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 
vt8500_rtc_irq(int irq,void * dev_id)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 
vt8500_rtc_read_time(struct device * dev,struct rtc_time * tm)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 
vt8500_rtc_set_time(struct device * dev,struct rtc_time * tm)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 	writel((bin2bcd(tm->tm_year % 100) << DATE_YEAR_S)
126 		| (bin2bcd(tm->tm_mon + 1) << DATE_MONTH_S)
127 		| (bin2bcd(tm->tm_mday))
128 		| ((tm->tm_year >= 200) << DATE_CENTURY_S),
129 		vt8500_rtc->regbase + VT8500_RTC_DS);
130 	writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
131 		| (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
132 		| (bin2bcd(tm->tm_min) << TIME_MIN_S)
133 		| (bin2bcd(tm->tm_sec)),
134 		vt8500_rtc->regbase + VT8500_RTC_TS);
135 
136 	return 0;
137 }
138 
vt8500_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)139 static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
140 {
141 	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
142 	u32 isr, alarm;
143 
144 	alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
145 	isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
146 
147 	alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
148 	alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
149 	alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
150 	alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
151 
152 	alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
153 	alrm->pending = (isr & VT8500_RTC_IS_ALARM) ? 1 : 0;
154 
155 	return rtc_valid_tm(&alrm->time);
156 }
157 
vt8500_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)158 static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
159 {
160 	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
161 
162 	writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
163 		| (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
164 		| (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
165 		| (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
166 		| (bin2bcd(alrm->time.tm_sec)),
167 		vt8500_rtc->regbase + VT8500_RTC_AS);
168 
169 	return 0;
170 }
171 
vt8500_alarm_irq_enable(struct device * dev,unsigned int enabled)172 static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
173 {
174 	struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
175 	unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
176 
177 	if (enabled)
178 		tmp |= ALARM_ENABLE_MASK;
179 	else
180 		tmp &= ~ALARM_ENABLE_MASK;
181 
182 	writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
183 	return 0;
184 }
185 
186 static const struct rtc_class_ops vt8500_rtc_ops = {
187 	.read_time = vt8500_rtc_read_time,
188 	.set_time = vt8500_rtc_set_time,
189 	.read_alarm = vt8500_rtc_read_alarm,
190 	.set_alarm = vt8500_rtc_set_alarm,
191 	.alarm_irq_enable = vt8500_alarm_irq_enable,
192 };
193 
vt8500_rtc_probe(struct platform_device * pdev)194 static int vt8500_rtc_probe(struct platform_device *pdev)
195 {
196 	struct vt8500_rtc *vt8500_rtc;
197 	int ret;
198 
199 	vt8500_rtc = devm_kzalloc(&pdev->dev,
200 			   sizeof(struct vt8500_rtc), GFP_KERNEL);
201 	if (!vt8500_rtc)
202 		return -ENOMEM;
203 
204 	spin_lock_init(&vt8500_rtc->lock);
205 	platform_set_drvdata(pdev, vt8500_rtc);
206 
207 	vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
208 	if (vt8500_rtc->irq_alarm < 0)
209 		return vt8500_rtc->irq_alarm;
210 
211 	vt8500_rtc->regbase = devm_platform_ioremap_resource(pdev, 0);
212 	if (IS_ERR(vt8500_rtc->regbase))
213 		return PTR_ERR(vt8500_rtc->regbase);
214 
215 	/* Enable RTC and set it to 24-hour mode */
216 	writel(VT8500_RTC_CR_ENABLE,
217 	       vt8500_rtc->regbase + VT8500_RTC_CR);
218 
219 	vt8500_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
220 	if (IS_ERR(vt8500_rtc->rtc))
221 		return PTR_ERR(vt8500_rtc->rtc);
222 
223 	vt8500_rtc->rtc->ops = &vt8500_rtc_ops;
224 	vt8500_rtc->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
225 	vt8500_rtc->rtc->range_max = RTC_TIMESTAMP_END_2199;
226 
227 	ret = devm_request_irq(&pdev->dev, vt8500_rtc->irq_alarm,
228 				vt8500_rtc_irq, 0, "rtc alarm", vt8500_rtc);
229 	if (ret < 0) {
230 		dev_err(&pdev->dev, "can't get irq %i, err %d\n",
231 			vt8500_rtc->irq_alarm, ret);
232 		return ret;
233 	}
234 
235 	return devm_rtc_register_device(vt8500_rtc->rtc);
236 }
237 
vt8500_rtc_remove(struct platform_device * pdev)238 static int vt8500_rtc_remove(struct platform_device *pdev)
239 {
240 	struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
241 
242 	/* Disable alarm matching */
243 	writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
244 
245 	return 0;
246 }
247 
248 static const struct of_device_id wmt_dt_ids[] = {
249 	{ .compatible = "via,vt8500-rtc", },
250 	{}
251 };
252 MODULE_DEVICE_TABLE(of, wmt_dt_ids);
253 
254 static struct platform_driver vt8500_rtc_driver = {
255 	.probe		= vt8500_rtc_probe,
256 	.remove		= vt8500_rtc_remove,
257 	.driver		= {
258 		.name	= "vt8500-rtc",
259 		.of_match_table = wmt_dt_ids,
260 	},
261 };
262 
263 module_platform_driver(vt8500_rtc_driver);
264 
265 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
266 MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
267 MODULE_LICENSE("GPL v2");
268 MODULE_ALIAS("platform:vt8500-rtc");
269