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 pl031_vendor_data - per-vendor variations
73 * @ops: the vendor-specific operations used on this silicon version
75 struct pl031_vendor_data {
76 struct rtc_class_ops ops;
80 struct pl031_vendor_data *vendor;
81 struct rtc_device *rtc;
87 static int pl031_alarm_irq_enable(struct device *dev,
90 struct pl031_local *ldata = dev_get_drvdata(dev);
93 /* Clear any pending alarm interrupts. */
94 writel(RTC_BIT_AI, ldata->base + RTC_ICR);
96 imsc = readl(ldata->base + RTC_IMSC);
99 writel(imsc | RTC_BIT_AI, ldata->base + RTC_IMSC);
101 writel(imsc & ~RTC_BIT_AI, ldata->base + RTC_IMSC);
107 * Convert Gregorian date to ST v2 RTC format.
109 static int pl031_stv2_tm_to_time(struct device *dev,
110 struct rtc_time *tm, unsigned long *st_time,
111 unsigned long *bcd_year)
113 int year = tm->tm_year + 1900;
114 int wday = tm->tm_wday;
116 /* wday masking is not working in hardware so wday must be valid */
117 if (wday < -1 || wday > 6) {
118 dev_err(dev, "invalid wday value %d\n", tm->tm_wday);
120 } else if (wday == -1) {
121 /* wday is not provided, calculate it here */
123 struct rtc_time calc_tm;
125 rtc_tm_to_time(tm, &time);
126 rtc_time_to_tm(time, &calc_tm);
127 wday = calc_tm.tm_wday;
130 *bcd_year = (bin2bcd(year % 100) | bin2bcd(year / 100) << 8);
132 *st_time = ((tm->tm_mon + 1) << RTC_MON_SHIFT)
133 | (tm->tm_mday << RTC_MDAY_SHIFT)
134 | ((wday + 1) << RTC_WDAY_SHIFT)
135 | (tm->tm_hour << RTC_HOUR_SHIFT)
136 | (tm->tm_min << RTC_MIN_SHIFT)
137 | (tm->tm_sec << RTC_SEC_SHIFT);
143 * Convert ST v2 RTC format to Gregorian date.
145 static int pl031_stv2_time_to_tm(unsigned long st_time, unsigned long bcd_year,
148 tm->tm_year = bcd2bin(bcd_year) + (bcd2bin(bcd_year >> 8) * 100);
149 tm->tm_mon = ((st_time & RTC_MON_MASK) >> RTC_MON_SHIFT) - 1;
150 tm->tm_mday = ((st_time & RTC_MDAY_MASK) >> RTC_MDAY_SHIFT);
151 tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1;
152 tm->tm_hour = ((st_time & RTC_HOUR_MASK) >> RTC_HOUR_SHIFT);
153 tm->tm_min = ((st_time & RTC_MIN_MASK) >> RTC_MIN_SHIFT);
154 tm->tm_sec = ((st_time & RTC_SEC_MASK) >> RTC_SEC_SHIFT);
156 tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
162 static int pl031_stv2_read_time(struct device *dev, struct rtc_time *tm)
164 struct pl031_local *ldata = dev_get_drvdata(dev);
166 pl031_stv2_time_to_tm(readl(ldata->base + RTC_DR),
167 readl(ldata->base + RTC_YDR), tm);
172 static int pl031_stv2_set_time(struct device *dev, struct rtc_time *tm)
175 unsigned long bcd_year;
176 struct pl031_local *ldata = dev_get_drvdata(dev);
179 ret = pl031_stv2_tm_to_time(dev, tm, &time, &bcd_year);
181 writel(bcd_year, ldata->base + RTC_YLR);
182 writel(time, ldata->base + RTC_LR);
188 static int pl031_stv2_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
190 struct pl031_local *ldata = dev_get_drvdata(dev);
193 ret = pl031_stv2_time_to_tm(readl(ldata->base + RTC_MR),
194 readl(ldata->base + RTC_YMR), &alarm->time);
196 alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
197 alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
202 static int pl031_stv2_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
204 struct pl031_local *ldata = dev_get_drvdata(dev);
206 unsigned long bcd_year;
209 /* At the moment, we can only deal with non-wildcarded alarm times. */
210 ret = rtc_valid_tm(&alarm->time);
212 ret = pl031_stv2_tm_to_time(dev, &alarm->time,
215 writel(bcd_year, ldata->base + RTC_YMR);
216 writel(time, ldata->base + RTC_MR);
218 pl031_alarm_irq_enable(dev, alarm->enabled);
225 static irqreturn_t pl031_interrupt(int irq, void *dev_id)
227 struct pl031_local *ldata = dev_id;
228 unsigned long rtcmis;
229 unsigned long events = 0;
231 rtcmis = readl(ldata->base + RTC_MIS);
232 if (rtcmis & RTC_BIT_AI) {
233 writel(RTC_BIT_AI, ldata->base + RTC_ICR);
234 events |= (RTC_AF | RTC_IRQF);
235 rtc_update_irq(ldata->rtc, 1, events);
243 static int pl031_read_time(struct device *dev, struct rtc_time *tm)
245 struct pl031_local *ldata = dev_get_drvdata(dev);
247 rtc_time_to_tm(readl(ldata->base + RTC_DR), tm);
