct mpc5121_rtc_data *rtc;
294	int err = 0;
295
296	rtc = devm_kzalloc(&op->dev, sizeof(*rtc), GFP_KERNEL);
297	if (!rtc)
298		return -ENOMEM;
299
300	rtc->regs = devm_platform_ioremap_resource(op, 0);
301	if (IS_ERR(rtc->regs)) {
302		dev_err(&op->dev, "%s: couldn't map io space\n", __func__);
303		return PTR_ERR(rtc->regs);
304	}
305
306	device_init_wakeup(&op->dev, 1);
307
308	platform_set_drvdata(op, rtc);
309
310	rtc->irq = irq_of_parse_and_map(op->dev.of_node, 1);
311	err = devm_request_irq(&op->dev, rtc->irq, mpc5121_rtc_handler, 0,
312			       "mpc5121-rtc", &op->dev);
313	if (err) {
314		dev_err(&op->dev, "%s: could not request irq: %i\n",
315							__func__, rtc->irq);
316		goto out_dispose;
317	}
318
319	rtc->irq_periodic = irq_of_parse_and_map(op->dev.of_node, 0);
320	err = devm_request_irq(&op->dev, rtc->irq_periodic,
321			       mpc5121_rtc_handler_upd, 0, "mpc5121-rtc_upd",
322			       &op->dev);
323	if (err) {
324		dev_err(&op->dev, "%s: could not request irq: %i\n",
325						__func__, rtc->irq_periodic);
326		goto out_dispose2;
327	}
328
329	rtc->rtc = devm_rtc_allocate_device(&op->dev);
330	if (IS_ERR(rtc->rtc)) {
331		err = PTR_ERR(rtc->rtc);
332		goto out_dispose2;
333	}
334
335	rtc->rtc->ops = &mpc5200_rtc_ops;
336	set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->rtc->features);
337	clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->rtc->features);
338	rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_0000;
339	rtc->rtc->range_max = 65733206399ULL; /* 4052-12-31 23:59:59 */
340
341	if (of_device_is_compatible(op->dev.of_node, "fsl,mpc5121-rtc")) {
342		u32 ka;
343		ka = in_be32(&rtc->regs->keep_alive);
344		if (ka & 0x02) {
345			dev_warn(&op->dev,
346				"mpc5121-rtc: Battery or oscillator failure!\n");
347			out_be32(&rtc->regs->keep_alive, ka);
348		}
349		rtc->rtc->ops = &mpc5121_rtc_ops;
350		/*
351		 * This is a limitation of the driver that abuses the target
352		 * time register, the actual maximum year for the mpc5121 is
353		 * also 4052.
354		 */
355		rtc->rtc->range_min = 0;
356		rtc->rtc->range_max = U32_MAX;
357	}
358
359	err = devm_rtc_register_device(rtc->rtc);
360	if (err)
361		goto out_dispose2;
362
363	return 0;
364
365out_dispose2:
366	irq_dispose_mapping(rtc->irq_periodic);
367out_dispose:
368	irq_dispose_mapping(rtc->irq);
369
370	return err;
371}
372
373static void mpc5121_rtc_remove(struct platform_device *op)
374{
375	struct mpc5121_rtc_data *rtc = platform_get_drvdata(op);
376	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
377
378	/* disable interrupt, so there are no nasty surprises */
379	out_8(&regs->alm_enable, 0);
380	out_8(&regs->int_enable, in_8(&regs->int_enable) & ~0x1);
381
382	irq_dispose_mapping(rtc->irq);
383	irq_dispose_mapping(rtc->irq_periodic);
384}
385
386#ifdef CONFIG_OF
387static const struct of_device_id mpc5121_rtc_match[] = {
388	{ .compatible = "fsl,mpc5121-rtc", },
389	{ .compatible = "fsl,mpc5200-rtc", },
390	{},
391};
392MODULE_DEVICE_TABLE(of, mpc5121_rtc_match);
393#endif
394
395static struct platform_driver mpc5121_rtc_driver = {
396	.driver = {
397		.name = "mpc5121-rtc",
398		.of_match_table = of_match_ptr(mpc5121_rtc_match),
399	},
400	.probe = mpc5121_rtc_probe,
401	.remove_new = mpc5121_rtc_remove,
402};
403
404module_platform_driver(mpc5121_rtc_driver);
405
406MODULE_LICENSE("GPL");
407MODULE_AUTHOR("John Rigby <jcrigby@gmail.com>");
408