Root/include/asm-generic/rtc.h

1/*
2 * include/asm-generic/rtc.h
3 *
4 * Author: Tom Rini <trini@mvista.com>
5 *
6 * Based on:
7 * drivers/char/rtc.c
8 *
9 * Please read the COPYING file for all license details.
10 */
11
12#ifndef __ASM_RTC_H__
13#define __ASM_RTC_H__
14
15#include <linux/mc146818rtc.h>
16#include <linux/rtc.h>
17#include <linux/bcd.h>
18#include <linux/delay.h>
19
20#define RTC_PIE 0x40 /* periodic interrupt enable */
21#define RTC_AIE 0x20 /* alarm interrupt enable */
22#define RTC_UIE 0x10 /* update-finished interrupt enable */
23
24/* some dummy definitions */
25#define RTC_BATT_BAD 0x100 /* battery bad */
26#define RTC_SQWE 0x08 /* enable square-wave output */
27#define RTC_DM_BINARY 0x04 /* all time/date values are BCD if clear */
28#define RTC_24H 0x02 /* 24 hour mode - else hours bit 7 means pm */
29#define RTC_DST_EN 0x01 /* auto switch DST - works f. USA only */
30
31/*
32 * Returns true if a clock update is in progress
33 */
34static inline unsigned char rtc_is_updating(void)
35{
36    unsigned char uip;
37    unsigned long flags;
38
39    spin_lock_irqsave(&rtc_lock, flags);
40    uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
41    spin_unlock_irqrestore(&rtc_lock, flags);
42    return uip;
43}
44
45static inline unsigned int __get_rtc_time(struct rtc_time *time)
46{
47    unsigned char ctrl;
48    unsigned long flags;
49
50#ifdef CONFIG_MACH_DECSTATION
51    unsigned int real_year;
52#endif
53
54    /*
55     * read RTC once any update in progress is done. The update
56     * can take just over 2ms. We wait 20ms. There is no need to
57     * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
58     * If you need to know *exactly* when a second has started, enable
59     * periodic update complete interrupts, (via ioctl) and then
60     * immediately read /dev/rtc which will block until you get the IRQ.
61     * Once the read clears, read the RTC time (again via ioctl). Easy.
62     */
63    if (rtc_is_updating())
64        mdelay(20);
65
66    /*
67     * Only the values that we read from the RTC are set. We leave
68     * tm_wday, tm_yday and tm_isdst untouched. Even though the
69     * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
70     * by the RTC when initially set to a non-zero value.
71     */
72    spin_lock_irqsave(&rtc_lock, flags);
73    time->tm_sec = CMOS_READ(RTC_SECONDS);
74    time->tm_min = CMOS_READ(RTC_MINUTES);
75    time->tm_hour = CMOS_READ(RTC_HOURS);
76    time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
77    time->tm_mon = CMOS_READ(RTC_MONTH);
78    time->tm_year = CMOS_READ(RTC_YEAR);
79#ifdef CONFIG_MACH_DECSTATION
80    real_year = CMOS_READ(RTC_DEC_YEAR);
81#endif
82    ctrl = CMOS_READ(RTC_CONTROL);
83    spin_unlock_irqrestore(&rtc_lock, flags);
84
85    if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
86    {
87        time->tm_sec = bcd2bin(time->tm_sec);
88        time->tm_min = bcd2bin(time->tm_min);
89        time->tm_hour = bcd2bin(time->tm_hour);
90        time->tm_mday = bcd2bin(time->tm_mday);
91        time->tm_mon = bcd2bin(time->tm_mon);
92        time->tm_year = bcd2bin(time->tm_year);
93    }
94
95#ifdef CONFIG_MACH_DECSTATION
96    time->tm_year += real_year - 72;
97#endif
98
99    /*
100     * Account for differences between how the RTC uses the values
101     * and how they are defined in a struct rtc_time;
102     */
103    if (time->tm_year <= 69)
104        time->tm_year += 100;
105
106    time->tm_mon--;
107
108    return RTC_24H;
109}
110
111#ifndef get_rtc_time
112#define get_rtc_time __get_rtc_time
113#endif
114
115/* Set the current date and time in the real time clock. */
116static inline int __set_rtc_time(struct rtc_time *time)
117{
118    unsigned long flags;
119    unsigned char mon, day, hrs, min, sec;
120    unsigned char save_control, save_freq_select;
121    unsigned int yrs;
122#ifdef CONFIG_MACH_DECSTATION
123    unsigned int real_yrs, leap_yr;
124#endif
125
126    yrs = time->tm_year;
127    mon = time->tm_mon + 1; /* tm_mon starts at zero */
128    day = time->tm_mday;
129    hrs = time->tm_hour;
130    min = time->tm_min;
131    sec = time->tm_sec;
132
133    if (yrs > 255) /* They are unsigned */
134        return -EINVAL;
135
136    spin_lock_irqsave(&rtc_lock, flags);
137#ifdef CONFIG_MACH_DECSTATION
138    real_yrs = yrs;
139    leap_yr = ((!((yrs + 1900) % 4) && ((yrs + 1900) % 100)) ||
140            !((yrs + 1900) % 400));
141    yrs = 72;
142
143    /*
144     * We want to keep the year set to 73 until March
145     * for non-leap years, so that Feb, 29th is handled
146     * correctly.
147     */
148    if (!leap_yr && mon < 3) {
149        real_yrs--;
150        yrs = 73;
151    }
152#endif
153    /* These limits and adjustments are independent of
154     * whether the chip is in binary mode or not.
155     */
156    if (yrs > 169) {
157        spin_unlock_irqrestore(&rtc_lock, flags);
158        return -EINVAL;
159    }
160
161    if (yrs >= 100)
162        yrs -= 100;
163
164    if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
165        || RTC_ALWAYS_BCD) {
166        sec = bin2bcd(sec);
167        min = bin2bcd(min);
168        hrs = bin2bcd(hrs);
169        day = bin2bcd(day);
170        mon = bin2bcd(mon);
171        yrs = bin2bcd(yrs);
172    }
173
174    save_control = CMOS_READ(RTC_CONTROL);
175    CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
176    save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
177    CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
178
179#ifdef CONFIG_MACH_DECSTATION
180    CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
181#endif
182    CMOS_WRITE(yrs, RTC_YEAR);
183    CMOS_WRITE(mon, RTC_MONTH);
184    CMOS_WRITE(day, RTC_DAY_OF_MONTH);
185    CMOS_WRITE(hrs, RTC_HOURS);
186    CMOS_WRITE(min, RTC_MINUTES);
187    CMOS_WRITE(sec, RTC_SECONDS);
188
189    CMOS_WRITE(save_control, RTC_CONTROL);
190    CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
191
192    spin_unlock_irqrestore(&rtc_lock, flags);
193
194    return 0;
195}
196
197#ifndef set_rtc_time
198#define set_rtc_time __set_rtc_time
199#endif
200
201static inline unsigned int get_rtc_ss(void)
202{
203    struct rtc_time h;
204
205    get_rtc_time(&h);
206    return h.tm_sec;
207}
208
209static inline int get_rtc_pll(struct rtc_pll_info *pll)
210{
211    return -EINVAL;
212}
213static inline int set_rtc_pll(struct rtc_pll_info *pll)
214{
215    return -EINVAL;
216}
217
218#endif /* __ASM_RTC_H__ */
219

Archive Download this file



interactive