1 /*
2 * Driver for NEC VR4100 series Real Time Clock unit.
3 *
4 * Copyright (C) 2003-2008 Yoichi Yuasa <yuasa@linux-mips.org>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 */
20 #include <linux/err.h>
21 #include <linux/fs.h>
22 #include <linux/init.h>
23 #include <linux/ioport.h>
24 #include <linux/interrupt.h>
25 #include <linux/module.h>
26 #include <linux/platform_device.h>
27 #include <linux/rtc.h>
28 #include <linux/spinlock.h>
29 #include <linux/types.h>
30 #include <linux/log2.h>
31
32 #include <asm/div64.h>
33 #include <asm/io.h>
34 #include <asm/uaccess.h>
35
36 MODULE_AUTHOR("Yoichi Yuasa <yuasa@linux-mips.org>");
37 MODULE_DESCRIPTION("NEC VR4100 series RTC driver");
38 MODULE_LICENSE("GPL v2");
39
40 /* RTC 1 registers */
41 #define ETIMELREG 0x00
42 #define ETIMEMREG 0x02
43 #define ETIMEHREG 0x04
44 /* RFU */
45 #define ECMPLREG 0x08
46 #define ECMPMREG 0x0a
47 #define ECMPHREG 0x0c
48 /* RFU */
49 #define RTCL1LREG 0x10
50 #define RTCL1HREG 0x12
51 #define RTCL1CNTLREG 0x14
52 #define RTCL1CNTHREG 0x16
53 #define RTCL2LREG 0x18
54 #define RTCL2HREG 0x1a
55 #define RTCL2CNTLREG 0x1c
56 #define RTCL2CNTHREG 0x1e
57
58 /* RTC 2 registers */
59 #define TCLKLREG 0x00
60 #define TCLKHREG 0x02
61 #define TCLKCNTLREG 0x04
62 #define TCLKCNTHREG 0x06
63 /* RFU */
64 #define RTCINTREG 0x1e
65 #define TCLOCK_INT 0x08
66 #define RTCLONG2_INT 0x04
67 #define RTCLONG1_INT 0x02
68 #define ELAPSEDTIME_INT 0x01
69
70 #define RTC_FREQUENCY 32768
71 #define MAX_PERIODIC_RATE 6553
72
73 static void __iomem *rtc1_base;
74 static void __iomem *rtc2_base;
75
76 #define rtc1_read(offset) readw(rtc1_base + (offset))
77 #define rtc1_write(offset, value) writew((value), rtc1_base + (offset))
78
79 #define rtc2_read(offset) readw(rtc2_base + (offset))
80 #define rtc2_write(offset, value) writew((value), rtc2_base + (offset))
81
82 static unsigned long epoch = 1970; /* Jan 1 1970 00:00:00 */
83
84 static DEFINE_SPINLOCK(rtc_lock);
85 static char rtc_name[] = "RTC";
86 static unsigned long periodic_count;
87 static unsigned int alarm_enabled;
88 static int aie_irq;
89 static int pie_irq;
90
91 static inline unsigned long read_elapsed_second(void)
92 {
93
94 unsigned long first_low, first_mid, first_high;
95
96 unsigned long second_low, second_mid, second_high;
97
98 do {
99 first_low = rtc1_read(ETIMELREG);
100 first_mid = rtc1_read(ETIMEMREG);
101 first_high = rtc1_read(ETIMEHREG);
102 second_low = rtc1_read(ETIMELREG);
103 second_mid = rtc1_read(ETIMEMREG);
104 second_high = rtc1_read(ETIMEHREG);
105 } while (first_low != second_low || first_mid != second_mid ||
106 first_high != second_high);
107
108 return (first_high << 17) | (first_mid << 1) | (first_low >> 15);
109 }
110
111 static inline void write_elapsed_second(unsigned long sec)
112 {
113 spin_lock_irq(&rtc_lock);
114
115 rtc1_write(ETIMELREG, (uint16_t)(sec << 15));
116 rtc1_write(ETIMEMREG, (uint16_t)(sec >> 1));
117 rtc1_write(ETIMEHREG, (uint16_t)(sec >> 17));
118
119 spin_unlock_irq(&rtc_lock);
120 }
121
122 static void vr41xx_rtc_release(struct device *dev)
123 {
124
125 spin_lock_irq(&rtc_lock);
126
127 rtc1_write(ECMPLREG, 0);
128 rtc1_write(ECMPMREG, 0);
129 rtc1_write(ECMPHREG, 0);
130 rtc1_write(RTCL1LREG, 0);
131 rtc1_write(RTCL1HREG, 0);
132
133 spin_unlock_irq(&rtc_lock);
134
135 disable_irq(aie_irq);
136 disable_irq(pie_irq);
137 }
138
139 static int vr41xx_rtc_read_time(struct device *dev, struct rtc_time *time)
140 {
141 unsigned long epoch_sec, elapsed_sec;
142
143 epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
144 elapsed_sec = read_elapsed_second();
145
