Root/drivers/rtc/rtc-pl031.c

1/*
2 * drivers/rtc/rtc-pl031.c
3 *
4 * Real Time Clock interface for ARM AMBA PrimeCell 031 RTC
5 *
6 * Author: Deepak Saxena <dsaxena@plexity.net>
7 *
8 * Copyright 2006 (c) MontaVista Software, Inc.
9 *
10 * Author: Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com>
11 * Copyright 2010 (c) ST-Ericsson AB
12 *
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.
17 */
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>
23#include <linux/io.h>
24#include <linux/bcd.h>
25#include <linux/delay.h>
26#include <linux/slab.h>
27
28/*
29 * Register definitions
30 */
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 */
46
47#define RTC_CR_CWEN (1 << 26) /* Clockwatch enable bit */
48
49#define RTC_TCR_EN (1 << 1) /* Periodic timer enable bit */
50
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. */
54
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 */
68
69#define RTC_TIMER_FREQ 32768
70
71/**
72 * struct pl031_vendor_data - per-vendor variations
73 * @ops: the vendor-specific operations used on this silicon version
74 * @clockwatch: if this is an ST Microelectronics silicon version with a
75 * clockwatch function
76 * @st_weekday: if this is an ST Microelectronics silicon version that need
77 * the weekday fix
78 * @irqflags: special IRQ flags per variant
79 */
80struct pl031_vendor_data {
81    struct rtc_class_ops ops;
82    bool clockwatch;
83    bool st_weekday;
84    unsigned long irqflags;
85};
86
87struct pl031_local {
88    struct pl031_vendor_data *vendor;
89    struct rtc_device *rtc;
90    void __iomem *base;
91};
92
93static int pl031_alarm_irq_enable(struct device *dev,
94    unsigned int enabled)
95{
96    struct pl031_local *ldata = dev_get_drvdata(dev);
97    unsigned long imsc;
98
99    /* Clear any pending alarm interrupts. */
100    writel(RTC_BIT_AI, ldata->base + RTC_ICR);
101
102    imsc = readl(ldata->base + RTC_IMSC);
103
104    if (enabled == 1)
105        writel(imsc | RTC_BIT_AI, ldata->base + RTC_IMSC);
106    else
107        writel(imsc & ~RTC_BIT_AI, ldata->base + RTC_IMSC);
108
109    return 0;
110}
111
112/*
113 * Convert Gregorian date to ST v2 RTC format.
114 */
115static int pl031_stv2_tm_to_time(struct device *dev,
116                 struct rtc_time *tm, unsigned long *st_time,
117    unsigned long *bcd_year)
118{
119    int year = tm->tm_year + 1900;
120    int wday = tm->tm_wday;
121
122    /* wday masking is not working in hardware so wday must be valid */
123    if (wday < -1 || wday > 6) {
124        dev_err(dev, "invalid wday value %d\n", tm->tm_wday);
125        return -EINVAL;
126    } else if (wday == -1) {
127        /* wday is not provided, calculate it here */
128        unsigned long time;
129        struct rtc_time calc_tm;
130
131        rtc_tm_to_time(tm, &time);
132        rtc_time_to_tm(time, &calc_tm);
133        wday = calc_tm.tm_wday;
134    }
135
136    *bcd_year = (bin2bcd(year % 100) | bin2bcd(year / 100) << 8);
137
138    *st_time = ((tm->tm_mon + 1) << RTC_MON_SHIFT)
139            | (tm->tm_mday << RTC_MDAY_SHIFT)
140            | ((wday + 1) << RTC_WDAY_SHIFT)
141            | (tm->tm_hour << RTC_HOUR_SHIFT)
142            | (tm->tm_min << RTC_MIN_SHIFT)
143            | (tm->tm_sec << RTC_SEC_SHIFT);
144
145    return 0;
146}
147
148/*
149 * Convert ST v2 RTC format to Gregorian date.
