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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * DS1286 Real Time Clock interface for Linux
4 *
5 * Copyright (C) 1998, 1999, 2000 Ralf Baechle
6 * Copyright (C) 2008 Thomas Bogendoerfer
7 *
8 * Based on code written by Paul Gortmaker.
9 */
10
11#include <linux/module.h>
12#include <linux/rtc.h>
13#include <linux/platform_device.h>
14#include <linux/bcd.h>
15#include <linux/rtc/ds1286.h>
16#include <linux/io.h>
17#include <linux/slab.h>
18
19struct ds1286_priv {
20 struct rtc_device *rtc;
21 u32 __iomem *rtcregs;
22 spinlock_t lock;
23};
24
25static inline u8 ds1286_rtc_read(struct ds1286_priv *priv, int reg)
26{
27 return __raw_readl(&priv->rtcregs[reg]) & 0xff;
28}
29
30static inline void ds1286_rtc_write(struct ds1286_priv *priv, u8 data, int reg)
31{
32 __raw_writel(data, &priv->rtcregs[reg]);
33}
34
35
36static int ds1286_alarm_irq_enable(struct device *dev, unsigned int enabled)
37{
38 struct ds1286_priv *priv = dev_get_drvdata(dev);
39 unsigned long flags;
40 unsigned char val;
41
42 /* Allow or mask alarm interrupts */
43 spin_lock_irqsave(&priv->lock, flags);
44 val = ds1286_rtc_read(priv, RTC_CMD);
45 if (enabled)
46 val &= ~RTC_TDM;
47 else
48 val |= RTC_TDM;
49 ds1286_rtc_write(priv, val, RTC_CMD);
50 spin_unlock_irqrestore(&priv->lock, flags);
51
52 return 0;
53}
54
55#ifdef CONFIG_RTC_INTF_DEV
56
57static int ds1286_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
58{
59 struct ds1286_priv *priv = dev_get_drvdata(dev);
60 unsigned long flags;
61 unsigned char val;
62
63 switch (cmd) {
64 case RTC_WIE_OFF:
65 /* Mask watchdog int. enab. bit */
66 spin_lock_irqsave(&priv->lock, flags);
67 val = ds1286_rtc_read(priv, RTC_CMD);
68 val |= RTC_WAM;
69 ds1286_rtc_write(priv, val, RTC_CMD);
70 spin_unlock_irqrestore(&priv->lock, flags);
71 break;
72 case RTC_WIE_ON:
73 /* Allow watchdog interrupts. */
74 spin_lock_irqsave(&priv->lock, flags);
75 val = ds1286_rtc_read(priv, RTC_CMD);
76 val &= ~RTC_WAM;
77 ds1286_rtc_write(priv, val, RTC_CMD);
78 spin_unlock_irqrestore(&priv->lock, flags);
79 break;
80 default:
81 return -ENOIOCTLCMD;
82 }
83 return 0;
84}
85
86#else
87#define ds1286_ioctl NULL
88#endif
89
90#ifdef CONFIG_PROC_FS
91
92static int ds1286_proc(struct device *dev, struct seq_file *seq)
93{
94 struct ds1286_priv *priv = dev_get_drvdata(dev);
95 unsigned char month, cmd, amode;
96 const char *s;
97
98 month = ds1286_rtc_read(priv, RTC_MONTH);
99 seq_printf(seq,
100 "oscillator\t: %s\n"
101 "square_wave\t: %s\n",
102 (month & RTC_EOSC) ? "disabled" : "enabled",
103 (month & RTC_ESQW) ? "disabled" : "enabled");
104
105 amode = ((ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x80) >> 5) |
106 ((ds1286_rtc_read(priv, RTC_HOURS_ALARM) & 0x80) >> 6) |
107 ((ds1286_rtc_read(priv, RTC_DAY_ALARM) & 0x80) >> 7);
108 switch (amode) {
109 case 7:
110 s = "each minute";
111 break;
112 case 3:
113 s = "minutes match";
114 break;
115 case 1:
116 s = "hours and minutes match";
117 break;
118 case 0:
119 s = "days, hours and minutes match";
120 break;
121 default:
122 s = "invalid";
123 break;
124 }
125 seq_printf(seq, "alarm_mode\t: %s\n", s);
126
127 cmd = ds1286_rtc_read(priv, RTC_CMD);
128 seq_printf(seq,
129 "alarm_enable\t: %s\n"
130 "wdog_alarm\t: %s\n"
131 "alarm_mask\t: %s\n"
132 "wdog_alarm_mask\t: %s\n"
133 "interrupt_mode\t: %s\n"
134 "INTB_mode\t: %s_active\n"
135 "interrupt_pins\t: %s\n",
136 (cmd & RTC_TDF) ? "yes" : "no",
137 (cmd & RTC_WAF) ? "yes" : "no",
138 (cmd & RTC_TDM) ? "disabled" : "enabled",
139 (cmd & RTC_WAM) ? "disabled" : "enabled",
140 (cmd & RTC_PU_LVL) ? "pulse" : "level",
141 (cmd & RTC_IBH_LO) ? "low" : "high",
142 (cmd & RTC_IPSW) ? "unswapped" : "swapped");
143 return 0;
144}
145
146#else
147#define ds1286_proc NULL
148#endif
149
150static int ds1286_read_time(struct device *dev, struct rtc_time *tm)
151{
152 struct ds1286_priv *priv = dev_get_drvdata(dev);
153 unsigned char save_control;
154 unsigned long flags;
155 unsigned long uip_watchdog = jiffies;
156
157 /*
158 * read RTC once any update in progress is done. The update
159 * can take just over 2ms. We wait 10 to 20ms. There is no need to
160 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
161 * If you need to know *exactly* when a second has started, enable
162 * periodic update complete interrupts, (via ioctl) and then
163 * immediately read /dev/rtc which will block until you get the IRQ.
