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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 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 
 74 static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm)
 75 {
 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;
 79         u8 century;
 80 
 81         century = bin2bcd((tm->tm_year + 1900) / 100);
 82 
 83         writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL);
 84 
 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);
 92 
 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);
 96         return 0;
 97 }
 98 
 99 static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm)
100 {
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;
106 
107         /* give enough time to update RTC in case of continuous read */
108         if (pdata->last_jiffies == jiffies)
109                 msleep(1);
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;
129 
130         if (rtc_valid_tm(tm) < 0) {
131                 dev_err(dev, "retrieved date/time is not valid.\n");
132                 rtc_time_to_tm(0, tm);
133         }
134         return 0;
135 }
136 
137 static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata)
138 {
139         void __iomem *ioaddr = pdata->ioaddr;
140         unsigned long flags;
141 
142         spin_lock_irqsave(&pdata->lock, flags);
143         writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
144                0x80 : bin2bcd(pdata->alrm_mday),
145                ioaddr + RTC_DATE_ALARM);
146         writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
147                0x80 : bin2bcd(pdata->alrm_hour),
148                ioaddr + RTC_HOURS_ALARM);
149         writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
150                0x80 : bin2bcd(pdata->alrm_min),
151                ioaddr + RTC_MINUTES_ALARM);
152         writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
153                0x80 : bin2bcd(pdata->alrm_sec),
154                ioaddr + RTC_SECONDS_ALARM);
155         writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS);
156         readb(ioaddr + RTC_FLAGS);      /* clear interrupts */
157         spin_unlock_irqrestore(&pdata->lock, flags);
158 }
159 
160 static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
161 {
162         struct platform_device *pdev = to_platform_device(dev);
163         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
164 
165         if (pdata->irq <= 0)
166                 return -EINVAL;
167         pdata->alrm_mday = alrm->time.tm_mday;
168         pdata->alrm_hour = alrm->time.tm_hour;
169         pdata->alrm_min = alrm->time.tm_min;
170         pdata->alrm_sec = alrm->time.tm_sec;
171         if (alrm->enabled)
172                 pdata->irqen |= RTC_AF;
173         ds1553_rtc_update_alarm(pdata);
174         return 0;
175 }
176 
177 static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
178 {
179         struct platform_device *pdev = to_platform_device(dev);
180         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
181 
182         if (pdata->irq <= 0)
183                 return -EINVAL;
184         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
185         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
186         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
187         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
188         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
189         return 0;
190 }
191 
192 static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id)
193 {
194         struct platform_device *pdev = dev_id;
195         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
196         void __iomem *ioaddr = pdata->ioaddr;
197         unsigned long events = 0;
198 
199         spin_lock(&pdata->lock);
200         /* read and clear interrupt */
201         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {
202                 events = RTC_IRQF;
203                 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
204                         events |= RTC_UF;
205                 else
206                         events |= RTC_AF;
207                 rtc_update_irq(pdata->rtc, 1, events);
208         }
209         spin_unlock(&pdata->lock);
210         return events ? IRQ_HANDLED : IRQ_NONE;
211 }
212 
213 static int ds1553_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
214 {
215         struct platform_device *pdev = to_platform_device(dev);
216         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
217 
218         if (pdata->irq <= 0)
219                 return -EINVAL;
220         if (enabled)
221                 pdata->irqen |= RTC_AF;
222         else
223                 pdata->irqen &= ~RTC_AF;
224         ds1553_rtc_update_alarm(pdata);
225         return 0;
226 }
227 
228 static const struct rtc_class_ops ds1553_rtc_ops = {
229         .read_time              = ds1553_rtc_read_time,
230         .set_time               = ds1553_rtc_set_time,
231         .read_alarm             = ds1553_rtc_read_alarm,
