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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 #define DRV_VERSION             "1.0"
 24 
 25 struct ds1286_priv {
 26         struct rtc_device *rtc;
 27         u32 __iomem *rtcregs;
 28         spinlock_t lock;
 29 };
 30 
 31 static inline u8 ds1286_rtc_read(struct ds1286_priv *priv, int reg)
 32 {
 33         return __raw_readl(&priv->rtcregs[reg]) & 0xff;
 34 }
 35 
 36 static inline void ds1286_rtc_write(struct ds1286_priv *priv, u8 data, int reg)
 37 {
 38         __raw_writel(data, &priv->rtcregs[reg]);
 39 }
 40 
 41 
 42 static int ds1286_alarm_irq_enable(struct device *dev, unsigned int enabled)
 43 {
 44         struct ds1286_priv *priv = dev_get_drvdata(dev);
 45         unsigned long flags;
 46         unsigned char val;
 47 
 48         /* Allow or mask alarm interrupts */
 49         spin_lock_irqsave(&priv->lock, flags);
 50         val = ds1286_rtc_read(priv, RTC_CMD);
 51         if (enabled)
 52                 val &=  ~RTC_TDM;
 53         else
 54                 val |=  RTC_TDM;
 55         ds1286_rtc_write(priv, val, RTC_CMD);
 56         spin_unlock_irqrestore(&priv->lock, flags);
 57 
 58         return 0;
 59 }
 60 
 61 #ifdef CONFIG_RTC_INTF_DEV
 62 
 63 static int ds1286_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 64 {
 65         struct ds1286_priv *priv = dev_get_drvdata(dev);
 66         unsigned long flags;
 67         unsigned char val;
 68 
 69         switch (cmd) {
 70         case RTC_WIE_OFF:
 71                 /* Mask watchdog int. enab. bit */
 72                 spin_lock_irqsave(&priv->lock, flags);
 73                 val = ds1286_rtc_read(priv, RTC_CMD);
 74                 val |= RTC_WAM;
 75                 ds1286_rtc_write(priv, val, RTC_CMD);
 76                 spin_unlock_irqrestore(&priv->lock, flags);
 77                 break;
 78         case RTC_WIE_ON:
 79                 /* Allow watchdog interrupts.   */
 80                 spin_lock_irqsave(&priv->lock, flags);
 81                 val = ds1286_rtc_read(priv, RTC_CMD);
 82                 val &= ~RTC_WAM;
 83                 ds1286_rtc_write(priv, val, RTC_CMD);
 84                 spin_unlock_irqrestore(&priv->lock, flags);
 85                 break;
 86         default:
 87                 return -ENOIOCTLCMD;
 88         }
 89         return 0;
 90 }
 91 
 92 #else
 93 #define ds1286_ioctl    NULL
 94 #endif
 95 
 96 #ifdef CONFIG_PROC_FS
 97 
 98 static int ds1286_proc(struct device *dev, struct seq_file *seq)
 99 {
100         struct ds1286_priv *priv = dev_get_drvdata(dev);
101         unsigned char month, cmd, amode;
102         const char *s;
103 
104         month = ds1286_rtc_read(priv, RTC_MONTH);
105         seq_printf(seq,
106                    "oscillator\t: %s\n"
107                    "square_wave\t: %s\n",
108                    (month & RTC_EOSC) ? "disabled" : "enabled",
109                    (month & RTC_ESQW) ? "disabled" : "enabled");
110 
111         amode = ((ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x80) >> 5) |
112                 ((ds1286_rtc_read(priv, RTC_HOURS_ALARM) & 0x80) >> 6) |
113                 ((ds1286_rtc_read(priv, RTC_DAY_ALARM) & 0x80) >> 7);
114         switch (amode) {
115         case 7:
116                 s = "each minute";
117                 break;
118         case 3:
119                 s = "minutes match";
120                 break;
121         case 1:
122                 s = "hours and minutes match";
123                 break;
124         case 0:
125                 s = "days, hours and minutes match";
126                 break;
127         default:
128                 s = "invalid";
129                 break;
130         }
131         seq_printf(seq, "alarm_mode\t: %s\n", s);
132 
133         cmd = ds1286_rtc_read(priv, RTC_CMD);
134         seq_printf(seq,
135                    "alarm_enable\t: %s\n"
136                    "wdog_alarm\t: %s\n"
137                    "alarm_mask\t: %s\n"
138                    "wdog_alarm_mask\t: %s\n"
139                    "interrupt_mode\t: %s\n"
140                    "INTB_mode\t: %s_active\n"
141                    "interrupt_pins\t: %s\n",
142                    (cmd & RTC_TDF) ? "yes" : "no",
143                    (cmd & RTC_WAF) ? "yes" : "no",
144                    (cmd & RTC_TDM) ? "disabled" : "enabled",
145                    (cmd & RTC_WAM) ? "disabled" : "enabled",
146                    (cmd & RTC_PU_LVL) ? "pulse" : "level",
147                    (cmd & RTC_IBH_LO) ? "low" : "high",
148                    (cmd & RTC_IPSW) ? "unswapped" : "swapped");
149         return 0;
150 }
151 
152 #else
153 #define ds1286_proc     NULL
154 #endif
155 
156 static int ds1286_read_time(struct device *dev, struct rtc_time *tm)
157 {
158         struct ds1286_priv *priv = dev_get_drvdata(dev);
159         unsigned char save_control;
160         unsigned long flags;
161         unsigned long uip_watchdog = jiffies;
162 
163         /*
164          * read RTC once any update in progress is done. The update
165          * can take just over 2ms. We wait 10 to 20ms. There is no need to
166          * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
167          * If you need to know *exactly* when a second has started, enable
168          * periodic update complete interrupts, (via ioctl) and then
169          * immediately read /dev/rtc which will block until you get the IRQ.
