Root/drivers/rtc/rtc-sa1100.c

1/*
2 * Real Time Clock interface for StrongARM SA1x00 and XScale PXA2xx
3 *
4 * Copyright (c) 2000 Nils Faerber
5 *
6 * Based on rtc.c by Paul Gortmaker
7 *
8 * Original Driver by Nils Faerber <nils@kernelconcepts.de>
9 *
10 * Modifications from:
11 * CIH <cih@coventive.com>
12 * Nicolas Pitre <nico@fluxnic.net>
13 * Andrew Christian <andrew.christian@hp.com>
14 *
15 * Converted to the RTC subsystem and Driver Model
16 * by Richard Purdie <rpurdie@rpsys.net>
17 *
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
22 */
23
24#include <linux/platform_device.h>
25#include <linux/module.h>
26#include <linux/clk.h>
27#include <linux/rtc.h>
28#include <linux/init.h>
29#include <linux/fs.h>
30#include <linux/interrupt.h>
31#include <linux/slab.h>
32#include <linux/string.h>
33#include <linux/of.h>
34#include <linux/pm.h>
35#include <linux/bitops.h>
36#include <linux/io.h>
37
38#include <mach/hardware.h>
39#include <mach/irqs.h>
40
41#if defined(CONFIG_ARCH_PXA) || defined(CONFIG_ARCH_MMP)
42#include <mach/regs-rtc.h>
43#endif
44
45#define RTC_DEF_DIVIDER (32768 - 1)
46#define RTC_DEF_TRIM 0
47#define RTC_FREQ 1024
48
49struct sa1100_rtc {
50    spinlock_t lock;
51    int irq_1hz;
52    int irq_alarm;
53    struct rtc_device *rtc;
54    struct clk *clk;
55};
56
57static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id)
58{
59    struct sa1100_rtc *info = dev_get_drvdata(dev_id);
60    struct rtc_device *rtc = info->rtc;
61    unsigned int rtsr;
62    unsigned long events = 0;
63
64    spin_lock(&info->lock);
65
66    rtsr = RTSR;
67    /* clear interrupt sources */
68    RTSR = 0;
69    /* Fix for a nasty initialization problem the in SA11xx RTSR register.
70     * See also the comments in sa1100_rtc_probe(). */
71    if (rtsr & (RTSR_ALE | RTSR_HZE)) {
72        /* This is the original code, before there was the if test
73         * above. This code does not clear interrupts that were not
74         * enabled. */
75        RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2);
76    } else {
77        /* For some reason, it is possible to enter this routine
78         * without interruptions enabled, it has been tested with
79         * several units (Bug in SA11xx chip?).
80         *
81         * This situation leads to an infinite "loop" of interrupt
82         * routine calling and as a result the processor seems to
83         * lock on its first call to open(). */
84        RTSR = RTSR_AL | RTSR_HZ;
85    }
86
87    /* clear alarm interrupt if it has occurred */
88    if (rtsr & RTSR_AL)
89        rtsr &= ~RTSR_ALE;
90    RTSR = rtsr & (RTSR_ALE | RTSR_HZE);
91
92    /* update irq data & counter */
93    if (rtsr & RTSR_AL)
94        events |= RTC_AF | RTC_IRQF;
95    if (rtsr & RTSR_HZ)
96        events |= RTC_UF | RTC_IRQF;
97
98    rtc_update_irq(rtc, 1, events);
99
100    spin_unlock(&info->lock);
101
102    return IRQ_HANDLED;
103}
104
105static int sa1100_rtc_open(struct device *dev)
106{
107    struct sa1100_rtc *info = dev_get_drvdata(dev);
108    struct rtc_device *rtc = info->rtc;
109    int ret;
110
111    ret = clk_prepare_enable(info->clk);
112    if (ret)
113        goto fail_clk;
114    ret = request_irq(info->irq_1hz, sa1100_rtc_interrupt, 0, "rtc 1Hz", dev);
115    if (ret) {
116        dev_err(dev, "IRQ %d already in use.\n", info->irq_1hz);
117        goto fail_ui;
118    }
119    ret = request_irq(info->irq_alarm, sa1100_rtc_interrupt, 0, "rtc Alrm", dev);
120    if (ret) {
121        dev_err(dev, "IRQ %d already in use.\n", info->irq_alarm);
122        goto fail_ai;
123    }
124    rtc->max_user_freq = RTC_FREQ;
125    rtc_irq_set_freq(rtc, NULL, RTC_FREQ);
126
127    return 0;
128
129 fail_ai:
130    free_irq(info->irq_1hz, dev);
