Merge branch 'resizex' (patches from Maciej)
[linux-2.6-microblaze.git] / drivers / rtc / rtc-ds1511.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * An rtc driver for the Dallas DS1511
4  *
5  * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
6  * Copyright (C) 2007 Andrew Sharp <andy.sharp@lsi.com>
7  *
8  * Real time clock driver for the Dallas 1511 chip, which also
9  * contains a watchdog timer.  There is a tiny amount of code that
10  * platform code could use to mess with the watchdog device a little
11  * bit, but not a full watchdog driver.
12  */
13
14 #include <linux/bcd.h>
15 #include <linux/init.h>
16 #include <linux/kernel.h>
17 #include <linux/gfp.h>
18 #include <linux/delay.h>
19 #include <linux/interrupt.h>
20 #include <linux/rtc.h>
21 #include <linux/platform_device.h>
22 #include <linux/io.h>
23 #include <linux/module.h>
24
25 enum ds1511reg {
26         DS1511_SEC = 0x0,
27         DS1511_MIN = 0x1,
28         DS1511_HOUR = 0x2,
29         DS1511_DOW = 0x3,
30         DS1511_DOM = 0x4,
31         DS1511_MONTH = 0x5,
32         DS1511_YEAR = 0x6,
33         DS1511_CENTURY = 0x7,
34         DS1511_AM1_SEC = 0x8,
35         DS1511_AM2_MIN = 0x9,
36         DS1511_AM3_HOUR = 0xa,
37         DS1511_AM4_DATE = 0xb,
38         DS1511_WD_MSEC = 0xc,
39         DS1511_WD_SEC = 0xd,
40         DS1511_CONTROL_A = 0xe,
41         DS1511_CONTROL_B = 0xf,
42         DS1511_RAMADDR_LSB = 0x10,
43         DS1511_RAMDATA = 0x13
44 };
45
46 #define DS1511_BLF1     0x80
47 #define DS1511_BLF2     0x40
48 #define DS1511_PRS      0x20
49 #define DS1511_PAB      0x10
50 #define DS1511_TDF      0x08
51 #define DS1511_KSF      0x04
52 #define DS1511_WDF      0x02
53 #define DS1511_IRQF     0x01
54 #define DS1511_TE       0x80
55 #define DS1511_CS       0x40
56 #define DS1511_BME      0x20
57 #define DS1511_TPE      0x10
58 #define DS1511_TIE      0x08
59 #define DS1511_KIE      0x04
60 #define DS1511_WDE      0x02
61 #define DS1511_WDS      0x01
62 #define DS1511_RAM_MAX  0x100
63
64 #define RTC_CMD         DS1511_CONTROL_B
65 #define RTC_CMD1        DS1511_CONTROL_A
66
67 #define RTC_ALARM_SEC   DS1511_AM1_SEC
68 #define RTC_ALARM_MIN   DS1511_AM2_MIN
69 #define RTC_ALARM_HOUR  DS1511_AM3_HOUR
70 #define RTC_ALARM_DATE  DS1511_AM4_DATE
71
72 #define RTC_SEC         DS1511_SEC
73 #define RTC_MIN         DS1511_MIN
74 #define RTC_HOUR        DS1511_HOUR
75 #define RTC_DOW         DS1511_DOW
76 #define RTC_DOM         DS1511_DOM
77 #define RTC_MON         DS1511_MONTH
78 #define RTC_YEAR        DS1511_YEAR
79 #define RTC_CENTURY     DS1511_CENTURY
80
81 #define RTC_TIE DS1511_TIE
82 #define RTC_TE  DS1511_TE
83
84 struct rtc_plat_data {
85         struct rtc_device *rtc;
86         void __iomem *ioaddr;           /* virtual base address */
87         int irq;
88         unsigned int irqen;
89         int alrm_sec;
90         int alrm_min;
91         int alrm_hour;
92         int alrm_mday;
93         spinlock_t lock;
94 };
95
96 static DEFINE_SPINLOCK(ds1511_lock);
97
98 static __iomem char *ds1511_base;
99 static u32 reg_spacing = 1;
100
101 static noinline void
102 rtc_write(uint8_t val, uint32_t reg)
103 {
104         writeb(val, ds1511_base + (reg * reg_spacing));
105 }
106
107 static noinline uint8_t
108 rtc_read(enum ds1511reg reg)
109 {
110         return readb(ds1511_base + (reg * reg_spacing));
111 }
112
113 static inline void
114 rtc_disable_update(void)
115 {
116         rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
117 }
118
119 static void
120 rtc_enable_update(void)
121 {
122         rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD);
123 }
124
125 /*
126  * #define DS1511_WDOG_RESET_SUPPORT
127  *
128  * Uncomment this if you want to use these routines in
129  * some platform code.
