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Linux/drivers/rtc/rtc-stk17ta8.c

  1 /*
  2  * A RTC driver for the Simtek STK17TA8
  3  *
  4  * By Thomas Hommel <thomas.hommel@ge.com>
  5  *
  6  * Based on the DS1553 driver from
  7  * Atsushi Nemoto <anemo@mba.ocn.ne.jp>
  8  *
  9  * This program is free software; you can redistribute it and/or modify
 10  * it under the terms of the GNU General Public License version 2 as
 11  * published by the Free Software Foundation.
 12  */
 13 
 14 #include <linux/bcd.h>
 15 #include <linux/init.h>
 16 #include <linux/kernel.h>
 17 #include <linux/gfp.h>
 18 #include <linux/delay.h>
 19 #include <linux/jiffies.h>
 20 #include <linux/interrupt.h>
 21 #include <linux/rtc.h>
 22 #include <linux/platform_device.h>
 23 #include <linux/io.h>
 24 #include <linux/module.h>
 25 
 26 #define RTC_REG_SIZE            0x20000
 27 #define RTC_OFFSET              0x1fff0
 28 
 29 #define RTC_FLAGS               (RTC_OFFSET + 0)
 30 #define RTC_CENTURY             (RTC_OFFSET + 1)
 31 #define RTC_SECONDS_ALARM       (RTC_OFFSET + 2)
 32 #define RTC_MINUTES_ALARM       (RTC_OFFSET + 3)
 33 #define RTC_HOURS_ALARM         (RTC_OFFSET + 4)
 34 #define RTC_DATE_ALARM          (RTC_OFFSET + 5)
 35 #define RTC_INTERRUPTS          (RTC_OFFSET + 6)
 36 #define RTC_WATCHDOG            (RTC_OFFSET + 7)
 37 #define RTC_CALIBRATION         (RTC_OFFSET + 8)
 38 #define RTC_SECONDS             (RTC_OFFSET + 9)
 39 #define RTC_MINUTES             (RTC_OFFSET + 10)
 40 #define RTC_HOURS               (RTC_OFFSET + 11)
 41 #define RTC_DAY                 (RTC_OFFSET + 12)
 42 #define RTC_DATE                (RTC_OFFSET + 13)
 43 #define RTC_MONTH               (RTC_OFFSET + 14)
 44 #define RTC_YEAR                (RTC_OFFSET + 15)
 45 
 46 #define RTC_SECONDS_MASK        0x7f
 47 #define RTC_DAY_MASK            0x07
 48 #define RTC_CAL_MASK            0x3f
 49 
 50 /* Bits in the Calibration register */
 51 #define RTC_STOP                0x80
 52 
 53 /* Bits in the Flags register */
 54 #define RTC_FLAGS_AF            0x40
 55 #define RTC_FLAGS_PF            0x20
 56 #define RTC_WRITE               0x02
 57 #define RTC_READ                0x01
 58 
 59 /* Bits in the Interrupts register */
 60 #define RTC_INTS_AIE            0x40
 61 
 62 struct rtc_plat_data {
 63         struct rtc_device *rtc;
 64         void __iomem *ioaddr;
 65         unsigned long last_jiffies;
 66         int irq;
 67         unsigned int irqen;
 68         int alrm_sec;
 69         int alrm_min;
 70         int alrm_hour;
 71         int alrm_mday;
 72         spinlock_t lock;
 73 };
 74 
 75 static int stk17ta8_rtc_set_time(struct device *dev, struct rtc_time *tm)
 76 {
 77         struct platform_device *pdev = to_platform_device(dev);
 78         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 79         void __iomem *ioaddr = pdata->ioaddr;
 80         u8 flags;
 81 
 82         flags = readb(pdata->ioaddr + RTC_FLAGS);
 83         writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
 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         writeb(bin2bcd((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY);
 93 
 94         writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
 95         return 0;
 96 }
 97 
 98 static int stk17ta8_rtc_read_time(struct device *dev, struct rtc_time *tm)
 99 {
100         struct platform_device *pdev = to_platform_device(dev);
101         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
102         void __iomem *ioaddr = pdata->ioaddr;
103         unsigned int year, month, day, hour, minute, second, week;
104         unsigned int century;
105         u8 flags;
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 
112         flags = readb(pdata->ioaddr + RTC_FLAGS);
113         writeb(flags | RTC_READ, ioaddr + RTC_FLAGS);
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);
122         writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS);
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 stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata)
140 {
141         void __iomem *ioaddr = pdata->ioaddr;
142         unsigned long irqflags;
143         u8 flags;
144 
145         spin_lock_irqsave(&pdata->lock, irqflags);
146 
147         flags = readb(ioaddr + RTC_FLAGS);
148         writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
149 
