xref: /openbmc/linux/drivers/rtc/rtc-vt8500.c (revision b830f94f)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * drivers/rtc/rtc-vt8500.c
4  *
5  *  Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
6  *
7  * Based on rtc-pxa.c
8  */
9 
10 #include <linux/module.h>
11 #include <linux/rtc.h>
12 #include <linux/init.h>
13 #include <linux/interrupt.h>
14 #include <linux/io.h>
15 #include <linux/bcd.h>
16 #include <linux/platform_device.h>
17 #include <linux/slab.h>
18 #include <linux/of.h>
19 
20 /*
21  * Register definitions
22  */
23 #define VT8500_RTC_TS		0x00	/* Time set */
24 #define VT8500_RTC_DS		0x04	/* Date set */
25 #define VT8500_RTC_AS		0x08	/* Alarm set */
26 #define VT8500_RTC_CR		0x0c	/* Control */
27 #define VT8500_RTC_TR		0x10	/* Time read */
28 #define VT8500_RTC_DR		0x14	/* Date read */
29 #define VT8500_RTC_WS		0x18	/* Write status */
30 #define VT8500_RTC_CL		0x20	/* Calibration */
31 #define VT8500_RTC_IS		0x24	/* Interrupt status */
32 #define VT8500_RTC_ST		0x28	/* Status */
33 
34 #define INVALID_TIME_BIT	(1 << 31)
35 
36 #define DATE_CENTURY_S		19
37 #define DATE_YEAR_S		11
38 #define DATE_YEAR_MASK		(0xff << DATE_YEAR_S)
39 #define DATE_MONTH_S		6
40 #define DATE_MONTH_MASK		(0x1f << DATE_MONTH_S)
41 #define DATE_DAY_MASK		0x3f
42 
43 #define TIME_DOW_S		20
44 #define TIME_DOW_MASK		(0x07 << TIME_DOW_S)
45 #define TIME_HOUR_S		14
46 #define TIME_HOUR_MASK		(0x3f << TIME_HOUR_S)
47 #define TIME_MIN_S		7
48 #define TIME_MIN_MASK		(0x7f << TIME_MIN_S)
49 #define TIME_SEC_MASK		0x7f
50 
51 #define ALARM_DAY_S		20
52 #define ALARM_DAY_MASK		(0x3f << ALARM_DAY_S)
53 
54 #define ALARM_DAY_BIT		(1 << 29)
55 #define ALARM_HOUR_BIT		(1 << 28)
56 #define ALARM_MIN_BIT		(1 << 27)
57 #define ALARM_SEC_BIT		(1 << 26)
58 
59 #define ALARM_ENABLE_MASK	(ALARM_DAY_BIT \
60 				| ALARM_HOUR_BIT \
61 				| ALARM_MIN_BIT \
62 				| ALARM_SEC_BIT)
63 
64 #define VT8500_RTC_CR_ENABLE	(1 << 0)	/* Enable RTC */
65 #define VT8500_RTC_CR_12H	(1 << 1)	/* 12h time format */
66 #define VT8500_RTC_CR_SM_ENABLE	(1 << 2)	/* Enable periodic irqs */
67 #define VT8500_RTC_CR_SM_SEC	(1 << 3)	/* 0: 1Hz/60, 1: 1Hz */
68 #define VT8500_RTC_CR_CALIB	(1 << 4)	/* Enable calibration */
69 
70 #define VT8500_RTC_IS_ALARM	(1 << 0)	/* Alarm interrupt status */
71 
72 struct vt8500_rtc {
73 	void __iomem		*regbase;
74 	int			irq_alarm;
75 	struct rtc_device	*rtc;
76 	spinlock_t		lock;		/* Protects this structure */
77 };
78 
79 static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
80 {
81 	struct vt8500_rtc *vt8500_rtc = dev_id;
82 	u32 isr;
83 	unsigned long events = 0;
84 
85 	spin_lock(&vt8500_rtc->lock);
86 
87 	/* clear interrupt sources */
88 	isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
89 	writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);
90 
91 	spin_unlock(&vt8500_rtc->lock);
92 
93 	if (isr & VT8500_RTC_IS_ALARM)
94 		events |= RTC_AF | RTC_IRQF;
95 
96 	rtc_update_irq(vt8500_rtc->rtc, 1, events);
97 
98 	return IRQ_HANDLED;
99 }
100 
101 static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
102 {
103 	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
104 	u32 date, time;
105 
106 	date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
107 	time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);
108 
109 	tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
110 	tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
111 	tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
112 	tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
113 	tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S) - 1;
114 	tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)
115 			+ ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
116 	tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;
117 
118 	return 0;
119 }
120 
121 static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
122 {
123 	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
124 
125 	if (tm->tm_year < 100) {
126 		dev_warn(dev, "Only years 2000-2199 are supported by the "
127 			      "hardware!\n");
128 		return -EINVAL;
129 	}
130 
131 	writel((bin2bcd(tm->tm_year % 100) << DATE_YEAR_S)
132 		| (bin2bcd(tm->tm_mon + 1) << DATE_MONTH_S)
133 		| (bin2bcd(tm->tm_mday))
134 		| ((tm->tm_year >= 200) << DATE_CENTURY_S),
135 		vt8500_rtc->regbase + VT8500_RTC_DS);
136 	writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
137 		| (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
