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__ */