Free Electrons

Embedded Linux Experts

  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
/*
 * Real-time clock driver for MPC5121
 *
 * Copyright 2007, Domen Puncer <domen.puncer@telargo.com>
 * Copyright 2008, Freescale Semiconductor, Inc. All rights reserved.
 * Copyright 2011, Dmitry Eremin-Solenikov
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/io.h>
#include <linux/slab.h>

struct mpc5121_rtc_regs {
	u8 set_time;		/* RTC + 0x00 */
	u8 hour_set;		/* RTC + 0x01 */
	u8 minute_set;		/* RTC + 0x02 */
	u8 second_set;		/* RTC + 0x03 */

	u8 set_date;		/* RTC + 0x04 */
	u8 month_set;		/* RTC + 0x05 */
	u8 weekday_set;		/* RTC + 0x06 */
	u8 date_set;		/* RTC + 0x07 */

	u8 write_sw;		/* RTC + 0x08 */
	u8 sw_set;		/* RTC + 0x09 */
	u16 year_set;		/* RTC + 0x0a */

	u8 alm_enable;		/* RTC + 0x0c */
	u8 alm_hour_set;	/* RTC + 0x0d */
	u8 alm_min_set;		/* RTC + 0x0e */
	u8 int_enable;		/* RTC + 0x0f */

	u8 reserved1;
	u8 hour;		/* RTC + 0x11 */
	u8 minute;		/* RTC + 0x12 */
	u8 second;		/* RTC + 0x13 */

	u8 month;		/* RTC + 0x14 */
	u8 wday_mday;		/* RTC + 0x15 */
	u16 year;		/* RTC + 0x16 */

	u8 int_alm;		/* RTC + 0x18 */
	u8 int_sw;		/* RTC + 0x19 */
	u8 alm_status;		/* RTC + 0x1a */
	u8 sw_minute;		/* RTC + 0x1b */

	u8 bus_error_1;		/* RTC + 0x1c */
	u8 int_day;		/* RTC + 0x1d */
	u8 int_min;		/* RTC + 0x1e */
	u8 int_sec;		/* RTC + 0x1f */

	/*
	 * target_time:
	 *	intended to be used for hibernation but hibernation
	 *	does not work on silicon rev 1.5 so use it for non-volatile
	 *	storage of offset between the actual_time register and linux
	 *	time
	 */
	u32 target_time;	/* RTC + 0x20 */
	/*
	 * actual_time:
	 *	readonly time since VBAT_RTC was last connected
	 */
	u32 actual_time;	/* RTC + 0x24 */
	u32 keep_alive;		/* RTC + 0x28 */
};

struct mpc5121_rtc_data {
	unsigned irq;
	unsigned irq_periodic;
	struct mpc5121_rtc_regs __iomem *regs;
	struct rtc_device *rtc;
	struct rtc_wkalrm wkalarm;
};

/*
 * Update second/minute/hour registers.
 *
 * This is just so alarm will work.
 */
static void mpc5121_rtc_update_smh(struct mpc5121_rtc_regs __iomem *regs,
				   struct rtc_time *tm)
{
	out_8(&regs->second_set, tm->tm_sec);
	out_8(&regs->minute_set, tm->tm_min);
	out_8(&regs->hour_set, tm->tm_hour);

	/* set time sequence */
	out_8(&regs->set_time, 0x1);
	out_8(&regs->set_time, 0x3);
	out_8(&regs->set_time, 0x1);
	out_8(&regs->set_time, 0x0);
}

static int mpc5121_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
	unsigned long now;

	/*
	 * linux time is actual_time plus the offset saved in target_time
	 */
	now = in_be32(&regs->actual_time) + in_be32(&regs->target_time);

	rtc_time_to_tm(now, tm);

	/*
	 * update second minute hour registers
	 * so alarms will work
	 */
	mpc5121_rtc_update_smh(regs, tm);

	return rtc_valid_tm(tm);
}

static int mpc5121_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
	int ret;
	unsigned long now;

	/*
	 * The actual_time register is read only so we write the offset
	 * between it and linux time to the target_time register.
	 */
	ret = rtc_tm_to_time(tm, &now);
	if (ret == 0)
		out_be32(&regs->target_time, now - in_be32(&regs->actual_time));

