aboutsummaryrefslogtreecommitdiff
path: root/drivers/rtc/rtc-pic32.c
blob: 64e1e4578492ab029c54be1e265598f611acce6f (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
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
/*
 * PIC32 RTC driver
 *
 * Joshua Henderson <joshua.henderson@microchip.com>
 * Copyright (C) 2016 Microchip Technology Inc.  All rights reserved.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/rtc.h>
#include <linux/bcd.h>

#include <asm/mach-pic32/pic32.h>

#define PIC32_RTCCON		0x00
#define PIC32_RTCCON_ON		BIT(15)
#define PIC32_RTCCON_SIDL	BIT(13)
#define PIC32_RTCCON_RTCCLKSEL	(3 << 9)
#define PIC32_RTCCON_RTCCLKON	BIT(6)
#define PIC32_RTCCON_RTCWREN	BIT(3)
#define PIC32_RTCCON_RTCSYNC	BIT(2)
#define PIC32_RTCCON_HALFSEC	BIT(1)
#define PIC32_RTCCON_RTCOE	BIT(0)

#define PIC32_RTCALRM		0x10
#define PIC32_RTCALRM_ALRMEN	BIT(15)
#define PIC32_RTCALRM_CHIME	BIT(14)
#define PIC32_RTCALRM_PIV	BIT(13)
#define PIC32_RTCALRM_ALARMSYNC	BIT(12)
#define PIC32_RTCALRM_AMASK	0x0F00
#define PIC32_RTCALRM_ARPT	0xFF

#define PIC32_RTCHOUR		0x23
#define PIC32_RTCMIN		0x22
#define PIC32_RTCSEC		0x21
#define PIC32_RTCYEAR		0x33
#define PIC32_RTCMON		0x32
#define PIC32_RTCDAY		0x31

#define PIC32_ALRMTIME		0x40
#define PIC32_ALRMDATE		0x50

#define PIC32_ALRMHOUR		0x43
#define PIC32_ALRMMIN		0x42
#define PIC32_ALRMSEC		0x41
#define PIC32_ALRMYEAR		0x53
#define PIC32_ALRMMON		0x52
#define PIC32_ALRMDAY		0x51

struct pic32_rtc_dev {
	struct rtc_device	*rtc;
	void __iomem		*reg_base;
	struct clk		*clk;
	spinlock_t		alarm_lock;
	int			alarm_irq;
	bool			alarm_clk_enabled;
};

static void pic32_rtc_alarm_clk_enable(struct pic32_rtc_dev *pdata,
				       bool enable)
{
	unsigned long flags;

	spin_lock_irqsave(&pdata->alarm_lock, flags);
	if (enable) {
		if (!pdata->alarm_clk_enabled) {
			clk_enable(pdata->clk);
			pdata->alarm_clk_enabled = true;
		}
	} else {
		if (pdata->alarm_clk_enabled) {
			clk_disable(pdata->clk);
			pdata->alarm_clk_enabled = false;
		}
	}
	spin_unlock_irqrestore(&pdata->alarm_lock, flags);
}

static irqreturn_t pic32_rtc_alarmirq(int irq, void *id)
{
	struct pic32_rtc_dev *pdata = (struct pic32_rtc_dev *)id;

	clk_enable(pdata->clk);
	rtc_update_irq(pdata->rtc, 1, RTC_AF | RTC_IRQF);
	clk_disable(pdata->clk);

	pic32_rtc_alarm_clk_enable(pdata, false);

	return IRQ_HANDLED;
}

static int pic32_rtc_setaie(struct device *dev, unsigned int enabled)
{
	struct pic32_rtc_dev *pdata = dev_get_drvdata(dev);
	void __iomem *base = pdata->reg_base;

	clk_enable(pdata->clk);

	writel(PIC32_RTCALRM_ALRMEN,
	       base + (enabled ? PIC32_SET(PIC32_RTCALRM) :
		       PIC32_CLR(PIC32_RTCALRM)));

	clk_disable(pdata->clk);

	pic32_rtc_alarm_clk_enable(pdata, enabled);

	return 0;
}

static int pic32_rtc_setfreq(struct device *dev, int freq)
{
	struct pic32_rtc_dev *pdata = dev_get_drvdata(dev);
	void __iomem *base = pdata->reg_base;

	clk_enable(pdata->clk);

	writel(PIC32_RTCALRM_AMASK, base + PIC32_CLR(PIC32_RTCALRM));
	writel(freq << 8, base + PIC32_SET(PIC32_RTCALRM));
	writel(PIC32_RTCALRM_CHIME, base + PIC32_SET(PIC32_RTCALRM));

	clk_disable(pdata->clk);

	return 0;
}

static int pic32_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
{
	struct pic32_rtc_dev *pdata = dev_get_drvdata(dev);
	void __iomem *base = pdata->reg_base;
	unsigned int tries = 0;

	clk_enable(pdata->clk);

	do {
		rtc_tm->tm_hour = readb(base + PIC32_RTCHOUR);
		rtc_tm->tm_min = readb(base + PIC32_RTCMIN);
		rtc_tm->tm_mon  = readb(base + PIC32_RTCMON);
		rtc_tm->tm_mday = readb(base + PIC32_RTCDAY);
		rtc_tm->tm_year = readb(base + PIC32_RTCYEAR);
		rtc_tm->tm_sec  = readb(base + PIC32_RTCSEC);

