2 * Driver for NEC VR4100 series Real Time Clock unit.
4 * Copyright (C) 2003-2008 Yoichi Yuasa <yuasa@linux-mips.org>
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.
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.
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
20 #include <linux/err.h>
22 #include <linux/init.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>
34 #include <asm/div64.h>
36 MODULE_AUTHOR("Yoichi Yuasa <yuasa@linux-mips.org>");
37 MODULE_DESCRIPTION("NEC VR4100 series RTC driver");
38 MODULE_LICENSE("GPL v2");
41 #define ETIMELREG 0x00
42 #define ETIMEMREG 0x02
43 #define ETIMEHREG 0x04
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
61 #define TCLKCNTLREG 0x04
62 #define TCLKCNTHREG 0x06
64 #define RTCINTREG 0x1e
65 #define TCLOCK_INT 0x08
66 #define RTCLONG2_INT 0x04
67 #define RTCLONG1_INT 0x02
68 #define ELAPSEDTIME_INT 0x01
70 #define RTC_FREQUENCY 32768
71 #define MAX_PERIODIC_RATE 6553
73 static void __iomem
*rtc1_base
;
74 static void __iomem
*rtc2_base
;
76 #define rtc1_read(offset) readw(rtc1_base + (offset))
77 #define rtc1_write(offset, value) writew((value), rtc1_base + (offset))
79 #define rtc2_read(offset) readw(rtc2_base + (offset))
80 #define rtc2_write(offset, value) writew((value), rtc2_base + (offset))
82 static unsigned long epoch
= 1970; /* Jan 1 1970 00:00:00 */
84 static DEFINE_SPINLOCK(rtc_lock
);
85 static char rtc_name
[] = "RTC";
86 static unsigned long periodic_count
;
87 static unsigned int alarm_enabled
;
91 static inline time64_t
read_elapsed_second(void)
94 unsigned long first_low
, first_mid
, first_high
;
96 unsigned long second_low
, second_mid
, second_high
;
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
);
108 return ((u64
)first_high
<< 17) | (first_mid
<< 1) | (first_low
>> 15);
111 static inline void write_elapsed_second(time64_t sec
)
113 spin_lock_irq(&rtc_lock
);
115 rtc1_write(ETIMELREG
, (uint16_t)(sec
<< 15));
116 rtc1_write(ETIMEMREG
, (uint16_t)(sec
>> 1));
117 rtc1_write(ETIMEHREG
, (uint16_t)(sec
>> 17));
119 spin_unlock_irq(&rtc_lock
);
122 static int vr41xx_rtc_read_time(struct device
*dev
, struct rtc_time
*time
)
124 time64_t epoch_sec
, elapsed_sec
;
126 epoch_sec
= mktime64(epoch
, 1, 1, 0, 0, 0);
127 elapsed_sec
= read_elapsed_second();
129 rtc_time64_to_tm(epoch_sec
+ elapsed_sec
, time
);
134 static int vr41xx_rtc_set_time(struct device
*dev
, struct rtc_time
*time
)
136 time64_t epoch_sec
, current_sec
;
138 epoch_sec
= mktime64(epoch
, 1, 1, 0, 0, 0);
139 current_sec
= mktime64(time
->tm_year
+ 1900, time
->tm_mon
+ 1, time
->tm_mday
,
140 time
->tm_hour
, time
->tm_min
, time
->tm_sec
);
142 write_elapsed_second(current_sec
- epoch_sec
);
147 static int vr41xx_rtc_read_alarm(struct device
*dev
, struct rtc_wkalrm
*wkalrm
)
149 unsigned long low
, mid
, high
;
150 struct rtc_time
*time
= &wkalrm
->time
;
152 spin_lock_irq(&rtc_lock
);
154 low
= rtc1_read(ECMPLREG
);
155 mid
= rtc1_read(ECMPMREG
);
156 high
= rtc1_read(ECMPHREG
);
157 wkalrm
->enabled
= alarm_enabled
;
159 spin_unlock_irq(&rtc_lock
);
161 rtc_time_to_tm((high
<< 17) | (mid
<< 1) | (low
>> 15), time
);
166 static int vr41xx_rtc_set_alarm(struct device
*dev
, struct rtc_wkalrm
*wkalrm
)
169 struct rtc_time
*time
= &wkalrm
->time
;
171 alarm_sec
= mktime64(time
->tm_year
+ 1900, time
->tm_mon
+ 1, time
->tm_mday
,
172 time
->tm_hour
, time
->tm_min
, time
->tm_sec
);