	/*
	 * update second minute hour registers
	 * so alarms will work
	 */
	mpc5121_rtc_update_smh(regs, tm);

	return 0;
}

static int mpc5200_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
	int tmp;

	tm->tm_sec = in_8(&regs->second);
	tm->tm_min = in_8(&regs->minute);

	/* 12 hour format? */
	if (in_8(&regs->hour) & 0x20)
		tm->tm_hour = (in_8(&regs->hour) >> 1) +
			(in_8(&regs->hour) & 1 ? 12 : 0);
	else
		tm->tm_hour = in_8(&regs->hour);

	tmp = in_8(&regs->wday_mday);
	tm->tm_mday = tmp & 0x1f;
	tm->tm_mon = in_8(&regs->month) - 1;
	tm->tm_year = in_be16(&regs->year) - 1900;
	tm->tm_wday = (tmp >> 5) % 7;
	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
	tm->tm_isdst = 0;

	return 0;
}

static int mpc5200_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;

	mpc5121_rtc_update_smh(regs, tm);

	/* date */
	out_8(&regs->month_set, tm->tm_mon + 1);
	out_8(&regs->weekday_set, tm->tm_wday ? tm->tm_wday : 7);
	out_8(&regs->date_set, tm->tm_mday);
	out_be16(&regs->year_set, tm->tm_year + 1900);

	/* set date sequence */
	out_8(&regs->set_date, 0x1);
	out_8(&regs->set_date, 0x3);
	out_8(&regs->set_date, 0x1);
	out_8(&regs->set_date, 0x0);

	return 0;
}

static int mpc5121_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;

	*alarm = rtc->wkalarm;

	alarm->pending = in_8(&regs->alm_status);

	return 0;
}

static int mpc5121_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{
	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;

	/*
	 * the alarm has no seconds so deal with it
	 */
	if (alarm->time.tm_sec) {
		alarm->time.tm_sec = 0;
		alarm->time.tm_min++;
		if (alarm->time.tm_min >= 60) {
			alarm->time.tm_min = 0;
			alarm->time.tm_hour++;
			if (alarm->time.tm_hour >= 24)
				alarm->time.tm_hour = 0;
		}
	}

	alarm->time.tm_mday = -1;
	alarm->time.tm_mon = -1;
	alarm->time.tm_year = -1;

	out_8(&regs->alm_min_set, alarm->time.tm_min);
	out_8(&regs->alm_hour_set, alarm->time.tm_hour);

	out_8(&regs->alm_enable, alarm->enabled);

	rtc->wkalarm = *alarm;
	return 0;
}

static irqreturn_t mpc5121_rtc_handler(int irq, void *dev)
{
	struct mpc5121_rtc_data *rtc = dev_get_drvdata((struct device *)dev);
	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;

	if (in_8(&regs->int_alm)) {
		/* acknowledge and clear status */
		out_8(&regs->int_alm, 1);
		out_8(&regs->alm_status, 1);

		rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static irqreturn_t mpc5121_rtc_handler_upd(int irq, void *dev)
{
	struct mpc5121_rtc_data *rtc = dev_get_drvdata((struct device *)dev);
	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;

	if (in_8(&regs->int_sec) && (in_8(&regs->int_enable) & 0x1)) {
		/* acknowledge */
		out_8(&regs->int_sec, 1);

		rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_UF);
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static int mpc5121_rtc_alarm_irq_enable(struct device *dev,
					unsigned int enabled)
{
	struct mpc5121_rtc_data *rtc = dev_get_drvdata(dev);
	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;
	int val;

	if (enabled)
		val = 1;
	else
		val = 0;

	out_8(&regs->alm_enable, val);
	rtc->wkalarm.enabled = val;

	return 0;
}

static const struct rtc_class_ops mpc5121_rtc_ops = {
	.read_time = mpc5121_rtc_read_time,
	.set_time = mpc5121_rtc_set_time,
	.read_alarm = mpc5121_rtc_read_alarm,
	.set_alarm = mpc5121_rtc_set_alarm,
	.alarm_irq_enable = mpc5121_rtc_alarm_irq_enable,
};

static const struct rtc_class_ops mpc5200_rtc_ops = {
	.read_time = mpc5200_rtc_read_time,
	.set_time = mpc5200_rtc_set_time,
	.read_alarm = mpc5121_rtc_read_alarm,
	.set_alarm = mpc5121_rtc_set_alarm,
	.alarm_irq_enable = mpc5121_rtc_alarm_irq_enable,
};

static int mpc5121_rtc_probe(struct platform_device *op)
{
	struct mpc5121_rtc_data *rtc;
	int err = 0;

