aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/rtc/rtc-sa1100.c
blob: 4595d3e645a7358676b5409b8ced918f306e07c2 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
/*
 * Real Time Clock interface for StrongARM SA1x00 and XScale PXA2xx
 *
 * Copyright (c) 2000 Nils Faerber
 *
 * Based on rtc.c by Paul Gortmaker
 *
 * Original Driver by Nils Faerber <nils@kernelconcepts.de>
 *
 * Modifications from:
 *   CIH <cih@coventive.com>
 *   Nicolas Pitre <nico@fluxnic.net>
 *   Andrew Christian <andrew.christian@hp.com>
 *
 * Converted to the RTC subsystem and Driver Model
 *   by Richard Purdie <rpurdie@rpsys.net>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/interrupt.h>
#include <linux/pm.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/io.h>

#include <mach/hardware.h>
#include <asm/irq.h>

#define RTC_DEF_DIVIDER		(32768 - 1)
#define RTC_DEF_TRIM		0
#define RTC_FREQ		1024

#define RCNR		0x00	/* RTC Count Register */
#define RTAR		0x04	/* RTC Alarm Register */
#define RTSR		0x08	/* RTC Status Register */
#define RTTR		0x0c	/* RTC Timer Trim Register */

#define RTSR_HZE	(1 << 3)	/* HZ interrupt enable */
#define RTSR_ALE	(1 << 2)	/* RTC alarm interrupt enable */
#define RTSR_HZ		(1 << 1)	/* HZ rising-edge detected */
#define RTSR_AL		(1 << 0)	/* RTC alarm detected */

#define rtc_readl(sa1100_rtc, reg)	\
	readl_relaxed((sa1100_rtc)->base + (reg))
#define rtc_writel(sa1100_rtc, reg, value)	\
	writel_relaxed((value), (sa1100_rtc)->base + (reg))

struct sa1100_rtc {
	struct resource		*ress;
	void __iomem		*base;
	struct clk		*clk;
	int			irq_1Hz;
	int			irq_Alrm;
	struct rtc_device	*rtc;
	spinlock_t		lock;		/* Protects this structure */
};
/*
 * Calculate the next alarm time given the requested alarm time mask
 * and the current time.
 */
static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now,
	struct rtc_time *alrm)
{
	unsigned long next_time;
	unsigned long now_time;

	next->tm_year = now->tm_year;
	next->tm_mon = now->tm_mon;
	next->tm_mday = now->tm_mday;
	next->tm_hour = alrm->tm_hour;
	next->tm_min = alrm->tm_min;
	next->tm_sec = alrm->tm_sec;

	rtc_tm_to_time(now, &now_time);
	rtc_tm_to_time(next, &next_time);

	if (next_time < now_time) {
		/* Advance one day */
		next_time += 60 * 60 * 24;
		rtc_time_to_tm(next_time, next);
	}
}

static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id)
{
	struct platform_device *pdev = to_platform_device(dev_id);
	struct sa1100_rtc *sa1100_rtc = platform_get_drvdata(pdev);
	unsigned int rtsr;
	unsigned long events = 0;

	spin_lock(&sa1100_rtc->lock);

	/* clear interrupt sources */
	rtsr = rtc_readl(sa1100_rtc, RTSR);
	rtc_writel(sa1100_rtc, RTSR, 0);

	/* Fix for a nasty initialization problem the in SA11xx RTSR register.
	 * See also the comments in sa1100_rtc_probe(). */
	if (rtsr & (RTSR_ALE | RTSR_HZE)) {
		/* This is the original code, before there was the if test
		 * above. This code does not clear interrupts that were not
		 * enabled. */
		rtc_writel(sa1100_rtc, RTSR, (RTSR_AL | RTSR_HZ) & (rtsr >> 2));
	} else {
		/* For some reason, it is possible to enter this routine
		 * without interruptions enabled, it has been tested with
		 * several units (Bug in SA11xx chip?).
		 *
		 * This situation leads to an infinite "loop" of interrupt
		 * routine calling and as a result the processor seems to
		 * lock on its first call to open(). */
		rtc_writel(sa1100_rtc, RTSR, (RTSR_AL | RTSR_HZ));
	}

	/* clear alarm interrupt if it has occurred */
	if (rtsr & RTSR_AL)
		rtsr &= ~RTSR_ALE;
	rtc_writel(sa1100_rtc, RTSR, rtsr & (RTSR_ALE | RTSR_HZE));