		/*
		 * The only way to work out whether the system was mid-update
		 * when we read it is to check the second counter, and if it
		 * is zero, then we re-try the entire read.
		 */
		tries += 1;
	} while (rtc_tm->tm_sec == 0 && tries < 2);

	rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
	rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
	rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
	rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
	rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon) - 1;
	rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);

	rtc_tm->tm_year += 100;

	dev_dbg(dev, "read time %04d.%02d.%02d %02d:%02d:%02d\n",
		1900 + rtc_tm->tm_year, rtc_tm->tm_mon, rtc_tm->tm_mday,
		rtc_tm->tm_hour, rtc_tm->tm_min, rtc_tm->tm_sec);

	clk_disable(pdata->clk);
	return rtc_valid_tm(rtc_tm);
}

static int pic32_rtc_settime(struct device *dev, struct rtc_time *tm)
{
	struct pic32_rtc_dev *pdata = dev_get_drvdata(dev);
	void __iomem *base = pdata->reg_base;
	int year = tm->tm_year - 100;

	dev_dbg(dev, "set time %04d.%02d.%02d %02d:%02d:%02d\n",
		1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
		tm->tm_hour, tm->tm_min, tm->tm_sec);

	if (year < 0 || year >= 100) {
		dev_err(dev, "rtc only supports 100 years\n");
		return -EINVAL;
	}

	clk_enable(pdata->clk);
	writeb(bin2bcd(tm->tm_sec),  base + PIC32_RTCSEC);
	writeb(bin2bcd(tm->tm_min),  base + PIC32_RTCMIN);
	writeb(bin2bcd(tm->tm_hour), base + PIC32_RTCHOUR);
	writeb(bin2bcd(tm->tm_mday), base + PIC32_RTCDAY);
	writeb(bin2bcd(tm->tm_mon + 1), base + PIC32_RTCMON);
	writeb(bin2bcd(year), base + PIC32_RTCYEAR);
	clk_disable(pdata->clk);

	return 0;
}

static int pic32_rtc_getalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct pic32_rtc_dev *pdata = dev_get_drvdata(dev);
	struct rtc_time *alm_tm = &alrm->time;
	void __iomem *base = pdata->reg_base;
	unsigned int alm_en;

	clk_enable(pdata->clk);
	alm_tm->tm_sec  = readb(base + PIC32_ALRMSEC);
	alm_tm->tm_min  = readb(base + PIC32_ALRMMIN);
	alm_tm->tm_hour = readb(base + PIC32_ALRMHOUR);
	alm_tm->tm_mon  = readb(base + PIC32_ALRMMON);
	alm_tm->tm_mday = readb(base + PIC32_ALRMDAY);
	alm_tm->tm_year = readb(base + PIC32_ALRMYEAR);

	alm_en = readb(base + PIC32_RTCALRM);

	alrm->enabled = (alm_en & PIC32_RTCALRM_ALRMEN) ? 1 : 0;

	dev_dbg(dev, "getalarm: %d, %04d.%02d.%02d %02d:%02d:%02d\n",
		alm_en,
		1900 + alm_tm->tm_year, alm_tm->tm_mon, alm_tm->tm_mday,
		alm_tm->tm_hour, alm_tm->tm_min, alm_tm->tm_sec);

	alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec);
	alm_tm->tm_min = bcd2bin(alm_tm->tm_min);
	alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour);
	alm_tm->tm_mday = bcd2bin(alm_tm->tm_mday);
	alm_tm->tm_mon = bcd2bin(alm_tm->tm_mon) - 1;
	alm_tm->tm_year = bcd2bin(alm_tm->tm_year);

	clk_disable(pdata->clk);
	return 0;
}

static int pic32_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct pic32_rtc_dev *pdata = dev_get_drvdata(dev);
	struct rtc_time *tm = &alrm->time;
	void __iomem *base = pdata->reg_base;

	clk_enable(pdata->clk);
	dev_dbg(dev, "setalarm: %d, %04d.%02d.%02d %02d:%02d:%02d\n",
		alrm->enabled,
		1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
		tm->tm_hour, tm->tm_min, tm->tm_sec);

	writel(0x00, base + PIC32_ALRMTIME);
	writel(0x00, base + PIC32_ALRMDATE);