164 * Once the read clears, read the RTC time (again via ioctl). Easy.
165 */
166
167 if (ds1286_rtc_read(priv, RTC_CMD) & RTC_TE)
168 while (time_before(jiffies, uip_watchdog + 2*HZ/100))
169 barrier();
170
171 /*
172 * Only the values that we read from the RTC are set. We leave
173 * tm_wday, tm_yday and tm_isdst untouched. Even though the
174 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
175 * by the RTC when initially set to a non-zero value.
176 */
177 spin_lock_irqsave(&priv->lock, flags);
178 save_control = ds1286_rtc_read(priv, RTC_CMD);
179 ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
180
181 tm->tm_sec = ds1286_rtc_read(priv, RTC_SECONDS);
182 tm->tm_min = ds1286_rtc_read(priv, RTC_MINUTES);
183 tm->tm_hour = ds1286_rtc_read(priv, RTC_HOURS) & 0x3f;
184 tm->tm_mday = ds1286_rtc_read(priv, RTC_DATE);
185 tm->tm_mon = ds1286_rtc_read(priv, RTC_MONTH) & 0x1f;
186 tm->tm_year = ds1286_rtc_read(priv, RTC_YEAR);
187
188 ds1286_rtc_write(priv, save_control, RTC_CMD);
189 spin_unlock_irqrestore(&priv->lock, flags);
190
191 tm->tm_sec = bcd2bin(tm->tm_sec);
192 tm->tm_min = bcd2bin(tm->tm_min);
193 tm->tm_hour = bcd2bin(tm->tm_hour);
194 tm->tm_mday = bcd2bin(tm->tm_mday);
195 tm->tm_mon = bcd2bin(tm->tm_mon);
196 tm->tm_year = bcd2bin(tm->tm_year);
197
198 /*
199 * Account for differences between how the RTC uses the values
200 * and how they are defined in a struct rtc_time;
201 */
202 if (tm->tm_year < 45)
203 tm->tm_year += 30;
204 tm->tm_year += 40;
205 if (tm->tm_year < 70)
206 tm->tm_year += 100;
207
208 tm->tm_mon--;
209
210 return 0;
211}
212
213static int ds1286_set_time(struct device *dev, struct rtc_time *tm)
214{
215 struct ds1286_priv *priv = dev_get_drvdata(dev);
216 unsigned char mon, day, hrs, min, sec;
217 unsigned char save_control;
218 unsigned int yrs;
219 unsigned long flags;
220
221 yrs = tm->tm_year + 1900;
222 mon = tm->tm_mon + 1; /* tm_mon starts at zero */
223 day = tm->tm_mday;
224 hrs = tm->tm_hour;
225 min = tm->tm_min;
226 sec = tm->tm_sec;
227
228 if (yrs < 1970)
229 return -EINVAL;
230
231 yrs -= 1940;
232 if (yrs > 255) /* They are unsigned */
233 return -EINVAL;
234
235 if (yrs >= 100)
236 yrs -= 100;
237
238 sec = bin2bcd(sec);
239 min = bin2bcd(min);
240 hrs = bin2bcd(hrs);
241 day = bin2bcd(day);
242 mon = bin2bcd(mon);
243 yrs = bin2bcd(yrs);
244
245 spin_lock_irqsave(&priv->lock, flags);
246 save_control = ds1286_rtc_read(priv, RTC_CMD);
247 ds1286_rtc_write(priv, (save_control|RTC_TE), RTC_CMD);
248
249 ds1286_rtc_write(priv, yrs, RTC_YEAR);
250 ds1286_rtc_write(priv, mon, RTC_MONTH);
251 ds1286_rtc_write(priv, day, RTC_DATE);
252 ds1286_rtc_write(priv, hrs, RTC_HOURS);
253 ds1286_rtc_write(priv, min, RTC_MINUTES);
254 ds1286_rtc_write(priv, sec, RTC_SECONDS);
255 ds1286_rtc_write(priv, 0, RTC_HUNDREDTH_SECOND);
256
257 ds1286_rtc_write(priv, save_control, RTC_CMD);
258 spin_unlock_irqrestore(&priv->lock, flags);
259 return 0;
260}
261
262static int ds1286_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
263{
264 struct ds1286_priv *priv = dev_get_drvdata(dev);
265 unsigned long flags;
266
267 /*
268 * Only the values that we read from the RTC are set. That
269 * means only tm_wday, tm_hour, tm_min.