146 rtc_time_to_tm(epoch_sec + elapsed_sec, time);
147
148 return 0;
149 }
150
151 static int vr41xx_rtc_set_time(struct device *dev, struct rtc_time *time)
152 {
153 unsigned long epoch_sec, current_sec;
154
155 epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
156 current_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
157 time->tm_hour, time->tm_min, time->tm_sec);
158
159 write_elapsed_second(current_sec - epoch_sec);
160
161 return 0;
162 }
163
164 static int vr41xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
165 {
166 unsigned long low, mid, high;
167 struct rtc_time *time = &wkalrm->time;
168
169 spin_lock_irq(&rtc_lock);
170
171 low = rtc1_read(ECMPLREG);
172 mid = rtc1_read(ECMPMREG);
173 high = rtc1_read(ECMPHREG);
174 wkalrm->enabled = alarm_enabled;
175
176 spin_unlock_irq(&rtc_lock);
177
178 rtc_time_to_tm((high << 17) | (mid << 1) | (low >> 15), time);
179
180 return 0;
181 }
182
183 static int vr41xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
184 {
185 unsigned long alarm_sec;
186 struct rtc_time *time = &wkalrm->time;
187
188 alarm_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
189 time->tm_hour, time->tm_min, time->tm_sec);
190
191 spin_lock_irq(&rtc_lock);
192
193 if (alarm_enabled)
194 disable_irq(aie_irq);
195
196 rtc1_write(ECMPLREG, (uint16_t)(alarm_sec << 15));
197 rtc1_write(ECMPMREG, (uint16_t)(alarm_sec >> 1));
198 rtc1_write(ECMPHREG, (uint16_t)(alarm_sec >> 17));
199
200 if (wkalrm->enabled)
201 enable_irq(aie_irq);
202
203 alarm_enabled = wkalrm->enabled;
204
205 spin_unlock_irq(&rtc_lock);
206
207 return 0;
208 }
209
210 static int vr41xx_rtc_irq_set_freq(struct device *dev, int freq)
211 {
212 unsigned long count;
213
214 if (!is_power_of_2(freq))
215 return -EINVAL;
216 count = RTC_FREQUENCY;
217 do_div(count, freq);
218
219 periodic_count = count;
220
221 spin_lock_irq(&rtc_lock);
222
223 rtc1_write(RTCL1LREG, count);
224 rtc1_write(RTCL1HREG, count >> 16);
225
226 spin_unlock_irq(&rtc_lock);
227
228 return 0;
229 }
230
231 static int vr41xx_rtc_irq_set_state(struct device *dev, int enabled)
232 {
233 if (enabled)
234 enable_irq(pie_irq);
235 else
236 disable_irq(pie_irq);
237
238 return 0;
239 }
240
241 static int vr41xx_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
242 {
243 switch (cmd) {
244 case RTC_AIE_ON:
245 spin_lock_irq(&rtc_lock);
246
247 if (!alarm_enabled) {
248 enable_irq(aie_irq);
249 alarm_enabled = 1;
250 }
251
252 spin_unlock_irq(&rtc_lock);
253 break;
254 case RTC_AIE_OFF:
255 spin_lock_irq(&rtc_lock);
256
257 if (alarm_enabled) {
258 disable_irq(aie_irq);
259 alarm_enabled = 0;
260 }
261
262 spin_unlock_irq(&rtc_lock);
263 break;
264 case RTC_EPOCH_READ:
265 return put_user(epoch, (unsigned long __user *)arg);
266 case RTC_EPOCH_SET:
267 /* Doesn't support before 1900 */
268 if (arg < 1900)
269 return -EINVAL;
270 epoch = arg;
271 break;
272 default:
273 return -ENOIOCTLCMD;
274 }
275
276 return 0;
277 }
278
279 static irqreturn_t elapsedtime_interrupt(int irq, void *dev_id)
280 {
281 struct platform_device *pdev = (struct platform_device *)dev_id;
282 struct rtc_device *rtc = platform_get_drvdata(pdev);
283
284 rtc2_write(RTCINTREG, ELAPSEDTIME_INT);
285
286 rtc_update_irq(rtc, 1, RTC_AF);
287
288 return IRQ_HANDLED;
289 }
290
291 static irqreturn_t rtclong1_interrupt(int irq, void *dev_id)
292 {
293 struct platform_device *pdev = (struct platform_device *)dev_id;
294 struct rtc_device *rtc = platform_get_drvdata(pdev);
295 unsigned long count = periodic_count;
296
297 rtc2_write(RTCINTREG, RTCLONG1_INT);
298
299 rtc1_write(RTCL1LREG, count);
300 rtc1_write(RTCL1HREG, count >> 16);
