aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/rtc/rtc-mxc.c
blob: 826ab64a8fa91d1a4524e7e3e7a2ae2ce565fec8 (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
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
/*
 * Copyright 2004-2008 Freescale Semiconductor, Inc. All Rights Reserved.
 *
 * The code contained herein is licensed under the GNU General Public
 * License. You may obtain a copy of the GNU General Public License
 * Version 2 or later at the following locations:
 *
 * http://www.opensource.org/licenses/gpl-license.html
 * http://www.gnu.org/copyleft/gpl.html
 */

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

#include <mach/hardware.h>

#define RTC_INPUT_CLK_32768HZ	(0x00 << 5)
#define RTC_INPUT_CLK_32000HZ	(0x01 << 5)
#define RTC_INPUT_CLK_38400HZ	(0x02 << 5)

#define RTC_SW_BIT      (1 << 0)
#define RTC_ALM_BIT     (1 << 2)
#define RTC_1HZ_BIT     (1 << 4)
#define RTC_2HZ_BIT     (1 << 7)
#define RTC_SAM0_BIT    (1 << 8)
#define RTC_SAM1_BIT    (1 << 9)
#define RTC_SAM2_BIT    (1 << 10)
#define RTC_SAM3_BIT    (1 << 11)
#define RTC_SAM4_BIT    (1 << 12)
#define RTC_SAM5_BIT    (1 << 13)
#define RTC_SAM6_BIT    (1 << 14)
#define RTC_SAM7_BIT    (1 << 15)
#define PIT_ALL_ON      (RTC_2HZ_BIT | RTC_SAM0_BIT | RTC_SAM1_BIT | \
			 RTC_SAM2_BIT | RTC_SAM3_BIT | RTC_SAM4_BIT | \
			 RTC_SAM5_BIT | RTC_SAM6_BIT | RTC_SAM7_BIT)

#define RTC_ENABLE_BIT  (1 << 7)

#define MAX_PIE_NUM     9
#define MAX_PIE_FREQ    512
static const u32 PIE_BIT_DEF[MAX_PIE_NUM][2] = {
	{ 2,		RTC_2HZ_BIT },
	{ 4,		RTC_SAM0_BIT },
	{ 8,		RTC_SAM1_BIT },
	{ 16,		RTC_SAM2_BIT },
	{ 32,		RTC_SAM3_BIT },
	{ 64,		RTC_SAM4_BIT },
	{ 128,		RTC_SAM5_BIT },
	{ 256,		RTC_SAM6_BIT },
	{ MAX_PIE_FREQ,	RTC_SAM7_BIT },
};

/* Those are the bits from a classic RTC we want to mimic */
#define RTC_IRQF	0x80	/* any of the following 3 is active */
#define RTC_PF		0x40	/* Periodic interrupt */
#define RTC_AF		0x20	/* Alarm interrupt */
#define RTC_UF		0x10	/* Update interrupt for 1Hz RTC */

#define MXC_RTC_TIME	0
#define MXC_RTC_ALARM	1

#define RTC_HOURMIN	0x00	/*  32bit rtc hour/min counter reg */
#define RTC_SECOND	0x04	/*  32bit rtc seconds counter reg */
#define RTC_ALRM_HM	0x08	/*  32bit rtc alarm hour/min reg */
#define RTC_ALRM_SEC	0x0C	/*  32bit rtc alarm seconds reg */
#define RTC_RTCCTL	0x10	/*  32bit rtc control reg */
#define RTC_RTCISR	0x14	/*  32bit rtc interrupt status reg */
#define RTC_RTCIENR	0x18	/*  32bit rtc interrupt enable reg */
#define RTC_STPWCH	0x1C	/*  32bit rtc stopwatch min reg */
#define RTC_DAYR	0x20	/*  32bit rtc days counter reg */
#define RTC_DAYALARM	0x24	/*  32bit rtc day alarm reg */
#define RTC_TEST1	0x28	/*  32bit rtc test reg 1 */
#define RTC_TEST2	0x2C	/*  32bit rtc test reg 2 */
#define RTC_TEST3	0x30	/*  32bit rtc test reg 3 */

struct rtc_plat_data {
	struct rtc_device *rtc;
	void __iomem *ioaddr;
	int irq;
	struct clk *clk;
	struct rtc_time g_rtc_alarm;
};

