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_time_to_tm(days1 * SEC_PER_DAY + seconds, tm);
87
88	return rtc_valid_tm(tm);
89}
90
91static int mc13xxx_rtc_set_mmss(struct device *dev, unsigned long 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	seconds = secs % SEC_PER_DAY;
99	days = secs / SEC_PER_DAY;
100
101	mc13xxx_lock(priv->mc13xxx);
102
103	/*
104	 * temporarily invalidate alarm to prevent triggering it when the day is
105	 * already updated while the time isn't yet.
106	 */
107	ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTODA, &alarmseconds);
108	if (unlikely(ret))
109		goto out;
110
111	if (alarmseconds < SEC_PER_DAY) {
112		ret = mc13xxx_reg_write(priv->mc13xxx,
113				MC13XXX_RTCTODA, 0x1ffff);
114		if (unlikely(ret))
115			goto out;
116	}
117
118	/*
119	 * write seconds=0 to prevent a day switch between writing days
120	 * and seconds below
121	 */
122	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTOD, 0);
123	if (unlikely(ret))
124		goto out;
125
126	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAY, days);
127	if (unlikely(ret))
128		goto out;
129
130	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTOD, seconds);
131	if (unlikely(ret))
132		goto out;
133
134	/* restore alarm */
135	if (alarmseconds < SEC_PER_DAY) {
136		ret = mc13xxx_reg_write(priv->mc13xxx,
137				MC13XXX_RTCTODA, alarmseconds);
138		if (unlikely(ret))
139			goto out;
140	}
141
142	if (!priv->valid) {
143		ret = mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_RTCRST);
144		if (unlikely(ret))
145			goto out;
146
147		ret = mc13xxx_irq_unmask(priv->mc13xxx, MC13XXX_IRQ_RTCRST);
148	}
149
150out:
151	priv->valid = !ret;
152
153	mc13xxx_unlock(priv->mc13xxx);
154
155	return ret;
156}
157
158static int mc13xxx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
159{
160	struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
161	unsigned seconds, days;
162	unsigned long s1970;
163	int enabled, pending;
164	int ret;
165
166	mc13xxx_lock(priv->mc13xxx);
167
168	ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCTODA, &seconds);
169	if (unlikely(ret))
170		goto out;
171	if (seconds >= SEC_PER_DAY) {
172		ret = -ENODATA;
173		goto out;
174	}
175
176	ret = mc13xxx_reg_read(priv->mc13xxx, MC13XXX_RTCDAY, &days);
177	if (unlikely(ret))
178		goto out;
179
180	ret = mc13xxx_irq_status(priv->mc13xxx, MC13XXX_IRQ_TODA,
181			&enabled, &pending);
182
183out:
184	mc13xxx_unlock(priv->mc13xxx);
185
186	if (ret)
187		return ret;
188
189	alarm->enabled = enabled;
190	alarm->pending = pending;
191
192	s1970 = days * SEC_PER_DAY + seconds;
193
194	rtc_time_to_tm(s1970, &alarm->time);
195	dev_dbg(dev, "%s: %lu\n", __func__, s1970);
196
197	return 0;
198}
199
200static int mc13xxx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
201{
202	struct mc13xxx_rtc *priv = dev_get_drvdata(dev);
203	unsigned long s1970;
204	unsigned seconds, days;
205	int ret;
206
207	mc13xxx_lock(priv->mc13xxx);
208
209	/* disable alarm to prevent false triggering */
210	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, 0x1ffff);
211	if (unlikely(ret))
212		goto out;
213
214	ret = mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TODA);
215	if (unlikely(ret))
216		goto out;
217
218	ret = rtc_tm_to_time(&alarm->time, &s1970);
219	if (unlikely(ret))
220		goto out;
221
222	dev_dbg(dev, "%s: o%2.s %lu\n", __func__, alarm->enabled ? "n" : "ff",
223			s1970);
224
225	ret = mc13xxx_rtc_irq_enable_unlocked(dev, alarm->enabled,
226			MC13XXX_IRQ_TODA);
227	if (unlikely(ret))
228		goto out;
229
230	seconds = s1970 % SEC_PER_DAY;
231	days = s1970 / SEC_PER_DAY;
232
233	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCDAYA, days);
234	if (unlikely(ret))
235		goto out;
236
237	ret = mc13xxx_reg_write(priv->mc13xxx, MC13XXX_RTCTODA, seconds);
