1 /*
2 * An rtc driver for the Dallas DS1553
3 *
4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11 #include <linux/bcd.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/gfp.h>
15 #include <linux/delay.h>
16 #include <linux/jiffies.h>
17 #include <linux/interrupt.h>
18 #include <linux/rtc.h>
19 #include <linux/platform_device.h>
20 #include <linux/io.h>
21 #include <linux/module.h>
22
23 #define RTC_REG_SIZE 0x2000
24 #define RTC_OFFSET 0x1ff0
25
26 #define RTC_FLAGS (RTC_OFFSET + 0)
27 #define RTC_SECONDS_ALARM (RTC_OFFSET + 2)
28 #define RTC_MINUTES_ALARM (RTC_OFFSET + 3)
29 #define RTC_HOURS_ALARM (RTC_OFFSET + 4)
30 #define RTC_DATE_ALARM (RTC_OFFSET + 5)
31 #define RTC_INTERRUPTS (RTC_OFFSET + 6)
32 #define RTC_WATCHDOG (RTC_OFFSET + 7)
33 #define RTC_CONTROL (RTC_OFFSET + 8)
34 #define RTC_CENTURY (RTC_OFFSET + 8)
35 #define RTC_SECONDS (RTC_OFFSET + 9)
36 #define RTC_MINUTES (RTC_OFFSET + 10)
37 #define RTC_HOURS (RTC_OFFSET + 11)
38 #define RTC_DAY (RTC_OFFSET + 12)
39 #define RTC_DATE (RTC_OFFSET + 13)
40 #define RTC_MONTH (RTC_OFFSET + 14)
41 #define RTC_YEAR (RTC_OFFSET + 15)
42
43 #define RTC_CENTURY_MASK 0x3f
44 #define RTC_SECONDS_MASK 0x7f
45 #define RTC_DAY_MASK 0x07
46
47 /* Bits in the Control/Century register */
48 #define RTC_WRITE 0x80
49 #define RTC_READ 0x40
50
51 /* Bits in the Seconds register */
52 #define RTC_STOP 0x80
53
54 /* Bits in the Flags register */
55 #define RTC_FLAGS_AF 0x40
56 #define RTC_FLAGS_BLF 0x10
57
58 /* Bits in the Interrupts register */
59 #define RTC_INTS_AE 0x80
60
61 struct rtc_plat_data {
62 struct rtc_device *rtc;
63 void __iomem *ioaddr;
64 unsigned long last_jiffies;
65 int irq;
66 unsigned int irqen;
67 int alrm_sec;
68 int alrm_min;
69 int alrm_hour;
70 int alrm_mday;
71 spinlock_t lock;
72 };
73
ds1553_rtc_set_time(struct device * dev,struct rtc_time * tm)74 static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm)
75 {
76 struct rtc_plat_data *pdata = dev_get_drvdata(dev);
77 void __iomem *ioaddr = pdata->ioaddr;
78 u8 century;
79
80 century = bin2bcd((tm->tm_year + 1900) / 100);
81
82 writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL);
83
84 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
85 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
86 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
87 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
88 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
89 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
90 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
91
92 /* RTC_CENTURY and RTC_CONTROL share same register */
93 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
94 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
95 return 0;
96 }
97
ds1553_rtc_read_time(struct device * dev,struct rtc_time * tm)98 static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm)
99 {
100 struct rtc_plat_data *pdata = dev_get_drvdata(dev);
101 void __iomem *ioaddr = pdata->ioaddr;
102 unsigned int year, month, day, hour, minute, second, week;
103 unsigned int century;
104
105 /* give enough time to update RTC in case of continuous read */
106 if (pdata->last_jiffies == jiffies)
107 msleep(1);
108 pdata->last_jiffies = jiffies;
109 writeb(RTC_READ, ioaddr + RTC_CONTROL);
110 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
111 minute = readb(ioaddr + RTC_MINUTES);
112 hour = readb(ioaddr + RTC_HOURS);
113 day = readb(ioaddr + RTC_DATE);
114 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
115 month = readb(ioaddr + RTC_MONTH);