/*
 * This function is used to obtain the RTC time or the alarm value in
 * second.
 */
static u32 get_alarm_or_time(struct device *dev, int time_alarm)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr;
	u32 day = 0, hr = 0, min = 0, sec = 0, hr_min = 0;

	switch (time_alarm) {
	case MXC_RTC_TIME:
		day = readw(ioaddr + RTC_DAYR);
		hr_min = readw(ioaddr + RTC_HOURMIN);
		sec = readw(ioaddr + RTC_SECOND);
		break;
	case MXC_RTC_ALARM:
		day = readw(ioaddr + RTC_DAYALARM);
		hr_min = readw(ioaddr + RTC_ALRM_HM) & 0xffff;
		sec = readw(ioaddr + RTC_ALRM_SEC);
		break;
	}

	hr = hr_min >> 8;
	min = hr_min & 0xff;

	return (((day * 24 + hr) * 60) + min) * 60 + sec;
}

/*
 * This function sets the RTC alarm value or the time value.
 */
static void set_alarm_or_time(struct device *dev, int time_alarm, u32 time)
{
	u32 day, hr, min, sec, temp;
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr;

	day = time / 86400;
	time -= day * 86400;

	/* time is within a day now */
	hr = time / 3600;
	time -= hr * 3600;

	/* time is within an hour now */
	min = time / 60;
	sec = time - min * 60;

	temp = (hr << 8) + min;

	switch (time_alarm) {
	case MXC_RTC_TIME:
		writew(day, ioaddr + RTC_DAYR);
		writew(sec, ioaddr + RTC_SECOND);
		writew(temp, ioaddr + RTC_HOURMIN);
		break;
	case MXC_RTC_ALARM:
		writew(day, ioaddr + RTC_DAYALARM);
		writew(sec, ioaddr + RTC_ALRM_SEC);
		writew(temp, ioaddr + RTC_ALRM_HM);
		break;
	}
}

/*
 * This function updates the RTC alarm registers and then clears all the
 * interrupt status bits.
 */
static int rtc_update_alarm(struct device *dev, struct rtc_time *alrm)
{
	struct rtc_time alarm_tm, now_tm;
	unsigned long now, time;
	int ret;
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr;

	now = get_alarm_or_time(dev, MXC_RTC_TIME);
	rtc_time_to_tm(now, &now_tm);
	alarm_tm.tm_year = now_tm.tm_year;
	alarm_tm.tm_mon = now_tm.tm_mon;
	alarm_tm.tm_mday = now_tm.tm_mday;
	alarm_tm.tm_hour = alrm->tm_hour;
	alarm_tm.tm_min = alrm->tm_min;
	alarm_tm.tm_sec = alrm->tm_sec;
	rtc_tm_to_time(&now_tm, &now);
	rtc_tm_to_time(&alarm_tm, &time);

	if (time < now) {
		time += 60 * 60 * 24;
		rtc_time_to_tm(time, &alarm_tm);
	}

	ret = rtc_tm_to_time(&alarm_tm, &time);

	/* clear all the interrupt status bits */
	writew(readw(ioaddr + RTC_RTCISR), ioaddr + RTC_RTCISR);
	set_alarm_or_time(dev, MXC_RTC_ALARM, time);

	return ret;
}

/* This function is the RTC interrupt service routine. */
static irqreturn_t mxc_rtc_interrupt(int irq, void *dev_id)
{
	struct platform_device *pdev = dev_id;
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr;
	u32 status;
	u32 events = 0;

	spin_lock_irq(&pdata->rtc->irq_lock);
	status = readw(ioaddr + RTC_RTCISR) & readw(ioaddr + RTC_RTCIENR);
	/* clear interrupt sources */
	writew(status, ioaddr + RTC_RTCISR);