	/* update irq data & counter */
	if (rtsr & RTSR_AL)
		events |= RTC_AF | RTC_IRQF;
	if (rtsr & RTSR_HZ)
		events |= RTC_UF | RTC_IRQF;

	rtc_update_irq(sa1100_rtc->rtc, 1, events);

	spin_unlock(&sa1100_rtc->lock);

	return IRQ_HANDLED;
}

static int sa1100_rtc_open(struct device *dev)
{
	struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
	int ret;

	ret = request_irq(sa1100_rtc->irq_1Hz, sa1100_rtc_interrupt,
				IRQF_DISABLED, "rtc 1Hz", dev);
	if (ret) {
		dev_err(dev, "IRQ %d already in use.\n", sa1100_rtc->irq_1Hz);
		goto fail_ui;
	}
	ret = request_irq(sa1100_rtc->irq_Alrm, sa1100_rtc_interrupt,
				IRQF_DISABLED, "rtc Alrm", dev);
	if (ret) {
		dev_err(dev, "IRQ %d already in use.\n", sa1100_rtc->irq_Alrm);
		goto fail_ai;
	}
	sa1100_rtc->rtc->max_user_freq = RTC_FREQ;
	rtc_irq_set_freq(sa1100_rtc->rtc, NULL, RTC_FREQ);

	return 0;

 fail_ai:
	free_irq(sa1100_rtc->irq_1Hz, dev);
 fail_ui:
	return ret;
}

static void sa1100_rtc_release(struct device *dev)
{
	struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);

	spin_lock_irq(&sa1100_rtc->lock);
	rtc_writel(sa1100_rtc, RTSR, 0);
	spin_unlock_irq(&sa1100_rtc->lock);

	free_irq(sa1100_rtc->irq_Alrm, dev);
	free_irq(sa1100_rtc->irq_1Hz, dev);
}

static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
	struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
	unsigned int rtsr;

	spin_lock_irq(&sa1100_rtc->lock);

	rtsr = rtc_readl(sa1100_rtc, RTSR);
	if (enabled)
		rtsr |= RTSR_ALE;
	else
		rtsr &= ~RTSR_ALE;
	rtc_writel(sa1100_rtc, RTSR, rtsr);

	spin_unlock_irq(&sa1100_rtc->lock);
	return 0;
}

static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);

	rtc_time_to_tm(rtc_readl(sa1100_rtc, RCNR), tm);
	return 0;
}

static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
	unsigned long time;
	int ret;

	ret = rtc_tm_to_time(tm, &time);
	if (ret == 0)
		rtc_writel(sa1100_rtc, RCNR, time);
	return ret;
}

static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
	unsigned long time;
	unsigned int rtsr;

	time = rtc_readl(sa1100_rtc, RCNR);
	rtc_time_to_tm(time, &alrm->time);
	rtsr = rtc_readl(sa1100_rtc, RTSR);
	alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0;
	alrm->pending = (rtsr & RTSR_AL) ? 1 : 0;
	return 0;
}

static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);
	struct rtc_time now_tm, alarm_tm;
	unsigned long time, alarm;
	unsigned int rtsr;

	spin_lock_irq(&sa1100_rtc->lock);

	time = rtc_readl(sa1100_rtc, RCNR);
	rtc_time_to_tm(time, &now_tm);
	rtc_next_alarm_time(&alarm_tm, &now_tm, &alrm->time);
	rtc_tm_to_time(&alarm_tm, &alarm);
	rtc_writel(sa1100_rtc, RTAR, alarm);

	rtsr = rtc_readl(sa1100_rtc, RTSR);
	if (alrm->enabled)
		rtsr |= RTSR_ALE;
	else
		rtsr &= ~RTSR_ALE;
	rtc_writel(sa1100_rtc, RTSR, rtsr);

	spin_unlock_irq(&sa1100_rtc->lock);

	return 0;
}

static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq)
{
	struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);

	seq_printf(seq, "trim/divider\t\t: 0x%08x\n",
			rtc_readl(sa1100_rtc, RTTR));
	seq_printf(seq, "RTSR\t\t\t: 0x%08x\n",
			rtc_readl(sa1100_rtc, RTSR));
	return 0;
}

static const struct rtc_class_ops sa1100_rtc_ops = {
	.open = sa1100_rtc_open,
	.release = sa1100_rtc_release,
	.read_time = sa1100_rtc_read_time,
	.set_time = sa1100_rtc_set_time,
	.read_alarm = sa1100_rtc_read_alarm,
	.set_alarm = sa1100_rtc_set_alarm,
	.proc = sa1100_rtc_proc,
	.alarm_irq_enable = sa1100_rtc_alarm_irq_enable,
};

static int sa1100_rtc_probe(struct platform_device *pdev)
{
	struct sa1100_rtc *sa1100_rtc;
	unsigned int rttr;
	int ret;

	sa1100_rtc = kzalloc(sizeof(struct sa1100_rtc), GFP_KERNEL);
	if (!sa1100_rtc)
		return -ENOMEM;

	spin_lock_init(&sa1100_rtc->lock);
	platform_set_drvdata(pdev, sa1100_rtc);

	ret = -ENXIO;
	sa1100_rtc->ress = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!sa1100_rtc->ress) {
		dev_err(&pdev->dev, "No I/O memory resource defined\n");
		goto err_ress;
	}