116 year = readb(ioaddr + RTC_YEAR);
117 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
118 writeb(0, ioaddr + RTC_CONTROL);
119 tm->tm_sec = bcd2bin(second);
120 tm->tm_min = bcd2bin(minute);
121 tm->tm_hour = bcd2bin(hour);
122 tm->tm_mday = bcd2bin(day);
123 tm->tm_wday = bcd2bin(week);
124 tm->tm_mon = bcd2bin(month) - 1;
125 /* year is 1900 + tm->tm_year */
126 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
127
128 return 0;
129 }
130
ds1553_rtc_update_alarm(struct rtc_plat_data * pdata)131 static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata)
132 {
133 void __iomem *ioaddr = pdata->ioaddr;
134 unsigned long flags;
135
136 spin_lock_irqsave(&pdata->lock, flags);
137 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
138 0x80 : bin2bcd(pdata->alrm_mday),
139 ioaddr + RTC_DATE_ALARM);
140 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
141 0x80 : bin2bcd(pdata->alrm_hour),
142 ioaddr + RTC_HOURS_ALARM);
143 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
144 0x80 : bin2bcd(pdata->alrm_min),
145 ioaddr + RTC_MINUTES_ALARM);
146 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
147 0x80 : bin2bcd(pdata->alrm_sec),
148 ioaddr + RTC_SECONDS_ALARM);
149 writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS);
150 readb(ioaddr + RTC_FLAGS); /* clear interrupts */
151 spin_unlock_irqrestore(&pdata->lock, flags);
152 }
153
ds1553_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alrm)154 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
155 {
156 struct rtc_plat_data *pdata = dev_get_drvdata(dev);
157
158 if (pdata->irq <= 0)
159 return -EINVAL;
160 pdata->alrm_mday = alrm->time.tm_mday;
161 pdata->alrm_hour = alrm->time.tm_hour;
162 pdata->alrm_min = alrm->time.tm_min;
163 pdata->alrm_sec = alrm->time.tm_sec;
164 if (alrm->enabled)
165 pdata->irqen |= RTC_AF;
166 ds1553_rtc_update_alarm(pdata);
167 return 0;
168 }
169
ds1553_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alrm)170 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
171 {
172 struct rtc_plat_data *pdata = dev_get_drvdata(dev);
173
174 if (pdata->irq <= 0)
175 return -EINVAL;
176 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
177 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
178 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
179 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
180 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
181 return 0;
182 }
183
ds1553_rtc_interrupt(int irq,void * dev_id)184 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id)
185 {
186 struct platform_device *pdev = dev_id;
187 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
188 void __iomem *ioaddr = pdata->ioaddr;
189 unsigned long events = 0;
190
191 spin_lock(&pdata->lock);
192 /* read and clear interrupt */
193 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {
194 events = RTC_IRQF;
195 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
196 events |= RTC_UF;
197 else
198 events |= RTC_AF;
199 rtc_update_irq(pdata->rtc, 1, events);
200 }
201 spin_unlock(&pdata->lock);
202 return events ? IRQ_HANDLED : IRQ_NONE;
203 }
204
ds1553_rtc_alarm_irq_enable(struct device * dev,unsigned int enabled)205 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
206 {
207 struct rtc_plat_data *pdata = dev_get_drvdata(dev);
208
209 if (pdata->irq <= 0)
210 return -EINVAL;
211 if (enabled)
212 pdata->irqen |= RTC_AF;
213 else
214 pdata->irqen &= ~RTC_AF;
215 ds1553_rtc_update_alarm(pdata);
216 return 0;
217 }
218
219 static const struct rtc_class_ops ds1553_rtc_ops = {
