2 * An rtc driver for the Dallas DS1553
4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
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.
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>
21 #include <linux/module.h>
23 #define RTC_REG_SIZE 0x2000
24 #define RTC_OFFSET 0x1ff0
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)
43 #define RTC_CENTURY_MASK 0x3f
44 #define RTC_SECONDS_MASK 0x7f
45 #define RTC_DAY_MASK 0x07
47 /* Bits in the Control/Century register */
48 #define RTC_WRITE 0x80
51 /* Bits in the Seconds register */
54 /* Bits in the Flags register */
55 #define RTC_FLAGS_AF 0x40
56 #define RTC_FLAGS_BLF 0x10
58 /* Bits in the Interrupts register */
59 #define RTC_INTS_AE 0x80
61 struct rtc_plat_data {
62 struct rtc_device *rtc;
64 unsigned long last_jiffies;
74 static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm)
76 struct platform_device *pdev = to_platform_device(dev);
77 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
78 void __iomem *ioaddr = pdata->ioaddr;
81 century = bin2bcd((tm->tm_year + 1900) / 100);
83 writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL);
85 writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
86 writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
87 writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
88 writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
89 writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
90 writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
91 writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
93 /* RTC_CENTURY and RTC_CONTROL share same register */
94 writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
95 writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
99 static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm)
101 struct platform_device *pdev = to_platform_device(dev);
102 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
103 void __iomem *ioaddr = pdata->ioaddr;
104 unsigned int year, month, day, hour, minute, second, week;
105 unsigned int century;
107 /* give enough time to update RTC in case of continuous read */
108 if (pdata->last_jiffies == jiffies)
110 pdata->last_jiffies = jiffies;
111 writeb(RTC_READ, ioaddr + RTC_CONTROL);
112 second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
113 minute = readb(ioaddr + RTC_MINUTES);
114 hour = readb(ioaddr + RTC_HOURS);
115 day = readb(ioaddr + RTC_DATE);
116 week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
117 month = readb(ioaddr + RTC_MONTH);
118 year = readb(ioaddr + RTC_YEAR);
119 century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
120 writeb(0, ioaddr + RTC_CONTROL);
121 tm->tm_sec = bcd2bin(second);
122 tm->tm_min = bcd2bin(minute);
123 tm->tm_hour = bcd2bin(hour);
124 tm->tm_mday = bcd2bin(day);
125 tm->tm_wday = bcd2bin(week);
126 tm->tm_mon = bcd2bin(month) - 1;
127 /* year is 1900 + tm->tm_year */
128 tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
133 static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata)
135 void __iomem *ioaddr = pdata->ioaddr;
138 spin_lock_irqsave(&pdata->lock, flags);
139 writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
140 0x80 : bin2bcd(pdata->alrm_mday),
141 ioaddr + RTC_DATE_ALARM);
142 writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
143 0x80 : bin2bcd(pdata->alrm_hour),
144 ioaddr + RTC_HOURS_ALARM);
145 writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
146 0x80 : bin2bcd(pdata->alrm_min),
147 ioaddr + RTC_MINUTES_ALARM);
148 writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
149 0x80 : bin2bcd(pdata->alrm_sec),
150 ioaddr + RTC_SECONDS_ALARM);
151 writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS);
152 readb(ioaddr + RTC_FLAGS); /* clear interrupts */
153 spin_unlock_irqrestore(&pdata->lock, flags);
156 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
158 struct platform_device *pdev = to_platform_device(dev);
159 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
163 pdata->alrm_mday = alrm->time.tm_mday;
164 pdata->alrm_hour = alrm->time.tm_hour;
165 pdata->alrm_min = alrm->time.tm_min;
166 pdata->alrm_sec = alrm->time.tm_sec;
168 pdata->irqen |= RTC_AF;
169 ds1553_rtc_update_alarm(pdata);