130  */
131 #ifdef DS1511_WDOG_RESET_SUPPORT
132 /*
133  * just enough code to set the watchdog timer so that it
134  * will reboot the system
135  */
136 void
137 ds1511_wdog_set(unsigned long deciseconds)
138 {
139         /*
140          * the wdog timer can take 99.99 seconds
141          */
142         deciseconds %= 10000;
143         /*
144          * set the wdog values in the wdog registers
145          */
146         rtc_write(bin2bcd(deciseconds % 100), DS1511_WD_MSEC);
147         rtc_write(bin2bcd(deciseconds / 100), DS1511_WD_SEC);
148         /*
149          * set wdog enable and wdog 'steering' bit to issue a reset
150          */
151         rtc_write(rtc_read(RTC_CMD) | DS1511_WDE | DS1511_WDS, RTC_CMD);
152 }
153
154 void
155 ds1511_wdog_disable(void)
156 {
157         /*
158          * clear wdog enable and wdog 'steering' bits
159          */
160         rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD);
161         /*
162          * clear the wdog counter
163          */
164         rtc_write(0, DS1511_WD_MSEC);
165         rtc_write(0, DS1511_WD_SEC);
166 }
167 #endif
168
169 /*
170  * set the rtc chip's idea of the time.
171  * stupidly, some callers call with year unmolested;
172  * and some call with  year = year - 1900.  thanks.
173  */
174 static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
175 {
176         u8 mon, day, dow, hrs, min, sec, yrs, cen;
177         unsigned long flags;
178
179         /*
180          * won't have to change this for a while
181          */
182         if (rtc_tm->tm_year < 1900)
183                 rtc_tm->tm_year += 1900;
184
185         if (rtc_tm->tm_year < 1970)
186                 return -EINVAL;
187
188         yrs = rtc_tm->tm_year % 100;
189         cen = rtc_tm->tm_year / 100;
190         mon = rtc_tm->tm_mon + 1;   /* tm_mon starts at zero */
191         day = rtc_tm->tm_mday;
192         dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */
193         hrs = rtc_tm->tm_hour;
194         min = rtc_tm->tm_min;
195         sec = rtc_tm->tm_sec;
196
197         if ((mon > 12) || (day == 0))
198                 return -EINVAL;
199
200         if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year))
201                 return -EINVAL;
202
203         if ((hrs >= 24) || (min >= 60) || (sec >= 60))
204                 return -EINVAL;
205
206         /*
207          * each register is a different number of valid bits
208          */
209         sec = bin2bcd(sec) & 0x7f;
210         min = bin2bcd(min) & 0x7f;
211         hrs = bin2bcd(hrs) & 0x3f;
212         day = bin2bcd(day) & 0x3f;
213         mon = bin2bcd(mon) & 0x1f;
214         yrs = bin2bcd(yrs) & 0xff;
215         cen = bin2bcd(cen) & 0xff;
216
217         spin_lock_irqsave(&ds1511_lock, flags);
218         rtc_disable_update();
219         rtc_write(cen, RTC_CENTURY);
220         rtc_write(yrs, RTC_YEAR);
221         rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON);
222         rtc_write(day, RTC_DOM);
223         rtc_write(hrs, RTC_HOUR);
224         rtc_write(min, RTC_MIN);
225         rtc_write(sec, RTC_SEC);
226         rtc_write(dow, RTC_DOW);
227         rtc_enable_update();
228         spin_unlock_irqrestore(&ds1511_lock, flags);
229
230         return 0;
231 }
232
233 static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
234 {
235         unsigned int century;
236         unsigned long flags;
237
238         spin_lock_irqsave(&ds1511_lock, flags);
239         rtc_disable_update();
240
241         rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f;
242         rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f;
243         rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f;
244         rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f;
245         rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7;
246         rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f;
247         rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f;
248         century = rtc_read(RTC_CENTURY);
249
250         rtc_enable_update();
251         spin_unlock_irqrestore(&ds1511_lock, flags);
252
253         rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
254         rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
255         rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
256         rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
257         rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
258         rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
259         rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
260         century = bcd2bin(century) * 100;
261
262         /*
263          * Account for differences between how the RTC uses the values
264          * and how they are defined in a struct rtc_time;
265          */
266         century += rtc_tm->tm_year;
267         rtc_tm->tm_year = century - 1900;
268
269         rtc_tm->tm_mon--;
270
271         return 0;
272 }
273
274 /*
275  * write the alarm register settings
276  *
277  * we only have the use to interrupt every second, otherwise
278  * known as the update interrupt, or the interrupt if the whole
279  * date/hours/mins/secs matches.  the ds1511 has many more
280  * permutations, but the kernel doesn't.
