xref: /openbmc/linux/drivers/rtc/rtc-vt8500.c (revision e23feb16)
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 
80 struct vt8500_rtc {
81 	void __iomem		*regbase;
82 	struct resource		*res;
83 	int			irq_alarm;
84 	struct rtc_device	*rtc;
85 	spinlock_t		lock;		/* Protects this structure */
86 };
87 
88 static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
89 {
90 	struct vt8500_rtc *vt8500_rtc = dev_id;
91 	u32 isr;
92 	unsigned long events = 0;
93 
94 	spin_lock(&vt8500_rtc->lock);
95 
96 	/* clear interrupt sources */
97 	isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
98 	writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);
99 
100 	spin_unlock(&vt8500_rtc->lock);
101 
102 	if (isr & VT8500_RTC_IS_ALARM)
103 		events |= RTC_AF | RTC_IRQF;
104 
105 	rtc_update_irq(vt8500_rtc->rtc, 1, events);
106 
107 	return IRQ_HANDLED;
108 }
109 
110 static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
111 {
112 	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
113 	u32 date, time;
114 
115 	date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
116 	time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);
117 
118 	tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
119 	tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
120 	tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
121 	tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
122 	tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S) - 1;
123 	tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)
124 			+ ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
125 	tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;
126 
127 	return 0;
128 }
129 
130 static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
131 {
132 	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
133 
134 	if (tm->tm_year < 100) {
135 		dev_warn(dev, "Only years 2000-2199 are supported by the "
136 			      "hardware!\n");
137 		return -EINVAL;
138 	}
139 
140 	writel((bin2bcd(tm->tm_year % 100) << DATE_YEAR_S)
141 		| (bin2bcd(tm->tm_mon + 1) << DATE_MONTH_S)
142 		| (bin2bcd(tm->tm_mday))
143 		| ((tm->tm_year >= 200) << DATE_CENTURY_S),
144 		vt8500_rtc->regbase + VT8500_RTC_DS);
145 	writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
146 		| (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
147 		| (bin2bcd(tm->tm_min) << TIME_MIN_S)
148 		| (bin2bcd(tm->tm_sec)),
149 		vt8500_rtc->regbase + VT8500_RTC_TS);
150 
151 	return 0;
152 }
153 
154 static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
155 {
156 	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
157 	u32 isr, alarm;
158 
159 	alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
160 	isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
161 
162 	alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
163 	alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
164 	alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
165 	alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
166 
167 	alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
168 	alrm->pending = (isr & VT8500_RTC_IS_ALARM) ? 1 : 0;
169 
170 	return rtc_valid_tm(&alrm->time);
171 }
172 
173 static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
174 {
175 	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
176 
177 	writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
178 		| (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
179 		| (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
180 		| (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
181 		| (bin2bcd(alrm->time.tm_sec)),
182 		vt8500_rtc->regbase + VT8500_RTC_AS);
183 
184 	return 0;
185 }
186 
187 static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
188 {
189 	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
190 	unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
191 
192 	if (enabled)
193 		tmp |= ALARM_ENABLE_MASK;
194 	else
195 		tmp &= ~ALARM_ENABLE_MASK;
196 
197 	writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
198 	return 0;
199 }
200 
201 static const struct rtc_class_ops vt8500_rtc_ops = {
202 	.read_time = vt8500_rtc_read_time,
203 	.set_time = vt8500_rtc_set_time,
204 	.read_alarm = vt8500_rtc_read_alarm,
205 	.set_alarm = vt8500_rtc_set_alarm,
206 	.alarm_irq_enable = vt8500_alarm_irq_enable,
207 };
208 
209 static int vt8500_rtc_probe(struct platform_device *pdev)
210 {
211 	struct vt8500_rtc *vt8500_rtc;
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->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
223 	if (!vt8500_rtc->res) {
224 		dev_err(&pdev->dev, "No I/O memory resource defined\n");
225 		return -ENXIO;
226 	}
227 
228 	vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
229 	if (vt8500_rtc->irq_alarm < 0) {
230 		dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
231 		return -ENXIO;
232 	}
233 
234 	vt8500_rtc->res = devm_request_mem_region(&pdev->dev,
235 					vt8500_rtc->res->start,
236 					resource_size(vt8500_rtc->res),
237 					"vt8500-rtc");
238 	if (vt8500_rtc->res == NULL) {
239 		dev_err(&pdev->dev, "failed to request I/O memory\n");
240 		return -EBUSY;
241 	}
242 
243 	vt8500_rtc->regbase = devm_ioremap(&pdev->dev, vt8500_rtc->res->start,
244 				      resource_size(vt8500_rtc->res));
245 	if (!vt8500_rtc->regbase) {
246 		dev_err(&pdev->dev, "Unable to map RTC I/O memory\n");
247 		ret = -EBUSY;
248 		goto err_return;
249 	}
250 
251 	/* Enable RTC and set it to 24-hour mode */
252 	writel(VT8500_RTC_CR_ENABLE,
253 	       vt8500_rtc->regbase + VT8500_RTC_CR);
254 
255 	vt8500_rtc->rtc = devm_rtc_device_register(&pdev->dev, "vt8500-rtc",
256 					      &vt8500_rtc_ops, THIS_MODULE);
257 	if (IS_ERR(vt8500_rtc->rtc)) {
258 		ret = PTR_ERR(vt8500_rtc->rtc);
259 		dev_err(&pdev->dev,
260 			"Failed to register RTC device -> %d\n", ret);
261 		goto err_return;
262 	}
263 
264 	ret = devm_request_irq(&pdev->dev, vt8500_rtc->irq_alarm,
265 				vt8500_rtc_irq, 0, "rtc alarm", vt8500_rtc);
266 	if (ret < 0) {
267 		dev_err(&pdev->dev, "can't get irq %i, err %d\n",
268 			vt8500_rtc->irq_alarm, ret);
269 		goto err_return;
270 	}
271 
272 	return 0;
273 
274 err_return:
275 	return ret;
276 }
277 
278 static int vt8500_rtc_remove(struct platform_device *pdev)
279 {
280 	struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
281 
282 	/* Disable alarm matching */
283 	writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
284 
285 	return 0;
286 }
287 
288 static const struct of_device_id wmt_dt_ids[] = {
289 	{ .compatible = "via,vt8500-rtc", },
290 	{}
291 };
292 
293 static struct platform_driver vt8500_rtc_driver = {
294 	.probe		= vt8500_rtc_probe,
295 	.remove		= vt8500_rtc_remove,
296 	.driver		= {
297 		.name	= "vt8500-rtc",
298 		.owner	= THIS_MODULE,
299 		.of_match_table = of_match_ptr(wmt_dt_ids),
300 	},
301 };
302 
303 module_platform_driver(vt8500_rtc_driver);
304 
305 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
306 MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
307 MODULE_LICENSE("GPL v2");
308 MODULE_ALIAS("platform:vt8500-rtc");
309