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Linux/drivers/rtc/rtc-ds1286.c

  1 /*
  2  * DS1286 Real Time Clock interface for Linux
  3  *
  4  * Copyright (C) 1998, 1999, 2000 Ralf Baechle
  5  * Copyright (C) 2008 Thomas Bogendoerfer
  6  *
  7  * Based on code written by Paul Gortmaker.
  8  *
  9  * This program is free software; you can redistribute it and/or modify it
 10  * under the terms of the GNU General Public License as published by the
 11  * Free Software Foundation; either version 2 of the License, or (at your
 12  * option) any later version.
 13  */
 14 
 15 #include <linux/module.h>
 16 #include <linux/rtc.h>
 17 #include <linux/platform_device.h>
 18 #include <linux/bcd.h>
 19 #include <linux/ds1286.h>
 20 #include <linux/io.h>
 21 #include <linux/slab.h>
 22 
 23 struct ds1286_priv {
 24         struct rtc_device *rtc;
 25         u32 __iomem *rtcregs;
 26         spinlock_t lock;
 27 };
 28 
 29 static inline u8 ds1286_rtc_read(struct ds1286_priv *priv, int reg)
 30 {
 31         return __raw_readl(&priv->rtcregs[reg]) & 0xff;
 32 }
 33 
 34 static inline void ds1286_rtc_write(struct ds1286_priv *priv, u8 data, int reg)
 35 {
 36         __raw_writel(data, &priv->rtcregs[reg]);
 37 }
 38 
 39 
 40 static int ds1286_alarm_irq_enable(struct device *dev, unsigned int enabled)
 41 {
 42         struct ds1286_priv *priv = dev_get_drvdata(dev);
 43         unsigned long flags;
 44         unsigned char val;
 45 
 46         /* Allow or mask alarm interrupts */
 47         spin_lock_irqsave(&priv->lock, flags);
 48         val = ds1286_rtc_read(priv, RTC_CMD);
 49         if (enabled)
 50                 val &=  ~RTC_TDM;
 51         else
 52                 val |=  RTC_TDM;
 53         ds1286_rtc_write(priv, val, RTC_CMD);
 54         spin_unlock_irqrestore(&priv->lock, flags);
 55 
 56         return 0;
 57 }
 58 
 59 #ifdef CONFIG_RTC_INTF_DEV
 60 
 61 static int ds1286_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 62 {
 63         struct ds1286_priv *priv = dev_get_drvdata(dev);
 64         unsigned long flags;
 65         unsigned char val;
 66 
 67         switch (cmd) {
 68         case RTC_WIE_OFF:
 69                 /* Mask watchdog int. enab. bit */
 70                 spin_lock_irqsave(&priv->lock, flags);
 71                 val = ds1286_rtc_read(priv, RTC_CMD);
 72                 val |= RTC_WAM;
 73                 ds1286_rtc_write(priv, val, RTC_CMD);
 74                 spin_unlock_irqrestore(&priv->lock, flags);
 75                 break;
 76         case RTC_WIE_ON:
 77                 /* Allow watchdog interrupts.   */
 78                 spin_lock_irqsave(&priv->lock, flags);
 79                 val = ds1286_rtc_read(priv, RTC_CMD);
 80                 val &= ~RTC_WAM;
 81                 ds1286_rtc_write(priv, val, RTC_CMD);
 82                 spin_unlock_irqrestore(&priv->lock, flags);
 83                 break;
 84         default:
 85                 return -ENOIOCTLCMD;
 86         }
 87         return 0;
 88 }
 89 
 90 #else
 91 #define ds1286_ioctl    NULL
 92 #endif
 93 
 94 #ifdef CONFIG_PROC_FS
 95 
 96 static int ds1286_proc(struct device *dev, struct seq_file *seq)
 97 {
 98         struct ds1286_priv *priv = dev_get_drvdata(dev);
 99         unsigned char month, cmd, amode;
100         const char *s;
101 
102         month = ds1286_rtc_read(priv, RTC_MONTH);
103         seq_printf(seq,
104                    "oscillator\t: %s\n"
105                    "square_wave\t: %s\n",
106                    (month & RTC_EOSC) ? "disabled" : "enabled",
107                    (month & RTC_ESQW) ? "disabled" : "enabled");
108 
109         amode = ((ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x80) >> 5) |
110                 ((ds1286_rtc_read(priv, RTC_HOURS_ALARM) & 0x80) >> 6) |
111                 ((ds1286_rtc_read(priv, RTC_DAY_ALARM) & 0x80) >> 7);
112         switch (amode) {
113         case 7:
114                 s = "each minute";
115                 break;
116         case 3:
117                 s = "minutes match";
118                 break;
119         case 1:
120                 s = "hours and minutes match";
121                 break;
122         case 0:
123                 s = "days, hours and minutes match";
124                 break;
125         default:
126                 s = "invalid";
127                 break;
128         }
129         seq_printf(seq, "alarm_mode\t: %s\n", s);
130 
131         cmd = ds1286_rtc_read(priv, RTC_CMD);
132         seq_printf(seq,
133                    "alarm_enable\t: %s\n"
134                    "wdog_alarm\t: %s\n"
135                    "alarm_mask\t: %s\n"
136                    "wdog_alarm_mask\t: %s\n"
137                    "interrupt_mode\t: %s\n"
138                    "INTB_mode\t: %s_active\n"
139                    "interrupt_pins\t: %s\n",
140                    (cmd & RTC_TDF) ? "yes" : "no",
141                    (cmd & RTC_WAF) ? "yes" : "no",
142                    (cmd & RTC_TDM) ? "disabled" : "enabled",
