1/*
2 * Real Time Clock driver for Freescale MC13XXX PMIC
3 *
4 * (C) 2009 Sascha Hauer, Pengutronix
5 * (C) 2009 Uwe Kleine-Koenig, Pengutronix
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/mfd/mc13xxx.h>
13#include <linux/platform_device.h>
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/slab.h>
17#include <linux/rtc.h>
18
19#define DRIVER_NAME "mc13xxx-rtc"
20
21#define MC13XXX_RTCTOD	20
22#define MC13XXX_RTCTODA	21
23#define MC13XXX_RTCDAY	22
24#define MC13XXX_RTCDAYA	23
25
26#define SEC_PER_DAY	(24 * 60 * 60)
27
28struct mc13xxx_rtc {
29	struct rtc_device *rtc;
30	struct mc13xxx *mc13xxx;
31	int valid;
32};
33
34static int mc13xxx_rtc_irq_enable_unlocked(struct device *dev,
35		unsigned int enabled, int irq)
36{
37	struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
38	int (*func)(struct mc13xxx *mc13xxx, int irq);
39
40	if (!priv->valid)
41		return -ENODATA;
42
43	func = enabled ? mc13xxx_irq_unmask : mc13xxx_irq_mask;
44	return func(priv->mc13xxx, irq);
45}
46
47static int mc13xxx_rtc_alarm_irq_enable(struct device *dev,
48					unsigned int enabled)
49{
50	struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
51	int ret;
52
53	mc13xxx_lock(priv->mc13xxx);
54
55	ret = mc13xxx_rtc_irq_enable_unlocked(dev, enabled, MC13XXX_IRQ_TODA);
56
57	mc13xxx_unlock(priv->mc13xxx);
58
59	return ret;
60}
61
62static int mc13xxx_rtc_read_time(struct device *dev, struct rtc_time *tm)
63{
64	struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
65	unsigned int seconds, days1, days2;
66
67	if (!priv->valid)
68		return -ENODATA;
69
70	do {
71		int ret;
72
73		ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days1);
74		if (ret)
75			return ret;
76
77		ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTOD, &seconds);
78		if (ret)
79			return ret;
80
81		ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days2);
82		if (ret)
83			return ret;
84	} while (days1 != days2);
85
86	rtc_time64_to_tm((time64_t)days1 * SEC_PER_DAY + seconds, tm);
87
88	return rtc_valid_tm(tm);
89}
90
91static int mc13xxx_rtc_set_mmss(struct device *dev, time64_t secs)
92{
93	struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
94	unsigned int seconds, days;
95	unsigned int alarmseconds;
96	int ret;
97
98	days = div_s64_rem(secs, SEC_PER_DAY, &seconds);
99
100	mc13xxx_lock(priv->mc13xxx);
101
102	/*
103	 * temporarily invalidate alarm to prevent triggering it when the day is
104	 * already updated while the time isn't yet.
105	 */
106	ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTODA, &alarmseconds);
107	if (unlikely(ret))
108		goto out;
109
110	if (alarmseconds < SEC_PER_DAY) {
111		ret = mc13xxx_reg_write(priv->mc13xxx,
112				MC13XXX_RTCTODA, 0x1ffff);
113		if (unlikely(ret))
114			goto out;
115	}
116
117	/*
118	 * write seconds=0 to prevent a day switch between writing days
119	 * and seconds below
120	 */
121	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTOD, 0);
122	if (unlikely(ret))
123		goto out;
124
125	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAY, days);
126	if (unlikely(ret))
127		goto out;
128
129	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTOD, seconds);
130	if (unlikely(ret))
131		goto out;
132
133	/* restore alarm */
134	if (alarmseconds < SEC_PER_DAY) {
135		ret = mc13xxx_reg_write(priv->mc13xxx,
136				MC13XXX_RTCTODA, alarmseconds);
137		if (unlikely(ret))
138			goto out;
139	}
140
141	if (!priv->valid) {
142		ret = mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_RTCRST);
143		if (unlikely(ret))
144			goto out;
145
146		ret = mc13xxx_irq_unmask(priv->mc13xxx, MC13XXX_IRQ_RTCRST);
147	}
148
149out:
150	priv->valid = !ret;
151
152	mc13xxx_unlock(priv->mc13xxx);
153
154	return ret;
155}
156
157static int mc13xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
158{
159	struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
160	unsigned seconds, days;
161	time64_t s1970;
162	int enabled, pending;
163	int ret;
164
165	mc13xxx_lock(priv->mc13xxx);
166
167	ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTODA, &seconds);
168	if (unlikely(ret))
169		goto out;
170	if (seconds >= SEC_PER_DAY) {
171		ret = -ENODATA;
172		goto out;
173	}
174
175	ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days);
176	if (unlikely(ret))
177		goto out;
178
179	ret = mc13xxx_irq_status(priv->mc13xxx, MC13XXX_IRQ_TODA,
180			&enabled, &pending);
181
182out:
183	mc13xxx_unlock(priv->mc13xxx);
184
185	if (ret)
186		return ret;
187
188	alarm->enabled = enabled;
189	alarm->pending = pending;
190
191	s1970 = (time64_t)days * SEC_PER_DAY + seconds;
192
193	rtc_time64_to_tm(s1970, &alarm->time);
194	dev_dbg(dev, "%s: %lld\n", __func__, (long long)s1970);
195
196	return 0;
197}
198
199static int mc13xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
