[linux.git] / drivers / rtc / rtc-mc146818-lib.c

#include <linux/bcd.h>
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/mc146818rtc.h>

#ifdef CONFIG_ACPI
#include <linux/acpi.h>
#endif

/*
 * Returns true if a clock update is in progress
 */
static inline unsigned char mc146818_is_updating(void)
{
	unsigned char uip;
	unsigned long flags;

	spin_lock_irqsave(&rtc_lock, flags);
	uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
	spin_unlock_irqrestore(&rtc_lock, flags);
	return uip;
}

unsigned int mc146818_get_time(struct rtc_time *time)
{
	unsigned char ctrl;
	unsigned long flags;
	unsigned char century = 0;

#ifdef CONFIG_MACH_DECSTATION
	unsigned int real_year;
#endif

	/*
	 * read RTC once any update in progress is done. The update
	 * can take just over 2ms. We wait 20ms. There is no need to
	 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
	 * If you need to know *exactly* when a second has started, enable
	 * periodic update complete interrupts, (via ioctl) and then
	 * immediately read /dev/rtc which will block until you get the IRQ.
	 * Once the read clears, read the RTC time (again via ioctl). Easy.
	 */
	if (mc146818_is_updating())
		mdelay(20);

	/*
	 * Only the values that we read from the RTC are set. We leave
	 * tm_wday, tm_yday and tm_isdst untouched. Even though the
	 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
	 * by the RTC when initially set to a non-zero value.
	 */
	spin_lock_irqsave(&rtc_lock, flags);
	time->tm_sec = CMOS_READ(RTC_SECONDS);
	time->tm_min = CMOS_READ(RTC_MINUTES);
	time->tm_hour = CMOS_READ(RTC_HOURS);
	time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
	time->tm_mon = CMOS_READ(RTC_MONTH);
	time->tm_year = CMOS_READ(RTC_YEAR);
#ifdef CONFIG_MACH_DECSTATION
	real_year = CMOS_READ(RTC_DEC_YEAR);
#endif
#ifdef CONFIG_ACPI
	if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
	    acpi_gbl_FADT.century)
		century = CMOS_READ(acpi_gbl_FADT.century);
#endif
	ctrl = CMOS_READ(RTC_CONTROL);
	spin_unlock_irqrestore(&rtc_lock, flags);

	if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
	{
		time->tm_sec = bcd2bin(time->tm_sec);
		time->tm_min = bcd2bin(time->tm_min);
		time->tm_hour = bcd2bin(time->tm_hour);
		time->tm_mday = bcd2bin(time->tm_mday);
		time->tm_mon = bcd2bin(time->tm_mon);
		time->tm_year = bcd2bin(time->tm_year);
		century = bcd2bin(century);
	}

#ifdef CONFIG_MACH_DECSTATION
	time->tm_year += real_year - 72;
#endif

	if (century)
		time->tm_year += (century - 19) * 100;

	/*
	 * Account for differences between how the RTC uses the values
	 * and how they are defined in a struct rtc_time;
	 */
	if (time->tm_year <= 69)
		time->tm_year += 100;

	time->tm_mon--;

	return RTC_24H;
}
EXPORT_SYMBOL_GPL(mc146818_get_time);

/* Set the current date and time in the real time clock. */
int mc146818_set_time(struct rtc_time *time)
{
	unsigned long flags;
	unsigned char mon, day, hrs, min, sec;
	unsigned char save_control, save_freq_select;
	unsigned int yrs;
#ifdef CONFIG_MACH_DECSTATION
	unsigned int real_yrs, leap_yr;
#endif
	unsigned char century = 0;

	yrs = time->tm_year;
	mon = time->tm_mon + 1;   /* tm_mon starts at zero */
	day = time->tm_mday;
	hrs = time->tm_hour;
	min = time->tm_min;
	sec = time->tm_sec;

	if (yrs > 255)	/* They are unsigned */
		return -EINVAL;

	spin_lock_irqsave(&rtc_lock, flags);
#ifdef CONFIG_MACH_DECSTATION
	real_yrs = yrs;
	leap_yr = ((!((yrs + 1900) % 4) && ((yrs + 1900) % 100)) ||
			!((yrs + 1900) % 400));
	yrs = 72;

