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 void 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
246 static const struct of_device_id wmt_dt_ids[] = {
247 { .compatible = "via,vt8500-rtc", },
248 {}
249 };
250 MODULE_DEVICE_TABLE(of, wmt_dt_ids);
251
252 static struct platform_driver vt8500_rtc_driver = {
253 .probe = vt8500_rtc_probe,
254 .remove_new = vt8500_rtc_remove,
255 .driver = {
256 .name = "vt8500-rtc",
257 .of_match_table = wmt_dt_ids,
258 },
259 };
260
261 module_platform_driver(vt8500_rtc_driver);
262
263 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
264 MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
265 MODULE_LICENSE("GPL v2");
266 MODULE_ALIAS("platform:vt8500-rtc");
267