143                    (cmd & RTC_WAM) ? "disabled" : "enabled",
144                    (cmd & RTC_PU_LVL) ? "pulse" : "level",
145                    (cmd & RTC_IBH_LO) ? "low" : "high",
146                    (cmd & RTC_IPSW) ? "unswapped" : "swapped");
147         return 0;
148 }
149 
150 #else
151 #define ds1286_proc     NULL
152 #endif
153 
154 static int ds1286_read_time(struct device *dev, struct rtc_time *tm)
155 {
156         struct ds1286_priv *priv = dev_get_drvdata(dev);
157         unsigned char save_control;
158         unsigned long flags;
159         unsigned long uip_watchdog = jiffies;
160 
161         /*
162          * read RTC once any update in progress is done. The update
163          * can take just over 2ms. We wait 10 to 20ms. There is no need to
164          * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
165          * If you need to know *exactly* when a second has started, enable
166          * periodic update complete interrupts, (via ioctl) and then
167          * immediately read /dev/rtc which will block until you get the IRQ.
168          * Once the read clears, read the RTC time (again via ioctl). Easy.
169          */
170 
171         if (ds1286_rtc_read(priv, RTC_CMD) & RTC_TE)
172                 while (time_before(jiffies, uip_watchdog + 2*HZ/100))
173                         barrier();
174 
175         /*
176          * Only the values that we read from the RTC are set. We leave
177          * tm_wday, tm_yday and tm_isdst untouched. Even though the
178          * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
179          * by the RTC when initially set to a non-zero value.
180          */
181         spin_lock_irqsave(&priv->lock, flags);
182         save_control = ds1286_rtc_read(priv, RTC_CMD);
183         ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
184 
185         tm->tm_sec = ds1286_rtc_read(priv, RTC_SECONDS);
186         tm->tm_min = ds1286_rtc_read(priv, RTC_MINUTES);
187         tm->tm_hour = ds1286_rtc_read(priv, RTC_HOURS) & 0x3f;
188         tm->tm_mday = ds1286_rtc_read(priv, RTC_DATE);
189         tm->tm_mon = ds1286_rtc_read(priv, RTC_MONTH) & 0x1f;
190         tm->tm_year = ds1286_rtc_read(priv, RTC_YEAR);
191 
192         ds1286_rtc_write(priv, save_control, RTC_CMD);
193         spin_unlock_irqrestore(&priv->lock, flags);
194 
195         tm->tm_sec = bcd2bin(tm->tm_sec);
196         tm->tm_min = bcd2bin(tm->tm_min);
197         tm->tm_hour = bcd2bin(tm->tm_hour);
198         tm->tm_mday = bcd2bin(tm->tm_mday);
199         tm->tm_mon = bcd2bin(tm->tm_mon);
200         tm->tm_year = bcd2bin(tm->tm_year);
201 
202         /*
203          * Account for differences between how the RTC uses the values
204          * and how they are defined in a struct rtc_time;
205          */
206         if (tm->tm_year < 45)
207                 tm->tm_year += 30;
208         tm->tm_year += 40;
209         if (tm->tm_year < 70)
210                 tm->tm_year += 100;
211 
212         tm->tm_mon--;
213 
214         return rtc_valid_tm(tm);
215 }
216 
217 static int ds1286_set_time(struct device *dev, struct rtc_time *tm)
218 {
219         struct ds1286_priv *priv = dev_get_drvdata(dev);
220         unsigned char mon, day, hrs, min, sec;
221         unsigned char save_control;
222         unsigned int yrs;
223         unsigned long flags;
224 
225         yrs = tm->tm_year + 1900;
226         mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
227         day = tm->tm_mday;
228         hrs = tm->tm_hour;
229         min = tm->tm_min;
230         sec = tm->tm_sec;
231 
232         if (yrs < 1970)
233                 return -EINVAL;
234 
235         yrs -= 1940;
236         if (yrs > 255)    /* They are unsigned */
237                 return -EINVAL;
238 
239         if (yrs >= 100)
240                 yrs -= 100;
241 
242         sec = bin2bcd(sec);
243         min = bin2bcd(min);
244         hrs = bin2bcd(hrs);
245         day = bin2bcd(day);
246         mon = bin2bcd(mon);
247         yrs = bin2bcd(yrs);
248 
249         spin_lock_irqsave(&priv->lock, flags);
250         save_control = ds1286_rtc_read(priv, RTC_CMD);
251         ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
252 
253         ds1286_rtc_write(priv, yrs, RTC_YEAR);
254         ds1286_rtc_write(priv, mon, RTC_MONTH);
255         ds1286_rtc_write(priv, day, RTC_DATE);
256         ds1286_rtc_write(priv, hrs, RTC_HOURS);
257         ds1286_rtc_write(priv, min, RTC_MINUTES);
258         ds1286_rtc_write(priv, sec, RTC_SECONDS);
259         ds1286_rtc_write(priv, 0, RTC_HUNDREDTH_SECOND);
260 
261         ds1286_rtc_write(priv, save_control, RTC_CMD);
262         spin_unlock_irqrestore(&priv->lock, flags);
263         return 0;
264 }
265 
266 static int ds1286_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
267 {
268         struct ds1286_priv *priv = dev_get_drvdata(dev);
269         unsigned long flags;
270 
271         /*
272          * Only the values that we read from the RTC are set. That
273          * means only tm_wday, tm_hour, tm_min.
