Root/drivers/rtc/rtc-ds1511.c

1/*
2 * An rtc driver for the Dallas DS1511
3 *
4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
5 * Copyright (C) 2007 Andrew Sharp <andy.sharp@lsi.com>
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 * Real time clock driver for the Dallas 1511 chip, which also
12 * contains a watchdog timer. There is a tiny amount of code that
13 * platform code could use to mess with the watchdog device a little
14 * bit, but not a full watchdog driver.
15 */
16
17#include <linux/bcd.h>
18#include <linux/init.h>
19#include <linux/kernel.h>
20#include <linux/gfp.h>
21#include <linux/delay.h>
22#include <linux/interrupt.h>
23#include <linux/rtc.h>
24#include <linux/platform_device.h>
25#include <linux/io.h>
26#include <linux/module.h>
27
28#define DRV_VERSION "0.6"
29
30enum ds1511reg {
31    DS1511_SEC = 0x0,
32    DS1511_MIN = 0x1,
33    DS1511_HOUR = 0x2,
34    DS1511_DOW = 0x3,
35    DS1511_DOM = 0x4,
36    DS1511_MONTH = 0x5,
37    DS1511_YEAR = 0x6,
38    DS1511_CENTURY = 0x7,
39    DS1511_AM1_SEC = 0x8,
40    DS1511_AM2_MIN = 0x9,
41    DS1511_AM3_HOUR = 0xa,
42    DS1511_AM4_DATE = 0xb,
43    DS1511_WD_MSEC = 0xc,
44    DS1511_WD_SEC = 0xd,
45    DS1511_CONTROL_A = 0xe,
46    DS1511_CONTROL_B = 0xf,
47    DS1511_RAMADDR_LSB = 0x10,
48    DS1511_RAMDATA = 0x13
49};
50
51#define DS1511_BLF1 0x80
52#define DS1511_BLF2 0x40
53#define DS1511_PRS 0x20
54#define DS1511_PAB 0x10
55#define DS1511_TDF 0x08
56#define DS1511_KSF 0x04
57#define DS1511_WDF 0x02
58#define DS1511_IRQF 0x01
59#define DS1511_TE 0x80
60#define DS1511_CS 0x40
61#define DS1511_BME 0x20
62#define DS1511_TPE 0x10
63#define DS1511_TIE 0x08
64#define DS1511_KIE 0x04
65#define DS1511_WDE 0x02
66#define DS1511_WDS 0x01
67#define DS1511_RAM_MAX 0xff
68
69#define RTC_CMD DS1511_CONTROL_B
70#define RTC_CMD1 DS1511_CONTROL_A
71
72#define RTC_ALARM_SEC DS1511_AM1_SEC
73#define RTC_ALARM_MIN DS1511_AM2_MIN
74#define RTC_ALARM_HOUR DS1511_AM3_HOUR
75#define RTC_ALARM_DATE DS1511_AM4_DATE
76
77#define RTC_SEC DS1511_SEC
78#define RTC_MIN DS1511_MIN
79#define RTC_HOUR DS1511_HOUR
80#define RTC_DOW DS1511_DOW
81#define RTC_DOM DS1511_DOM
82#define RTC_MON DS1511_MONTH
83#define RTC_YEAR DS1511_YEAR
84#define RTC_CENTURY DS1511_CENTURY
85
86#define RTC_TIE DS1511_TIE
87#define RTC_TE DS1511_TE
88
89struct rtc_plat_data {
90    struct rtc_device *rtc;
91    void __iomem *ioaddr; /* virtual base address */
92    int size; /* amount of memory mapped */
93    int irq;
94    unsigned int irqen;
95    int alrm_sec;
96    int alrm_min;
97    int alrm_hour;
98    int alrm_mday;
99    spinlock_t lock;
100};
101
102static DEFINE_SPINLOCK(ds1511_lock);
103
104static __iomem char *ds1511_base;
105static u32 reg_spacing = 1;
106
107 static noinline void
108rtc_write(uint8_t val, uint32_t reg)
109{
110    writeb(val, ds1511_base + (reg * reg_spacing));
111}
112
113 static inline void
114rtc_write_alarm(uint8_t val, enum ds1511reg reg)
115{
116    rtc_write((val | 0x80), reg);
117}
118
119 static noinline uint8_t
120rtc_read(enum ds1511reg reg)
121{
122    return readb(ds1511_base + (reg * reg_spacing));
123}
124
125 static inline void
126rtc_disable_update(void)
127{
128    rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
129}
130
131 static void
132rtc_enable_update(void)
133{
134    rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD);
135}
136
137/*
138 * #define DS1511_WDOG_RESET_SUPPORT
139 *
140 * Uncomment this if you want to use these routines in
141 * some platform code.