	pic32_rtc_setaie(dev, alrm->enabled);

	clk_disable(pdata->clk);
	return 0;
}

static int pic32_rtc_proc(struct device *dev, struct seq_file *seq)
{
	struct pic32_rtc_dev *pdata = dev_get_drvdata(dev);
	void __iomem *base = pdata->reg_base;
	unsigned int repeat;

	clk_enable(pdata->clk);

	repeat = readw(base + PIC32_RTCALRM);
	repeat &= PIC32_RTCALRM_ARPT;
	seq_printf(seq, "periodic_IRQ\t: %s\n", repeat  ? "yes" : "no");

	clk_disable(pdata->clk);
	return 0;
}

static const struct rtc_class_ops pic32_rtcops = {
	.read_time	  = pic32_rtc_gettime,
	.set_time	  = pic32_rtc_settime,
	.read_alarm	  = pic32_rtc_getalarm,
	.set_alarm	  = pic32_rtc_setalarm,
	.proc		  = pic32_rtc_proc,
	.alarm_irq_enable = pic32_rtc_setaie,
};

static void pic32_rtc_enable(struct pic32_rtc_dev *pdata, int en)
{
	void __iomem *base = pdata->reg_base;

	if (!base)
		return;

	clk_enable(pdata->clk);
	if (!en) {
		writel(PIC32_RTCCON_ON, base + PIC32_CLR(PIC32_RTCCON));
	} else {
		pic32_syskey_unlock();

		writel(PIC32_RTCCON_RTCWREN, base + PIC32_SET(PIC32_RTCCON));
		writel(3 << 9, base + PIC32_CLR(PIC32_RTCCON));

		if (!(readl(base + PIC32_RTCCON) & PIC32_RTCCON_ON))
			writel(PIC32_RTCCON_ON, base + PIC32_SET(PIC32_RTCCON));
	}
	clk_disable(pdata->clk);
}

static int pic32_rtc_remove(struct platform_device *pdev)
{
	struct pic32_rtc_dev *pdata = platform_get_drvdata(pdev);

	pic32_rtc_setaie(&pdev->dev, 0);
	clk_unprepare(pdata->clk);
	pdata->clk = NULL;

	return 0;
}

static int pic32_rtc_probe(struct platform_device *pdev)
{
	struct pic32_rtc_dev *pdata;
	struct resource *res;
	int ret;

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

	platform_set_drvdata(pdev, pdata);

	pdata->alarm_irq = platform_get_irq(pdev, 0);
	if (pdata->alarm_irq < 0) {
		dev_err(&pdev->dev, "no irq for alarm\n");
		return pdata->alarm_irq;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	pdata->reg_base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(pdata->reg_base))
		return PTR_ERR(pdata->reg_base);

	pdata->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(pdata->clk)) {
		dev_err(&pdev->dev, "failed to find rtc clock source\n");
		ret = PTR_ERR(pdata->clk);
		pdata->clk = NULL;
		return ret;
	}

	spin_lock_init(&pdata->alarm_lock);

	clk_prepare_enable(pdata->clk);

	pic32_rtc_enable(pdata, 1);

	device_init_wakeup(&pdev->dev, 1);

	pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
						 &pic32_rtcops,
						 THIS_MODULE);
	if (IS_ERR(pdata->rtc)) {
		ret = PTR_ERR(pdata->rtc);
		goto err_nortc;
	}

	pdata->rtc->max_user_freq = 128;

	pic32_rtc_setfreq(&pdev->dev, 1);
	ret = devm_request_irq(&pdev->dev, pdata->alarm_irq,
			       pic32_rtc_alarmirq, 0,
			       dev_name(&pdev->dev), pdata);
	if (ret) {
		dev_err(&pdev->dev,
			"IRQ %d error %d\n", pdata->alarm_irq, ret);
		goto err_nortc;
	}

	clk_disable(pdata->clk);

	return 0;

err_nortc:
	pic32_rtc_enable(pdata, 0);
	clk_disable_unprepare(pdata->clk);

	return ret;
}

static const struct of_device_id pic32_rtc_dt_ids[] = {
	{ .compatible = "microchip,pic32mzda-rtc" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, pic32_rtc_dt_ids);

static struct platform_driver pic32_rtc_driver = {
	.probe		= pic32_rtc_probe,
	.remove		= pic32_rtc_remove,
	.driver		= {
		.name	= "pic32-rtc",
		.owner	= THIS_MODULE,
		.of_match_table	= of_match_ptr(pic32_rtc_dt_ids),
	},
};
module_platform_driver(pic32_rtc_driver);

MODULE_DESCRIPTION("Microchip PIC32 RTC Driver");
MODULE_AUTHOR("Joshua Henderson <joshua.henderson@microchip.com>");
MODULE_LICENSE("GPL");