summaryrefslogtreecommitdiffstats
path: root/drivers/rtc/rtc-sa1100.c
blob: 2bc8aad47219180f58799a4b89523a9cf8298234 (plain)
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
/*
 * 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@cam.org>
 *   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/string.h>
#include <linux/pm.h>

#include <asm/bitops.h>
#include <asm/hardware.h>
#include <asm/irq.h>
#include <asm/rtc.h>

#ifdef CONFIG_ARCH_PXA
#include <asm/arch/pxa-regs.h>
#endif

#define TIMER_FREQ		CLOCK_TICK_RATE
#define RTC_DEF_DIVIDER		32768 - 1
#define RTC_DEF_TRIM		0

static unsigned long rtc_freq = 1024;
static struct rtc_time rtc_alarm;
static spinlock_t sa1100_rtc_lock = SPIN_LOCK_UNLOCKED;

static int rtc_update_alarm(struct rtc_time *alrm)
{
	struct rtc_time alarm_tm, now_tm;
	unsigned long now, time;
	int ret;

	do {
		now = RCNR;
		rtc_time_to_tm(now, &now_tm);
		rtc_next_alarm_time(&alarm_tm, &now_tm, alrm);
		ret = rtc_tm_to_time(&alarm_tm, &time);
		if (ret != 0)
			break;

		RTSR = RTSR & (RTSR_HZE|RTSR_ALE|RTSR_AL);
		RTAR = time;
	} while (now != RCNR);

	return ret;
}

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

	spin_lock(&sa1100_rtc_lock);

	rtsr = RTSR;
	/* clear interrupt sources */
	RTSR = 0;
	RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2);

	/* clear alarm interrupt if it has occurred */
	if (rtsr & RTSR_AL)
		rtsr &= ~RTSR_ALE;
	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(&rtc->class_dev, 1, events);

	if (rtsr & RTSR_AL && rtc_periodic_alarm(&rtc_alarm))
		rtc_update_alarm(&rtc_alarm);

	spin_unlock(&sa1100_rtc_lock);

	return IRQ_HANDLED;
}

static int rtc_timer1_count;

static irqreturn_t timer1_interrupt(int irq, void *dev_id,
		struct pt_regs *regs)
{
	struct platform_device *pdev = to_platform_device(dev_id);
	struct rtc_device *rtc = platform_get_drvdata(pdev);

	/*
	 * If we match for the first time, rtc_timer1_count will be 1.
	 * Otherwise, we wrapped around (very unlikely but
	 * still possible) so compute the amount of missed periods.
	 * The match reg is updated only when the data is actually retrieved
	 * to avoid unnecessary interrupts.
	 */
	OSSR = OSSR_M1;	/* clear match on timer1 */

	rtc_update_irq(&rtc->class_dev, rtc_timer1_count, RTC_PF | RTC_IRQF);

	if (rtc_timer1_count == 1)
		rtc_timer1_count = (rtc_freq * ((1<<30)/(TIMER_FREQ>>2)));

	return IRQ_HANDLED;
}

static int sa1100_rtc_read_callback(struct device *dev, int data)
{
	if (data & RTC_PF) {
		/* interpolate missed periods and set match for the next */
		unsigned long period = TIMER_FREQ/rtc_freq;
		unsigned long oscr = OSCR;
		unsigned long osmr1 = OSMR1;
		unsigned long missed = (oscr - osmr1)/period;
		data += missed << 8;
		OSSR = OSSR_M1;	/* clear match on timer 1 */
		OSMR1 = osmr1 + (missed + 1)*period;
		/* Ensure we didn't miss another match in the mean time.
		 * Here we compare (match - OSCR) 8 instead of 0 --
		 * see comment in pxa_timer_interrupt() for explanation.
		 */
		while( (signed long)((osmr1 = OSMR1) - OSCR) <= 8 ) {
			data += 0x100;
			OSSR = OSSR_M1;	/* clear match on timer 1 */
			OSMR1 = osmr1 + period;
		}
	}
	return data;
}

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

	ret = request_irq(IRQ_RTC1Hz, sa1100_rtc_interrupt, SA_INTERRUPT,
				"rtc 1Hz", dev);
	if (ret) {
		dev_err(dev, "IRQ %d already in use.\n", IRQ_RTC1Hz);
		goto fail_ui;
	}
	ret = request_irq(IRQ_RTCAlrm, sa1100_rtc_interrupt, SA_INTERRUPT,
				"rtc Alrm", dev);
	if (ret) {
		dev_err(dev, "IRQ %d already in use.\n", IRQ_RTCAlrm);
		goto fail_ai;
	}
	ret = request_irq(IRQ_OST1, timer1_interrupt, SA_INTERRUPT,
				"rtc timer", dev);
	if (ret) {
		dev_err(dev, "IRQ %d already in use.\n", IRQ_OST1);
		goto fail_pi;
	}
	return 0;

 fail_pi:
	free_irq(IRQ_RTCAlrm, dev);
 fail_ai:
	free_irq(IRQ_RTC1Hz, dev);
 fail_ui:
	return ret;
}

static void sa1100_rtc_release(struct device *dev)
{
	spin_lock_irq(&sa1100_rtc_lock);
	RTSR = 0;
	OIER &= ~OIER_E1;
	OSSR = OSSR_M1;
	spin_unlock_irq(&sa1100_rtc_lock);