138 		| (bin2bcd(tm->tm_min) << TIME_MIN_S)
139 		| (bin2bcd(tm->tm_sec)),
140 		vt8500_rtc->regbase + VT8500_RTC_TS);
141 
142 	return 0;
143 }
144 
145 static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
146 {
147 	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
148 	u32 isr, alarm;
149 
150 	alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
151 	isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
152 
153 	alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
154 	alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
155 	alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
156 	alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
157 
158 	alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
159 	alrm->pending = (isr & VT8500_RTC_IS_ALARM) ? 1 : 0;
160 
161 	return rtc_valid_tm(&alrm->time);
162 }
163 
164 static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
165 {
166 	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
167 
168 	writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
169 		| (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
170 		| (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
171 		| (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
172 		| (bin2bcd(alrm->time.tm_sec)),
173 		vt8500_rtc->regbase + VT8500_RTC_AS);
174 
175 	return 0;
176 }
177 
178 static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
179 {
180 	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
181 	unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
182 
183 	if (enabled)
184 		tmp |= ALARM_ENABLE_MASK;
185 	else
186 		tmp &= ~ALARM_ENABLE_MASK;
187 
188 	writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
189 	return 0;
190 }
191 
192 static const struct rtc_class_ops vt8500_rtc_ops = {
193 	.read_time = vt8500_rtc_read_time,
194 	.set_time = vt8500_rtc_set_time,
195 	.read_alarm = vt8500_rtc_read_alarm,
196 	.set_alarm = vt8500_rtc_set_alarm,
197 	.alarm_irq_enable = vt8500_alarm_irq_enable,
198 };
199 
200 static int vt8500_rtc_probe(struct platform_device *pdev)
201 {
202 	struct vt8500_rtc *vt8500_rtc;
203 	struct resource	*res;
204 	int ret;
205 
206 	vt8500_rtc = devm_kzalloc(&pdev->dev,
207 			   sizeof(struct vt8500_rtc), GFP_KERNEL);
208 	if (!vt8500_rtc)
209 		return -ENOMEM;
210 
211 	spin_lock_init(&vt8500_rtc->lock);
212 	platform_set_drvdata(pdev, vt8500_rtc);
213 
214 	vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
215 	if (vt8500_rtc->irq_alarm < 0) {
216 		dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
217 		return vt8500_rtc->irq_alarm;
218 	}
219 
220 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
221 	vt8500_rtc->regbase = devm_ioremap_resource(&pdev->dev, res);
222 	if (IS_ERR(vt8500_rtc->regbase))
223 		return PTR_ERR(vt8500_rtc->regbase);
224 
225 	/* Enable RTC and set it to 24-hour mode */
226 	writel(VT8500_RTC_CR_ENABLE,
227 	       vt8500_rtc->regbase + VT8500_RTC_CR);
228 
229 	vt8500_rtc->rtc = devm_rtc_device_register(&pdev->dev, "vt8500-rtc",
230 					      &vt8500_rtc_ops, THIS_MODULE);
231 	if (IS_ERR(vt8500_rtc->rtc)) {
232 		ret = PTR_ERR(vt8500_rtc->rtc);
233 		dev_err(&pdev->dev,
234 			"Failed to register RTC device -> %d\n", ret);
235 		goto err_return;
236 	}
237 
238 	ret = devm_request_irq(&pdev->dev, vt8500_rtc->irq_alarm,
239 				vt8500_rtc_irq, 0, "rtc alarm", vt8500_rtc);
240 	if (ret < 0) {
241 		dev_err(&pdev->dev, "can't get irq %i, err %d\n",
242 			vt8500_rtc->irq_alarm, ret);
243 		goto err_return;
244 	}
245 
246 	return 0;
247 
248 err_return:
249 	return ret;
250 }
251 
252 static int vt8500_rtc_remove(struct platform_device *pdev)
253 {
254 	struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
255 
256 	/* Disable alarm matching */
257 	writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
258 
259 	return 0;
260 }
261 
262 static const struct of_device_id wmt_dt_ids[] = {
263 	{ .compatible = "via,vt8500-rtc", },
264 	{}
265 };
266 MODULE_DEVICE_TABLE(of, wmt_dt_ids);
267 
268 static struct platform_driver vt8500_rtc_driver = {
269 	.probe		= vt8500_rtc_probe,
270 	.remove		= vt8500_rtc_remove,
271 	.driver		= {
272 		.name	= "vt8500-rtc",
273 		.of_match_table = wmt_dt_ids,
274 	},
275 };
276 
277 module_platform_driver(vt8500_rtc_driver);
278 
279 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
280 MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
281 MODULE_LICENSE("GPL v2");
282 MODULE_ALIAS("platform:vt8500-rtc");
283