270 */
271 spin_lock_irqsave(&priv->lock, flags);
272 alm->time.tm_min = ds1286_rtc_read(priv, RTC_MINUTES_ALARM) & 0x7f;
273 alm->time.tm_hour = ds1286_rtc_read(priv, RTC_HOURS_ALARM) & 0x1f;
274 alm->time.tm_wday = ds1286_rtc_read(priv, RTC_DAY_ALARM) & 0x07;
275 ds1286_rtc_read(priv, RTC_CMD);
276 spin_unlock_irqrestore(&priv->lock, flags);
277
278 alm->time.tm_min = bcd2bin(alm->time.tm_min);
279 alm->time.tm_hour = bcd2bin(alm->time.tm_hour);
280 alm->time.tm_sec = 0;
281 return 0;
282}
283
284static int ds1286_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
285{
286 struct ds1286_priv *priv = dev_get_drvdata(dev);
287 unsigned char hrs, min, sec;
288
289 hrs = alm->time.tm_hour;
290 min = alm->time.tm_min;
291 sec = alm->time.tm_sec;
292
293 if (hrs >= 24)
294 hrs = 0xff;
295
296 if (min >= 60)
297 min = 0xff;
298
299 if (sec != 0)
300 return -EINVAL;
301
302 min = bin2bcd(min);
303 hrs = bin2bcd(hrs);
304
305 spin_lock(&priv->lock);
306 ds1286_rtc_write(priv, hrs, RTC_HOURS_ALARM);
307 ds1286_rtc_write(priv, min, RTC_MINUTES_ALARM);
308 spin_unlock(&priv->lock);
309
310 return 0;
311}
312
313static const struct rtc_class_ops ds1286_ops = {
314 .ioctl = ds1286_ioctl,
315 .proc = ds1286_proc,
316 .read_time = ds1286_read_time,
317 .set_time = ds1286_set_time,
318 .read_alarm = ds1286_read_alarm,
319 .set_alarm = ds1286_set_alarm,
320 .alarm_irq_enable = ds1286_alarm_irq_enable,
321};
322
323static int ds1286_probe(struct platform_device *pdev)
324{
325 struct rtc_device *rtc;
326 struct ds1286_priv *priv;
327
328 priv = devm_kzalloc(&pdev->dev, sizeof(struct ds1286_priv), GFP_KERNEL);
329 if (!priv)
330 return -ENOMEM;
331
332 priv->rtcregs = devm_platform_ioremap_resource(pdev, 0);
333 if (IS_ERR(priv->rtcregs))
334 return PTR_ERR(priv->rtcregs);
335
336 spin_lock_init(&priv->lock);
337 platform_set_drvdata(pdev, priv);
338 rtc = devm_rtc_device_register(&pdev->dev, "ds1286", &ds1286_ops,
339 THIS_MODULE);
340 if (IS_ERR(rtc))
341 return PTR_ERR(rtc);
342 priv->rtc = rtc;
343 return 0;
344}
345
346static struct platform_driver ds1286_platform_driver = {
347 .driver = {
348 .name = "rtc-ds1286",
349 },
350 .probe = ds1286_probe,
351};
352
353module_platform_driver(ds1286_platform_driver);
354
355MODULE_AUTHOR("Thomas Bogendoerfer <[email protected]>");
356MODULE_DESCRIPTION("DS1286 RTC driver");
357MODULE_LICENSE("GPL");
358MODULE_ALIAS("platform:rtc-ds1286");