173 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
175 struct platform_device *pdev = to_platform_device(dev);
176 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
180 alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
181 alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
182 alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
183 alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
184 alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
188 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id)
190 struct platform_device *pdev = dev_id;
191 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
192 void __iomem *ioaddr = pdata->ioaddr;
193 unsigned long events = 0;
195 spin_lock(&pdata->lock);
196 /* read and clear interrupt */
197 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {
199 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
203 rtc_update_irq(pdata->rtc, 1, events);
205 spin_unlock(&pdata->lock);
206 return events ? IRQ_HANDLED : IRQ_NONE;
209 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
211 struct platform_device *pdev = to_platform_device(dev);
212 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
217 pdata->irqen |= RTC_AF;
219 pdata->irqen &= ~RTC_AF;
220 ds1553_rtc_update_alarm(pdata);
224 static const struct rtc_class_ops ds1553_rtc_ops = {
225 .read_time = ds1553_rtc_read_time,
226 .set_time = ds1553_rtc_set_time,
227 .read_alarm = ds1553_rtc_read_alarm,
228 .set_alarm = ds1553_rtc_set_alarm,
229 .alarm_irq_enable = ds1553_rtc_alarm_irq_enable,
232 static int ds1553_nvram_read(void *priv, unsigned int pos, void *val,
235 struct platform_device *pdev = priv;
236 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
237 void __iomem *ioaddr = pdata->ioaddr;
240 for (; bytes; bytes--)
241 *buf++ = readb(ioaddr + pos++);
245 static int ds1553_nvram_write(void *priv, unsigned int pos, void *val,
248 struct platform_device *pdev = priv;
249 struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
250 void __iomem *ioaddr = pdata->ioaddr;
253 for (; bytes; bytes--)
254 writeb(*buf++, ioaddr + pos++);
258 static int ds1553_rtc_probe(struct platform_device *pdev)
260 struct resource *res;
261 unsigned int cen, sec;
262 struct rtc_plat_data *pdata;
263 void __iomem *ioaddr;
265 struct nvmem_config nvmem_cfg = {
266 .name = "ds1553_nvram",
270 .reg_read = ds1553_nvram_read,
271 .reg_write = ds1553_nvram_write,
275 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
279 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
280 ioaddr = devm_ioremap_resource(&pdev->dev, res);
282 return PTR_ERR(ioaddr);
283 pdata->ioaddr = ioaddr;
284 pdata->irq = platform_get_irq(pdev, 0);
286 /* turn RTC on if it was not on */
287 sec = readb(ioaddr + RTC_SECONDS);
288 if (sec & RTC_STOP) {
289 sec &= RTC_SECONDS_MASK;
290 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
291 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
292 writeb(sec, ioaddr + RTC_SECONDS);
293 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
295 if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
296 dev_warn(&pdev->dev, "voltage-low detected.\n");
298 spin_lock_init(&pdata->lock);
299 pdata->last_jiffies = jiffies;
300 platform_set_drvdata(pdev, pdata);
302 pdata->rtc = devm_rtc_allocate_device(&pdev->dev);
303 if (IS_ERR(pdata->rtc))
304 return PTR_ERR(pdata->rtc);
306 pdata->rtc->ops = &ds1553_rtc_ops;
307 pdata->rtc->nvram_old_abi = true;
309 ret = rtc_register_device(pdata->rtc);
313 if (pdata->irq > 0) {
314 writeb(0, ioaddr + RTC_INTERRUPTS);
315 if (devm_request_irq(&pdev->dev, pdata->irq,
316 ds1553_rtc_interrupt,
317 0, pdev->name, pdev) < 0) {
318 dev_warn(&pdev->dev, "interrupt not available.\n");
323 if (rtc_nvmem_register(pdata->rtc, &nvmem_cfg))
324 dev_err(&pdev->dev, "unable to register nvmem\n");
329 /* work with hotplug and coldplug */
330 MODULE_ALIAS("platform:rtc-ds1553");
332 static struct platform_driver ds1553_rtc_driver = {
333 .probe = ds1553_rtc_probe,
335 .name = "rtc-ds1553",
339 module_platform_driver(ds1553_rtc_driver);
341 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
342 MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
343 MODULE_LICENSE("GPL");