252 static int pl031_set_time(struct device *dev, struct rtc_time *tm)
255 struct pl031_local *ldata = dev_get_drvdata(dev);
258 ret = rtc_tm_to_time(tm, &time);
261 writel(time, ldata->base + RTC_LR);
266 static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
268 struct pl031_local *ldata = dev_get_drvdata(dev);
270 rtc_time_to_tm(readl(ldata->base + RTC_MR), &alarm->time);
272 alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
273 alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
278 static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
280 struct pl031_local *ldata = dev_get_drvdata(dev);
284 /* At the moment, we can only deal with non-wildcarded alarm times. */
285 ret = rtc_valid_tm(&alarm->time);
287 ret = rtc_tm_to_time(&alarm->time, &time);
289 writel(time, ldata->base + RTC_MR);
290 pl031_alarm_irq_enable(dev, alarm->enabled);
297 static int pl031_remove(struct amba_device *adev)
299 struct pl031_local *ldata = dev_get_drvdata(&adev->dev);
301 amba_set_drvdata(adev, NULL);
302 free_irq(adev->irq[0], ldata->rtc);
303 rtc_device_unregister(ldata->rtc);
304 iounmap(ldata->base);
306 amba_release_regions(adev);
311 static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
314 struct pl031_local *ldata;
315 struct pl031_vendor_data *vendor = id->data;
316 struct rtc_class_ops *ops = &vendor->ops;
319 ret = amba_request_regions(adev, NULL);
323 ldata = kzalloc(sizeof(struct pl031_local), GFP_KERNEL);
328 ldata->vendor = vendor;
330 ldata->base = ioremap(adev->res.start, resource_size(&adev->res));
337 amba_set_drvdata(adev, ldata);
339 ldata->hw_designer = amba_manf(adev);
340 ldata->hw_revision = amba_rev(adev);
342 dev_dbg(&adev->dev, "designer ID = 0x%02x\n", ldata->hw_designer);
343 dev_dbg(&adev->dev, "revision = 0x%01x\n", ldata->hw_revision);
345 /* Enable the clockwatch on ST Variants */
346 if (ldata->hw_designer == AMBA_VENDOR_ST)
347 writel(readl(ldata->base + RTC_CR) | RTC_CR_CWEN,
348 ldata->base + RTC_CR);
351 * On ST PL031 variants, the RTC reset value does not provide correct
352 * weekday for 2000-01-01. Correct the erroneous sunday to saturday.
354 if (ldata->hw_designer == AMBA_VENDOR_ST) {
355 if (readl(ldata->base + RTC_YDR) == 0x2000) {
356 time = readl(ldata->base + RTC_DR);
358 (RTC_MON_MASK | RTC_MDAY_MASK | RTC_WDAY_MASK))
360 time = time | (0x7 << RTC_WDAY_SHIFT);
361 writel(0x2000, ldata->base + RTC_YLR);
362 writel(time, ldata->base + RTC_LR);
367 ldata->rtc = rtc_device_register("pl031", &adev->dev, ops,
369 if (IS_ERR(ldata->rtc)) {
370 ret = PTR_ERR(ldata->rtc);
374 if (request_irq(adev->irq[0], pl031_interrupt,
375 0, "rtc-pl031", ldata)) {
383 rtc_device_unregister(ldata->rtc);
385 iounmap(ldata->base);
386 amba_set_drvdata(adev, NULL);
390 amba_release_regions(adev);
396 /* Operations for the original ARM version */
397 static struct pl031_vendor_data arm_pl031 = {
399 .read_time = pl031_read_time,
400 .set_time = pl031_set_time,
401 .read_alarm = pl031_read_alarm,
402 .set_alarm = pl031_set_alarm,
403 .alarm_irq_enable = pl031_alarm_irq_enable,
407 /* The First ST derivative */
408 static struct pl031_vendor_data stv1_pl031 = {
410 .read_time = pl031_read_time,
411 .set_time = pl031_set_time,
412 .read_alarm = pl031_read_alarm,
413 .set_alarm = pl031_set_alarm,
414 .alarm_irq_enable = pl031_alarm_irq_enable,
418 /* And the second ST derivative */
419 static struct pl031_vendor_data stv2_pl031 = {
421 .read_time = pl031_stv2_read_time,
422 .set_time = pl031_stv2_set_time,
423 .read_alarm = pl031_stv2_read_alarm,
424 .set_alarm = pl031_stv2_set_alarm,
425 .alarm_irq_enable = pl031_alarm_irq_enable,
429 static struct amba_id pl031_ids[] = {
435 /* ST Micro variants */
449 MODULE_DEVICE_TABLE(amba, pl031_ids);
451 static struct amba_driver pl031_driver = {
455 .id_table = pl031_ids,
456 .probe = pl031_probe,
457 .remove = pl031_remove,
460 module_amba_driver(pl031_driver);
462 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net");
463 MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
464 MODULE_LICENSE("GPL");