aboutsummaryrefslogtreecommitdiff
path: root/drivers/rtc/rtc-vt8500.c
blob: c2d6331fc712c7244a87d33ef1e2d6d3cfa7fdca (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
/*
 * drivers/rtc/rtc-vt8500.c
 *
 *  Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
 *
 * Based on rtc-pxa.c
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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/module.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/bcd.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/of.h>

/*
 * Register definitions
 */
#define VT8500_RTC_TS		0x00	/* Time set */
#define VT8500_RTC_DS		0x04	/* Date set */
#define VT8500_RTC_AS		0x08	/* Alarm set */
#define VT8500_RTC_CR		0x0c	/* Control */
#define VT8500_RTC_TR		0x10	/* Time read */
#define VT8500_RTC_DR		0x14	/* Date read */
#define VT8500_RTC_WS		0x18	/* Write status */
#define VT8500_RTC_CL		0x20	/* Calibration */
#define VT8500_RTC_IS		0x24	/* Interrupt status */
#define VT8500_RTC_ST		0x28	/* Status */

#define INVALID_TIME_BIT	(1 << 31)

#define DATE_CENTURY_S		19
#define DATE_YEAR_S		11
#define DATE_YEAR_MASK		(0xff << DATE_YEAR_S)
#define DATE_MONTH_S		6
#define DATE_MONTH_MASK		(0x1f << DATE_MONTH_S)
#define DATE_DAY_MASK		0x3f

#define TIME_DOW_S		20
#define TIME_DOW_MASK		(0x07 << TIME_DOW_S)
#define TIME_HOUR_S		14
#define TIME_HOUR_MASK		(0x3f << TIME_HOUR_S)
#define TIME_MIN_S		7
#define TIME_MIN_MASK		(0x7f << TIME_MIN_S)
#define TIME_SEC_MASK		0x7f

#define ALARM_DAY_S		20
#define ALARM_DAY_MASK		(0x3f << ALARM_DAY_S)

#define ALARM_DAY_BIT		(1 << 29)
#define ALARM_HOUR_BIT		(1 << 28)
#define ALARM_MIN_BIT		(1 << 27)
#define ALARM_SEC_BIT		(1 << 26)

#define ALARM_ENABLE_MASK	(ALARM_DAY_BIT \
				| ALARM_HOUR_BIT \
				| ALARM_MIN_BIT \
				| ALARM_SEC_BIT)

#define VT8500_RTC_CR_ENABLE	(1 << 0)	/* Enable RTC */
#define VT8500_RTC_CR_12H	(1 << 1)	/* 12h time format */
#define VT8500_RTC_CR_SM_ENABLE	(1 << 2)	/* Enable periodic irqs */
#define VT8500_RTC_CR_SM_SEC	(1 << 3)	/* 0: 1Hz/60, 1: 1Hz */
#define VT8500_RTC_CR_CALIB	(1 << 4)	/* Enable calibration */

#define VT8500_RTC_IS_ALARM	(1 << 0)	/* Alarm interrupt status */

struct vt8500_rtc {
	void __iomem		*regbase;
	struct resource		*res;
	int			irq_alarm;
	struct rtc_device	*rtc;
	spinlock_t		lock;		/* Protects this structure */
};

static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
{
	struct vt8500_rtc *vt8500_rtc = dev_id;
	u32 isr;
	unsigned long events = 0;

	spin_lock(&vt8500_rtc->lock);

	/* clear interrupt sources */
	isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
	writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);

	spin_unlock(&vt8500_rtc->lock);

	if (isr & VT8500_RTC_IS_ALARM)
		events |= RTC_AF | RTC_IRQF;

	rtc_update_irq(vt8500_rtc->rtc, 1, events);

	return IRQ_HANDLED;
}

static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
	u32 date, time;

	date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
	time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);

	tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
	tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
	tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
	tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
	tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S) - 1;
	tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)
			+ ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
	tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;

	return 0;
}

static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);

	if (tm->tm_year < 100) {
		dev_warn(dev, "Only years 2000-2199 are supported by the "
			      "hardware!\n");
		return -EINVAL;
	}

	writel((bin2bcd(tm->tm_year % 100) << DATE_YEAR_S)
		| (bin2bcd(tm->tm_mon + 1) << DATE_MONTH_S)
		| (bin2bcd(tm->tm_mday))
		| ((tm->tm_year >= 200) << DATE_CENTURY_S),
		vt8500_rtc->regbase + VT8500_RTC_DS);
	writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
		| (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
		| (bin2bcd(tm->tm_min) << TIME_MIN_S)
		| (bin2bcd(tm->tm_sec)),
		vt8500_rtc->regbase + VT8500_RTC_TS);