281  */
282 static void
283 ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
284 {
285         unsigned long flags;
286
287         spin_lock_irqsave(&pdata->lock, flags);
288         rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
289                0x80 : bin2bcd(pdata->alrm_mday) & 0x3f,
290                RTC_ALARM_DATE);
291         rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
292                0x80 : bin2bcd(pdata->alrm_hour) & 0x3f,
293                RTC_ALARM_HOUR);
294         rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
295                0x80 : bin2bcd(pdata->alrm_min) & 0x7f,
296                RTC_ALARM_MIN);
297         rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
298                0x80 : bin2bcd(pdata->alrm_sec) & 0x7f,
299                RTC_ALARM_SEC);
300         rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD);
301         rtc_read(RTC_CMD1);     /* clear interrupts */
302         spin_unlock_irqrestore(&pdata->lock, flags);
303 }
304
305 static int
306 ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
307 {
308         struct rtc_plat_data *pdata = dev_get_drvdata(dev);
309
310         if (pdata->irq <= 0)
311                 return -EINVAL;
312
313         pdata->alrm_mday = alrm->time.tm_mday;
314         pdata->alrm_hour = alrm->time.tm_hour;
315         pdata->alrm_min = alrm->time.tm_min;
316         pdata->alrm_sec = alrm->time.tm_sec;
317         if (alrm->enabled)
318                 pdata->irqen |= RTC_AF;
319
320         ds1511_rtc_update_alarm(pdata);
321         return 0;
322 }
323
324 static int
325 ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
326 {
327         struct rtc_plat_data *pdata = dev_get_drvdata(dev);
328
329         if (pdata->irq <= 0)
330                 return -EINVAL;
331
332         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
333         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
334         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
335         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
336         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
337         return 0;
338 }
339
340 static irqreturn_t
341 ds1511_interrupt(int irq, void *dev_id)
342 {
343         struct platform_device *pdev = dev_id;
344         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
345         unsigned long events = 0;
346
347         spin_lock(&pdata->lock);
348         /*
349          * read and clear interrupt
350          */
351         if (rtc_read(RTC_CMD1) & DS1511_IRQF) {
352                 events = RTC_IRQF;
353                 if (rtc_read(RTC_ALARM_SEC) & 0x80)
354                         events |= RTC_UF;
355                 else
356                         events |= RTC_AF;
357                 rtc_update_irq(pdata->rtc, 1, events);
358         }
359         spin_unlock(&pdata->lock);
360         return events ? IRQ_HANDLED : IRQ_NONE;
361 }
362
363 static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
364 {
365         struct rtc_plat_data *pdata = dev_get_drvdata(dev);
366
367         if (pdata->irq <= 0)
368                 return -EINVAL;
369         if (enabled)
370                 pdata->irqen |= RTC_AF;
371         else
372                 pdata->irqen &= ~RTC_AF;
373         ds1511_rtc_update_alarm(pdata);
374         return 0;
375 }
376
377 static const struct rtc_class_ops ds1511_rtc_ops = {
378         .read_time              = ds1511_rtc_read_time,
379         .set_time               = ds1511_rtc_set_time,
380         .read_alarm             = ds1511_rtc_read_alarm,
381         .set_alarm              = ds1511_rtc_set_alarm,
382         .alarm_irq_enable       = ds1511_rtc_alarm_irq_enable,