142 */
143#ifdef DS1511_WDOG_RESET_SUPPORT
144/*
145 * just enough code to set the watchdog timer so that it
146 * will reboot the system
147 */
148 void
149ds1511_wdog_set(unsigned long deciseconds)
150{
151    /*
152     * the wdog timer can take 99.99 seconds
153     */
154    deciseconds %= 10000;
155    /*
156     * set the wdog values in the wdog registers
157     */
158    rtc_write(bin2bcd(deciseconds % 100), DS1511_WD_MSEC);
159    rtc_write(bin2bcd(deciseconds / 100), DS1511_WD_SEC);
160    /*
161     * set wdog enable and wdog 'steering' bit to issue a reset
162     */
163    rtc_write(DS1511_WDE | DS1511_WDS, RTC_CMD);
164}
165
166 void
167ds1511_wdog_disable(void)
168{
169    /*
170     * clear wdog enable and wdog 'steering' bits
171     */
172    rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD);
173    /*
174     * clear the wdog counter
175     */
176    rtc_write(0, DS1511_WD_MSEC);
177    rtc_write(0, DS1511_WD_SEC);
178}
179#endif
180
181/*
182 * set the rtc chip's idea of the time.
183 * stupidly, some callers call with year unmolested;
184 * and some call with year = year - 1900. thanks.
185 */
186static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
187{
188    u8 mon, day, dow, hrs, min, sec, yrs, cen;
189    unsigned long flags;
190
191    /*
192     * won't have to change this for a while
193     */
194    if (rtc_tm->tm_year < 1900) {
195        rtc_tm->tm_year += 1900;
196    }
197
198    if (rtc_tm->tm_year < 1970) {
199        return -EINVAL;
200    }
201    yrs = rtc_tm->tm_year % 100;
202    cen = rtc_tm->tm_year / 100;
203    mon = rtc_tm->tm_mon + 1; /* tm_mon starts at zero */
204    day = rtc_tm->tm_mday;
205    dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */
206    hrs = rtc_tm->tm_hour;
207    min = rtc_tm->tm_min;
208    sec = rtc_tm->tm_sec;
209
210    if ((mon > 12) || (day == 0)) {
211        return -EINVAL;
212    }
213
214    if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year)) {
215        return -EINVAL;
216    }
217
218    if ((hrs >= 24) || (min >= 60) || (sec >= 60)) {
219        return -EINVAL;
220    }
221
222    /*
223     * each register is a different number of valid bits
224     */
225    sec = bin2bcd(sec) & 0x7f;
226    min = bin2bcd(min) & 0x7f;
227    hrs = bin2bcd(hrs) & 0x3f;
228    day = bin2bcd(day) & 0x3f;
229    mon = bin2bcd(mon) & 0x1f;
230    yrs = bin2bcd(yrs) & 0xff;
231    cen = bin2bcd(cen) & 0xff;
232
233    spin_lock_irqsave(&ds1511_lock, flags);
234    rtc_disable_update();
235    rtc_write(cen, RTC_CENTURY);
236    rtc_write(yrs, RTC_YEAR);
237    rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON);
238    rtc_write(day, RTC_DOM);
239    rtc_write(hrs, RTC_HOUR);
240    rtc_write(min, RTC_MIN);
241    rtc_write(sec, RTC_SEC);
242    rtc_write(dow, RTC_DOW);
243    rtc_enable_update();
244    spin_unlock_irqrestore(&ds1511_lock, flags);
245
246    return 0;
247}
248
249static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
250{
251    unsigned int century;
252    unsigned long flags;
253
254    spin_lock_irqsave(&ds1511_lock, flags);
255    rtc_disable_update();
256
257    rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f;
258    rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f;
259    rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f;
260    rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f;
261    rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7;
262    rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f;
263    rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f;
264    century = rtc_read(RTC_CENTURY);
265
266    rtc_enable_update();
267    spin_unlock_irqrestore(&ds1511_lock, flags);
268
269    rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
270    rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
271    rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
272    rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
273    rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
274    rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
275    rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
276    century = bcd2bin(century) * 100;
277
278    /*
279     * Account for differences between how the RTC uses the values
280     * and how they are defined in a struct rtc_time;
281     */
282    century += rtc_tm->tm_year;
283    rtc_tm->tm_year = century - 1900;
284
285    rtc_tm->tm_mon--;
286
287    if (rtc_valid_tm(rtc_tm) < 0) {
288        dev_err(dev, "retrieved date/time is not valid.\n");
289        rtc_time_to_tm(0, rtc_tm);
290    }
291    return 0;
292}
293
294/*
295 * write the alarm register settings
296 *
297 * we only have the use to interrupt every second, otherwise
298 * known as the update interrupt, or the interrupt if the whole
299 * date/hours/mins/secs matches. the ds1511 has many more
300 * permutations, but the kernel doesn't.