131 fail_ui:
132    clk_disable_unprepare(info->clk);
133 fail_clk:
134    return ret;
135}
136
137static void sa1100_rtc_release(struct device *dev)
138{
139    struct sa1100_rtc *info = dev_get_drvdata(dev);
140
141    spin_lock_irq(&info->lock);
142    RTSR = 0;
143    spin_unlock_irq(&info->lock);
144
145    free_irq(info->irq_alarm, dev);
146    free_irq(info->irq_1hz, dev);
147    clk_disable_unprepare(info->clk);
148}
149
150static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
151{
152    struct sa1100_rtc *info = dev_get_drvdata(dev);
153
154    spin_lock_irq(&info->lock);
155    if (enabled)
156        RTSR |= RTSR_ALE;
157    else
158        RTSR &= ~RTSR_ALE;
159    spin_unlock_irq(&info->lock);
160    return 0;
161}
162
163static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm)
164{
165    rtc_time_to_tm(RCNR, tm);
166    return 0;
167}
168
169static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm)
170{
171    unsigned long time;
172    int ret;
173
174    ret = rtc_tm_to_time(tm, &time);
175    if (ret == 0)
176        RCNR = time;
177    return ret;
178}
179
180static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
181{
182    u32 rtsr;
183
184    rtsr = RTSR;
185    alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0;
186    alrm->pending = (rtsr & RTSR_AL) ? 1 : 0;
187    return 0;
188}
189
190static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
191{
192    struct sa1100_rtc *info = dev_get_drvdata(dev);
193    unsigned long time;
194    int ret;
195
196    spin_lock_irq(&info->lock);
197    ret = rtc_tm_to_time(&alrm->time, &time);
198    if (ret != 0)
199        goto out;
200    RTSR = RTSR & (RTSR_HZE|RTSR_ALE|RTSR_AL);
201    RTAR = time;
202    if (alrm->enabled)
203        RTSR |= RTSR_ALE;
204    else
205        RTSR &= ~RTSR_ALE;
206out:
207    spin_unlock_irq(&info->lock);
208
209    return ret;
210}
211
212static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq)
213{
214    seq_printf(seq, "trim/divider\t\t: 0x%08x\n", (u32) RTTR);
215    seq_printf(seq, "RTSR\t\t\t: 0x%08x\n", (u32)RTSR);
216
217    return 0;
218}
219
220static const struct rtc_class_ops sa1100_rtc_ops = {
221    .open = sa1100_rtc_open,
222    .release = sa1100_rtc_release,
223    .read_time = sa1100_rtc_read_time,
224    .set_time = sa1100_rtc_set_time,
225    .read_alarm = sa1100_rtc_read_alarm,
226    .set_alarm = sa1100_rtc_set_alarm,
227    .proc = sa1100_rtc_proc,
228    .alarm_irq_enable = sa1100_rtc_alarm_irq_enable,
229};
230
231static int sa1100_rtc_probe(struct platform_device *pdev)
232{
233    struct rtc_device *rtc;
234    struct sa1100_rtc *info;
235    int irq_1hz, irq_alarm, ret = 0;
236
237    irq_1hz = platform_get_irq_byname(pdev, "rtc 1Hz");
238    irq_alarm = platform_get_irq_byname(pdev, "rtc alarm");
239    if (irq_1hz < 0 || irq_alarm < 0)
240        return -ENODEV;
241
242    info = kzalloc(sizeof(struct sa1100_rtc), GFP_KERNEL);
243    if (!info)
244        return -ENOMEM;
245    info->clk = clk_get(&pdev->dev, NULL);
246    if (IS_ERR(info->clk)) {
247        dev_err(&pdev->dev, "failed to find rtc clock source\n");
248        ret = PTR_ERR(info->clk);
249        goto err_clk;
250    }
251    info->irq_1hz = irq_1hz;
252    info->irq_alarm = irq_alarm;
253    spin_lock_init(&info->lock);
254    platform_set_drvdata(pdev, info);
255
256    /*
257     * According to the manual we should be able to let RTTR be zero
258     * and then a default diviser for a 32.768KHz clock is used.
259     * Apparently this doesn't work, at least for my SA1110 rev 5.
260     * If the clock divider is uninitialized then reset it to the
261     * default value to get the 1Hz clock.
262     */
263    if (RTTR == 0) {