383 };
384
385 static int ds1511_nvram_read(void *priv, unsigned int pos, void *buf,
386                              size_t size)
387 {
388         int i;
389
390         rtc_write(pos, DS1511_RAMADDR_LSB);
391         for (i = 0; i < size; i++)
392                 *(char *)buf++ = rtc_read(DS1511_RAMDATA);
393
394         return 0;
395 }
396
397 static int ds1511_nvram_write(void *priv, unsigned int pos, void *buf,
398                               size_t size)
399 {
400         int i;
401
402         rtc_write(pos, DS1511_RAMADDR_LSB);
403         for (i = 0; i < size; i++)
404                 rtc_write(*(char *)buf++, DS1511_RAMDATA);
405
406         return 0;
407 }
408
409 static int ds1511_rtc_probe(struct platform_device *pdev)
410 {
411         struct rtc_plat_data *pdata;
412         int ret = 0;
413         struct nvmem_config ds1511_nvmem_cfg = {
414                 .name = "ds1511_nvram",
415                 .word_size = 1,
416                 .stride = 1,
417                 .size = DS1511_RAM_MAX,
418                 .reg_read = ds1511_nvram_read,
419                 .reg_write = ds1511_nvram_write,
420                 .priv = &pdev->dev,
421         };
422
423         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
424         if (!pdata)
425                 return -ENOMEM;
426
427         ds1511_base = devm_platform_ioremap_resource(pdev, 0);
428         if (IS_ERR(ds1511_base))
429                 return PTR_ERR(ds1511_base);
430         pdata->ioaddr = ds1511_base;
431         pdata->irq = platform_get_irq(pdev, 0);
432
433         /*
434          * turn on the clock and the crystal, etc.
435          */
436         rtc_write(DS1511_BME, RTC_CMD);
437         rtc_write(0, RTC_CMD1);
438         /*
439          * clear the wdog counter
440          */
441         rtc_write(0, DS1511_WD_MSEC);
442         rtc_write(0, DS1511_WD_SEC);
443         /*
444          * start the clock
445          */
446         rtc_enable_update();
447
448         /*
449          * check for a dying bat-tree
450          */
451         if (rtc_read(RTC_CMD1) & DS1511_BLF1)
452                 dev_warn(&pdev->dev, "voltage-low detected.\n");
453
454         spin_lock_init(&pdata->lock);
455         platform_set_drvdata(pdev, pdata);
456
457         pdata->rtc = devm_rtc_allocate_device(&pdev->dev);
458         if (IS_ERR(pdata->rtc))
459                 return PTR_ERR(pdata->rtc);
460
461         pdata->rtc->ops = &ds1511_rtc_ops;
462
463         ret = devm_rtc_register_device(pdata->rtc);
464         if (ret)
465                 return ret;
466
467         devm_rtc_nvmem_register(pdata->rtc, &ds1511_nvmem_cfg);
468
469         /*
470          * if the platform has an interrupt in mind for this device,
471          * then by all means, set it
472          */
473         if (pdata->irq > 0) {
474                 rtc_read(RTC_CMD1);
475                 if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt,
476                         IRQF_SHARED, pdev->name, pdev) < 0) {
477
478                         dev_warn(&pdev->dev, "interrupt not available.\n");
479                         pdata->irq = 0;
480                 }
481         }
482
483         return 0;
484 }
485
486 /* work with hotplug and coldplug */
487 MODULE_ALIAS("platform:ds1511");
488
489 static struct platform_driver ds1511_rtc_driver = {
490         .probe          = ds1511_rtc_probe,
491         .driver         = {
492                 .name   = "ds1511",
493         },
494 };
495
496 module_platform_driver(ds1511_rtc_driver);
497
498 MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
499 MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
500 MODULE_LICENSE("GPL");