1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Real Time Clock driver for Freescale MC13XXX PMIC
4 *
5 * (C) 2009 Sascha Hauer, Pengutronix
6 * (C) 2009 Uwe Kleine-Koenig, Pengutronix
7 */
8
9#include <linux/mfd/mc13xxx.h>
10#include <linux/platform_device.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/mod_devicetable.h>
14#include <linux/slab.h>
15#include <linux/rtc.h>
16
17#define DRIVER_NAME "mc13xxx-rtc"
18
19#define MC13XXX_RTCTOD	20
20#define MC13XXX_RTCTODA	21
21#define MC13XXX_RTCDAY	22
22#define MC13XXX_RTCDAYA	23
23
24#define SEC_PER_DAY	(24 * 60 * 60)
25
26struct mc13xxx_rtc {
27	struct rtc_device *rtc;
28	struct mc13xxx *mc13xxx;
29	int valid;
30};
31
32static int mc13xxx_rtc_irq_enable_unlocked(struct device *dev,
33		unsigned int enabled, int irq)
34{
35	struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
36	int (*func)(struct mc13xxx *mc13xxx, int irq);
37
38	if (!priv->valid)
39		return -ENODATA;
40
41	func = enabled ? mc13xxx_irq_unmask : mc13xxx_irq_mask;
42	return func(priv->mc13xxx, irq);
43}
44
45static int mc13xxx_rtc_alarm_irq_enable(struct device *dev,
46					unsigned int enabled)
47{
48	struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
49	int ret;
50
51	mc13xxx_lock(priv->mc13xxx);
52
53	ret = mc13xxx_rtc_irq_enable_unlocked(dev, enabled, MC13XXX_IRQ_TODA);
54
55	mc13xxx_unlock(priv->mc13xxx);
56
57	return ret;
58}
59
60static int mc13xxx_rtc_read_time(struct device *dev, struct rtc_time *tm)
61{
62	struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
63	unsigned int seconds, days1, days2;
64
65	if (!priv->valid)
66		return -ENODATA;
67
68	do {
69		int ret;
70
71		ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days1);
72		if (ret)
73			return ret;
74
75		ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTOD, &seconds);
76		if (ret)
77			return ret;
78
79		ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days2);
80		if (ret)
81			return ret;
82	} while (days1 != days2);
83
84	rtc_time64_to_tm((time64_t)days1 * SEC_PER_DAY + seconds, tm);
85
86	return 0;
87}
88
89static int mc13xxx_rtc_set_time(struct device *dev, struct rtc_time *tm)
90{
91	struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
92	unsigned int seconds, days;
93	unsigned int alarmseconds;
94	int ret;
95
96	days = div_s64_rem(rtc_tm_to_time64(tm), SEC_PER_DAY, &seconds);
97
98	mc13xxx_lock(priv->mc13xxx);
99
100	/*
101	 * temporarily invalidate alarm to prevent triggering it when the day is
102	 * already updated while the time isn't yet.
103	 */
104	ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTODA, &alarmseconds);
105	if (unlikely(ret))
106		goto out;
107
108	if (alarmseconds < SEC_PER_DAY) {
109		ret = mc13xxx_reg_write(priv->mc13xxx,
110				MC13XXX_RTCTODA, 0x1ffff);
111		if (unlikely(ret))
112			goto out;
113	}
114
115	/*
116	 * write seconds=0 to prevent a day switch between writing days
117	 * and seconds below
118	 */
119	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTOD, 0);
120	if (unlikely(ret))
121		goto out;
122
123	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAY, days);
124	if (unlikely(ret))
125		goto out;
126
127	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTOD, seconds);
128	if (unlikely(ret))
129		goto out;
130
131	/* restore alarm */
132	if (alarmseconds < SEC_PER_DAY) {
133		ret = mc13xxx_reg_write(priv->mc13xxx,
134				MC13XXX_RTCTODA, alarmseconds);
135		if (unlikely(ret))
136			goto out;
137	}
138
139	if (!priv->valid) {
140		ret = mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_RTCRST);
141		if (unlikely(ret))
142			goto out;
143
144		ret = mc13xxx_irq_unmask(priv->mc13xxx, MC13XXX_IRQ_RTCRST);
145	}
146
147out:
148	priv->valid = !ret;
149
150	mc13xxx_unlock(priv->mc13xxx);
151
152	return ret;
153}
154
155static int mc13xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
156{
157	struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
158	unsigned int seconds, days;
159	time64_t s1970;
160	int enabled, pending;
161	int ret;
162
163	mc13xxx_lock(priv->mc13xxx);
164
165	ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTODA, &seconds);
166	if (unlikely(ret))
167		goto out;
168	if (seconds >= SEC_PER_DAY) {
169		ret = -ENODATA;
170		goto out;
171	}
172
173	ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days);
174	if (unlikely(ret))
175		goto out;
176
177	ret = mc13xxx_irq_status(priv->mc13xxx, MC13XXX_IRQ_TODA,
178			&enabled, &pending);
179
180out:
181	mc13xxx_unlock(priv->mc13xxx);
182
183	if (ret)
184		return ret;
185
186	alarm->enabled = enabled;
187	alarm->pending = pending;
188
189	s1970 = (time64_t)days * SEC_PER_DAY + seconds;