238
239out:
240	mc13xxx_unlock(priv->mc13xxx);
241
242	return ret;
243}
244
245static irqreturn_t mc13xxx_rtc_alarm_handler(int irq, void *dev)
246{
247	struct mc13xxx_rtc *priv = dev;
248	struct mc13xxx *mc13xxx = priv->mc13xxx;
249
250	rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_AF);
251
252	mc13xxx_irq_ack(mc13xxx, irq);
253
254	return IRQ_HANDLED;
255}
256
257static irqreturn_t mc13xxx_rtc_update_handler(int irq, void *dev)
258{
259	struct mc13xxx_rtc *priv = dev;
260	struct mc13xxx *mc13xxx = priv->mc13xxx;
261
262	rtc_update_irq(priv->rtc, 1, RTC_IRQF | RTC_UF);
263
264	mc13xxx_irq_ack(mc13xxx, irq);
265
266	return IRQ_HANDLED;
267}
268
269static const struct rtc_class_ops mc13xxx_rtc_ops = {
270	.read_time = mc13xxx_rtc_read_time,
271	.set_mmss = mc13xxx_rtc_set_mmss,
272	.read_alarm = mc13xxx_rtc_read_alarm,
273	.set_alarm = mc13xxx_rtc_set_alarm,
274	.alarm_irq_enable = mc13xxx_rtc_alarm_irq_enable,
275};
276
277static irqreturn_t mc13xxx_rtc_reset_handler(int irq, void *dev)
278{
279	struct mc13xxx_rtc *priv = dev;
280	struct mc13xxx *mc13xxx = priv->mc13xxx;
281
282	priv->valid = 0;
283
284	mc13xxx_irq_mask(mc13xxx, irq);
285
286	return IRQ_HANDLED;
287}
288
289static int __init mc13xxx_rtc_probe(struct platform_device *pdev)
290{
291	int ret;
292	struct mc13xxx_rtc *priv;
293	struct mc13xxx *mc13xxx;
294
295	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
296	if (!priv)
297		return -ENOMEM;
298
299	mc13xxx = dev_get_drvdata(pdev->dev.parent);
300	priv->mc13xxx = mc13xxx;
301	priv->valid = 1;
302
303	platform_set_drvdata(pdev, priv);
304
305	mc13xxx_lock(mc13xxx);
306
307	mc13xxx_irq_ack(mc13xxx, MC13XXX_IRQ_RTCRST);
308
309	ret = mc13xxx_irq_request(mc13xxx, MC13XXX_IRQ_RTCRST,
310			mc13xxx_rtc_reset_handler, DRIVER_NAME, priv);
311	if (ret)
312		goto err_irq_request;
313
314	ret = mc13xxx_irq_request(mc13xxx, MC13XXX_IRQ_1HZ,
315			mc13xxx_rtc_update_handler, DRIVER_NAME, priv);
316	if (ret)
317		goto err_irq_request;
318
319	ret = mc13xxx_irq_request_nounmask(mc13xxx, MC13XXX_IRQ_TODA,
320			mc13xxx_rtc_alarm_handler, DRIVER_NAME, priv);
321	if (ret)
322		goto err_irq_request;
323
324	mc13xxx_unlock(mc13xxx);
325
326	priv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
327					     &mc13xxx_rtc_ops, THIS_MODULE);
328
329	return 0;
330
331err_irq_request:
332	mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_TODA, priv);
333	mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_1HZ, priv);
334	mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_RTCRST, priv);
335
336	mc13xxx_unlock(mc13xxx);
337
338	return ret;
339}
340
341static int mc13xxx_rtc_remove(struct platform_device *pdev)
342{
343	struct mc13xxx_rtc *priv = platform_get_drvdata(pdev);
344
345	mc13xxx_lock(priv->mc13xxx);
346
347	mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TODA, priv);
348	mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_1HZ, priv);
349	mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_RTCRST, priv);
350
351	mc13xxx_unlock(priv->mc13xxx);
352
353	return 0;
354}
355
356static const struct platform_device_id mc13xxx_rtc_idtable[] = {
357	{
358		.name = "mc13783-rtc",
359	}, {
360		.name = "mc13892-rtc",
361	}, {
362		.name = "mc34708-rtc",
363	},
364	{ /* sentinel */ }
365};
366MODULE_DEVICE_TABLE(platform, mc13xxx_rtc_idtable);
367
368static struct platform_driver mc13xxx_rtc_driver = {
369	.id_table = mc13xxx_rtc_idtable,
370	.remove = mc13xxx_rtc_remove,
371	.driver = {
372		.name = DRIVER_NAME,
373		.owner = THIS_MODULE,
374	},
375};
376
377module_platform_driver_probe(mc13xxx_rtc_driver, &mc13xxx_rtc_probe);
378
379MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
380MODULE_DESCRIPTION("RTC driver for Freescale MC13XXX PMIC");
381MODULE_LICENSE("GPL v2");
382