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Linux/drivers/rtc/rtc-vr41xx.c

  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/io.h>
 24 #include <linux/ioport.h>
 25 #include <linux/interrupt.h>
 26 #include <linux/module.h>
 27 #include <linux/platform_device.h>
 28 #include <linux/rtc.h>
 29 #include <linux/spinlock.h>
 30 #include <linux/types.h>
 31 #include <linux/uaccess.h>
 32 #include <linux/log2.h>
 33 
 34 #include <asm/div64.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_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
211 {
212         switch (cmd) {
213         case RTC_EPOCH_READ:
214                 return put_user(epoch, (unsigned long __user *)arg);
215         case RTC_EPOCH_SET:
216                 /* Doesn't support before 1900 */
217                 if (arg < 1900)
218                         return -EINVAL;
219                 epoch = arg;
220                 break;
221         default:
222                 return -ENOIOCTLCMD;
223         }
224 
225         return 0;
226 }
227 
228 static int vr41xx_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
229 {
230         spin_lock_irq(&rtc_lock);
231         if (enabled) {
232                 if (!alarm_enabled) {
233                         enable_irq(aie_irq);
234                         alarm_enabled = 1;
235                 }
236         } else {
237                 if (alarm_enabled) {
238                         disable_irq(aie_irq);
239                         alarm_enabled = 0;
240                 }
241         }
242         spin_unlock_irq(&rtc_lock);
243         return 0;
244 }
245 
246 static irqreturn_t elapsedtime_interrupt(int irq, void *dev_id)
247 {
248         struct platform_device *pdev = (struct platform_device *)dev_id;
249         struct rtc_device *rtc = platform_get_drvdata(pdev);
250 
251         rtc2_write(RTCINTREG, ELAPSEDTIME_INT);
252 
253         rtc_update_irq(rtc, 1, RTC_AF);
254 
255         return IRQ_HANDLED;
256 }
257 
258 static irqreturn_t rtclong1_interrupt(int irq, void *dev_id)
259 {
260         struct platform_device *pdev = (struct platform_device *)dev_id;
261         struct rtc_device *rtc = platform_get_drvdata(pdev);
262         unsigned long count = periodic_count;
263 
264         rtc2_write(RTCINTREG, RTCLONG1_INT);
265 
266         rtc1_write(RTCL1LREG, count);
267         rtc1_write(RTCL1HREG, count >> 16);
268 
269         rtc_update_irq(rtc, 1, RTC_PF);
270 
271         return IRQ_HANDLED;
272 }
273 
274 static const struct rtc_class_ops vr41xx_rtc_ops = {
275         .release        = vr41xx_rtc_release,
276         .ioctl          = vr41xx_rtc_ioctl,
277         .read_time      = vr41xx_rtc_read_time,
278         .set_time       = vr41xx_rtc_set_time,
279         .read_alarm     = vr41xx_rtc_read_alarm,
280         .set_alarm      = vr41xx_rtc_set_alarm,
281 };
282 
283 static int rtc_probe(struct platform_device *pdev)
284 {
285         struct resource *res;
286         struct rtc_device *rtc;
287         int retval;
288 
289         if (pdev->num_resources != 4)
290                 return -EBUSY;
291 
292         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
293         if (!res)
294                 return -EBUSY;
295 
296         rtc1_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
297         if (!rtc1_base)
298                 return -EBUSY;
299 
300         res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
301         if (!res) {
302                 retval = -EBUSY;
303                 goto err_rtc1_iounmap;
304         }
305 
306         rtc2_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
307         if (!rtc2_base) {
308                 retval = -EBUSY;
309                 goto err_rtc1_iounmap;
310         }
311 
312         rtc = devm_rtc_device_register(&pdev->dev, rtc_name, &vr41xx_rtc_ops,
313                                         THIS_MODULE);
314         if (IS_ERR(rtc)) {
315                 retval = PTR_ERR(rtc);
316                 goto err_iounmap_all;
317         }
318 
319         rtc->max_user_freq = MAX_PERIODIC_RATE;
320 
321         spin_lock_irq(&rtc_lock);
322 
323         rtc1_write(ECMPLREG, 0);
324         rtc1_write(ECMPMREG, 0);
325         rtc1_write(ECMPHREG, 0);
326         rtc1_write(RTCL1LREG, 0);
327         rtc1_write(RTCL1HREG, 0);
328 
329         spin_unlock_irq(&rtc_lock);
330 
331         aie_irq = platform_get_irq(pdev, 0);
332         if (aie_irq <= 0) {
333                 retval = -EBUSY;
334                 goto err_iounmap_all;
335         }
336 
337         retval = devm_request_irq(&pdev->dev, aie_irq, elapsedtime_interrupt, 0,
338                                 "elapsed_time", pdev);
339         if (retval < 0)
340                 goto err_iounmap_all;
341 
342         pie_irq = platform_get_irq(pdev, 1);
343         if (pie_irq <= 0) {
344                 retval = -EBUSY;
345                 goto err_iounmap_all;
346         }
347 
348         retval = devm_request_irq(&pdev->dev, pie_irq, rtclong1_interrupt, 0,
349                                 "rtclong1", pdev);
350         if (retval < 0)
351                 goto err_iounmap_all;
352 
353         platform_set_drvdata(pdev, rtc);
354 
355         disable_irq(aie_irq);
356         disable_irq(pie_irq);
357 
358         dev_info(&pdev->dev, "Real Time Clock of NEC VR4100 series\n");
359 
360         return 0;
361 
362 err_iounmap_all:
363         rtc2_base = NULL;
364 
365 err_rtc1_iounmap:
366         rtc1_base = NULL;
367 
368         return retval;
369 }
370 
371 /* work with hotplug and coldplug */
372 MODULE_ALIAS("platform:RTC");
373 
374 static struct platform_driver rtc_platform_driver = {
375         .probe          = rtc_probe,
376         .driver         = {
377                 .name   = rtc_name,
378                 .owner  = THIS_MODULE,
379         },
380 };
381 
382 module_platform_driver(rtc_platform_driver);
383 

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