	free_irq(IRQ_OST1, dev);
	free_irq(IRQ_RTCAlrm, dev);
	free_irq(IRQ_RTC1Hz, dev);
}


static int sa1100_rtc_ioctl(struct device *dev, unsigned int cmd,
		unsigned long arg)
{
	switch(cmd) {
	case RTC_AIE_OFF:
		spin_lock_irq(&sa1100_rtc_lock);
		RTSR &= ~RTSR_ALE;
		spin_unlock_irq(&sa1100_rtc_lock);
		return 0;
	case RTC_AIE_ON:
		spin_lock_irq(&sa1100_rtc_lock);
		RTSR |= RTSR_ALE;
		spin_unlock_irq(&sa1100_rtc_lock);
		return 0;
	case RTC_UIE_OFF:
		spin_lock_irq(&sa1100_rtc_lock);
		RTSR &= ~RTSR_HZE;
		spin_unlock_irq(&sa1100_rtc_lock);
		return 0;
	case RTC_UIE_ON:
		spin_lock_irq(&sa1100_rtc_lock);
		RTSR |= RTSR_HZE;
		spin_unlock_irq(&sa1100_rtc_lock);
		return 0;
	case RTC_PIE_OFF:
		spin_lock_irq(&sa1100_rtc_lock);
		OIER &= ~OIER_E1;
		spin_unlock_irq(&sa1100_rtc_lock);
		return 0;
	case RTC_PIE_ON:
		if ((rtc_freq > 64) && !capable(CAP_SYS_RESOURCE))
			return -EACCES;
		spin_lock_irq(&sa1100_rtc_lock);
		OSMR1 = TIMER_FREQ/rtc_freq + OSCR;
		OIER |= OIER_E1;
		rtc_timer1_count = 1;
		spin_unlock_irq(&sa1100_rtc_lock);
		return 0;
	case RTC_IRQP_READ:
		return put_user(rtc_freq, (unsigned long *)arg);
	case RTC_IRQP_SET:
		if (arg < 1 || arg > TIMER_FREQ)
			return -EINVAL;
		if ((arg > 64) && (!capable(CAP_SYS_RESOURCE)))
			return -EACCES;
		rtc_freq = arg;
		return 0;
	}
	return -EINVAL;
}

static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	rtc_time_to_tm(RCNR, tm);
	return 0;
}

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

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

static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	memcpy(&alrm->time, &rtc_alarm, sizeof(struct rtc_time));
	alrm->pending = RTSR & RTSR_AL ? 1 : 0;
	return 0;
}

static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	int ret;

	spin_lock_irq(&sa1100_rtc_lock);
	ret = rtc_update_alarm(&alrm->time);
	if (ret == 0) {
		memcpy(&rtc_alarm, &alrm->time, sizeof(struct rtc_time));

		if (alrm->enabled)
			enable_irq_wake(IRQ_RTCAlrm);
		else
			disable_irq_wake(IRQ_RTCAlrm);
	}
	spin_unlock_irq(&sa1100_rtc_lock);

	return ret;
}

static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq)
{
	seq_printf(seq, "trim/divider\t: 0x%08lx\n", RTTR);
	seq_printf(seq, "alarm_IRQ\t: %s\n",
			(RTSR & RTSR_ALE) ? "yes" : "no" );
	seq_printf(seq, "update_IRQ\t: %s\n",
			(RTSR & RTSR_HZE) ? "yes" : "no");
	seq_printf(seq, "periodic_IRQ\t: %s\n",
			(OIER & OIER_E1) ? "yes" : "no");
	seq_printf(seq, "periodic_freq\t: %ld\n", rtc_freq);

	return 0;
}

static struct rtc_class_ops sa1100_rtc_ops = {
	.open = sa1100_rtc_open,
	.read_callback = sa1100_rtc_read_callback,
	.release = sa1100_rtc_release,
	.ioctl = sa1100_rtc_ioctl,
	.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,
};

static int sa1100_rtc_probe(struct platform_device *pdev)
{
	struct rtc_device *rtc;

	/*
	 * 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 (RTTR == 0) {
		RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16);
		dev_warn(&pdev->dev, "warning: initializing default clock divider/trim value\n");
		/* The current RTC value probably doesn't make sense either */
		RCNR = 0;
	}

	rtc = rtc_device_register(pdev->name, &pdev->dev, &sa1100_rtc_ops,
				THIS_MODULE);

	if (IS_ERR(rtc))
		return PTR_ERR(rtc);

	platform_set_drvdata(pdev, rtc);

	return 0;
}

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

 	if (rtc)
		rtc_device_unregister(rtc);

	return 0;
}

static struct platform_driver sa1100_rtc_driver = {
	.probe		= sa1100_rtc_probe,
	.remove		= sa1100_rtc_remove,
	.driver		= {
		.name		= "sa1100-rtc",
	},
};

static int __init sa1100_rtc_init(void)
{
	return platform_driver_register(&sa1100_rtc_driver);
}

static void __exit sa1100_rtc_exit(void)
{
	platform_driver_unregister(&sa1100_rtc_driver);
}

module_init(sa1100_rtc_init);
module_exit(sa1100_rtc_exit);

MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud