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Linux/drivers/rtc/rtc-ds1553.c

  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 DRV_VERSION "0.3"
 24 
 25 #define RTC_REG_SIZE            0x2000
 26 #define RTC_OFFSET              0x1ff0
 27 
 28 #define RTC_FLAGS               (RTC_OFFSET + 0)
 29 #define RTC_SECONDS_ALARM       (RTC_OFFSET + 2)
 30 #define RTC_MINUTES_ALARM       (RTC_OFFSET + 3)
 31 #define RTC_HOURS_ALARM         (RTC_OFFSET + 4)
 32 #define RTC_DATE_ALARM          (RTC_OFFSET + 5)
 33 #define RTC_INTERRUPTS          (RTC_OFFSET + 6)
 34 #define RTC_WATCHDOG            (RTC_OFFSET + 7)
 35 #define RTC_CONTROL             (RTC_OFFSET + 8)
 36 #define RTC_CENTURY             (RTC_OFFSET + 8)
 37 #define RTC_SECONDS             (RTC_OFFSET + 9)
 38 #define RTC_MINUTES             (RTC_OFFSET + 10)
 39 #define RTC_HOURS               (RTC_OFFSET + 11)
 40 #define RTC_DAY                 (RTC_OFFSET + 12)
 41 #define RTC_DATE                (RTC_OFFSET + 13)
 42 #define RTC_MONTH               (RTC_OFFSET + 14)
 43 #define RTC_YEAR                (RTC_OFFSET + 15)
 44 
 45 #define RTC_CENTURY_MASK        0x3f
 46 #define RTC_SECONDS_MASK        0x7f
 47 #define RTC_DAY_MASK            0x07
 48 
 49 /* Bits in the Control/Century register */
 50 #define RTC_WRITE               0x80
 51 #define RTC_READ                0x40
 52 
 53 /* Bits in the Seconds register */
 54 #define RTC_STOP                0x80
 55 
 56 /* Bits in the Flags register */
 57 #define RTC_FLAGS_AF            0x40
 58 #define RTC_FLAGS_BLF           0x10
 59 
 60 /* Bits in the Interrupts register */
 61 #define RTC_INTS_AE             0x80
 62 
 63 struct rtc_plat_data {
 64         struct rtc_device *rtc;
 65         void __iomem *ioaddr;
 66         unsigned long last_jiffies;
 67         int irq;
 68         unsigned int irqen;
 69         int alrm_sec;
 70         int alrm_min;
 71         int alrm_hour;
 72         int alrm_mday;
 73         spinlock_t lock;
 74 };
 75 
 76 static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm)
 77 {
 78         struct platform_device *pdev = to_platform_device(dev);
 79         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 80         void __iomem *ioaddr = pdata->ioaddr;
 81         u8 century;
 82 
 83         century = bin2bcd((tm->tm_year + 1900) / 100);
 84 
 85         writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL);
 86 
 87         writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
 88         writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
 89         writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
 90         writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
 91         writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
 92         writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
 93         writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
 94 
 95         /* RTC_CENTURY and RTC_CONTROL share same register */
 96         writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
 97         writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
 98         return 0;
 99 }
100 
101 static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm)
102 {
103         struct platform_device *pdev = to_platform_device(dev);
104         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
105         void __iomem *ioaddr = pdata->ioaddr;
106         unsigned int year, month, day, hour, minute, second, week;
107         unsigned int century;
108 
109         /* give enough time to update RTC in case of continuous read */
110         if (pdata->last_jiffies == jiffies)
111                 msleep(1);
112         pdata->last_jiffies = jiffies;
113         writeb(RTC_READ, ioaddr + RTC_CONTROL);
114         second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
115         minute = readb(ioaddr + RTC_MINUTES);
116         hour = readb(ioaddr + RTC_HOURS);
117         day = readb(ioaddr + RTC_DATE);
118         week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
119         month = readb(ioaddr + RTC_MONTH);
120         year = readb(ioaddr + RTC_YEAR);
121         century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
122         writeb(0, ioaddr + RTC_CONTROL);
123         tm->tm_sec = bcd2bin(second);
124         tm->tm_min = bcd2bin(minute);
125         tm->tm_hour = bcd2bin(hour);
126         tm->tm_mday = bcd2bin(day);
127         tm->tm_wday = bcd2bin(week);
128         tm->tm_mon = bcd2bin(month) - 1;
129         /* year is 1900 + tm->tm_year */
130         tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
131 
132         if (rtc_valid_tm(tm) < 0) {
133                 dev_err(dev, "retrieved date/time is not valid.\n");
134                 rtc_time_to_tm(0, tm);
135         }
136         return 0;
137 }
138 
139 static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata)
140 {
141         void __iomem *ioaddr = pdata->ioaddr;
142         unsigned long flags;
143 
144         spin_lock_irqsave(&pdata->lock, flags);
145         writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
146                0x80 : bin2bcd(pdata->alrm_mday),
147                ioaddr + RTC_DATE_ALARM);
148         writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
149                0x80 : bin2bcd(pdata->alrm_hour),
150                ioaddr + RTC_HOURS_ALARM);
151         writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
152                0x80 : bin2bcd(pdata->alrm_min),
153                ioaddr + RTC_MINUTES_ALARM);
154         writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
155                0x80 : bin2bcd(pdata->alrm_sec),
156                ioaddr + RTC_SECONDS_ALARM);
157         writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS);
158         readb(ioaddr + RTC_FLAGS);      /* clear interrupts */
159         spin_unlock_irqrestore(&pdata->lock, flags);
160 }
161 
162 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
163 {
164         struct platform_device *pdev = to_platform_device(dev);
165         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
166 
167         if (pdata->irq <= 0)
168                 return -EINVAL;
169         pdata->alrm_mday = alrm->time.tm_mday;
170         pdata->alrm_hour = alrm->time.tm_hour;
171         pdata->alrm_min = alrm->time.tm_min;
172         pdata->alrm_sec = alrm->time.tm_sec;
173         if (alrm->enabled)
174                 pdata->irqen |= RTC_AF;
175         ds1553_rtc_update_alarm(pdata);
176         return 0;
177 }
178 
179 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
180 {
181         struct platform_device *pdev = to_platform_device(dev);
182         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
183 
184         if (pdata->irq <= 0)
185                 return -EINVAL;
186         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
187         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
188         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
189         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
190         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
191         return 0;
192 }
193 
194 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id)
195 {
196         struct platform_device *pdev = dev_id;
197         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
198         void __iomem *ioaddr = pdata->ioaddr;
199         unsigned long events = 0;
200 
201         spin_lock(&pdata->lock);
202         /* read and clear interrupt */
203         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {
204                 events = RTC_IRQF;
205                 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
206                         events |= RTC_UF;
207                 else
208                         events |= RTC_AF;
209                 rtc_update_irq(pdata->rtc, 1, events);
210         }
211         spin_unlock(&pdata->lock);
212         return events ? IRQ_HANDLED : IRQ_NONE;
213 }
214 
215 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
216 {
217         struct platform_device *pdev = to_platform_device(dev);
218         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
219 
220         if (pdata->irq <= 0)
221                 return -EINVAL;
222         if (enabled)
223                 pdata->irqen |= RTC_AF;
224         else
225                 pdata->irqen &= ~RTC_AF;
226         ds1553_rtc_update_alarm(pdata);
227         return 0;
228 }
229 
230 static const struct rtc_class_ops ds1553_rtc_ops = {
231         .read_time              = ds1553_rtc_read_time,
232         .set_time               = ds1553_rtc_set_time,
233         .read_alarm             = ds1553_rtc_read_alarm,
234         .set_alarm              = ds1553_rtc_set_alarm,
235         .alarm_irq_enable       = ds1553_rtc_alarm_irq_enable,
236 };
237 
238 static ssize_t ds1553_nvram_read(struct file *filp, struct kobject *kobj,
239                                  struct bin_attribute *bin_attr,
240                                  char *buf, loff_t pos, size_t size)
241 {
242         struct device *dev = container_of(kobj, struct device, kobj);
243         struct platform_device *pdev = to_platform_device(dev);
244         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
245         void __iomem *ioaddr = pdata->ioaddr;
246         ssize_t count;
247 
248         for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
249                 *buf++ = readb(ioaddr + pos++);
250         return count;
251 }
252 
253 static ssize_t ds1553_nvram_write(struct file *filp, struct kobject *kobj,
254                                   struct bin_attribute *bin_attr,
255                                   char *buf, loff_t pos, size_t size)
256 {
257         struct device *dev = container_of(kobj, struct device, kobj);
258         struct platform_device *pdev = to_platform_device(dev);
259         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
260         void __iomem *ioaddr = pdata->ioaddr;
261         ssize_t count;
262 
263         for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
264                 writeb(*buf++, ioaddr + pos++);
265         return count;
266 }
267 
268 static struct bin_attribute ds1553_nvram_attr = {
269         .attr = {
270                 .name = "nvram",
271                 .mode = S_IRUGO | S_IWUSR,
272         },
273         .size = RTC_OFFSET,
274         .read = ds1553_nvram_read,
275         .write = ds1553_nvram_write,
276 };
277 
278 static int ds1553_rtc_probe(struct platform_device *pdev)
279 {
280         struct resource *res;
281         unsigned int cen, sec;
282         struct rtc_plat_data *pdata;
283         void __iomem *ioaddr;
284         int ret = 0;
285 
286         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
287         if (!pdata)
288                 return -ENOMEM;
289 
290         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
291         ioaddr = devm_ioremap_resource(&pdev->dev, res);
292         if (IS_ERR(ioaddr))
293                 return PTR_ERR(ioaddr);
294         pdata->ioaddr = ioaddr;
295         pdata->irq = platform_get_irq(pdev, 0);
296 
297         /* turn RTC on if it was not on */
298         sec = readb(ioaddr + RTC_SECONDS);
299         if (sec & RTC_STOP) {
300                 sec &= RTC_SECONDS_MASK;
301                 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
302                 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
303                 writeb(sec, ioaddr + RTC_SECONDS);
304                 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
305         }
306         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
307                 dev_warn(&pdev->dev, "voltage-low detected.\n");
308 
309         spin_lock_init(&pdata->lock);
310         pdata->last_jiffies = jiffies;
311         platform_set_drvdata(pdev, pdata);
312 
313         pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
314                                   &ds1553_rtc_ops, THIS_MODULE);
315         if (IS_ERR(pdata->rtc))
316                 return PTR_ERR(pdata->rtc);
317 
318         if (pdata->irq > 0) {
319                 writeb(0, ioaddr + RTC_INTERRUPTS);
320                 if (devm_request_irq(&pdev->dev, pdata->irq,
321                                 ds1553_rtc_interrupt,
322                                 0, pdev->name, pdev) < 0) {
323                         dev_warn(&pdev->dev, "interrupt not available.\n");
324                         pdata->irq = 0;
325                 }
326         }
327 
328         ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
329         if (ret)
330                 dev_err(&pdev->dev, "unable to create sysfs file: %s\n",
331                         ds1553_nvram_attr.attr.name);
332 
333         return 0;
334 }
335 
336 static int ds1553_rtc_remove(struct platform_device *pdev)
337 {
338         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
339 
340         sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
341         if (pdata->irq > 0)
342                 writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
343         return 0;
344 }
345 
346 /* work with hotplug and coldplug */
347 MODULE_ALIAS("platform:rtc-ds1553");
348 
349 static struct platform_driver ds1553_rtc_driver = {
350         .probe          = ds1553_rtc_probe,
351         .remove         = ds1553_rtc_remove,
352         .driver         = {
353                 .name   = "rtc-ds1553",
354                 .owner  = THIS_MODULE,
355         },
356 };
357 
358 module_platform_driver(ds1553_rtc_driver);
359 
360 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
361 MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
362 MODULE_LICENSE("GPL");
363 MODULE_VERSION(DRV_VERSION);
364 

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