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 int irq_alarm;
83 struct rtc_device *rtc;
84 spinlock_t lock; /* Protects this structure */
85 };
86
vt8500_rtc_irq(int irq,void * dev_id)87 static 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
vt8500_rtc_read_time(struct device * dev,struct rtc_time * tm)109 static 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
vt8500_rtc_set_time(struct device * dev,struct rtc_time * tm)129 static 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
vt8500_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)153 static 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
vt8500_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)172 static 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
vt8500_alarm_irq_enable(struct device * dev,unsigned int enabled)186 static 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
200 static 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
vt8500_rtc_probe(struct platform_device * pdev)208 static 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
256 err_return:
257 return ret;
258 }
259
vt8500_rtc_remove(struct platform_device * pdev)260 static 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
270 static const struct of_device_id wmt_dt_ids[] = {
271 { .compatible = "via,vt8500-rtc", },
272 {}
273 };
274 MODULE_DEVICE_TABLE(of, wmt_dt_ids);
275
276 static struct platform_driver vt8500_rtc_driver = {
277 .probe = vt8500_rtc_probe,
278 .remove = vt8500_rtc_remove,
279 .driver = {
280 .name = "vt8500-rtc",
281 .of_match_table = wmt_dt_ids,
282 },
283 };
284
285 module_platform_driver(vt8500_rtc_driver);
286
287 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
288 MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
289 MODULE_LICENSE("GPL v2");
290 MODULE_ALIAS("platform:vt8500-rtc");
291