2 * drivers/rtc/rtc-pl031.c
4 * Real Time Clock interface for ARM AMBA PrimeCell 031 RTC
6 * Author: Deepak Saxena <dsaxena@plexity.net>
8 * Copyright 2006 (c) MontaVista Software, Inc.
10 * Author: Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com>
11 * Copyright 2010 (c) ST-Ericsson AB
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
18 #include <linux/module.h>
19 #include <linux/rtc.h>
20 #include <linux/init.h>
21 #include <linux/interrupt.h>
22 #include <linux/amba/bus.h>
24 #include <linux/bcd.h>
25 #include <linux/delay.h>
26 #include <linux/slab.h>
29 * Register definitions
31 #define RTC_DR 0x00 /* Data read register */
32 #define RTC_MR 0x04 /* Match register */
33 #define RTC_LR 0x08 /* Data load register */
34 #define RTC_CR 0x0c /* Control register */
35 #define RTC_IMSC 0x10 /* Interrupt mask and set register */
36 #define RTC_RIS 0x14 /* Raw interrupt status register */
37 #define RTC_MIS 0x18 /* Masked interrupt status register */
38 #define RTC_ICR 0x1c /* Interrupt clear register */
39 /* ST variants have additional timer functionality */
40 #define RTC_TDR 0x20 /* Timer data read register */
41 #define RTC_TLR 0x24 /* Timer data load register */
42 #define RTC_TCR 0x28 /* Timer control register */
43 #define RTC_YDR 0x30 /* Year data read register */
44 #define RTC_YMR 0x34 /* Year match register */
45 #define RTC_YLR 0x38 /* Year data load register */
47 #define RTC_CR_CWEN (1 << 26) /* Clockwatch enable bit */
49 #define RTC_TCR_EN (1 << 1) /* Periodic timer enable bit */
51 /* Common bit definitions for Interrupt status and control registers */
52 #define RTC_BIT_AI (1 << 0) /* Alarm interrupt bit */
53 #define RTC_BIT_PI (1 << 1) /* Periodic interrupt bit. ST variants only. */
55 /* Common bit definations for ST v2 for reading/writing time */
56 #define RTC_SEC_SHIFT 0
57 #define RTC_SEC_MASK (0x3F << RTC_SEC_SHIFT) /* Second [0-59] */
58 #define RTC_MIN_SHIFT 6
59 #define RTC_MIN_MASK (0x3F << RTC_MIN_SHIFT) /* Minute [0-59] */
60 #define RTC_HOUR_SHIFT 12
61 #define RTC_HOUR_MASK (0x1F << RTC_HOUR_SHIFT) /* Hour [0-23] */
62 #define RTC_WDAY_SHIFT 17
63 #define RTC_WDAY_MASK (0x7 << RTC_WDAY_SHIFT) /* Day of Week [1-7] 1=Sunday */
64 #define RTC_MDAY_SHIFT 20
65 #define RTC_MDAY_MASK (0x1F << RTC_MDAY_SHIFT) /* Day of Month [1-31] */
66 #define RTC_MON_SHIFT 25
67 #define RTC_MON_MASK (0xF << RTC_MON_SHIFT) /* Month [1-12] 1=January */
69 #define RTC_TIMER_FREQ 32768
72 struct rtc_device *rtc;
78 static int pl031_alarm_irq_enable(struct device *dev,
81 struct pl031_local *ldata = dev_get_drvdata(dev);
84 /* Clear any pending alarm interrupts. */
85 writel(RTC_BIT_AI, ldata->base + RTC_ICR);
87 imsc = readl(ldata->base + RTC_IMSC);
90 writel(imsc | RTC_BIT_AI, ldata->base + RTC_IMSC);
92 writel(imsc & ~RTC_BIT_AI, ldata->base + RTC_IMSC);
98 * Convert Gregorian date to ST v2 RTC format.
