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Linux/drivers/rtc/rtc-mc13xxx.c

  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 
 28 struct mc13xxx_rtc {
 29         struct rtc_device *rtc;
 30         struct mc13xxx *mc13xxx;
 31         int valid;
 32 };
 33 
 34 static 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 
 47 static 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 
 62 static 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 
 91 static 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 
149 out:
150         priv->valid = !ret;
151 
152         mc13xxx_unlock(priv->mc13xxx);
153 
154         return ret;
155 }
156 
157 static 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 
182 out:
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 
199 static 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: %s %lld\n", __func__, alarm->enabled ? "on" : "off",
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 
235 out:
236         mc13xxx_unlock(priv->mc13xxx);
237 
238         return ret;
239 }
240 
241 static 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 
253 static const struct rtc_class_ops mc13xxx_rtc_ops = {
254         .read_time = mc13xxx_rtc_read_time,
255         .set_mmss64 = mc13xxx_rtc_set_mmss,
256         .read_alarm = mc13xxx_rtc_read_alarm,
257         .set_alarm = mc13xxx_rtc_set_alarm,
258         .alarm_irq_enable = mc13xxx_rtc_alarm_irq_enable,
259 };
260 
261 static irqreturn_t mc13xxx_rtc_reset_handler(int irq, void *dev)
262 {
263         struct mc13xxx_rtc *priv = dev;
264         struct mc13xxx *mc13xxx = priv->mc13xxx;
265 
266         priv->valid = 0;
267 
268         mc13xxx_irq_mask(mc13xxx, irq);
269 
270         return IRQ_HANDLED;
271 }
272 
273 static int __init mc13xxx_rtc_probe(struct platform_device *pdev)
274 {
275         int ret;
276         struct mc13xxx_rtc *priv;
277         struct mc13xxx *mc13xxx;
278 
279         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
280         if (!priv)
281                 return -ENOMEM;
282 
283         mc13xxx = dev_get_drvdata(pdev->dev.parent);
284         priv->mc13xxx = mc13xxx;
285         priv->valid = 1;
286 
287         platform_set_drvdata(pdev, priv);
288 
289         mc13xxx_lock(mc13xxx);
290 
291         mc13xxx_irq_ack(mc13xxx, MC13XXX_IRQ_RTCRST);
292 
293         ret = mc13xxx_irq_request(mc13xxx, MC13XXX_IRQ_RTCRST,
294                         mc13xxx_rtc_reset_handler, DRIVER_NAME, priv);
295         if (ret)
296                 goto err_irq_request;
297 
298         ret = mc13xxx_irq_request_nounmask(mc13xxx, MC13XXX_IRQ_TODA,
299                         mc13xxx_rtc_alarm_handler, DRIVER_NAME, priv);
300         if (ret)
301                 goto err_irq_request;
302 
303         mc13xxx_unlock(mc13xxx);
304 
305         priv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
306                                              &mc13xxx_rtc_ops, THIS_MODULE);
307 
308         return 0;
309 
310 err_irq_request:
311         mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_TODA, priv);
312         mc13xxx_irq_free(mc13xxx, MC13XXX_IRQ_RTCRST, priv);
313 
314         mc13xxx_unlock(mc13xxx);
315 
316         return ret;
317 }
318 
319 static int mc13xxx_rtc_remove(struct platform_device *pdev)
320 {
321         struct mc13xxx_rtc *priv = platform_get_drvdata(pdev);
322 
323         mc13xxx_lock(priv->mc13xxx);
324 
325         mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TODA, priv);
326         mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_RTCRST, priv);
327 
328         mc13xxx_unlock(priv->mc13xxx);
329 
330         return 0;
331 }
332 
333 static const struct platform_device_id mc13xxx_rtc_idtable[] = {
334         {
335                 .name = "mc13783-rtc",
336         }, {
337                 .name = "mc13892-rtc",
338         }, {
339                 .name = "mc34708-rtc",
340         },
341         { /* sentinel */ }
342 };
343 MODULE_DEVICE_TABLE(platform, mc13xxx_rtc_idtable);
344 
345 static struct platform_driver mc13xxx_rtc_driver = {
346         .id_table = mc13xxx_rtc_idtable,
347         .remove = mc13xxx_rtc_remove,
348         .driver = {
349                 .name = DRIVER_NAME,
350         },
351 };
352 
353 module_platform_driver_probe(mc13xxx_rtc_driver, &mc13xxx_rtc_probe);
354 
355 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
356 MODULE_DESCRIPTION("RTC driver for Freescale MC13XXX PMIC");
357 MODULE_LICENSE("GPL v2");
358 

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