301 */
302 static void
303ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
304{
305    unsigned long flags;
306
307    spin_lock_irqsave(&pdata->lock, flags);
308    rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
309           0x80 : bin2bcd(pdata->alrm_mday) & 0x3f,
310           RTC_ALARM_DATE);
311    rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
312           0x80 : bin2bcd(pdata->alrm_hour) & 0x3f,
313           RTC_ALARM_HOUR);
314    rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
315           0x80 : bin2bcd(pdata->alrm_min) & 0x7f,
316           RTC_ALARM_MIN);
317    rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
318           0x80 : bin2bcd(pdata->alrm_sec) & 0x7f,
319           RTC_ALARM_SEC);
320    rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD);
321    rtc_read(RTC_CMD1); /* clear interrupts */
322    spin_unlock_irqrestore(&pdata->lock, flags);
323}
324
325 static int
326ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
327{
328    struct platform_device *pdev = to_platform_device(dev);
329    struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
330
331    if (pdata->irq <= 0)
332        return -EINVAL;
333
334    pdata->alrm_mday = alrm->time.tm_mday;
335    pdata->alrm_hour = alrm->time.tm_hour;
336    pdata->alrm_min = alrm->time.tm_min;
337    pdata->alrm_sec = alrm->time.tm_sec;
338    if (alrm->enabled) {
339        pdata->irqen |= RTC_AF;
340    }
341    ds1511_rtc_update_alarm(pdata);
342    return 0;
343}
344
345 static int
346ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
347{
348    struct platform_device *pdev = to_platform_device(dev);
349    struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
350
351    if (pdata->irq <= 0)
352        return -EINVAL;
353
354    alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
355    alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
356    alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
357    alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
358    alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
359    return 0;
360}
361
362 static irqreturn_t
363ds1511_interrupt(int irq, void *dev_id)
364{
365    struct platform_device *pdev = dev_id;
366    struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
367    unsigned long events = 0;
368
369    spin_lock(&pdata->lock);
370    /*
371     * read and clear interrupt
372     */
373    if (rtc_read(RTC_CMD1) & DS1511_IRQF) {
374        events = RTC_IRQF;
375        if (rtc_read(RTC_ALARM_SEC) & 0x80)
376            events |= RTC_UF;
377        else
378            events |= RTC_AF;
379        if (likely(pdata->rtc))
380            rtc_update_irq(pdata->rtc, 1, events);
381    }
382    spin_unlock(&pdata->lock);
383    return events ? IRQ_HANDLED : IRQ_NONE;
384}
385
386static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
387{
388    struct platform_device *pdev = to_platform_device(dev);
389    struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
390
391    if (pdata->irq <= 0)
392        return -EINVAL;
393    if (enabled)
394        pdata->irqen |= RTC_AF;
395    else
396        pdata->irqen &= ~RTC_AF;
397    ds1511_rtc_update_alarm(pdata);
398    return 0;
399}
400
401static const struct rtc_class_ops ds1511_rtc_ops = {
402    .read_time = ds1511_rtc_read_time,
403    .set_time = ds1511_rtc_set_time,
404    .read_alarm = ds1511_rtc_read_alarm,
405    .set_alarm = ds1511_rtc_set_alarm,
406    .alarm_irq_enable = ds1511_rtc_alarm_irq_enable,
407};
408
409 static ssize_t
410ds1511_nvram_read(struct file *filp, struct kobject *kobj,
411          struct bin_attribute *ba,
412          char *buf, loff_t pos, size_t size)
413{
414    ssize_t count;
415
416    /*
417     * if count is more than one, turn on "burst" mode
418     * turn it off when you're done
419     */
420    if (size > 1) {
421        rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
422    }
423    if (pos > DS1511_RAM_MAX) {
424        pos = DS1511_RAM_MAX;
425    }
426    if (size + pos > DS1511_RAM_MAX + 1) {
427        size = DS1511_RAM_MAX - pos + 1;
428    }
429    rtc_write(pos, DS1511_RAMADDR_LSB);
430    for (count = 0; size > 0; count++, size--) {
431        *buf++ = rtc_read(DS1511_RAMDATA);
432    }
433    if (count > 1) {
434        rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
435    }
436    return count;
437}
438
439 static ssize_t