200{
201	struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
202	time64_t s1970;
203	u32 seconds, days;
204	int ret;
205
206	mc13xxx_lock(priv->mc13xxx);
207
208	/* disable alarm to prevent false triggering */
209	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, 0x1ffff);
210	if (unlikely(ret))
211		goto out;
212
213	ret = mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TODA);
214	if (unlikely(ret))
215		goto out;
216
217	s1970 = rtc_tm_to_time64(&alarm->time);
218
219	dev_dbg(dev, "%s: o%2.s %lld\n", __func__, alarm->enabled ? "n" : "ff",
220			(long long)s1970);
221
222	ret = mc13xxx_rtc_irq_enable_unlocked(dev, alarm->enabled,
223			MC13XXX_IRQ_TODA);
224	if (unlikely(ret))
225		goto out;
226
227	days = div_s64_rem(s1970, SEC_PER_DAY, &seconds);
228
229	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAYA, days);
230	if (unlikely(ret))
231		goto out;
232
233	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, seconds);
234
235out:
236	mc13xxx_unlock(priv->mc13xxx);
237
238	return ret;
239}
240
241static irqreturn_t mc13xxx_rtc_alarm_handler(int irq, void *dev)
242{
243	struct mc13xxx_rtc *priv = dev;
244	struct mc13xxx *mc13xxx = priv->mc13xxx;
245
246	rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_AF);
247
248	mc13xxx_irq_ack(mc13xxx, irq);
249
250	return IRQ_HANDLED;
251}
252
253static irqreturn_t mc13xxx_rtc_update_handler(int irq, void *dev)
254{
255	struct mc13xxx_rtc *priv = dev;
256	struct mc13xxx *mc13xxx = priv->mc13xxx;
257
258	rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_UF);
259
260	mc13xxx_irq_ack(mc13xxx, irq);
261
262	return IRQ_HANDLED;
263}
264
265static const struct rtc_class_ops mc13xxx_rtc_ops = {
266	.read_time = mc13xxx_rtc_read_time,
267	.set_mmss64 = mc13xxx_rtc_set_mmss,
268	.read_alarm = mc13xxx_rtc_read_alarm,
269	.set_alarm = mc13xxx_rtc_set_alarm,
270	.alarm_irq_enable = mc13xxx_rtc_alarm_irq_enable,
271};
272
273static irqreturn_t mc13xxx_rtc_reset_handler(int irq, void *dev)
274{
275	struct mc13xxx_rtc *priv = dev;
276	struct mc13xxx *mc13xxx = priv->mc13xxx;
277
278	priv->valid = 0;
279
280	mc13xxx_irq_mask(mc13xxx, irq);
281
282	return IRQ_HANDLED;
283}
284
285static int __init mc13xxx_rtc_probe(struct platform_device *pdev)
286{
287	int ret;
288	struct mc13xxx_rtc *priv;
289	struct mc13xxx *mc13xxx;
290
291	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
292	if (!priv)
293		return -ENOMEM;
294
295	mc13xxx = dev_get_drvdata(pdev->dev.parent);
296	priv->mc13xxx = mc13xxx;
297	priv->valid = 1;
298
299	platform_set_drvdata(pdev, priv);
300
301	mc13xxx_lock(mc13xxx);
302
303	mc13xxx_irq_ack(mc13xxx, MC13XXX_IRQ_RTCRST);
304
305	ret = mc13xxx_irq_request(mc13xxx, MC13XXX_IRQ_RTCRST,
306			mc13xxx_rtc_reset_handler, DRIVER_NAME, priv);
307	if (ret)
308		goto err_irq_request;
309
310	ret = mc13xxx_irq_request(mc13xxx, MC13XXX_IRQ_1HZ,
311			mc13xxx_rtc_update_handler, DRIVER_NAME, priv);
312	if (ret)
313		goto err_irq_request;
314
315	ret = mc13xxx_irq_request_nounmask(mc13xxx, MC13XXX_IRQ_TODA,
316			mc13xxx_rtc_alarm_handler, DRIVER_NAME, priv);
317	if (ret)
318		goto err_irq_request;
319
320	mc13xxx_unlock(mc13xxx);
321
322	priv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
323					     &mc13xxx_rtc_ops, THIS_MODULE);
324
325	return 0;
326
327err_irq_request:
328	mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_TODA, priv);
329	mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_1HZ, priv);
330	mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_RTCRST, priv);
331
332	mc13xxx_unlock(mc13xxx);
333
334	return ret;
335}
336
337static int mc13xxx_rtc_remove(struct platform_device *pdev)
338{
339	struct mc13xxx_rtc *priv = platform_get_drvdata(pdev);
340
341	mc13xxx_lock(priv->mc13xxx);
342
343	mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TODA, priv);
344	mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_1HZ, priv);
345	mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_RTCRST, priv);
346
347	mc13xxx_unlock(priv->mc13xxx);
348
349	return 0;
350}
351
352static const struct platform_device_id mc13xxx_rtc_idtable[] = {
353	{
354		.name = "mc13783-rtc",
355	}, {
356		.name = "mc13892-rtc",
357	}, {
358		.name = "mc34708-rtc",
359	},
360	{ /* sentinel */ }
361};
362MODULE_DEVICE_TABLE(platform, mc13xxx_rtc_idtable);
363
364static struct platform_driver mc13xxx_rtc_driver = {
365	.id_table = mc13xxx_rtc_idtable,
366	.remove = mc13xxx_rtc_remove,
367	.driver = {
368		.name = DRIVER_NAME,
369	},
370};
371
372module_platform_driver_probe(mc13xxx_rtc_driver, &mc13xxx_rtc_probe);
373
374MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
375MODULE_DESCRIPTION("RTC driver for Freescale MC13XXX PMIC");
376MODULE_LICENSE("GPL v2");
377