	sa1100_rtc->irq_1Hz = platform_get_irq(pdev, 0);
	if (sa1100_rtc->irq_1Hz < 0) {
		dev_err(&pdev->dev, "No 1Hz IRQ resource defined\n");
		goto err_ress;
	}
	sa1100_rtc->irq_Alrm = platform_get_irq(pdev, 1);
	if (sa1100_rtc->irq_Alrm < 0) {
		dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
		goto err_ress;
	}

	ret = -ENOMEM;
	sa1100_rtc->base = ioremap(sa1100_rtc->ress->start,
				resource_size(sa1100_rtc->ress));
	if (!sa1100_rtc->base) {
		dev_err(&pdev->dev, "Unable to map pxa RTC I/O memory\n");
		goto err_map;
	}

	sa1100_rtc->clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(sa1100_rtc->clk)) {
		dev_err(&pdev->dev, "failed to find rtc clock source\n");
		ret = PTR_ERR(sa1100_rtc->clk);
		goto err_clk;
	}
	clk_prepare(sa1100_rtc->clk);
	clk_enable(sa1100_rtc->clk);

	/*
	 * According to the manual we should be able to let RTTR be zero
	 * and then a default diviser for a 32.768KHz clock is used.
	 * Apparently this doesn't work, at least for my SA1110 rev 5.
	 * If the clock divider is uninitialized then reset it to the
	 * default value to get the 1Hz clock.
	 */
	if (rtc_readl(sa1100_rtc, RTTR) == 0) {
		rttr = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16);
		rtc_writel(sa1100_rtc, RTTR, rttr);
		dev_warn(&pdev->dev, "warning: initializing default clock"
			 " divider/trim value\n");
		/* The current RTC value probably doesn't make sense either */
		rtc_writel(sa1100_rtc, RCNR, 0);
	}

	device_init_wakeup(&pdev->dev, 1);

	sa1100_rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
						&sa1100_rtc_ops, THIS_MODULE);
	if (IS_ERR(sa1100_rtc->rtc)) {
		dev_err(&pdev->dev, "Failed to register RTC device -> %d\n",
			ret);
		goto err_rtc_reg;
	}
	/* Fix for a nasty initialization problem the in SA11xx RTSR register.
	 * See also the comments in sa1100_rtc_interrupt().
	 *
	 * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an
	 * interrupt pending, even though interrupts were never enabled.
	 * In this case, this bit it must be reset before enabling
	 * interruptions to avoid a nonexistent interrupt to occur.
	 *
	 * In principle, the same problem would apply to bit 0, although it has
	 * never been observed to happen.
	 *
	 * This issue is addressed both here and in sa1100_rtc_interrupt().
	 * If the issue is not addressed here, in the times when the processor
	 * wakes up with the bit set there will be one spurious interrupt.
	 *
	 * The issue is also dealt with in sa1100_rtc_interrupt() to be on the
	 * safe side, once the condition that lead to this strange
	 * initialization is unknown and could in principle happen during
	 * normal processing.
	 *
	 * Notice that clearing bit 1 and 0 is accomplished by writting ONES to
	 * the corresponding bits in RTSR. */
	rtc_writel(sa1100_rtc, RTSR, (RTSR_AL | RTSR_HZ));

	return 0;

err_rtc_reg:
err_clk:
	iounmap(sa1100_rtc->base);
err_ress:
err_map:
	kfree(sa1100_rtc);
	return ret;
}

static int sa1100_rtc_remove(struct platform_device *pdev)
{
	struct sa1100_rtc *sa1100_rtc = platform_get_drvdata(pdev);

	rtc_device_unregister(sa1100_rtc->rtc);
	clk_disable(sa1100_rtc->clk);
	clk_unprepare(sa1100_rtc->clk);
	iounmap(sa1100_rtc->base);
	return 0;
}

#ifdef CONFIG_PM
static int sa1100_rtc_suspend(struct device *dev)
{
	struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
		enable_irq_wake(sa1100_rtc->irq_Alrm);
	return 0;
}

static int sa1100_rtc_resume(struct device *dev)
{
	struct sa1100_rtc *sa1100_rtc = dev_get_drvdata(dev);

	if (device_may_wakeup(dev))
		disable_irq_wake(sa1100_rtc->irq_Alrm);
	return 0;
}

static const struct dev_pm_ops sa1100_rtc_pm_ops = {
	.suspend	= sa1100_rtc_suspend,
	.resume		= sa1100_rtc_resume,
};
#endif

static struct platform_driver sa1100_rtc_driver = {
	.probe		= sa1100_rtc_probe,
	.remove		= sa1100_rtc_remove,
	.driver		= {
		.name	= "sa1100-rtc",
#ifdef CONFIG_PM
		.pm	= &sa1100_rtc_pm_ops,
#endif
	},
};

module_platform_driver(sa1100_rtc_driver);

MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:sa1100-rtc");