1 // SPDX-License-Identifier: GPL-2.0-only
3 * An rtc driver for the Dallas DS1511
5 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
6 * Copyright (C) 2007 Andrew Sharp <andy.sharp@lsi.com>
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.
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>
23 #include <linux/module.h>
36 DS1511_AM3_HOUR = 0xa,
37 DS1511_AM4_DATE = 0xb,
40 DS1511_CONTROL_A = 0xe,
41 DS1511_CONTROL_B = 0xf,
42 DS1511_RAMADDR_LSB = 0x10,
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
64 #define RTC_CMD DS1511_CONTROL_B
65 #define RTC_CMD1 DS1511_CONTROL_A
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
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
81 #define RTC_TIE DS1511_TIE
82 #define RTC_TE DS1511_TE
84 struct rtc_plat_data {
85 struct rtc_device *rtc;
86 void __iomem *ioaddr; /* virtual base address */
96 static DEFINE_SPINLOCK(ds1511_lock);
98 static __iomem char *ds1511_base;
99 static u32 reg_spacing = 1;
102 rtc_write(uint8_t val, uint32_t reg)
104 writeb(val, ds1511_base + (reg * reg_spacing));
107 static noinline uint8_t
108 rtc_read(enum ds1511reg reg)
110 return readb(ds1511_base + (reg * reg_spacing));
114 rtc_disable_update(void)
116 rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
120 rtc_enable_update(void)
122 rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD);
126 * #define DS1511_WDOG_RESET_SUPPORT
128 * Uncomment this if you want to use these routines in
129 * some platform code.
131 #ifdef DS1511_WDOG_RESET_SUPPORT
133 * just enough code to set the watchdog timer so that it
134 * will reboot the system
137 ds1511_wdog_set(unsigned long deciseconds)
140 * the wdog timer can take 99.99 seconds
142 deciseconds %= 10000;
144 * set the wdog values in the wdog registers
146 rtc_write(bin2bcd(deciseconds % 100), DS1511_WD_MSEC);
147 rtc_write(bin2bcd(deciseconds / 100), DS1511_WD_SEC);
149 * set wdog enable and wdog 'steering' bit to issue a reset
151 rtc_write(rtc_read(RTC_CMD) | DS1511_WDE | DS1511_WDS, RTC_CMD);
155 ds1511_wdog_disable(void)
158 * clear wdog enable and wdog 'steering' bits
160 rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD);
162 * clear the wdog counter
164 rtc_write(0, DS1511_WD_MSEC);
165 rtc_write(0, DS1511_WD_SEC);
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.
174 static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
176 u8 mon, day, dow, hrs, min, sec, yrs, cen;
180 * won't have to change this for a while
182 if (rtc_tm->tm_year < 1900)
183 rtc_tm->tm_year += 1900;
185 if (rtc_tm->tm_year < 1970)
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;
197 if ((mon > 12) || (day == 0))
200 if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year))
203 if ((hrs >= 24) || (min >= 60) || (sec >= 60))
207 * each register is a different number of valid bits
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;
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);
228 spin_unlock_irqrestore(&ds1511_lock, flags);
233 static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
235 unsigned int century;
238 spin_lock_irqsave(&ds1511_lock, flags);
239 rtc_disable_update();
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);
251 spin_unlock_irqrestore(&ds1511_lock, flags);
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;
263 * Account for differences between how the RTC uses the values
264 * and how they are defined in a struct rtc_time;
266 century += rtc_tm->tm_year;
267 rtc_tm->tm_year = century - 1900;
275 * write the alarm register settings
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.
283 ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
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,
291 rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
292 0x80 : bin2bcd(pdata->alrm_hour) & 0x3f,
294 rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
295 0x80 : bin2bcd(pdata->alrm_min) & 0x7f,
297 rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
298 0x80 : bin2bcd(pdata->alrm_sec) & 0x7f,
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);
306 ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
308 struct rtc_plat_data *pdata = dev_get_drvdata(dev);
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;
318 pdata->irqen |= RTC_AF;
320 ds1511_rtc_update_alarm(pdata);
325 ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
327 struct rtc_plat_data *pdata = dev_get_drvdata(dev);
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;
341 ds1511_interrupt(int irq, void *dev_id)
343 struct platform_device *pdev = dev_id;
344 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
345 unsigned long events = 0;
347 spin_lock(&pdata->lock);
349 * read and clear interrupt
351 if (rtc_read(RTC_CMD1) & DS1511_IRQF) {
353 if (rtc_read(RTC_ALARM_SEC) & 0x80)
357 rtc_update_irq(pdata->rtc, 1, events);
359 spin_unlock(&pdata->lock);
360 return events ? IRQ_HANDLED : IRQ_NONE;
363 static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
365 struct rtc_plat_data *pdata = dev_get_drvdata(dev);
370 pdata->irqen |= RTC_AF;
372 pdata->irqen &= ~RTC_AF;
373 ds1511_rtc_update_alarm(pdata);
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,
385 static int ds1511_nvram_read(void *priv, unsigned int pos, void *buf,
390 rtc_write(pos, DS1511_RAMADDR_LSB);
391 for (i = 0; i < size; i++)
392 *(char *)buf++ = rtc_read(DS1511_RAMDATA);
397 static int ds1511_nvram_write(void *priv, unsigned int pos, void *buf,
402 rtc_write(pos, DS1511_RAMADDR_LSB);
403 for (i = 0; i < size; i++)
404 rtc_write(*(char *)buf++, DS1511_RAMDATA);
409 static int ds1511_rtc_probe(struct platform_device *pdev)
411 struct rtc_plat_data *pdata;
413 struct nvmem_config ds1511_nvmem_cfg = {
414 .name = "ds1511_nvram",
417 .size = DS1511_RAM_MAX,
418 .reg_read = ds1511_nvram_read,
419 .reg_write = ds1511_nvram_write,
423 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
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);
434 * turn on the clock and the crystal, etc.
436 rtc_write(DS1511_BME, RTC_CMD);
437 rtc_write(0, RTC_CMD1);
439 * clear the wdog counter
441 rtc_write(0, DS1511_WD_MSEC);
442 rtc_write(0, DS1511_WD_SEC);
449 * check for a dying bat-tree
451 if (rtc_read(RTC_CMD1) & DS1511_BLF1)
452 dev_warn(&pdev->dev, "voltage-low detected.\n");
454 spin_lock_init(&pdata->lock);
455 platform_set_drvdata(pdev, pdata);
457 pdata->rtc = devm_rtc_allocate_device(&pdev->dev);
458 if (IS_ERR(pdata->rtc))
459 return PTR_ERR(pdata->rtc);
461 pdata->rtc->ops = &ds1511_rtc_ops;
463 ret = devm_rtc_register_device(pdata->rtc);
467 devm_rtc_nvmem_register(pdata->rtc, &ds1511_nvmem_cfg);
470 * if the platform has an interrupt in mind for this device,
471 * then by all means, set it
473 if (pdata->irq > 0) {
475 if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt,
476 IRQF_SHARED, pdev->name, pdev) < 0) {
478 dev_warn(&pdev->dev, "interrupt not available.\n");
486 /* work with hotplug and coldplug */
487 MODULE_ALIAS("platform:ds1511");
489 static struct platform_driver ds1511_rtc_driver = {
490 .probe = ds1511_rtc_probe,
496 module_platform_driver(ds1511_rtc_driver);
498 MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
499 MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
500 MODULE_LICENSE("GPL");