Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/drivers/rtc/rtc-spear.c

  1 /*
  2  * drivers/rtc/rtc-spear.c
  3  *
  4  * Copyright (C) 2010 ST Microelectronics
  5  * Rajeev Kumar<rajeev-dlh.kumar@st.com>
  6  *
  7  * This file is licensed under the terms of the GNU General Public
  8  * License version 2. This program is licensed "as is" without any
  9  * warranty of any kind, whether express or implied.
 10  */
 11 
 12 #include <linux/bcd.h>
 13 #include <linux/clk.h>
 14 #include <linux/delay.h>
 15 #include <linux/init.h>
 16 #include <linux/io.h>
 17 #include <linux/irq.h>
 18 #include <linux/module.h>
 19 #include <linux/of.h>
 20 #include <linux/platform_device.h>
 21 #include <linux/rtc.h>
 22 #include <linux/slab.h>
 23 #include <linux/spinlock.h>
 24 
 25 /* RTC registers */
 26 #define TIME_REG                0x00
 27 #define DATE_REG                0x04
 28 #define ALARM_TIME_REG          0x08
 29 #define ALARM_DATE_REG          0x0C
 30 #define CTRL_REG                0x10
 31 #define STATUS_REG              0x14
 32 
 33 /* TIME_REG & ALARM_TIME_REG */
 34 #define SECONDS_UNITS           (0xf<<0)        /* seconds units position */
 35 #define SECONDS_TENS            (0x7<<4)        /* seconds tens position */
 36 #define MINUTES_UNITS           (0xf<<8)        /* minutes units position */
 37 #define MINUTES_TENS            (0x7<<12)       /* minutes tens position */
 38 #define HOURS_UNITS             (0xf<<16)       /* hours units position */
 39 #define HOURS_TENS              (0x3<<20)       /* hours tens position */
 40 
 41 /* DATE_REG & ALARM_DATE_REG */
 42 #define DAYS_UNITS              (0xf<<0)        /* days units position */
 43 #define DAYS_TENS               (0x3<<4)        /* days tens position */
 44 #define MONTHS_UNITS            (0xf<<8)        /* months units position */
 45 #define MONTHS_TENS             (0x1<<12)       /* months tens position */
 46 #define YEARS_UNITS             (0xf<<16)       /* years units position */
 47 #define YEARS_TENS              (0xf<<20)       /* years tens position */
 48 #define YEARS_HUNDREDS          (0xf<<24)       /* years hundereds position */
 49 #define YEARS_MILLENIUMS        (0xf<<28)       /* years millenium position */
 50 
 51 /* MASK SHIFT TIME_REG & ALARM_TIME_REG*/
 52 #define SECOND_SHIFT            0x00            /* seconds units */
 53 #define MINUTE_SHIFT            0x08            /* minutes units position */
 54 #define HOUR_SHIFT              0x10            /* hours units position */
 55 #define MDAY_SHIFT              0x00            /* Month day shift */
 56 #define MONTH_SHIFT             0x08            /* Month shift */
 57 #define YEAR_SHIFT              0x10            /* Year shift */
 58 
 59 #define SECOND_MASK             0x7F
 60 #define MIN_MASK                0x7F
 61 #define HOUR_MASK               0x3F
 62 #define DAY_MASK                0x3F
 63 #define MONTH_MASK              0x7F
 64 #define YEAR_MASK               0xFFFF
 65 
 66 /* date reg equal to time reg, for debug only */
 67 #define TIME_BYP                (1<<9)
 68 #define INT_ENABLE              (1<<31)         /* interrupt enable */
 69 
 70 /* STATUS_REG */
 71 #define CLK_UNCONNECTED         (1<<0)
 72 #define PEND_WR_TIME            (1<<2)
 73 #define PEND_WR_DATE            (1<<3)
 74 #define LOST_WR_TIME            (1<<4)
 75 #define LOST_WR_DATE            (1<<5)
 76 #define RTC_INT_MASK            (1<<31)
 77 #define STATUS_BUSY             (PEND_WR_TIME | PEND_WR_DATE)
 78 #define STATUS_FAIL             (LOST_WR_TIME | LOST_WR_DATE)
 79 
 80 struct spear_rtc_config {
 81         struct rtc_device *rtc;
 82         struct clk *clk;
 83         spinlock_t lock;
 84         void __iomem *ioaddr;
 85         unsigned int irq_wake;
 86 };
 87 
 88 static inline void spear_rtc_clear_interrupt(struct spear_rtc_config *config)