	/*
	 * We want to keep the year set to 73 until March
	 * for non-leap years, so that Feb, 29th is handled
	 * correctly.
	 */
	if (!leap_yr && mon < 3) {
		real_yrs--;
		yrs = 73;
	}
#endif

#ifdef CONFIG_ACPI
	if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
	    acpi_gbl_FADT.century) {
		century = (yrs + 1900) / 100;
		yrs %= 100;
	}
#endif

	/* These limits and adjustments are independent of
	 * whether the chip is in binary mode or not.
	 */
	if (yrs > 169) {
		spin_unlock_irqrestore(&rtc_lock, flags);
		return -EINVAL;
	}

	if (yrs >= 100)
		yrs -= 100;

	if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
	    || RTC_ALWAYS_BCD) {
		sec = bin2bcd(sec);
		min = bin2bcd(min);
		hrs = bin2bcd(hrs);
		day = bin2bcd(day);
		mon = bin2bcd(mon);
		yrs = bin2bcd(yrs);
		century = bin2bcd(century);
	}

	save_control = CMOS_READ(RTC_CONTROL);
	CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
	save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
	CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);

#ifdef CONFIG_MACH_DECSTATION
	CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
#endif
	CMOS_WRITE(yrs, RTC_YEAR);
	CMOS_WRITE(mon, RTC_MONTH);
	CMOS_WRITE(day, RTC_DAY_OF_MONTH);
	CMOS_WRITE(hrs, RTC_HOURS);
	CMOS_WRITE(min, RTC_MINUTES);
	CMOS_WRITE(sec, RTC_SECONDS);
#ifdef CONFIG_ACPI
	if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
	    acpi_gbl_FADT.century)
		CMOS_WRITE(century, acpi_gbl_FADT.century);
#endif

	CMOS_WRITE(save_control, RTC_CONTROL);
	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);

	spin_unlock_irqrestore(&rtc_lock, flags);