190
191	rtc_time64_to_tm(s1970, &alarm->time);
192	dev_dbg(dev, "%s: %lld\n", __func__, (long long)s1970);
193
194	return 0;
195}
196
197static int mc13xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
198{
199	struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
200	time64_t s1970;
201	u32 seconds, days;
202	int ret;
203
204	mc13xxx_lock(priv->mc13xxx);
205
206	/* disable alarm to prevent false triggering */
207	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, 0x1ffff);
208	if (unlikely(ret))
209		goto out;
210
211	ret = mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TODA);
212	if (unlikely(ret))
213		goto out;
214
215	s1970 = rtc_tm_to_time64(&alarm->time);
216
217	dev_dbg(dev, "%s: %s %lld\n", __func__, alarm->enabled ? "on" : "off",
218			(long long)s1970);
219
220	ret = mc13xxx_rtc_irq_enable_unlocked(dev, alarm->enabled,
221			MC13XXX_IRQ_TODA);
222	if (unlikely(ret))
223		goto out;
224
225	days = div_s64_rem(s1970, SEC_PER_DAY, &seconds);
226
227	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAYA, days);
228	if (unlikely(ret))
229		goto out;
230
231	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, seconds);
232
233out:
234	mc13xxx_unlock(priv->mc13xxx);
235
236	return ret;
237}
238
239static irqreturn_t mc13xxx_rtc_alarm_handler(int irq, void *dev)
240{
241	struct mc13xxx_rtc *priv = dev;
242	struct mc13xxx *mc13xxx = priv->mc13xxx;
243
244	rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_AF);
245
246	mc13xxx_irq_ack(mc13xxx, irq);
247
248	return IRQ_HANDLED;
249}
250
251static const struct rtc_class_ops mc13xxx_rtc_ops = {
252	.read_time = mc13xxx_rtc_read_time,
253	.set_time = mc13xxx_rtc_set_time,
254	.read_alarm = mc13xxx_rtc_read_alarm,
255	.set_alarm = mc13xxx_rtc_set_alarm,
256	.alarm_irq_enable = mc13xxx_rtc_alarm_irq_enable,
257};
258
259static irqreturn_t mc13xxx_rtc_reset_handler(int irq, void *dev)
260{
261	struct mc13xxx_rtc *priv = dev;
262	struct mc13xxx *mc13xxx = priv->mc13xxx;
263
264	priv->valid = 0;
265
266	mc13xxx_irq_mask(mc13xxx, irq);
267
268	return IRQ_HANDLED;
269}
270
271static int __init mc13xxx_rtc_probe(struct platform_device *pdev)
272{
273	int ret;
274	struct mc13xxx_rtc *priv;
275	struct mc13xxx *mc13xxx;
276
277	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
278	if (!priv)
279		return -ENOMEM;
280
281	mc13xxx = dev_get_drvdata(pdev->dev.parent);
282	priv->mc13xxx = mc13xxx;
283	priv->valid = 1;
284
285	priv->rtc = devm_rtc_allocate_device(&pdev->dev);
286	if (IS_ERR(priv->rtc))
287		return PTR_ERR(priv->rtc);
288	platform_set_drvdata(pdev, priv);
289
290	priv->rtc->ops = &mc13xxx_rtc_ops;
291	/* 15bit days + hours, minutes, seconds */
292	priv->rtc->range_max = (timeu64_t)(1 << 15) * SEC_PER_DAY - 1;
293
294	mc13xxx_lock(mc13xxx);
295
296	mc13xxx_irq_ack(mc13xxx, MC13XXX_IRQ_RTCRST);
297
298	ret = mc13xxx_irq_request(mc13xxx, MC13XXX_IRQ_RTCRST,
299			mc13xxx_rtc_reset_handler, DRIVER_NAME, priv);
300	if (ret)
301		goto err_irq_request;
302
303	ret = mc13xxx_irq_request_nounmask(mc13xxx, MC13XXX_IRQ_TODA,
304			mc13xxx_rtc_alarm_handler, DRIVER_NAME, priv);
305	if (ret)
306		goto err_irq_request;
307
308	mc13xxx_unlock(mc13xxx);
309
310	ret = devm_rtc_register_device(priv->rtc);
311	if (ret) {
312		mc13xxx_lock(mc13xxx);
313		goto err_irq_request;
314	}
315
316	return 0;
317
318err_irq_request:
319	mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_TODA, priv);
320	mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_RTCRST, priv);
321
322	mc13xxx_unlock(mc13xxx);
323
324	return ret;
325}
326
327static void mc13xxx_rtc_remove(struct platform_device *pdev)
328{
329	struct mc13xxx_rtc *priv = platform_get_drvdata(pdev);
330
331	mc13xxx_lock(priv->mc13xxx);
332
333	mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TODA, priv);
334	mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_RTCRST, priv);
335
336	mc13xxx_unlock(priv->mc13xxx);
337}
338
339static const struct platform_device_id mc13xxx_rtc_idtable[] = {
340	{
341		.name = "mc13783-rtc",
342	}, {
343		.name = "mc13892-rtc",
344	}, {
345		.name = "mc34708-rtc",
346	},
347	{ /* sentinel */ }
348};
349MODULE_DEVICE_TABLE(platform, mc13xxx_rtc_idtable);
350
351static struct platform_driver mc13xxx_rtc_driver = {
352	.id_table = mc13xxx_rtc_idtable,
353	.remove_new = mc13xxx_rtc_remove,
354	.driver = {
355		.name = DRIVER_NAME,
356	},
357};
358
359module_platform_driver_probe(mc13xxx_rtc_driver, &mc13xxx_rtc_probe);
360
361MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
362MODULE_DESCRIPTION("RTC driver for Freescale MC13XXX PMIC");
363MODULE_LICENSE("GPL v2");
364