xref: /openbmc/linux/drivers/rtc/rtc-mc13xxx.c (revision 99c3a136)
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 
26 struct mc13xxx_rtc {
27 	struct rtc_device *rtc;
28 	struct mc13xxx *mc13xxx;
29 	int valid;
30 };
31 
mc13xxx_rtc_irq_enable_unlocked(struct device * dev,unsigned int enabled,int irq)32 static 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 
mc13xxx_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)45 static 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 
mc13xxx_rtc_read_time(struct device * dev,struct rtc_time * tm)60 static 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 
mc13xxx_rtc_set_time(struct device * dev,struct rtc_time * tm)89 static 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 
147 out:
148 	priv->valid = !ret;
149 
150 	mc13xxx_unlock(priv->mc13xxx);
151 
152 	return ret;
153 }
154 
mc13xxx_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alarm)155 static 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 
180 out:
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 
mc13xxx_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alarm)197 static 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 
233 out:
234 	mc13xxx_unlock(priv->mc13xxx);
235 
236 	return ret;
237 }
238 
mc13xxx_rtc_alarm_handler(int irq,void * dev)239 static 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 
251 static 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 
mc13xxx_rtc_reset_handler(int irq,void * dev)259 static 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 
mc13xxx_rtc_probe(struct platform_device * pdev)271 static 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 
318 err_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 
mc13xxx_rtc_remove(struct platform_device * pdev)327 static 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 
339 static 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 };
349 MODULE_DEVICE_TABLE(platform, mc13xxx_rtc_idtable);
350 
351 static 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 
359 module_platform_driver_probe(mc13xxx_rtc_driver, &mc13xxx_rtc_probe);
360 
361 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
362 MODULE_DESCRIPTION("RTC driver for Freescale MC13XXX PMIC");
363 MODULE_LICENSE("GPL v2");
364