150         writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
151                0x80 : bin2bcd(pdata->alrm_mday),
152                ioaddr + RTC_DATE_ALARM);
153         writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
154                0x80 : bin2bcd(pdata->alrm_hour),
155                ioaddr + RTC_HOURS_ALARM);
156         writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
157                0x80 : bin2bcd(pdata->alrm_min),
158                ioaddr + RTC_MINUTES_ALARM);
159         writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
160                0x80 : bin2bcd(pdata->alrm_sec),
161                ioaddr + RTC_SECONDS_ALARM);
162         writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS);
163         readb(ioaddr + RTC_FLAGS);      /* clear interrupts */
164         writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
165         spin_unlock_irqrestore(&pdata->lock, irqflags);
166 }
167 
168 static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
169 {
170         struct platform_device *pdev = to_platform_device(dev);
171         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
172 
173         if (pdata->irq <= 0)
174                 return -EINVAL;
175         pdata->alrm_mday = alrm->time.tm_mday;
176         pdata->alrm_hour = alrm->time.tm_hour;
177         pdata->alrm_min = alrm->time.tm_min;
178         pdata->alrm_sec = alrm->time.tm_sec;
179         if (alrm->enabled)
180                 pdata->irqen |= RTC_AF;
181         stk17ta8_rtc_update_alarm(pdata);
182         return 0;
183 }
184 
185 static int stk17ta8_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
186 {
187         struct platform_device *pdev = to_platform_device(dev);
188         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
189 
190         if (pdata->irq <= 0)
191                 return -EINVAL;
192         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
193         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
194         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
195         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
196         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
197         return 0;
198 }
199 
200 static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id)
201 {
202         struct platform_device *pdev = dev_id;
203         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
204         void __iomem *ioaddr = pdata->ioaddr;
205         unsigned long events = 0;
206 
207         spin_lock(&pdata->lock);
208         /* read and clear interrupt */
209         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {
210                 events = RTC_IRQF;
211                 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
212                         events |= RTC_UF;
213                 else
214                         events |= RTC_AF;
215                 rtc_update_irq(pdata->rtc, 1, events);
216         }
217         spin_unlock(&pdata->lock);
218         return events ? IRQ_HANDLED : IRQ_NONE;
219 }
220 
221 static int stk17ta8_rtc_alarm_irq_enable(struct device *dev,
222         unsigned int enabled)
223 {
224         struct platform_device *pdev = to_platform_device(dev);
225         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
226 
227         if (pdata->irq <= 0)
228                 return -EINVAL;
229         if (enabled)
230                 pdata->irqen |= RTC_AF;
231         else
232                 pdata->irqen &= ~RTC_AF;
233         stk17ta8_rtc_update_alarm(pdata);
234         return 0;
235 }
236 
237 static const struct rtc_class_ops stk17ta8_rtc_ops = {
238         .read_time              = stk17ta8_rtc_read_time,
239         .set_time               = stk17ta8_rtc_set_time,
240         .read_alarm             = stk17ta8_rtc_read_alarm,
241         .set_alarm              = stk17ta8_rtc_set_alarm,
242         .alarm_irq_enable       = stk17ta8_rtc_alarm_irq_enable,
243 };
244 
245 static ssize_t stk17ta8_nvram_read(struct file *filp, struct kobject *kobj,
246                                  struct bin_attribute *attr, char *buf,
247                                  loff_t pos, size_t size)
248 {
249         struct device *dev = container_of(kobj, struct device, kobj);
250         struct platform_device *pdev = to_platform_device(dev);
251         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
