1/*
2 * drivers/rtc/rtc-vt8500.c
3 *
4 *  Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
5 *
6 * Based on rtc-pxa.c
7 *
8 * This software is licensed under the terms of the GNU General Public
9 * License version 2, as published by the Free Software Foundation, and
10 * may be copied, distributed, and modified under those terms.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 */
17
18#include <linux/module.h>
19#include <linux/rtc.h>
20#include <linux/init.h>
21#include <linux/interrupt.h>
22#include <linux/io.h>
23#include <linux/bcd.h>
24#include <linux/platform_device.h>
25#include <linux/slab.h>
26#include <linux/of.h>
27
28/*
29 * Register definitions
30 */
31#define VT8500_RTC_TS		0x00	/* Time set */
32#define VT8500_RTC_DS		0x04	/* Date set */
33#define VT8500_RTC_AS		0x08	/* Alarm set */
34#define VT8500_RTC_CR		0x0c	/* Control */
35#define VT8500_RTC_TR		0x10	/* Time read */
36#define VT8500_RTC_DR		0x14	/* Date read */
37#define VT8500_RTC_WS		0x18	/* Write status */
38#define VT8500_RTC_CL		0x20	/* Calibration */
39#define VT8500_RTC_IS		0x24	/* Interrupt status */
40#define VT8500_RTC_ST		0x28	/* Status */
41
42#define INVALID_TIME_BIT	(1 << 31)
43
44#define DATE_CENTURY_S		19
45#define DATE_YEAR_S		11
46#define DATE_YEAR_MASK		(0xff << DATE_YEAR_S)
47#define DATE_MONTH_S		6
48#define DATE_MONTH_MASK		(0x1f << DATE_MONTH_S)
49#define DATE_DAY_MASK		0x3f
50
51#define TIME_DOW_S		20
52#define TIME_DOW_MASK		(0x07 << TIME_DOW_S)
53#define TIME_HOUR_S		14
54#define TIME_HOUR_MASK		(0x3f << TIME_HOUR_S)
55#define TIME_MIN_S		7
56#define TIME_MIN_MASK		(0x7f << TIME_MIN_S)
57#define TIME_SEC_MASK		0x7f
58
59#define ALARM_DAY_S		20
60#define ALARM_DAY_MASK		(0x3f << ALARM_DAY_S)
61
62#define ALARM_DAY_BIT		(1 << 29)
63#define ALARM_HOUR_BIT		(1 << 28)
64#define ALARM_MIN_BIT		(1 << 27)
65#define ALARM_SEC_BIT		(1 << 26)
66
67#define ALARM_ENABLE_MASK	(ALARM_DAY_BIT \
68				| ALARM_HOUR_BIT \
69				| ALARM_MIN_BIT \
70				| ALARM_SEC_BIT)
71
72#define VT8500_RTC_CR_ENABLE	(1 << 0)	/* Enable RTC */
73#define VT8500_RTC_CR_12H	(1 << 1)	/* 12h time format */
74#define VT8500_RTC_CR_SM_ENABLE	(1 << 2)	/* Enable periodic irqs */
75#define VT8500_RTC_CR_SM_SEC	(1 << 3)	/* 0: 1Hz/60, 1: 1Hz */
76#define VT8500_RTC_CR_CALIB	(1 << 4)	/* Enable calibration */
77
78#define VT8500_RTC_IS_ALARM	(1 << 0)	/* Alarm interrupt status */
79
80struct vt8500_rtc {
81	void __iomem		*regbase;
82	int			irq_alarm;
83	struct rtc_device	*rtc;
84	spinlock_t		lock;		/* Protects this structure */
85};
86
87static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
88{
89	struct vt8500_rtc *vt8500_rtc = dev_id;
90	u32 isr;
91	unsigned long events = 0;
92
93	spin_lock(&vt8500_rtc->lock);
94
95	/* clear interrupt sources */
96	isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
97	writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);
98
99	spin_unlock(&vt8500_rtc->lock);
100
101	if (isr & VT8500_RTC_IS_ALARM)
102		events |= RTC_AF | RTC_IRQF;
103
104	rtc_update_irq(vt8500_rtc->rtc, 1, events);
105
106	return IRQ_HANDLED;
107}
108
109static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
110{
111	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
112	u32 date, time;
113
114	date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
115	time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);
116
117	tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
118	tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
119	tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
120	tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
121	tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S) - 1;
122	tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)
123			+ ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
124	tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;
125
126	return 0;
127}
128
129static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
130{
131	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
132
133	if (tm->tm_year < 100) {
134		dev_warn(dev, "Only years 2000-2199 are supported by the "
135			      "hardware!\n");
136		return -EINVAL;
137	}
138
139	writel((bin2bcd(tm->tm_year % 100) << DATE_YEAR_S)
140		| (bin2bcd(tm->tm_mon + 1) << DATE_MONTH_S)
141		| (bin2bcd(tm->tm_mday))
142		| ((tm->tm_year >= 200) << DATE_CENTURY_S),
143		vt8500_rtc->regbase + VT8500_RTC_DS);
144	writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