150 */
151static int pl031_stv2_time_to_tm(unsigned long st_time, unsigned long bcd_year,
152    struct rtc_time *tm)
153{
154    tm->tm_year = bcd2bin(bcd_year) + (bcd2bin(bcd_year >> 8) * 100);
155    tm->tm_mon = ((st_time & RTC_MON_MASK) >> RTC_MON_SHIFT) - 1;
156    tm->tm_mday = ((st_time & RTC_MDAY_MASK) >> RTC_MDAY_SHIFT);
157    tm->tm_wday = ((st_time & RTC_WDAY_MASK) >> RTC_WDAY_SHIFT) - 1;
158    tm->tm_hour = ((st_time & RTC_HOUR_MASK) >> RTC_HOUR_SHIFT);
159    tm->tm_min = ((st_time & RTC_MIN_MASK) >> RTC_MIN_SHIFT);
160    tm->tm_sec = ((st_time & RTC_SEC_MASK) >> RTC_SEC_SHIFT);
161
162    tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
163    tm->tm_year -= 1900;
164
165    return 0;
166}
167
168static int pl031_stv2_read_time(struct device *dev, struct rtc_time *tm)
169{
170    struct pl031_local *ldata = dev_get_drvdata(dev);
171
172    pl031_stv2_time_to_tm(readl(ldata->base + RTC_DR),
173            readl(ldata->base + RTC_YDR), tm);
174
175    return 0;
176}
177
178static int pl031_stv2_set_time(struct device *dev, struct rtc_time *tm)
179{
180    unsigned long time;
181    unsigned long bcd_year;
182    struct pl031_local *ldata = dev_get_drvdata(dev);
183    int ret;
184
185    ret = pl031_stv2_tm_to_time(dev, tm, &time, &bcd_year);
186    if (ret == 0) {
187        writel(bcd_year, ldata->base + RTC_YLR);
188        writel(time, ldata->base + RTC_LR);
189    }
190
191    return ret;
192}
193
194static int pl031_stv2_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
195{
196    struct pl031_local *ldata = dev_get_drvdata(dev);
197    int ret;
198
199    ret = pl031_stv2_time_to_tm(readl(ldata->base + RTC_MR),
200            readl(ldata->base + RTC_YMR), &alarm->time);
201
202    alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
203    alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
204
205    return ret;
206}
207
208static int pl031_stv2_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
209{
210    struct pl031_local *ldata = dev_get_drvdata(dev);
211    unsigned long time;
212    unsigned long bcd_year;
213    int ret;
214
215    /* At the moment, we can only deal with non-wildcarded alarm times. */
216    ret = rtc_valid_tm(&alarm->time);
217    if (ret == 0) {
218        ret = pl031_stv2_tm_to_time(dev, &alarm->time,
219                        &time, &bcd_year);
220        if (ret == 0) {
221            writel(bcd_year, ldata->base + RTC_YMR);
222            writel(time, ldata->base + RTC_MR);
223
224            pl031_alarm_irq_enable(dev, alarm->enabled);
225        }
226    }
227
228    return ret;
229}
230
231static irqreturn_t pl031_interrupt(int irq, void *dev_id)
232{
233    struct pl031_local *ldata = dev_id;
234    unsigned long rtcmis;
235    unsigned long events = 0;
236
237    rtcmis = readl(ldata->base + RTC_MIS);
238    if (rtcmis & RTC_BIT_AI) {
239        writel(RTC_BIT_AI, ldata->base + RTC_ICR);
240        events |= (RTC_AF | RTC_IRQF);
241        rtc_update_irq(ldata->rtc, 1, events);
242
243        return IRQ_HANDLED;
244    }
245
246    return IRQ_NONE;
247}
248
249static int pl031_read_time(struct device *dev, struct rtc_time *tm)
250{
251    struct pl031_local *ldata = dev_get_drvdata(dev);
252
253    rtc_time_to_tm(readl(ldata->base + RTC_DR), tm);
254
255    return 0;
256}
257
258static int pl031_set_time(struct device *dev, struct rtc_time *tm)
259{
260    unsigned long time;
261    struct pl031_local *ldata = dev_get_drvdata(dev);
262    int ret;
263
264    ret = rtc_tm_to_time(tm, &time);
265
266    if (ret == 0)
267        writel(time, ldata->base + RTC_LR);
268
269    return ret;
270}
271
272static int pl031_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
273{
274    struct pl031_local *ldata = dev_get_drvdata(dev);
275
276    rtc_time_to_tm(readl(ldata->base + RTC_MR), &alarm->time);
277
278    alarm->pending = readl(ldata->base + RTC_RIS) & RTC_BIT_AI;
279    alarm->enabled = readl(ldata->base + RTC_IMSC) & RTC_BIT_AI;
280
281    return 0;
282}
283
284static int pl031_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
285{
286    struct pl031_local *ldata = dev_get_drvdata(dev);
287    unsigned long time;
288    int ret;
289
290    /* At the moment, we can only deal with non-wildcarded alarm times. */
291    ret = rtc_valid_tm(&alarm->time);
292    if (ret == 0) {
293        ret = rtc_tm_to_time(&alarm->time, &time);
294        if (ret == 0) {
295            writel(time, ldata->base + RTC_MR);
296            pl031_alarm_irq_enable(dev, alarm->enabled);
297        }
298    }
299
300    return ret;
301}
302
303static int pl031_remove(struct amba_device *adev)
304{
305    struct pl031_local *ldata = dev_get_drvdata(&adev->dev);
306
307    amba_set_drvdata(adev, NULL);
308    free_irq(adev->irq[0], ldata->rtc);
309    rtc_device_unregister(ldata->rtc);
310    iounmap(ldata->base);
311    kfree(ldata);
312    amba_release_regions(adev);
313
314    return 0;
315}
316
317static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
318{
319    int ret;
320    struct pl031_local *ldata;
321    struct pl031_vendor_data *vendor = id->data;
322    struct rtc_class_ops *ops = &vendor->ops;
323    unsigned long time;
324
325    ret = amba_request_regions(adev, NULL);
326    if (ret)
327        goto err_req;
328
329    ldata = kzalloc(sizeof(struct pl031_local), GFP_KERNEL);
330    if (!ldata) {
331        ret = -ENOMEM;
332        goto out;
333    }
334    ldata->vendor = vendor;
335
336    ldata->base = ioremap(adev->res.start, resource_size(&adev->res));
337
338    if (!ldata->base) {
339        ret = -ENOMEM;
340        goto out_no_remap;
341    }
342
343    amba_set_drvdata(adev, ldata);
344
345    dev_dbg(&adev->dev, "designer ID = 0x%02x\n", amba_manf(adev));
346    dev_dbg(&adev->dev, "revision = 0x%01x\n", amba_rev(adev));
347
348    /* Enable the clockwatch on ST Variants */
349    if (vendor->clockwatch)
350        writel(readl(ldata->base + RTC_CR) | RTC_CR_CWEN,
351               ldata->base + RTC_CR);
352
353    /*
354     * On ST PL031 variants, the RTC reset value does not provide correct
355     * weekday for 2000-01-01. Correct the erroneous sunday to saturday.