252         void __iomem *ioaddr = pdata->ioaddr;
253         ssize_t count;
254 
255         for (count = 0; count < size; count++)
256                 *buf++ = readb(ioaddr + pos++);
257         return count;
258 }
259 
260 static ssize_t stk17ta8_nvram_write(struct file *filp, struct kobject *kobj,
261                                   struct bin_attribute *attr, char *buf,
262                                   loff_t pos, size_t size)
263 {
264         struct device *dev = container_of(kobj, struct device, kobj);
265         struct platform_device *pdev = to_platform_device(dev);
266         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
267         void __iomem *ioaddr = pdata->ioaddr;
268         ssize_t count;
269 
270         for (count = 0; count < size; count++)
271                 writeb(*buf++, ioaddr + pos++);
272         return count;
273 }
274 
275 static struct bin_attribute stk17ta8_nvram_attr = {
276         .attr = {
277                 .name = "nvram",
278                 .mode = S_IRUGO | S_IWUSR,
279         },
280         .size = RTC_OFFSET,
281         .read = stk17ta8_nvram_read,
282         .write = stk17ta8_nvram_write,
283 };
284 
285 static int stk17ta8_rtc_probe(struct platform_device *pdev)
286 {
287         struct resource *res;
288         unsigned int cal;
289         unsigned int flags;
290         struct rtc_plat_data *pdata;
291         void __iomem *ioaddr;
292         int ret = 0;
293 
294         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
295         if (!pdata)
296                 return -ENOMEM;
297 
298         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
299         ioaddr = devm_ioremap_resource(&pdev->dev, res);
300         if (IS_ERR(ioaddr))
301                 return PTR_ERR(ioaddr);
302         pdata->ioaddr = ioaddr;
303         pdata->irq = platform_get_irq(pdev, 0);
304 
305         /* turn RTC on if it was not on */
306         cal = readb(ioaddr + RTC_CALIBRATION);
307         if (cal & RTC_STOP) {
308                 cal &= RTC_CAL_MASK;
309                 flags = readb(ioaddr + RTC_FLAGS);
310                 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
311                 writeb(cal, ioaddr + RTC_CALIBRATION);
312                 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
313         }
314         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF)
315                 dev_warn(&pdev->dev, "voltage-low detected.\n");
316 
317         spin_lock_init(&pdata->lock);
318         pdata->last_jiffies = jiffies;
319         platform_set_drvdata(pdev, pdata);
320         if (pdata->irq > 0) {
321                 writeb(0, ioaddr + RTC_INTERRUPTS);
322                 if (devm_request_irq(&pdev->dev, pdata->irq,
323                                 stk17ta8_rtc_interrupt,
324                                 IRQF_SHARED,
325                                 pdev->name, pdev) < 0) {
326                         dev_warn(&pdev->dev, "interrupt not available.\n");
327                         pdata->irq = 0;
328                 }
329         }
330 
331         pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
332                                   &stk17ta8_rtc_ops, THIS_MODULE);
333         if (IS_ERR(pdata->rtc))
334                 return PTR_ERR(pdata->rtc);
335 
336         ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
337 
338         return ret;
339 }
340 
341 static int stk17ta8_rtc_remove(struct platform_device *pdev)
342 {
343         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
344 
345         sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
346         if (pdata->irq > 0)
347                 writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
348         return 0;
349 }
350 
351 /* work with hotplug and coldplug */
352 MODULE_ALIAS("platform:stk17ta8");
353 
354 static struct platform_driver stk17ta8_rtc_driver = {
355         .probe          = stk17ta8_rtc_probe,
356         .remove         = stk17ta8_rtc_remove,
357         .driver         = {
358                 .name   = "stk17ta8",
359         },
360 };
361 
362 module_platform_driver(stk17ta8_rtc_driver);
363 
364 MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>");
365 MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver");
366 MODULE_LICENSE("GPL");
367 

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