	/* clear alarm interrupt if it has occurred */
	if (status & RTC_ALM_BIT)
		status &= ~RTC_ALM_BIT;

	/* update irq data & counter */
	if (status & RTC_ALM_BIT)
		events |= (RTC_AF | RTC_IRQF);

	if (status & RTC_1HZ_BIT)
		events |= (RTC_UF | RTC_IRQF);

	if (status & PIT_ALL_ON)
		events |= (RTC_PF | RTC_IRQF);

	if ((status & RTC_ALM_BIT) && rtc_valid_tm(&pdata->g_rtc_alarm))
		rtc_update_alarm(&pdev->dev, &pdata->g_rtc_alarm);

	rtc_update_irq(pdata->rtc, 1, events);
	spin_unlock_irq(&pdata->rtc->irq_lock);

	return IRQ_HANDLED;
}

/*
 * Clear all interrupts and release the IRQ
 */
static void mxc_rtc_release(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr;

	spin_lock_irq(&pdata->rtc->irq_lock);

	/* Disable all rtc interrupts */
	writew(0, ioaddr + RTC_RTCIENR);

	/* Clear all interrupt status */
	writew(0xffffffff, ioaddr + RTC_RTCISR);

	spin_unlock_irq(&pdata->rtc->irq_lock);
}

static void mxc_rtc_irq_enable(struct device *dev, unsigned int bit,
				unsigned int enabled)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr;
	u32 reg;

	spin_lock_irq(&pdata->rtc->irq_lock);
	reg = readw(ioaddr + RTC_RTCIENR);

	if (enabled)
		reg |= bit;
	else
		reg &= ~bit;

	writew(reg, ioaddr + RTC_RTCIENR);
	spin_unlock_irq(&pdata->rtc->irq_lock);
}

static int mxc_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
	mxc_rtc_irq_enable(dev, RTC_ALM_BIT, enabled);
	return 0;
}

/*
 * This function reads the current RTC time into tm in Gregorian date.
 */
static int mxc_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	u32 val;

	/* Avoid roll-over from reading the different registers */
	do {
		val = get_alarm_or_time(dev, MXC_RTC_TIME);
	} while (val != get_alarm_or_time(dev, MXC_RTC_TIME));

	rtc_time_to_tm(val, tm);

	return 0;
}

/*
 * This function sets the internal RTC time based on tm in Gregorian date.
 */
static int mxc_rtc_set_mmss(struct device *dev, unsigned long time)
{
	/* Avoid roll-over from reading the different registers */
	do {
		set_alarm_or_time(dev, MXC_RTC_TIME, time);
	} while (time != get_alarm_or_time(dev, MXC_RTC_TIME));

	return 0;
}

/*
 * This function reads the current alarm value into the passed in 'alrm'
 * argument. It updates the alrm's pending field value based on the whether
 * an alarm interrupt occurs or not.
 */
static int mxc_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	void __iomem *ioaddr = pdata->ioaddr;

	rtc_time_to_tm(get_alarm_or_time(dev, MXC_RTC_ALARM), &alrm->time);
	alrm->pending = ((readw(ioaddr + RTC_RTCISR) & RTC_ALM_BIT)) ? 1 : 0;

	return 0;
}

/*
 * This function sets the RTC alarm based on passed in alrm.
 */
static int mxc_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
	int ret;

	if (rtc_valid_tm(&alrm->time)) {
		if (alrm->time.tm_sec > 59 ||
		    alrm->time.tm_hour > 23 ||
		    alrm->time.tm_min > 59)
			return -EINVAL;

		ret = rtc_update_alarm(dev, &alrm->time);
	} else {
		ret = rtc_valid_tm(&alrm->time);
		if (ret)
			return ret;

		ret = rtc_update_alarm(dev, &alrm->time);
	}

	if (ret)
		return ret;

	memcpy(&pdata->g_rtc_alarm, &alrm->time, sizeof(struct rtc_time));
	mxc_rtc_irq_enable(dev, RTC_ALM_BIT, alrm->enabled);

