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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_time_to_tm(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, 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 
150 out:
151         priv->valid = !ret;
152 
153         mc13xxx_unlock(priv->mc13xxx);
154 
155         return ret;
156 }
157 
158 static 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 
183 out:
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 
200 static 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 
239 out:
240         mc13xxx_unlock(priv->mc13xxx);
241 
242         return ret;
243 }
244 
245 static 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 
257 static 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 
269 static 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 
277 static 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 
289 static 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 
331 err_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 
341 static 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 
356 static 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 };
366 MODULE_DEVICE_TABLE(platform, mc13xxx_rtc_idtable);
367 
368 static 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 
377 module_platform_driver_probe(mc13xxx_rtc_driver, &mc13xxx_rtc_probe);
378 
379 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
380 MODULE_DESCRIPTION("RTC driver for Freescale MC13XXX PMIC");
381 MODULE_LICENSE("GPL v2");
382 

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