301
302 rtc_update_irq(rtc, 1, RTC_PF);
303
304 return IRQ_HANDLED;
305 }
306
307 static const struct rtc_class_ops vr41xx_rtc_ops = {
308 .release = vr41xx_rtc_release,
309 .ioctl = vr41xx_rtc_ioctl,
310 .read_time = vr41xx_rtc_read_time,
311 .set_time = vr41xx_rtc_set_time,
312 .read_alarm = vr41xx_rtc_read_alarm,
313 .set_alarm = vr41xx_rtc_set_alarm,
314 .irq_set_freq = vr41xx_rtc_irq_set_freq,
315 .irq_set_state = vr41xx_rtc_irq_set_state,
316 };
317
318 static int __devinit rtc_probe(struct platform_device *pdev)
319 {
320 struct resource *res;
321 struct rtc_device *rtc;
322 int retval;
323
324 if (pdev->num_resources != 4)
325 return -EBUSY;
326
327 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
328 if (!res)
329 return -EBUSY;
330
331 rtc1_base = ioremap(res->start, res->end - res->start + 1);
332 if (!rtc1_base)
333 return -EBUSY;
334
335 res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
336 if (!res) {
337 retval = -EBUSY;
338 goto err_rtc1_iounmap;
339 }
340
341 rtc2_base = ioremap(res->start, res->end - res->start + 1);
342 if (!rtc2_base) {
343 retval = -EBUSY;
344 goto err_rtc1_iounmap;
345 }
346
347 rtc = rtc_device_register(rtc_name, &pdev->dev, &vr41xx_rtc_ops, THIS_MODULE);
348 if (IS_ERR(rtc)) {
349 retval = PTR_ERR(rtc);
350 goto err_iounmap_all;
351 }
352
353 rtc->max_user_freq = MAX_PERIODIC_RATE;
354
355 spin_lock_irq(&rtc_lock);
356
357 rtc1_write(ECMPLREG, 0);
358 rtc1_write(ECMPMREG, 0);
359 rtc1_write(ECMPHREG, 0);
360 rtc1_write(RTCL1LREG, 0);
361 rtc1_write(RTCL1HREG, 0);
362
363 spin_unlock_irq(&rtc_lock);
364
365 aie_irq = platform_get_irq(pdev, 0);
366 if (aie_irq <= 0) {
367 retval = -EBUSY;
368 goto err_device_unregister;
369 }
370
371 retval = request_irq(aie_irq, elapsedtime_interrupt, IRQF_DISABLED,
372 "elapsed_time", pdev);
373 if (retval < 0)
374 goto err_device_unregister;
375
376 pie_irq = platform_get_irq(pdev, 1);
377 if (pie_irq <= 0)
378 goto err_free_irq;
379
380 retval = request_irq(pie_irq, rtclong1_interrupt, IRQF_DISABLED,
381 "rtclong1", pdev);
382 if (retval < 0)
383 goto err_free_irq;
384
385 platform_set_drvdata(pdev, rtc);
386
387 disable_irq(aie_irq);
388 disable_irq(pie_irq);
389
390 printk(KERN_INFO "rtc: Real Time Clock of NEC VR4100 series\n");
391
392 return 0;
393
394 err_free_irq:
395 free_irq(aie_irq, pdev);
396
397 err_device_unregister:
398 rtc_device_unregister(rtc);
399
400 err_iounmap_all:
401 iounmap(rtc2_base);
402 rtc2_base = NULL;
403
404 err_rtc1_iounmap:
405 iounmap(rtc1_base);
406 rtc1_base = NULL;
407
408 return retval;
409 }
410
411 static int __devexit rtc_remove(struct platform_device *pdev)
412 {
413 struct rtc_device *rtc;
414
415 rtc = platform_get_drvdata(pdev);
416 if (rtc)
417 rtc_device_unregister(rtc);
418
419 platform_set_drvdata(pdev, NULL);
420
421 free_irq(aie_irq, pdev);
422 free_irq(pie_irq, pdev);
423 if (rtc1_base)
424 iounmap(rtc1_base);
425 if (rtc2_base)
426 iounmap(rtc2_base);
427
428 return 0;
429 }
430
431 /* work with hotplug and coldplug */
432 MODULE_ALIAS("platform:RTC");
433
434 static struct platform_driver rtc_platform_driver = {
435 .probe = rtc_probe,
436 .remove = __devexit_p(rtc_remove),
437 .driver = {
438 .name = rtc_name,
439 .owner = THIS_MODULE,
440 },
441 };
442
443 static int __init vr41xx_rtc_init(void)
444 {
445 return platform_driver_register(&rtc_platform_driver);
446 }
447
448 static void __exit vr41xx_rtc_exit(void)
449 {
450 platform_driver_unregister(&rtc_platform_driver);
451 }
452
453 module_init(vr41xx_rtc_init);
454 module_exit(vr41xx_rtc_exit);
455
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