220 .read_time = ds1553_rtc_read_time,
221 .set_time = ds1553_rtc_set_time,
222 .read_alarm = ds1553_rtc_read_alarm,
223 .set_alarm = ds1553_rtc_set_alarm,
224 .alarm_irq_enable = ds1553_rtc_alarm_irq_enable,
225 };
226
ds1553_nvram_read(void * priv,unsigned int pos,void * val,size_t bytes)227 static int ds1553_nvram_read(void *priv, unsigned int pos, void *val,
228 size_t bytes)
229 {
230 struct platform_device *pdev = priv;
231 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
232 void __iomem *ioaddr = pdata->ioaddr;
233 u8 *buf = val;
234
235 for (; bytes; bytes--)
236 *buf++ = readb(ioaddr + pos++);
237 return 0;
238 }
239
ds1553_nvram_write(void * priv,unsigned int pos,void * val,size_t bytes)240 static int ds1553_nvram_write(void *priv, unsigned int pos, void *val,
241 size_t bytes)
242 {
243 struct platform_device *pdev = priv;
244 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
245 void __iomem *ioaddr = pdata->ioaddr;
246 u8 *buf = val;
247
248 for (; bytes; bytes--)
249 writeb(*buf++, ioaddr + pos++);
250 return 0;
251 }
252
ds1553_rtc_probe(struct platform_device * pdev)253 static int ds1553_rtc_probe(struct platform_device *pdev)
254 {
255 struct resource *res;
256 unsigned int cen, sec;
257 struct rtc_plat_data *pdata;
258 void __iomem *ioaddr;
259 int ret = 0;
260 struct nvmem_config nvmem_cfg = {
261 .name = "ds1553_nvram",
262 .word_size = 1,
263 .stride = 1,
264 .size = RTC_OFFSET,
265 .reg_read = ds1553_nvram_read,
266 .reg_write = ds1553_nvram_write,
267 .priv = pdev,
268 };
269
270 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
271 if (!pdata)
272 return -ENOMEM;
273
274 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
275 ioaddr = devm_ioremap_resource(&pdev->dev, res);
276 if (IS_ERR(ioaddr))
277 return PTR_ERR(ioaddr);
278 pdata->ioaddr = ioaddr;
279 pdata->irq = platform_get_irq(pdev, 0);
280
281 /* turn RTC on if it was not on */
282 sec = readb(ioaddr + RTC_SECONDS);
283 if (sec & RTC_STOP) {
284 sec &= RTC_SECONDS_MASK;
285 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
286 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
287 writeb(sec, ioaddr + RTC_SECONDS);
288 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
289 }
290 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
291 dev_warn(&pdev->dev, "voltage-low detected.\n");
292
293 spin_lock_init(&pdata->lock);
294 pdata->last_jiffies = jiffies;
295 platform_set_drvdata(pdev, pdata);
296
297 pdata->rtc = devm_rtc_allocate_device(&pdev->dev);
298 if (IS_ERR(pdata->rtc))
299 return PTR_ERR(pdata->rtc);
300
301 pdata->rtc->ops = &ds1553_rtc_ops;
302 pdata->rtc->nvram_old_abi = true;
303
304 ret = rtc_register_device(pdata->rtc);
305 if (ret)
306 return ret;
307
308 if (pdata->irq > 0) {
309 writeb(0, ioaddr + RTC_INTERRUPTS);
310 if (devm_request_irq(&pdev->dev, pdata->irq,
311 ds1553_rtc_interrupt,
312 0, pdev->name, pdev) < 0) {
313 dev_warn(&pdev->dev, "interrupt not available.\n");
314 pdata->irq = 0;
315 }
316 }
317
318 if (rtc_nvmem_register(pdata->rtc, &nvmem_cfg))
319 dev_err(&pdev->dev, "unable to register nvmem\n");
320
321 return 0;
322 }
323
324 /* work with hotplug and coldplug */
325 MODULE_ALIAS("platform:rtc-ds1553");
326
327 static struct platform_driver ds1553_rtc_driver = {
328 .probe = ds1553_rtc_probe,
329 .driver = {
330 .name = "rtc-ds1553",
331 },
332 };
333
334 module_platform_driver(ds1553_rtc_driver);
335
336 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
337 MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
338 MODULE_LICENSE("GPL");
339