264        RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16);
265        dev_warn(&pdev->dev, "warning: "
266            "initializing default clock divider/trim value\n");
267        /* The current RTC value probably doesn't make sense either */
268        RCNR = 0;
269    }
270
271    device_init_wakeup(&pdev->dev, 1);
272
273    rtc = rtc_device_register(pdev->name, &pdev->dev, &sa1100_rtc_ops,
274        THIS_MODULE);
275
276    if (IS_ERR(rtc)) {
277        ret = PTR_ERR(rtc);
278        goto err_dev;
279    }
280    info->rtc = rtc;
281
282    /* Fix for a nasty initialization problem the in SA11xx RTSR register.
283     * See also the comments in sa1100_rtc_interrupt().
284     *
285     * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an
286     * interrupt pending, even though interrupts were never enabled.
287     * In this case, this bit it must be reset before enabling
288     * interruptions to avoid a nonexistent interrupt to occur.
289     *
290     * In principle, the same problem would apply to bit 0, although it has
291     * never been observed to happen.
292     *
293     * This issue is addressed both here and in sa1100_rtc_interrupt().
294     * If the issue is not addressed here, in the times when the processor
295     * wakes up with the bit set there will be one spurious interrupt.
296     *
297     * The issue is also dealt with in sa1100_rtc_interrupt() to be on the
298     * safe side, once the condition that lead to this strange
299     * initialization is unknown and could in principle happen during
300     * normal processing.
301     *
302     * Notice that clearing bit 1 and 0 is accomplished by writting ONES to
303     * the corresponding bits in RTSR. */
304    RTSR = RTSR_AL | RTSR_HZ;
305
306    return 0;
307err_dev:
308    platform_set_drvdata(pdev, NULL);
309    clk_put(info->clk);
310err_clk:
311    kfree(info);
312    return ret;
313}
314
315static int sa1100_rtc_remove(struct platform_device *pdev)
316{
317    struct sa1100_rtc *info = platform_get_drvdata(pdev);
318
319    if (info) {
320        rtc_device_unregister(info->rtc);
321        clk_put(info->clk);
322        platform_set_drvdata(pdev, NULL);
323        kfree(info);
324    }
325
326    return 0;
327}
328
329#ifdef CONFIG_PM
330static int sa1100_rtc_suspend(struct device *dev)
331{
332    struct sa1100_rtc *info = dev_get_drvdata(dev);
333    if (device_may_wakeup(dev))
334        enable_irq_wake(info->irq_alarm);
335    return 0;
336}
337
338static int sa1100_rtc_resume(struct device *dev)
339{
340    struct sa1100_rtc *info = dev_get_drvdata(dev);
341    if (device_may_wakeup(dev))
342        disable_irq_wake(info->irq_alarm);
343    return 0;
344}
345
346static const struct dev_pm_ops sa1100_rtc_pm_ops = {
347    .suspend = sa1100_rtc_suspend,
348    .resume = sa1100_rtc_resume,
349};
350#endif
351
352static struct of_device_id sa1100_rtc_dt_ids[] = {
353    { .compatible = "mrvl,sa1100-rtc", },
354    { .compatible = "mrvl,mmp-rtc", },
355    {}
356};
357MODULE_DEVICE_TABLE(of, sa1100_rtc_dt_ids);
358
359static struct platform_driver sa1100_rtc_driver = {
360    .probe = sa1100_rtc_probe,
361    .remove = sa1100_rtc_remove,
362    .driver = {
363        .name = "sa1100-rtc",
364#ifdef CONFIG_PM
365        .pm = &sa1100_rtc_pm_ops,
366#endif
367        .of_match_table = sa1100_rtc_dt_ids,
368    },
369};
370
371module_platform_driver(sa1100_rtc_driver);
372
373MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
374MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)");
375MODULE_LICENSE("GPL");
376MODULE_ALIAS("platform:sa1100-rtc");
377

Archive Download this file

Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master

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



interactive