232         .set_alarm              = ds1553_rtc_set_alarm,
233         .alarm_irq_enable       = ds1553_rtc_alarm_irq_enable,
234 };
235 
236 static ssize_t ds1553_nvram_read(struct file *filp, struct kobject *kobj,
237                                  struct bin_attribute *bin_attr,
238                                  char *buf, loff_t pos, size_t size)
239 {
240         struct device *dev = container_of(kobj, struct device, kobj);
241         struct platform_device *pdev = to_platform_device(dev);
242         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
243         void __iomem *ioaddr = pdata->ioaddr;
244         ssize_t count;
245 
246         for (count = 0; count < size; count++)
247                 *buf++ = readb(ioaddr + pos++);
248         return count;
249 }
250 
251 static ssize_t ds1553_nvram_write(struct file *filp, struct kobject *kobj,
252                                   struct bin_attribute *bin_attr,
253                                   char *buf, loff_t pos, size_t size)
254 {
255         struct device *dev = container_of(kobj, struct device, kobj);
256         struct platform_device *pdev = to_platform_device(dev);
257         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
258         void __iomem *ioaddr = pdata->ioaddr;
259         ssize_t count;
260 
261         for (count = 0; count < size; count++)
262                 writeb(*buf++, ioaddr + pos++);
263         return count;
264 }
265 
266 static struct bin_attribute ds1553_nvram_attr = {
267         .attr = {
268                 .name = "nvram",
269                 .mode = S_IRUGO | S_IWUSR,
270         },
271         .size = RTC_OFFSET,
272         .read = ds1553_nvram_read,
273         .write = ds1553_nvram_write,
274 };
275 
276 static int ds1553_rtc_probe(struct platform_device *pdev)
277 {
278         struct resource *res;
279         unsigned int cen, sec;
280         struct rtc_plat_data *pdata;
281         void __iomem *ioaddr;
282         int ret = 0;
283 
284         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
285         if (!pdata)
286                 return -ENOMEM;
287 
288         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
289         ioaddr = devm_ioremap_resource(&pdev->dev, res);
290         if (IS_ERR(ioaddr))
291                 return PTR_ERR(ioaddr);
292         pdata->ioaddr = ioaddr;
293         pdata->irq = platform_get_irq(pdev, 0);
294 
295         /* turn RTC on if it was not on */
296         sec = readb(ioaddr + RTC_SECONDS);
297         if (sec & RTC_STOP) {
298                 sec &= RTC_SECONDS_MASK;
299                 cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
300                 writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
301                 writeb(sec, ioaddr + RTC_SECONDS);
302                 writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
303         }
304         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
305                 dev_warn(&pdev->dev, "voltage-low detected.\n");
306 
307         spin_lock_init(&pdata->lock);
308         pdata->last_jiffies = jiffies;
309         platform_set_drvdata(pdev, pdata);
310 
311         pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
312                                   &ds1553_rtc_ops, THIS_MODULE);
313         if (IS_ERR(pdata->rtc))
314                 return PTR_ERR(pdata->rtc);
315 
316         if (pdata->irq > 0) {
317                 writeb(0, ioaddr + RTC_INTERRUPTS);
318                 if (devm_request_irq(&pdev->dev, pdata->irq,
319                                 ds1553_rtc_interrupt,
320                                 0, pdev->name, pdev) < 0) {
321                         dev_warn(&pdev->dev, "interrupt not available.\n");
322                         pdata->irq = 0;
323                 }
324         }
325 
326         ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
327         if (ret)
328                 dev_err(&pdev->dev, "unable to create sysfs file: %s\n",
329                         ds1553_nvram_attr.attr.name);
330 
331         return 0;
332 }
333 
334 static int ds1553_rtc_remove(struct platform_device *pdev)
335 {
336         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
337 
338         sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
339         if (pdata->irq > 0)
340                 writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
341         return 0;
342 }
343 
344 /* work with hotplug and coldplug */
345 MODULE_ALIAS("platform:rtc-ds1553");
346 
347 static struct platform_driver ds1553_rtc_driver = {
348         .probe          = ds1553_rtc_probe,
349         .remove         = ds1553_rtc_remove,
350         .driver         = {
351                 .name   = "rtc-ds1553",
352         },
353 };
354 
355 module_platform_driver(ds1553_rtc_driver);
356 
357 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
358 MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
359 MODULE_LICENSE("GPL");
360 

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