174 spin_lock_irq(&rtc_lock
);
177 disable_irq(aie_irq
);
179 rtc1_write(ECMPLREG
, (uint16_t)(alarm_sec
<< 15));
180 rtc1_write(ECMPMREG
, (uint16_t)(alarm_sec
>> 1));
181 rtc1_write(ECMPHREG
, (uint16_t)(alarm_sec
>> 17));
186 alarm_enabled
= wkalrm
->enabled
;
188 spin_unlock_irq(&rtc_lock
);
193 static int vr41xx_rtc_ioctl(struct device
*dev
, unsigned int cmd
, unsigned long arg
)
197 return put_user(epoch
, (unsigned long __user
*)arg
);
199 /* Doesn't support before 1900 */
211 static int vr41xx_rtc_alarm_irq_enable(struct device
*dev
, unsigned int enabled
)
213 spin_lock_irq(&rtc_lock
);
215 if (!alarm_enabled
) {
221 disable_irq(aie_irq
);
225 spin_unlock_irq(&rtc_lock
);
229 static irqreturn_t
elapsedtime_interrupt(int irq
, void *dev_id
)
231 struct platform_device
*pdev
= (struct platform_device
*)dev_id
;
232 struct rtc_device
*rtc
= platform_get_drvdata(pdev
);
234 rtc2_write(RTCINTREG
, ELAPSEDTIME_INT
);
236 rtc_update_irq(rtc
, 1, RTC_AF
);
241 static irqreturn_t
rtclong1_interrupt(int irq
, void *dev_id
)
243 struct platform_device
*pdev
= (struct platform_device
*)dev_id
;
244 struct rtc_device
*rtc
= platform_get_drvdata(pdev
);
245 unsigned long count
= periodic_count
;
247 rtc2_write(RTCINTREG
, RTCLONG1_INT
);
249 rtc1_write(RTCL1LREG
, count
);
250 rtc1_write(RTCL1HREG
, count
>> 16);
252 rtc_update_irq(rtc
, 1, RTC_PF
);
257 static const struct rtc_class_ops vr41xx_rtc_ops
= {
258 .ioctl
= vr41xx_rtc_ioctl
,
259 .read_time
= vr41xx_rtc_read_time
,
260 .set_time
= vr41xx_rtc_set_time
,
261 .read_alarm
= vr41xx_rtc_read_alarm
,
262 .set_alarm
= vr41xx_rtc_set_alarm
,
263 .alarm_irq_enable
= vr41xx_rtc_alarm_irq_enable
,
266 static int rtc_probe(struct platform_device
*pdev
)
268 struct resource
*res
;
269 struct rtc_device
*rtc
;
272 if (pdev
->num_resources
!= 4)
275 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
279 rtc1_base
= devm_ioremap(&pdev
->dev
, res
->start
, resource_size(res
));
283 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 1);
286 goto err_rtc1_iounmap
;
289 rtc2_base
= devm_ioremap(&pdev
->dev
, res
->start
, resource_size(res
));
292 goto err_rtc1_iounmap
;
295 rtc
= devm_rtc_allocate_device(&pdev
->dev
);
297 retval
= PTR_ERR(rtc
);
298 goto err_iounmap_all
;
301 rtc
->ops
= &vr41xx_rtc_ops
;
303 /* 48-bit counter at 32.768 kHz */
304 rtc
->range_max
= (1ULL << 33) - 1;
305 rtc
->max_user_freq
= MAX_PERIODIC_RATE
;
307 spin_lock_irq(&rtc_lock
);
309 rtc1_write(ECMPLREG
, 0);
310 rtc1_write(ECMPMREG
, 0);
311 rtc1_write(ECMPHREG
, 0);
312 rtc1_write(RTCL1LREG
, 0);
313 rtc1_write(RTCL1HREG
, 0);
315 spin_unlock_irq(&rtc_lock
);
317 aie_irq
= platform_get_irq(pdev
, 0);
320 goto err_iounmap_all
;
323 retval
= devm_request_irq(&pdev
->dev
, aie_irq
, elapsedtime_interrupt
, 0,
324 "elapsed_time", pdev
);
326 goto err_iounmap_all
;
328 pie_irq
= platform_get_irq(pdev
, 1);
331 goto err_iounmap_all
;
334 retval
= devm_request_irq(&pdev
->dev
, pie_irq
, rtclong1_interrupt
, 0,
337 goto err_iounmap_all
;
339 platform_set_drvdata(pdev
, rtc
);
341 disable_irq(aie_irq
);
342 disable_irq(pie_irq
);
344 dev_info(&pdev
->dev
, "Real Time Clock of NEC VR4100 series\n");
346 retval
= rtc_register_device(rtc
);
348 goto err_iounmap_all
;
361 /* work with hotplug and coldplug */
362 MODULE_ALIAS("platform:RTC");
364 static struct platform_driver rtc_platform_driver
= {
371 module_platform_driver(rtc_platform_driver
);