	return 0;
}

/* RTC layer */
static struct rtc_class_ops mxc_rtc_ops = {
	.release		= mxc_rtc_release,
	.read_time		= mxc_rtc_read_time,
	.set_mmss		= mxc_rtc_set_mmss,
	.read_alarm		= mxc_rtc_read_alarm,
	.set_alarm		= mxc_rtc_set_alarm,
	.alarm_irq_enable	= mxc_rtc_alarm_irq_enable,
};

static int __init mxc_rtc_probe(struct platform_device *pdev)
{
	struct resource *res;
	struct rtc_device *rtc;
	struct rtc_plat_data *pdata = NULL;
	u32 reg;
	unsigned long rate;
	int ret;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENODEV;

	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
	if (!pdata)
		return -ENOMEM;

	if (!devm_request_mem_region(&pdev->dev, res->start,
				     resource_size(res), pdev->name))
		return -EBUSY;

	pdata->ioaddr = devm_ioremap(&pdev->dev, res->start,
				     resource_size(res));

	pdata->clk = clk_get(&pdev->dev, "rtc");
	if (IS_ERR(pdata->clk)) {
		dev_err(&pdev->dev, "unable to get clock!\n");
		ret = PTR_ERR(pdata->clk);
		goto exit_free_pdata;
	}

	clk_enable(pdata->clk);
	rate = clk_get_rate(pdata->clk);

	if (rate == 32768)
		reg = RTC_INPUT_CLK_32768HZ;
	else if (rate == 32000)
		reg = RTC_INPUT_CLK_32000HZ;
	else if (rate == 38400)
		reg = RTC_INPUT_CLK_38400HZ;
	else {
		dev_err(&pdev->dev, "rtc clock is not valid (%lu)\n", rate);
		ret = -EINVAL;
		goto exit_put_clk;
	}

	reg |= RTC_ENABLE_BIT;
	writew(reg, (pdata->ioaddr + RTC_RTCCTL));
	if (((readw(pdata->ioaddr + RTC_RTCCTL)) & RTC_ENABLE_BIT) == 0) {
		dev_err(&pdev->dev, "hardware module can't be enabled!\n");
		ret = -EIO;
		goto exit_put_clk;
	}

	rtc = rtc_device_register(pdev->name, &pdev->dev, &mxc_rtc_ops,
				  THIS_MODULE);
	if (IS_ERR(rtc)) {
		ret = PTR_ERR(rtc);
		goto exit_put_clk;
	}

	pdata->rtc = rtc;
	platform_set_drvdata(pdev, pdata);

	/* Configure and enable the RTC */
	pdata->irq = platform_get_irq(pdev, 0);

	if (pdata->irq >= 0 &&
	    devm_request_irq(&pdev->dev, pdata->irq, mxc_rtc_interrupt,
			     IRQF_SHARED, pdev->name, pdev) < 0) {
		dev_warn(&pdev->dev, "interrupt not available.\n");
		pdata->irq = -1;
	}

	return 0;

exit_put_clk:
	clk_disable(pdata->clk);
	clk_put(pdata->clk);

exit_free_pdata:

	return ret;
}

static int __exit mxc_rtc_remove(struct platform_device *pdev)
{
	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

	rtc_device_unregister(pdata->rtc);

	clk_disable(pdata->clk);
	clk_put(pdata->clk);
	platform_set_drvdata(pdev, NULL);

	return 0;
}

static struct platform_driver mxc_rtc_driver = {
	.driver = {
		   .name	= "mxc_rtc",
		   .owner	= THIS_MODULE,
	},
	.remove		= __exit_p(mxc_rtc_remove),
};

static int __init mxc_rtc_init(void)
{
	return platform_driver_probe(&mxc_rtc_driver, mxc_rtc_probe);
}

static void __exit mxc_rtc_exit(void)
{
	platform_driver_unregister(&mxc_rtc_driver);
}

module_init(mxc_rtc_init);
module_exit(mxc_rtc_exit);

MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
MODULE_DESCRIPTION("RTC driver for Freescale MXC");
MODULE_LICENSE("GPL");