 89 {
 90         unsigned int val;
 91         unsigned long flags;
 92 
 93         spin_lock_irqsave(&config->lock, flags);
 94         val = readl(config->ioaddr + STATUS_REG);
 95         val |= RTC_INT_MASK;
 96         writel(val, config->ioaddr + STATUS_REG);
 97         spin_unlock_irqrestore(&config->lock, flags);
 98 }
 99 
100 static inline void spear_rtc_enable_interrupt(struct spear_rtc_config *config)
101 {
102         unsigned int val;
103 
104         val = readl(config->ioaddr + CTRL_REG);
105         if (!(val & INT_ENABLE)) {
106                 spear_rtc_clear_interrupt(config);
107                 val |= INT_ENABLE;
108                 writel(val, config->ioaddr + CTRL_REG);
109         }
110 }
111 
112 static inline void spear_rtc_disable_interrupt(struct spear_rtc_config *config)
113 {
114         unsigned int val;
115 
116         val = readl(config->ioaddr + CTRL_REG);
117         if (val & INT_ENABLE) {
118                 val &= ~INT_ENABLE;
119                 writel(val, config->ioaddr + CTRL_REG);
120         }
121 }
122 
123 static inline int is_write_complete(struct spear_rtc_config *config)
124 {
125         int ret = 0;
126         unsigned long flags;
127 
128         spin_lock_irqsave(&config->lock, flags);
129         if ((readl(config->ioaddr + STATUS_REG)) & STATUS_FAIL)
130                 ret = -EIO;
131         spin_unlock_irqrestore(&config->lock, flags);
132 
133         return ret;
134 }
135 
136 static void rtc_wait_not_busy(struct spear_rtc_config *config)
137 {
138         int status, count = 0;
139         unsigned long flags;
140 
141         /* Assuming BUSY may stay active for 80 msec) */
142         for (count = 0; count < 80; count++) {
143                 spin_lock_irqsave(&config->lock, flags);
144                 status = readl(config->ioaddr + STATUS_REG);
145                 spin_unlock_irqrestore(&config->lock, flags);
146                 if ((status & STATUS_BUSY) == 0)
147                         break;
148                 /* check status busy, after each msec */
149                 msleep(1);
150         }
151 }
152 
153 static irqreturn_t spear_rtc_irq(int irq, void *dev_id)
154 {
155         struct spear_rtc_config *config = dev_id;
156         unsigned long flags, events = 0;
157         unsigned int irq_data;
158 
159         spin_lock_irqsave(&config->lock, flags);
160         irq_data = readl(config->ioaddr + STATUS_REG);
161         spin_unlock_irqrestore(&config->lock, flags);
162 
163         if ((irq_data & RTC_INT_MASK)) {
164                 spear_rtc_clear_interrupt(config);
165                 events = RTC_IRQF | RTC_AF;
166                 rtc_update_irq(config->rtc, 1, events);
167                 return IRQ_HANDLED;
168         } else
169                 return IRQ_NONE;
170 
171 }
172 
173 static int tm2bcd(struct rtc_time *tm)
174 {
175         if (rtc_valid_tm(tm) != 0)
176                 return -EINVAL;
177         tm->tm_sec = bin2bcd(tm->tm_sec);
178         tm->tm_min = bin2bcd(tm->tm_min);
179         tm->tm_hour = bin2bcd(tm->tm_hour);
180         tm->tm_mday = bin2bcd(tm->tm_mday);
181         tm->tm_mon = bin2bcd(tm->tm_mon + 1);
182         tm->tm_year = bin2bcd(tm->tm_year);
183 
184         return 0;
185 }
186 
187 static void bcd2tm(struct rtc_time *tm)
188 {
189         tm->tm_sec = bcd2bin(tm->tm_sec);
190         tm->tm_min = bcd2bin(tm->tm_min);
191         tm->tm_hour = bcd2bin(tm->tm_hour);
192         tm->tm_mday = bcd2bin(tm->tm_mday);
193         tm->tm_mon = bcd2bin(tm->tm_mon) - 1;
194         /* epoch == 1900 */
195         tm->tm_year = bcd2bin(tm->tm_year);
196 }
197 
198 /*
199  * spear_rtc_read_time - set the time
200  * @dev: rtc device in use
201  * @tm: holds date and time
202  *
203  * This function read time and date. On success it will return 0
204  * otherwise -ve error is returned.
205  */
206 static int spear_rtc_read_time(struct device *dev, struct rtc_time *tm)
207 {
208         struct spear_rtc_config *config = dev_get_drvdata(dev);
209         unsigned int time, date;
210 
211         /* we don't report wday/yday/isdst ... */
212         rtc_wait_not_busy(config);
213 
214         time = readl(config->ioaddr + TIME_REG);
215         date = readl(config->ioaddr + DATE_REG);
216         tm->tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
217         tm->tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
218         tm->tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
219         tm->tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
220         tm->tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
221         tm->tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
222 
223         bcd2tm(tm);
224         return 0;
225 }
226 
227 /*
228  * spear_rtc_set_time - set the time
229  * @dev: rtc device in use
230  * @tm: holds date and time
231  *
232  * This function set time and date. On success it will return 0
233  * otherwise -ve error is returned.
234  */
235 static int spear_rtc_set_time(struct device *dev, struct rtc_time *tm)
236 {
237         struct spear_rtc_config *config = dev_get_drvdata(dev);
238         unsigned int time, date;
239 
240         if (tm2bcd(tm) < 0)
241                 return -EINVAL;
242 
243         rtc_wait_not_busy(config);
244         time = (tm->tm_sec << SECOND_SHIFT) | (tm->tm_min << MINUTE_SHIFT) |
245                 (tm->tm_hour << HOUR_SHIFT);
246         date = (tm->tm_mday << MDAY_SHIFT) | (tm->tm_mon << MONTH_SHIFT) |
247                 (tm->tm_year << YEAR_SHIFT);
248         writel(time, config->ioaddr + TIME_REG);
249         writel(date, config->ioaddr + DATE_REG);
250 
251         return is_write_complete(config);
252 }
253 
254 /*
255  * spear_rtc_read_alarm - read the alarm time
256  * @dev: rtc device in use
257  * @alm: holds alarm date and time
258  *
259  * This function read alarm time and date. On success it will return 0
260  * otherwise -ve error is returned.
261  */
262 static int spear_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
263 {
264         struct spear_rtc_config *config = dev_get_drvdata(dev);
265         unsigned int time, date;
266 
267         rtc_wait_not_busy(config);
268 
269         time = readl(config->ioaddr + ALARM_TIME_REG);
270         date = readl(config->ioaddr + ALARM_DATE_REG);
271         alm->time.tm_sec = (time >> SECOND_SHIFT) & SECOND_MASK;
272         alm->time.tm_min = (time >> MINUTE_SHIFT) & MIN_MASK;
273         alm->time.tm_hour = (time >> HOUR_SHIFT) & HOUR_MASK;
274         alm->time.tm_mday = (date >> MDAY_SHIFT) & DAY_MASK;
275         alm->time.tm_mon = (date >> MONTH_SHIFT) & MONTH_MASK;
276         alm->time.tm_year = (date >> YEAR_SHIFT) & YEAR_MASK;
277 
278         bcd2tm(&alm->time);
279         alm->enabled = readl(config->ioaddr + CTRL_REG) & INT_ENABLE;
280 
281         return 0;
282 }
283 
284 /*
285  * spear_rtc_set_alarm - set the alarm time
286  * @dev: rtc device in use
287  * @alm: holds alarm date and time
288  *
289  * This function set alarm time and date. On success it will return 0
290  * otherwise -ve error is returned.
291  */
292 static int spear_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
293 {
294         struct spear_rtc_config *config = dev_get_drvdata(dev);
295         unsigned int time, date;
296         int err;
297 
298         if (tm2bcd(&alm->time) < 0)
299                 return -EINVAL;
300 
301         rtc_wait_not_busy(config);
302 
303         time = (alm->time.tm_sec << SECOND_SHIFT) | (alm->time.tm_min <<
304                         MINUTE_SHIFT) | (alm->time.tm_hour << HOUR_SHIFT);
305         date = (alm->time.tm_mday << MDAY_SHIFT) | (alm->time.tm_mon <<
306                         MONTH_SHIFT) | (alm->time.tm_year << YEAR_SHIFT);
307 
308         writel(time, config->ioaddr + ALARM_TIME_REG);
309         writel(date, config->ioaddr + ALARM_DATE_REG);
310         err = is_write_complete(config);
311         if (err < 0)
312                 return err;
313 
314         if (alm->enabled)
315                 spear_rtc_enable_interrupt(config);
316         else
317                 spear_rtc_disable_interrupt(config);
318 
319         return 0;
320 }
321 
322 static int spear_alarm_irq_enable(struct device *dev, unsigned int enabled)
323 {
324         struct spear_rtc_config *config = dev_get_drvdata(dev);
325         int ret = 0;
326 
327         spear_rtc_clear_interrupt(config);
328 
329         switch (enabled) {
330         case 0:
331                 /* alarm off */
332                 spear_rtc_disable_interrupt(config);
333                 break;
334         case 1:
335                 /* alarm on */
336                 spear_rtc_enable_interrupt(config);
337                 break;
338         default:
339                 ret = -EINVAL;
340                 break;
341         }
342 
343         return ret;
344 }
345 
346 static struct rtc_class_ops spear_rtc_ops = {
347         .read_time = spear_rtc_read_time,
348         .set_time = spear_rtc_set_time,
349         .read_alarm = spear_rtc_read_alarm,
350         .set_alarm = spear_rtc_set_alarm,
351         .alarm_irq_enable = spear_alarm_irq_enable,
352 };
353 
354 static int spear_rtc_probe(struct platform_device *pdev)
355 {
356         struct resource *res;
357         struct spear_rtc_config *config;
358         int status = 0;
359         int irq;
360 
361         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
362         if (!res) {
363                 dev_err(&pdev->dev, "no resource defined\n");
364                 return -EBUSY;
365         }
366 
367         config = devm_kzalloc(&pdev->dev, sizeof(*config), GFP_KERNEL);
368         if (!config)
369                 return -ENOMEM;
370 
371         /* alarm irqs */
372         irq = platform_get_irq(pdev, 0);
373         if (irq < 0) {
374                 dev_err(&pdev->dev, "no update irq?\n");
375                 return irq;
376         }
377 
378         status = devm_request_irq(&pdev->dev, irq, spear_rtc_irq, 0, pdev->name,
379                         config);
380         if (status) {
381                 dev_err(&pdev->dev, "Alarm interrupt IRQ%d already claimed\n",
382                                 irq);
383                 return status;
384         }
385 
386         config->ioaddr = devm_ioremap_resource(&pdev->dev, res);
387         if (IS_ERR(config->ioaddr))
388                 return PTR_ERR(config->ioaddr);
389 
390         config->clk = devm_clk_get(&pdev->dev, NULL);
391         if (IS_ERR(config->clk))
392                 return PTR_ERR(config->clk);
393 
394         status = clk_prepare_enable(config->clk);
395         if (status < 0)
396                 return status;
397 
398         spin_lock_init(&config->lock);