	return 0;
}

static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
	u32 isr, alarm;

	alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
	isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);

	alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
	alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
	alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
	alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));

	alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
	alrm->pending = (isr & VT8500_RTC_IS_ALARM) ? 1 : 0;

	return rtc_valid_tm(&alrm->time);
}

static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);

	writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
		| (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
		| (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
		| (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
		| (bin2bcd(alrm->time.tm_sec)),
		vt8500_rtc->regbase + VT8500_RTC_AS);

	return 0;
}

static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
	unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);

	if (enabled)
		tmp |= ALARM_ENABLE_MASK;
	else
		tmp &= ~ALARM_ENABLE_MASK;

	writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
	return 0;
}

static const struct rtc_class_ops vt8500_rtc_ops = {
	.read_time = vt8500_rtc_read_time,
	.set_time = vt8500_rtc_set_time,
	.read_alarm = vt8500_rtc_read_alarm,
	.set_alarm = vt8500_rtc_set_alarm,
	.alarm_irq_enable = vt8500_alarm_irq_enable,
};

static int vt8500_rtc_probe(struct platform_device *pdev)
{
	struct vt8500_rtc *vt8500_rtc;
	int ret;

	vt8500_rtc = devm_kzalloc(&pdev->dev,
			   sizeof(struct vt8500_rtc), GFP_KERNEL);
	if (!vt8500_rtc)
		return -ENOMEM;

	spin_lock_init(&vt8500_rtc->lock);
	platform_set_drvdata(pdev, vt8500_rtc);

	vt8500_rtc->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!vt8500_rtc->res) {
		dev_err(&pdev->dev, "No I/O memory resource defined\n");
		return -ENXIO;
	}

	vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
	if (vt8500_rtc->irq_alarm < 0) {
		dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
		return -ENXIO;
	}

	vt8500_rtc->res = devm_request_mem_region(&pdev->dev,
					vt8500_rtc->res->start,
					resource_size(vt8500_rtc->res),
					"vt8500-rtc");
	if (vt8500_rtc->res == NULL) {
		dev_err(&pdev->dev, "failed to request I/O memory\n");
		return -EBUSY;
	}

	vt8500_rtc->regbase = devm_ioremap(&pdev->dev, vt8500_rtc->res->start,
				      resource_size(vt8500_rtc->res));
	if (!vt8500_rtc->regbase) {
		dev_err(&pdev->dev, "Unable to map RTC I/O memory\n");
		ret = -EBUSY;
		goto err_return;
	}

	/* Enable RTC and set it to 24-hour mode */
	writel(VT8500_RTC_CR_ENABLE,
	       vt8500_rtc->regbase + VT8500_RTC_CR);

	vt8500_rtc->rtc = devm_rtc_device_register(&pdev->dev, "vt8500-rtc",
					      &vt8500_rtc_ops, THIS_MODULE);
	if (IS_ERR(vt8500_rtc->rtc)) {
		ret = PTR_ERR(vt8500_rtc->rtc);
		dev_err(&pdev->dev,
			"Failed to register RTC device -> %d\n", ret);
		goto err_return;
	}

	ret = devm_request_irq(&pdev->dev, vt8500_rtc->irq_alarm,
				vt8500_rtc_irq, 0, "rtc alarm", vt8500_rtc);
	if (ret < 0) {
		dev_err(&pdev->dev, "can't get irq %i, err %d\n",
			vt8500_rtc->irq_alarm, ret);
		goto err_return;
	}

	return 0;

err_return:
	return ret;
}

static int vt8500_rtc_remove(struct platform_device *pdev)
{
	struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);

	/* Disable alarm matching */
	writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);

	return 0;
}

static const struct of_device_id wmt_dt_ids[] = {
	{ .compatible = "via,vt8500-rtc", },
	{}
};

static struct platform_driver vt8500_rtc_driver = {
	.probe		= vt8500_rtc_probe,
	.remove		= vt8500_rtc_remove,
	.driver		= {
		.name	= "vt8500-rtc",
		.owner	= THIS_MODULE,
		.of_match_table = of_match_ptr(wmt_dt_ids),
	},
};

module_platform_driver(vt8500_rtc_driver);

MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:vt8500-rtc");