356     */
357    if (vendor->st_weekday) {
358        if (readl(ldata->base + RTC_YDR) == 0x2000) {
359            time = readl(ldata->base + RTC_DR);
360            if ((time &
361                 (RTC_MON_MASK | RTC_MDAY_MASK | RTC_WDAY_MASK))
362                == 0x02120000) {
363                time = time | (0x7 << RTC_WDAY_SHIFT);
364                writel(0x2000, ldata->base + RTC_YLR);
365                writel(time, ldata->base + RTC_LR);
366            }
367        }
368    }
369
370    ldata->rtc = rtc_device_register("pl031", &adev->dev, ops,
371                    THIS_MODULE);
372    if (IS_ERR(ldata->rtc)) {
373        ret = PTR_ERR(ldata->rtc);
374        goto out_no_rtc;
375    }
376
377    if (request_irq(adev->irq[0], pl031_interrupt,
378            vendor->irqflags, "rtc-pl031", ldata)) {
379        ret = -EIO;
380        goto out_no_irq;
381    }
382
383    return 0;
384
385out_no_irq:
386    rtc_device_unregister(ldata->rtc);
387out_no_rtc:
388    iounmap(ldata->base);
389    amba_set_drvdata(adev, NULL);
390out_no_remap:
391    kfree(ldata);
392out:
393    amba_release_regions(adev);
394err_req:
395
396    return ret;
397}
398
399/* Operations for the original ARM version */
400static struct pl031_vendor_data arm_pl031 = {
401    .ops = {
402        .read_time = pl031_read_time,
403        .set_time = pl031_set_time,
404        .read_alarm = pl031_read_alarm,
405        .set_alarm = pl031_set_alarm,
406        .alarm_irq_enable = pl031_alarm_irq_enable,
407    },
408    .irqflags = IRQF_NO_SUSPEND,
409};
410
411/* The First ST derivative */
412static struct pl031_vendor_data stv1_pl031 = {
413    .ops = {
414        .read_time = pl031_read_time,
415        .set_time = pl031_set_time,
416        .read_alarm = pl031_read_alarm,
417        .set_alarm = pl031_set_alarm,
418        .alarm_irq_enable = pl031_alarm_irq_enable,
419    },
420    .clockwatch = true,
421    .st_weekday = true,
422    .irqflags = IRQF_NO_SUSPEND,
423};
424
425/* And the second ST derivative */
426static struct pl031_vendor_data stv2_pl031 = {
427    .ops = {
428        .read_time = pl031_stv2_read_time,
429        .set_time = pl031_stv2_set_time,
430        .read_alarm = pl031_stv2_read_alarm,
431        .set_alarm = pl031_stv2_set_alarm,
432        .alarm_irq_enable = pl031_alarm_irq_enable,
433    },
434    .clockwatch = true,
435    .st_weekday = true,
436    /*
437     * This variant shares the IRQ with another block and must not
438     * suspend that IRQ line.
439     */
440    .irqflags = IRQF_SHARED | IRQF_NO_SUSPEND,
441};
442
443static struct amba_id pl031_ids[] = {
444    {
445        .id = 0x00041031,
446        .mask = 0x000fffff,
447        .data = &arm_pl031,
448    },
449    /* ST Micro variants */
450    {
451        .id = 0x00180031,
452        .mask = 0x00ffffff,
453        .data = &stv1_pl031,
454    },
455    {
456        .id = 0x00280031,
457        .mask = 0x00ffffff,
458        .data = &stv2_pl031,
459    },
460    {0, 0},
461};
462
463MODULE_DEVICE_TABLE(amba, pl031_ids);
464
465static struct amba_driver pl031_driver = {
466    .drv = {
467        .name = "rtc-pl031",
468    },
469    .id_table = pl031_ids,
470    .probe = pl031_probe,
471    .remove = pl031_remove,
472};
473
474module_amba_driver(pl031_driver);
475
476MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net");
477MODULE_DESCRIPTION("ARM AMBA PL031 RTC Driver");
478MODULE_LICENSE("GPL");
479

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