100 static int pl031_stv2_tm_to_time(struct device *dev,
101 struct rtc_time *tm, unsigned long *st_time,
102 unsigned long *bcd_year)
104 int year = tm->tm_year + 1900;
105 int wday = tm->tm_wday;
107 /* wday masking is not working in hardware so wday must be valid */
108 if (wday < -1 || wday > 6) {
109 dev_err(dev, "invalid wday value %d\n", tm->tm_wday);
111 } else if (wday == -1) {
112 /* wday is not provided, calculate it here */
114 struct rtc_time calc_tm;
116 rtc_tm_to_time(tm, &time);
117 rtc_time_to_tm(time, &calc_tm);
118 wday = calc_tm.tm_wday;
121 *bcd_year = (bin2bcd(year % 100) | bin2bcd(year / 100) << 8);
123 *st_time = ((tm->tm_mon + 1) << RTC_MON_SHIFT)
124 | (tm->tm_mday << RTC_MDAY_SHIFT)
125 | ((wday + 1) << RTC_WDAY_SHIFT)
126 | (tm->tm_hour << RTC_HOUR_SHIFT)
127 | (tm->tm_min << RTC_MIN_SHIFT)
128 | (tm->tm_sec << RTC_SEC_SHIFT);
134 * Convert ST v2 RTC format to Gregorian date.
136 static int pl031_stv2_time_to_tm(unsigned long st_time, unsigned long bcd_year,
139 tm->tm_year = bcd2bin(bcd_year) + (bcd2bin(bcd_year >> 8) * 100);
140 tm->tm_mon = ((st_time & RTC_MON_MASK) >> RTC_MON_SHIFT) - 1;
141 tm->tm_mday = ((st_time & RTC_MDAY_MASK) >> RTC_MDAY_SHIFT);
142 tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1;
143 tm->tm_hour = ((st_time & RTC_HOUR_MASK) >> RTC_HOUR_SHIFT);
144 tm->tm_min = ((st_time & RTC_MIN_MASK) >> RTC_MIN_SHIFT);
145 tm->tm_sec = ((st_time & RTC_SEC_MASK) >> RTC_SEC_SHIFT);
147 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
153 static int pl031_stv2_read_time(struct device *dev, struct rtc_time *tm)
155 struct pl031_local *ldata = dev_get_drvdata(dev);
157 pl031_stv2_time_to_tm(readl(ldata->base + RTC_DR),
158 readl(ldata->base + RTC_YDR), tm);
163 static int pl031_stv2_set_time(struct device *dev, struct rtc_time *tm)
166 unsigned long bcd_year;
167 struct pl031_local *ldata = dev_get_drvdata(dev);
170 ret = pl031_stv2_tm_to_time(dev, tm, &time, &bcd_year);
172 writel(bcd_year, ldata->base + RTC_YLR);
173 writel(time, ldata->base + RTC_LR);
179 static int pl031_stv2_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
181 struct pl031_local *ldata = dev_get_drvdata(dev);
184 ret = pl031_stv2_time_to_tm(readl(ldata->base + RTC_MR),
185 readl(ldata->base + RTC_YMR), &alarm->time);
187 alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
188 alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
193 static int pl031_stv2_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
195 struct pl031_local *ldata = dev_get_drvdata(dev);
197 unsigned long bcd_year;
200 /* At the moment, we can only deal with non-wildcarded alarm times. */
201 ret = rtc_valid_tm(&alarm->time);
203 ret = pl031_stv2_tm_to_time(dev, &alarm->time,
206 writel(bcd_year, ldata->base + RTC_YMR);
207 writel(time, ldata->base + RTC_MR);
209 pl031_alarm_irq_enable(dev, alarm->enabled);
216 static irqreturn_t pl031_interrupt(int irq, void *dev_id)
218 struct pl031_local *ldata = dev_id;
219 unsigned long rtcmis;
220 unsigned long events = 0;
222 rtcmis = readl(ldata->base + RTC_MIS);
223 if (rtcmis & RTC_BIT_AI) {
224 writel(RTC_BIT_AI, ldata->base + RTC_ICR);
225 events |= (RTC_AF | RTC_IRQF);
226 rtc_update_irq(ldata->rtc, 1, events);
234 static int pl031_read_time(struct device *dev, struct rtc_time *tm)
236 struct pl031_local *ldata = dev_get_drvdata(dev);
238 rtc_time_to_tm(readl(ldata->base + RTC_DR), tm);
243 static int pl031_set_time(struct device *dev, struct rtc_time *tm)
246 struct pl031_local *ldata = dev_get_drvdata(dev);
249 ret = rtc_tm_to_time(tm, &time);
252 writel(time, ldata->base + RTC_LR);
257 static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
259 struct pl031_local *ldata = dev_get_drvdata(dev);
