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