274          */
275         spin_lock_irqsave(&priv->lock, flags);
276         alm->time.tm_min = ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x7f;
277         alm->time.tm_hour = ds1286_rtc_read(priv, RTC_HOURS_ALARM)  & 0x1f;
278         alm->time.tm_wday = ds1286_rtc_read(priv, RTC_DAY_ALARM)    & 0x07;
279         ds1286_rtc_read(priv, RTC_CMD);
280         spin_unlock_irqrestore(&priv->lock, flags);
281 
282         alm->time.tm_min = bcd2bin(alm->time.tm_min);
283         alm->time.tm_hour = bcd2bin(alm->time.tm_hour);
284         alm->time.tm_sec = 0;
285         return 0;
286 }
287 
288 static int ds1286_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
289 {
290         struct ds1286_priv *priv = dev_get_drvdata(dev);
291         unsigned char hrs, min, sec;
292 
293         hrs = alm->time.tm_hour;
294         min = alm->time.tm_min;
295         sec = alm->time.tm_sec;
296 
297         if (hrs >= 24)
298                 hrs = 0xff;
299 
300         if (min >= 60)
301                 min = 0xff;
302 
303         if (sec != 0)
304                 return -EINVAL;
305 
306         min = bin2bcd(min);
307         hrs = bin2bcd(hrs);
308 
309         spin_lock(&priv->lock);
310         ds1286_rtc_write(priv, hrs, RTC_HOURS_ALARM);
311         ds1286_rtc_write(priv, min, RTC_MINUTES_ALARM);
312         spin_unlock(&priv->lock);
313 
314         return 0;
315 }
316 
317 static const struct rtc_class_ops ds1286_ops = {
318         .ioctl          = ds1286_ioctl,
319         .proc           = ds1286_proc,
320         .read_time      = ds1286_read_time,
321         .set_time       = ds1286_set_time,
322         .read_alarm     = ds1286_read_alarm,
323         .set_alarm      = ds1286_set_alarm,
324         .alarm_irq_enable = ds1286_alarm_irq_enable,
325 };
326 
327 static int ds1286_probe(struct platform_device *pdev)
328 {
329         struct rtc_device *rtc;
330         struct resource *res;
331         struct ds1286_priv *priv;
332 
333         priv = devm_kzalloc(&pdev->dev, sizeof(struct ds1286_priv), GFP_KERNEL);
334         if (!priv)
335                 return -ENOMEM;
336 
337         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
338         priv->rtcregs = devm_ioremap_resource(&pdev->dev, res);
339         if (IS_ERR(priv->rtcregs))
340                 return PTR_ERR(priv->rtcregs);
341 
342         spin_lock_init(&priv->lock);
343         platform_set_drvdata(pdev, priv);
344         rtc = devm_rtc_device_register(&pdev->dev, "ds1286", &ds1286_ops,
345                                         THIS_MODULE);
346         if (IS_ERR(rtc))
347                 return PTR_ERR(rtc);
348         priv->rtc = rtc;
349         return 0;
350 }
351 
352 static struct platform_driver ds1286_platform_driver = {
353         .driver         = {
354                 .name   = "rtc-ds1286",
355         },
356         .probe          = ds1286_probe,
357 };
358 
359 module_platform_driver(ds1286_platform_driver);
360 
361 MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
362 MODULE_DESCRIPTION("DS1286 RTC driver");
363 MODULE_LICENSE("GPL");
364 MODULE_ALIAS("platform:rtc-ds1286");
365 

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