261 rtc_time_to_tm(readl(ldata->base + RTC_MR), &alarm->time);
263 alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
264 alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
269 static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
271 struct pl031_local *ldata = dev_get_drvdata(dev);
275 /* At the moment, we can only deal with non-wildcarded alarm times. */
276 ret = rtc_valid_tm(&alarm->time);
278 ret = rtc_tm_to_time(&alarm->time, &time);
280 writel(time, ldata->base + RTC_MR);
281 pl031_alarm_irq_enable(dev, alarm->enabled);
288 static int pl031_remove(struct amba_device *adev)
290 struct pl031_local *ldata = dev_get_drvdata(&adev->dev);
292 amba_set_drvdata(adev, NULL);
293 free_irq(adev->irq[0], ldata->rtc);
294 rtc_device_unregister(ldata->rtc);
295 iounmap(ldata->base);
297 amba_release_regions(adev);
302 static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
305 struct pl031_local *ldata;
306 struct rtc_class_ops *ops = id->data;
309 ret = amba_request_regions(adev, NULL);
313 ldata = kzalloc(sizeof(struct pl031_local), GFP_KERNEL);
319 ldata->base = ioremap(adev->res.start, resource_size(&adev->res));
326 amba_set_drvdata(adev, ldata);
328 ldata->hw_designer = amba_manf(adev);
329 ldata->hw_revision = amba_rev(adev);
331 dev_dbg(&adev->dev, "designer ID = 0x%02x\n", ldata->hw_designer);
332 dev_dbg(&adev->dev, "revision = 0x%01x\n", ldata->hw_revision);
334 /* Enable the clockwatch on ST Variants */
335 if (ldata->hw_designer == AMBA_VENDOR_ST)
336 writel(readl(ldata->base + RTC_CR) | RTC_CR_CWEN,
337 ldata->base + RTC_CR);
340 * On ST PL031 variants, the RTC reset value does not provide correct
341 * weekday for 2000-01-01. Correct the erroneous sunday to saturday.
343 if (ldata->hw_designer == AMBA_VENDOR_ST) {
344 if (readl(ldata->base + RTC_YDR) == 0x2000) {
345 time = readl(ldata->base + RTC_DR);
347 (RTC_MON_MASK | RTC_MDAY_MASK | RTC_WDAY_MASK))
349 time = time | (0x7 << RTC_WDAY_SHIFT);
350 writel(0x2000, ldata->base + RTC_YLR);
351 writel(time, ldata->base + RTC_LR);
356 ldata->rtc = rtc_device_register("pl031", &adev->dev, ops,
358 if (IS_ERR(ldata->rtc)) {
359 ret = PTR_ERR(ldata->rtc);
363 if (request_irq(adev->irq[0], pl031_interrupt,
364 0, "rtc-pl031", ldata)) {
372 rtc_device_unregister(ldata->rtc);
374 iounmap(ldata->base);
375 amba_set_drvdata(adev, NULL);
379 amba_release_regions(adev);
385 /* Operations for the original ARM version */
386 static struct rtc_class_ops arm_pl031_ops = {
387 .read_time = pl031_read_time,
388 .set_time = pl031_set_time,
389 .read_alarm = pl031_read_alarm,
390 .set_alarm = pl031_set_alarm,
391 .alarm_irq_enable = pl031_alarm_irq_enable,
394 /* The First ST derivative */
395 static struct rtc_class_ops stv1_pl031_ops = {
396 .read_time = pl031_read_time,
397 .set_time = pl031_set_time,
398 .read_alarm = pl031_read_alarm,
399 .set_alarm = pl031_set_alarm,
400 .alarm_irq_enable = pl031_alarm_irq_enable,
403 /* And the second ST derivative */
404 static struct rtc_class_ops stv2_pl031_ops = {
405 .read_time = pl031_stv2_read_time,
406 .set_time = pl031_stv2_set_time,
407 .read_alarm = pl031_stv2_read_alarm,
408 .set_alarm = pl031_stv2_set_alarm,
409 .alarm_irq_enable = pl031_alarm_irq_enable,
412 static struct amba_id pl031_ids[] = {
416 .data = &arm_pl031_ops,
418 /* ST Micro variants */
422 .data = &stv1_pl031_ops,
427 .data = &stv2_pl031_ops,
432 MODULE_DEVICE_TABLE(amba, pl031_ids);
434 static struct amba_driver pl031_driver = {
438 .id_table = pl031_ids,
439 .probe = pl031_probe,
440 .remove = pl031_remove,
443 module_amba_driver(pl031_driver);
445 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net");
446 MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
447 MODULE_LICENSE("GPL");