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/rtc/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
ds1286_rtc_read(struct ds1286_priv * priv,int reg)29 static inline u8 ds1286_rtc_read(struct ds1286_priv *priv, int reg)
30 {
31 return __raw_readl(&priv->rtcregs[reg]) & 0xff;
32 }
33
ds1286_rtc_write(struct ds1286_priv * priv,u8 data,int reg)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
ds1286_alarm_irq_enable(struct device * dev,unsigned int enabled)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
ds1286_ioctl(struct device * dev,unsigned int cmd,unsigned long arg)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
ds1286_proc(struct device * dev,struct seq_file * seq)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
ds1286_read_time(struct device * dev,struct rtc_time * tm)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 0;
215 }
216
ds1286_set_time(struct device * dev,struct rtc_time * tm)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
ds1286_read_alarm(struct device * dev,struct rtc_wkalrm * alm)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
ds1286_set_alarm(struct device * dev,struct rtc_wkalrm * alm)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
ds1286_probe(struct platform_device * pdev)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