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

	rtc->regs = of_iomap(op->dev.of_node, 0);
	if (!rtc->regs) {
		dev_err(&op->dev, "%s: couldn't map io space\n", __func__);
		return -ENOSYS;
	}

	device_init_wakeup(&op->dev, 1);

	platform_set_drvdata(op, rtc);

	rtc->irq = irq_of_parse_and_map(op->dev.of_node, 1);
	err = request_irq(rtc->irq, mpc5121_rtc_handler, 0,
						"mpc5121-rtc", &op->dev);
	if (err) {
		dev_err(&op->dev, "%s: could not request irq: %i\n",
							__func__, rtc->irq);
		goto out_dispose;
	}

	rtc->irq_periodic = irq_of_parse_and_map(op->dev.of_node, 0);
	err = request_irq(rtc->irq_periodic, mpc5121_rtc_handler_upd,
				0, "mpc5121-rtc_upd", &op->dev);
	if (err) {
		dev_err(&op->dev, "%s: could not request irq: %i\n",
						__func__, rtc->irq_periodic);
		goto out_dispose2;
	}

	if (of_device_is_compatible(op->dev.of_node, "fsl,mpc5121-rtc")) {
		u32 ka;
		ka = in_be32(&rtc->regs->keep_alive);
		if (ka & 0x02) {
			dev_warn(&op->dev,
				"mpc5121-rtc: Battery or oscillator failure!\n");
			out_be32(&rtc->regs->keep_alive, ka);
		}

		rtc->rtc = devm_rtc_device_register(&op->dev, "mpc5121-rtc",
						&mpc5121_rtc_ops, THIS_MODULE);
	} else {
		rtc->rtc = devm_rtc_device_register(&op->dev, "mpc5200-rtc",
						&mpc5200_rtc_ops, THIS_MODULE);
	}

	if (IS_ERR(rtc->rtc)) {
		err = PTR_ERR(rtc->rtc);
		goto out_free_irq;
	}
	rtc->rtc->uie_unsupported = 1;

	return 0;

out_free_irq:
	free_irq(rtc->irq_periodic, &op->dev);
out_dispose2:
	irq_dispose_mapping(rtc->irq_periodic);
	free_irq(rtc->irq, &op->dev);
out_dispose:
	irq_dispose_mapping(rtc->irq);
	iounmap(rtc->regs);

	return err;
}

static int mpc5121_rtc_remove(struct platform_device *op)
{
	struct mpc5121_rtc_data *rtc = platform_get_drvdata(op);
	struct mpc5121_rtc_regs __iomem *regs = rtc->regs;

	/* disable interrupt, so there are no nasty surprises */
	out_8(&regs->alm_enable, 0);
	out_8(&regs->int_enable, in_8(&regs->int_enable) & ~0x1);

	iounmap(rtc->regs);
	free_irq(rtc->irq, &op->dev);
	free_irq(rtc->irq_periodic, &op->dev);
	irq_dispose_mapping(rtc->irq);
	irq_dispose_mapping(rtc->irq_periodic);

	return 0;
}

#ifdef CONFIG_OF
static const struct of_device_id mpc5121_rtc_match[] = {
	{ .compatible = "fsl,mpc5121-rtc", },
	{ .compatible = "fsl,mpc5200-rtc", },
	{},
};
MODULE_DEVICE_TABLE(of, mpc5121_rtc_match);
#endif

static struct platform_driver mpc5121_rtc_driver = {
	.driver = {
		.name = "mpc5121-rtc",
		.of_match_table = of_match_ptr(mpc5121_rtc_match),
	},
	.probe = mpc5121_rtc_probe,
	.remove = mpc5121_rtc_remove,
};

module_platform_driver(mpc5121_rtc_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("John Rigby <jcrigby@gmail.com>");