170          * Once the read clears, read the RTC time (again via ioctl). Easy.
171          */
172 
173         if (ds1286_rtc_read(priv, RTC_CMD) & RTC_TE)
174                 while (time_before(jiffies, uip_watchdog + 2*HZ/100))
175                         barrier();
176 
177         /*
178          * Only the values that we read from the RTC are set. We leave
179          * tm_wday, tm_yday and tm_isdst untouched. Even though the
180          * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
181          * by the RTC when initially set to a non-zero value.
182          */
183         spin_lock_irqsave(&priv->lock, flags);
184         save_control = ds1286_rtc_read(priv, RTC_CMD);
185         ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
186 
187         tm->tm_sec = ds1286_rtc_read(priv, RTC_SECONDS);
188         tm->tm_min = ds1286_rtc_read(priv, RTC_MINUTES);
189         tm->tm_hour = ds1286_rtc_read(priv, RTC_HOURS) & 0x3f;
190         tm->tm_mday = ds1286_rtc_read(priv, RTC_DATE);
191         tm->tm_mon = ds1286_rtc_read(priv, RTC_MONTH) & 0x1f;
192         tm->tm_year = ds1286_rtc_read(priv, RTC_YEAR);
193 
194         ds1286_rtc_write(priv, save_control, RTC_CMD);
195         spin_unlock_irqrestore(&priv->lock, flags);
196 
197         tm->tm_sec = bcd2bin(tm->tm_sec);
198         tm->tm_min = bcd2bin(tm->tm_min);
199         tm->tm_hour = bcd2bin(tm->tm_hour);
200         tm->tm_mday = bcd2bin(tm->tm_mday);
201         tm->tm_mon = bcd2bin(tm->tm_mon);
202         tm->tm_year = bcd2bin(tm->tm_year);
203 
204         /*
205          * Account for differences between how the RTC uses the values
206          * and how they are defined in a struct rtc_time;
207          */
208         if (tm->tm_year < 45)
209                 tm->tm_year += 30;
210         tm->tm_year += 40;
211         if (tm->tm_year < 70)
212                 tm->tm_year += 100;
213 
214         tm->tm_mon--;
215 
216         return rtc_valid_tm(tm);
217 }
218 
219 static int ds1286_set_time(struct device *dev, struct rtc_time *tm)
220 {
221         struct ds1286_priv *priv = dev_get_drvdata(dev);
222         unsigned char mon, day, hrs, min, sec;
223         unsigned char save_control;
224         unsigned int yrs;
225         unsigned long flags;
226 
227         yrs = tm->tm_year + 1900;
228         mon = tm->tm_mon + 1;   /* tm_mon starts at zero */
229         day = tm->tm_mday;
230         hrs = tm->tm_hour;
231         min = tm->tm_min;
232         sec = tm->tm_sec;
233 
234         if (yrs < 1970)
235                 return -EINVAL;
236 
237         yrs -= 1940;
238         if (yrs > 255)    /* They are unsigned */
239                 return -EINVAL;
240 
241         if (yrs >= 100)
242                 yrs -= 100;
243 
244         sec = bin2bcd(sec);
245         min = bin2bcd(min);
246         hrs = bin2bcd(hrs);
247         day = bin2bcd(day);
248         mon = bin2bcd(mon);
249         yrs = bin2bcd(yrs);
250 
251         spin_lock_irqsave(&priv->lock, flags);
252         save_control = ds1286_rtc_read(priv, RTC_CMD);
253         ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
254 
255         ds1286_rtc_write(priv, yrs, RTC_YEAR);
256         ds1286_rtc_write(priv, mon, RTC_MONTH);
257         ds1286_rtc_write(priv, day, RTC_DATE);
258         ds1286_rtc_write(priv, hrs, RTC_HOURS);
259         ds1286_rtc_write(priv, min, RTC_MINUTES);
260         ds1286_rtc_write(priv, sec, RTC_SECONDS);
261         ds1286_rtc_write(priv, 0, RTC_HUNDREDTH_SECOND);
262 
263         ds1286_rtc_write(priv, save_control, RTC_CMD);
264         spin_unlock_irqrestore(&priv->lock, flags);
265         return 0;
266 }
267 
268 static int ds1286_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
269 {
270         struct ds1286_priv *priv = dev_get_drvdata(dev);
271         unsigned long flags;
272 
273         /*
274          * Only the values that we read from the RTC are set. That
275          * means only tm_wday, tm_hour, tm_min.