145		| (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
146		| (bin2bcd(tm->tm_min) << TIME_MIN_S)
147		| (bin2bcd(tm->tm_sec)),
148		vt8500_rtc->regbase + VT8500_RTC_TS);
149
150	return 0;
151}
152
153static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
154{
155	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
156	u32 isr, alarm;
157
158	alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
159	isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
160
161	alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
162	alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
163	alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
164	alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
165
166	alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
167	alrm->pending = (isr & VT8500_RTC_IS_ALARM) ? 1 : 0;
168
169	return rtc_valid_tm(&alrm->time);
170}
171
172static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
173{
174	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
175
176	writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
177		| (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
178		| (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
179		| (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
180		| (bin2bcd(alrm->time.tm_sec)),
181		vt8500_rtc->regbase + VT8500_RTC_AS);
182
183	return 0;
184}
185
186static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
187{
188	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
189	unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
190
191	if (enabled)
192		tmp |= ALARM_ENABLE_MASK;
193	else
194		tmp &= ~ALARM_ENABLE_MASK;
195
196	writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
197	return 0;
198}
199
200static const struct rtc_class_ops vt8500_rtc_ops = {
201	.read_time = vt8500_rtc_read_time,
202	.set_time = vt8500_rtc_set_time,
203	.read_alarm = vt8500_rtc_read_alarm,
204	.set_alarm = vt8500_rtc_set_alarm,
205	.alarm_irq_enable = vt8500_alarm_irq_enable,
206};
207
208static int vt8500_rtc_probe(struct platform_device *pdev)
209{
210	struct vt8500_rtc *vt8500_rtc;
211	struct resource	*res;
212	int ret;
213
214	vt8500_rtc = devm_kzalloc(&pdev->dev,
215			   sizeof(struct vt8500_rtc), GFP_KERNEL);
216	if (!vt8500_rtc)
217		return -ENOMEM;
218
219	spin_lock_init(&vt8500_rtc->lock);
220	platform_set_drvdata(pdev, vt8500_rtc);
221
222	vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
223	if (vt8500_rtc->irq_alarm < 0) {
224		dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
225		return vt8500_rtc->irq_alarm;
226	}
227
228	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
229	vt8500_rtc->regbase = devm_ioremap_resource(&pdev->dev, res);
230	if (IS_ERR(vt8500_rtc->regbase))
231		return PTR_ERR(vt8500_rtc->regbase);
232
233	/* Enable RTC and set it to 24-hour mode */
234	writel(VT8500_RTC_CR_ENABLE,
235	       vt8500_rtc->regbase + VT8500_RTC_CR);
236
237	vt8500_rtc->rtc = devm_rtc_device_register(&pdev->dev, "vt8500-rtc",
238					      &vt8500_rtc_ops, THIS_MODULE);
239	if (IS_ERR(vt8500_rtc->rtc)) {
240		ret = PTR_ERR(vt8500_rtc->rtc);
241		dev_err(&pdev->dev,
242			"Failed to register RTC device -> %d\n", ret);
243		goto err_return;
244	}
245
246	ret = devm_request_irq(&pdev->dev, vt8500_rtc->irq_alarm,
247				vt8500_rtc_irq, 0, "rtc alarm", vt8500_rtc);
248	if (ret < 0) {
249		dev_err(&pdev->dev, "can't get irq %i, err %d\n",
250			vt8500_rtc->irq_alarm, ret);
251		goto err_return;
252	}
253
254	return 0;
255
256err_return:
257	return ret;
258}
259
260static int vt8500_rtc_remove(struct platform_device *pdev)
261{
262	struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
263
264	/* Disable alarm matching */
265	writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
266
267	return 0;
268}
269
270static const struct of_device_id wmt_dt_ids[] = {
271	{ .compatible = "via,vt8500-rtc", },
272	{}
273};
274
275static struct platform_driver vt8500_rtc_driver = {
276	.probe		= vt8500_rtc_probe,
277	.remove		= vt8500_rtc_remove,
278	.driver		= {
279		.name	= "vt8500-rtc",
280		.owner	= THIS_MODULE,
281		.of_match_table = wmt_dt_ids,
282	},
283};
284
285module_platform_driver(vt8500_rtc_driver);
286
287MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
288MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
289MODULE_LICENSE("GPL v2");
290MODULE_ALIAS("platform:vt8500-rtc");
291