399         platform_set_drvdata(pdev, config);
400 
401         config->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
402                                         &spear_rtc_ops, THIS_MODULE);
403         if (IS_ERR(config->rtc)) {
404                 dev_err(&pdev->dev, "can't register RTC device, err %ld\n",
405                                 PTR_ERR(config->rtc));
406                 status = PTR_ERR(config->rtc);
407                 goto err_disable_clock;
408         }
409 
410         config->rtc->uie_unsupported = 1;
411 
412         if (!device_can_wakeup(&pdev->dev))
413                 device_init_wakeup(&pdev->dev, 1);
414 
415         return 0;
416 
417 err_disable_clock:
418         clk_disable_unprepare(config->clk);
419 
420         return status;
421 }
422 
423 static int spear_rtc_remove(struct platform_device *pdev)
424 {
425         struct spear_rtc_config *config = platform_get_drvdata(pdev);
426 
427         spear_rtc_disable_interrupt(config);
428         clk_disable_unprepare(config->clk);
429         device_init_wakeup(&pdev->dev, 0);
430 
431         return 0;
432 }
433 
434 #ifdef CONFIG_PM_SLEEP
435 static int spear_rtc_suspend(struct device *dev)
436 {
437         struct platform_device *pdev = to_platform_device(dev);
438         struct spear_rtc_config *config = platform_get_drvdata(pdev);
439         int irq;
440 
441         irq = platform_get_irq(pdev, 0);
442         if (device_may_wakeup(&pdev->dev)) {
443                 if (!enable_irq_wake(irq))
444                         config->irq_wake = 1;
445         } else {
446                 spear_rtc_disable_interrupt(config);
447                 clk_disable(config->clk);
448         }
449 
450         return 0;
451 }
452 
453 static int spear_rtc_resume(struct device *dev)
454 {
455         struct platform_device *pdev = to_platform_device(dev);
456         struct spear_rtc_config *config = platform_get_drvdata(pdev);
457         int irq;
458 
459         irq = platform_get_irq(pdev, 0);
460 
461         if (device_may_wakeup(&pdev->dev)) {
462                 if (config->irq_wake) {
463                         disable_irq_wake(irq);
464                         config->irq_wake = 0;
465                 }
466         } else {
467                 clk_enable(config->clk);
468                 spear_rtc_enable_interrupt(config);
469         }
470 
471         return 0;
472 }
473 #endif
474 
475 static SIMPLE_DEV_PM_OPS(spear_rtc_pm_ops, spear_rtc_suspend, spear_rtc_resume);
476 
477 static void spear_rtc_shutdown(struct platform_device *pdev)
478 {
479         struct spear_rtc_config *config = platform_get_drvdata(pdev);
480 
481         spear_rtc_disable_interrupt(config);
482         clk_disable(config->clk);
483 }
484 
485 #ifdef CONFIG_OF
486 static const struct of_device_id spear_rtc_id_table[] = {
487         { .compatible = "st,spear600-rtc" },
488         {}
489 };
490 MODULE_DEVICE_TABLE(of, spear_rtc_id_table);
491 #endif
492 
493 static struct platform_driver spear_rtc_driver = {
494         .probe = spear_rtc_probe,
495         .remove = spear_rtc_remove,
496         .shutdown = spear_rtc_shutdown,
497         .driver = {
498                 .name = "rtc-spear",
499                 .pm = &spear_rtc_pm_ops,
500                 .of_match_table = of_match_ptr(spear_rtc_id_table),
501         },
502 };
503 
504 module_platform_driver(spear_rtc_driver);
505 
506 MODULE_ALIAS("platform:rtc-spear");
507 MODULE_AUTHOR("Rajeev Kumar <rajeev-dlh.kumar@st.com>");
508 MODULE_DESCRIPTION("ST SPEAr Realtime Clock Driver (RTC)");
509 MODULE_LICENSE("GPL");
510 

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