276          */
277         spin_lock_irqsave(&priv->lock, flags);
278         alm->time.tm_min = ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x7f;
279         alm->time.tm_hour = ds1286_rtc_read(priv, RTC_HOURS_ALARM)  & 0x1f;
280         alm->time.tm_wday = ds1286_rtc_read(priv, RTC_DAY_ALARM)    & 0x07;
281         ds1286_rtc_read(priv, RTC_CMD);
282         spin_unlock_irqrestore(&priv->lock, flags);
283 
284         alm->time.tm_min = bcd2bin(alm->time.tm_min);
285         alm->time.tm_hour = bcd2bin(alm->time.tm_hour);
286         alm->time.tm_sec = 0;
287         return 0;
288 }
289 
290 static int ds1286_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
291 {
292         struct ds1286_priv *priv = dev_get_drvdata(dev);
293         unsigned char hrs, min, sec;
294 
295         hrs = alm->time.tm_hour;
296         min = alm->time.tm_min;
297         sec = alm->time.tm_sec;
298 
299         if (hrs >= 24)
300                 hrs = 0xff;
301 
302         if (min >= 60)
303                 min = 0xff;
304 
305         if (sec != 0)
306                 return -EINVAL;
307 
308         min = bin2bcd(min);
309         hrs = bin2bcd(hrs);
310 
311         spin_lock(&priv->lock);
312         ds1286_rtc_write(priv, hrs, RTC_HOURS_ALARM);
313         ds1286_rtc_write(priv, min, RTC_MINUTES_ALARM);
314         spin_unlock(&priv->lock);
315 
316         return 0;
317 }
318 
319 static const struct rtc_class_ops ds1286_ops = {
320         .ioctl          = ds1286_ioctl,
321         .proc           = ds1286_proc,
322         .read_time      = ds1286_read_time,
323         .set_time       = ds1286_set_time,
324         .read_alarm     = ds1286_read_alarm,
325         .set_alarm      = ds1286_set_alarm,
326         .alarm_irq_enable = ds1286_alarm_irq_enable,
327 };
328 
329 static int ds1286_probe(struct platform_device *pdev)
330 {
331         struct rtc_device *rtc;
332         struct resource *res;
333         struct ds1286_priv *priv;
334 
335         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
336         if (!res)
337                 return -ENODEV;
338         priv = devm_kzalloc(&pdev->dev, sizeof(struct ds1286_priv), GFP_KERNEL);
339         if (!priv)
340                 return -ENOMEM;
341 
342         priv->rtcregs = devm_ioremap_resource(&pdev->dev, res);
343         if (IS_ERR(priv->rtcregs))
344                 return PTR_ERR(priv->rtcregs);
345 
346         spin_lock_init(&priv->lock);
347         platform_set_drvdata(pdev, priv);
348         rtc = devm_rtc_device_register(&pdev->dev, "ds1286", &ds1286_ops,
349                                         THIS_MODULE);
350         if (IS_ERR(rtc))
351                 return PTR_ERR(rtc);
352         priv->rtc = rtc;
353         return 0;
354 }
355 
356 static struct platform_driver ds1286_platform_driver = {
357         .driver         = {
358                 .name   = "rtc-ds1286",
359                 .owner  = THIS_MODULE,
360         },
361         .probe          = ds1286_probe,
362 };
363 
364 module_platform_driver(ds1286_platform_driver);
365 
366 MODULE_AUTHOR("Thomas Bogendoerfer <tsbogend@alpha.franken.de>");
367 MODULE_DESCRIPTION("DS1286 RTC driver");
368 MODULE_LICENSE("GPL");
369 MODULE_VERSION(DRV_VERSION);
370 MODULE_ALIAS("platform:rtc-ds1286");
371 

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