440ds1511_nvram_write(struct file *filp, struct kobject *kobj,
441           struct bin_attribute *bin_attr,
442           char *buf, loff_t pos, size_t size)
443{
444    ssize_t count;
445
446    /*
447     * if count is more than one, turn on "burst" mode
448     * turn it off when you're done
449     */
450    if (size > 1) {
451        rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
452    }
453    if (pos > DS1511_RAM_MAX) {
454        pos = DS1511_RAM_MAX;
455    }
456    if (size + pos > DS1511_RAM_MAX + 1) {
457        size = DS1511_RAM_MAX - pos + 1;
458    }
459    rtc_write(pos, DS1511_RAMADDR_LSB);
460    for (count = 0; size > 0; count++, size--) {
461        rtc_write(*buf++, DS1511_RAMDATA);
462    }
463    if (count > 1) {
464        rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
465    }
466    return count;
467}
468
469static struct bin_attribute ds1511_nvram_attr = {
470    .attr = {
471        .name = "nvram",
472        .mode = S_IRUGO | S_IWUSR,
473    },
474    .size = DS1511_RAM_MAX,
475    .read = ds1511_nvram_read,
476    .write = ds1511_nvram_write,
477};
478
479 static int __devinit
480ds1511_rtc_probe(struct platform_device *pdev)
481{
482    struct rtc_device *rtc;
483    struct resource *res;
484    struct rtc_plat_data *pdata;
485    int ret = 0;
486
487    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
488    if (!res) {
489        return -ENODEV;
490    }
491    pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
492    if (!pdata)
493        return -ENOMEM;
494    pdata->size = resource_size(res);
495    if (!devm_request_mem_region(&pdev->dev, res->start, pdata->size,
496            pdev->name))
497        return -EBUSY;
498    ds1511_base = devm_ioremap(&pdev->dev, res->start, pdata->size);
499    if (!ds1511_base)
500        return -ENOMEM;
501    pdata->ioaddr = ds1511_base;
502    pdata->irq = platform_get_irq(pdev, 0);
503
504    /*
505     * turn on the clock and the crystal, etc.
506     */
507    rtc_write(0, RTC_CMD);
508    rtc_write(0, RTC_CMD1);
509    /*
510     * clear the wdog counter
511     */
512    rtc_write(0, DS1511_WD_MSEC);
513    rtc_write(0, DS1511_WD_SEC);
514    /*
515     * start the clock
516     */
517    rtc_enable_update();
518
519    /*
520     * check for a dying bat-tree
521     */
522    if (rtc_read(RTC_CMD1) & DS1511_BLF1) {
523        dev_warn(&pdev->dev, "voltage-low detected.\n");
524    }
525
526    spin_lock_init(&pdata->lock);
527    platform_set_drvdata(pdev, pdata);
528    /*
529     * if the platform has an interrupt in mind for this device,
530     * then by all means, set it
531     */
532    if (pdata->irq > 0) {
533        rtc_read(RTC_CMD1);
534        if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt,
535            IRQF_SHARED, pdev->name, pdev) < 0) {
536
537            dev_warn(&pdev->dev, "interrupt not available.\n");
538            pdata->irq = 0;
539        }
540    }
541
542    rtc = rtc_device_register(pdev->name, &pdev->dev, &ds1511_rtc_ops,
543        THIS_MODULE);
544    if (IS_ERR(rtc))
545        return PTR_ERR(rtc);
546    pdata->rtc = rtc;
547
548    ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
549    if (ret)
550        rtc_device_unregister(pdata->rtc);
551    return ret;
552}
553
554 static int __devexit
555ds1511_rtc_remove(struct platform_device *pdev)
556{
557    struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
558
559    sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
560    rtc_device_unregister(pdata->rtc);
561    if (pdata->irq > 0) {
562        /*
563         * disable the alarm interrupt
564         */
565        rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD);
566        rtc_read(RTC_CMD1);
567    }
568    return 0;
569}
570
571/* work with hotplug and coldplug */
572MODULE_ALIAS("platform:ds1511");
573
574static struct platform_driver ds1511_rtc_driver = {
575    .probe = ds1511_rtc_probe,
576    .remove = __devexit_p(ds1511_rtc_remove),
577    .driver = {
578        .name = "ds1511",
579        .owner = THIS_MODULE,
580    },
581};
582
583module_platform_driver(ds1511_rtc_driver);
584
585MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
586MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
587MODULE_LICENSE("GPL");
588MODULE_VERSION(DRV_VERSION);
589

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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9



interactive