	return 0;
}
EXPORT_SYMBOL_GPL(mc146818_set_time);
Commit	Line	Data
d6faca40 AB	1	#include <linux/bcd.h>
	2	#include <linux/delay.h>
	3	#include <linux/export.h>
	4	#include <linux/mc146818rtc.h>
	5
	6	#ifdef CONFIG_ACPI
	7	#include <linux/acpi.h>
	8	#endif
	9
	10	/*
	11	* Returns true if a clock update is in progress
	12	*/
	13	static inline unsigned char mc146818_is_updating(void)
	14	{
	15	unsigned char uip;
	16	unsigned long flags;
	17
	18	spin_lock_irqsave(&rtc_lock, flags);
	19	uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
	20	spin_unlock_irqrestore(&rtc_lock, flags);
	21	return uip;
	22	}
	23
	24	unsigned int mc146818_get_time(struct rtc_time *time)
	25	{
	26	unsigned char ctrl;
	27	unsigned long flags;
	28	unsigned char century = 0;
	29
	30	#ifdef CONFIG_MACH_DECSTATION
	31	unsigned int real_year;
	32	#endif
	33
	34	/*
	35	* read RTC once any update in progress is done. The update
	36	* can take just over 2ms. We wait 20ms. There is no need to
	37	* to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
	38	* If you need to know exactly when a second has started, enable
	39	* periodic update complete interrupts, (via ioctl) and then
	40	* immediately read /dev/rtc which will block until you get the IRQ.
	41	* Once the read clears, read the RTC time (again via ioctl). Easy.
	42	*/
	43	if (mc146818_is_updating())
	44	mdelay(20);
	45
	46	/*
	47	* Only the values that we read from the RTC are set. We leave
	48	* tm_wday, tm_yday and tm_isdst untouched. Even though the
	49	* RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
	50	* by the RTC when initially set to a non-zero value.
	51	*/
	52	spin_lock_irqsave(&rtc_lock, flags);
	53	time->tm_sec = CMOS_READ(RTC_SECONDS);
	54	time->tm_min = CMOS_READ(RTC_MINUTES);
	55	time->tm_hour = CMOS_READ(RTC_HOURS);
	56	time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
	57	time->tm_mon = CMOS_READ(RTC_MONTH);
	58	time->tm_year = CMOS_READ(RTC_YEAR);
	59	#ifdef CONFIG_MACH_DECSTATION
	60	real_year = CMOS_READ(RTC_DEC_YEAR);
	61	#endif
	62	#ifdef CONFIG_ACPI
	63	if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
	64	acpi_gbl_FADT.century)
65	century = CMOS_READ(acpi_gbl_FADT.century);
66	#endif
67	ctrl = CMOS_READ(RTC_CONTROL);
68	spin_unlock_irqrestore(&rtc_lock, flags);
69
70	if (!(ctrl & RTC_DM_BINARY) \|\| RTC_ALWAYS_BCD)
71	{
72	time->tm_sec = bcd2bin(time->tm_sec);
73	time->tm_min = bcd2bin(time->tm_min);
74	time->tm_hour = bcd2bin(time->tm_hour);
75	time->tm_mday = bcd2bin(time->tm_mday);
76	time->tm_mon = bcd2bin(time->tm_mon);
77	time->tm_year = bcd2bin(time->tm_year);
78	century = bcd2bin(century);
79	}
80
81	#ifdef CONFIG_MACH_DECSTATION
82	time->tm_year += real_year - 72;
83	#endif
84
85	if (century)
86	time->tm_year += (century - 19) * 100;
87
88	/*
89	* Account for differences between how the RTC uses the values
90	* and how they are defined in a struct rtc_time;
91	*/
92	if (time->tm_year <= 69)
93	time->tm_year += 100;
94
95	time->tm_mon--;
96
97	return RTC_24H;
98	}
99	EXPORT_SYMBOL_GPL(mc146818_get_time);
100
101	/* Set the current date and time in the real time clock. */
102	int mc146818_set_time(struct rtc_time *time)
103	{
104	unsigned long flags;
105	unsigned char mon, day, hrs, min, sec;
106	unsigned char save_control, save_freq_select;
107	unsigned int yrs;
108	#ifdef CONFIG_MACH_DECSTATION
109	unsigned int real_yrs, leap_yr;
110	#endif
111	unsigned char century = 0;
112
113	yrs = time->tm_year;
114	mon = time->tm_mon + 1; /* tm_mon starts at zero */
115	day = time->tm_mday;
116	hrs = time->tm_hour;
117	min = time->tm_min;
118	sec = time->tm_sec;
119
120	if (yrs > 255) /* They are unsigned */
121	return -EINVAL;
122
123	spin_lock_irqsave(&rtc_lock, flags);
124	#ifdef CONFIG_MACH_DECSTATION
125	real_yrs = yrs;
126	leap_yr = ((!((yrs + 1900) % 4) && ((yrs + 1900) % 100)) \|\|
127	!((yrs + 1900) % 400));
128	yrs = 72;
129
130	/*
131	* We want to keep the year set to 73 until March
132	* for non-leap years, so that Feb, 29th is handled
133	* correctly.
134	*/
135	if (!leap_yr && mon < 3) {
136	real_yrs--;
137	yrs = 73;
138	}
139	#endif
140
141	#ifdef CONFIG_ACPI
142	if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
143	acpi_gbl_FADT.century) {
144	century = (yrs + 1900) / 100;
145	yrs %= 100;
146	}
147	#endif
148
149	/* These limits and adjustments are independent of
150	* whether the chip is in binary mode or not.
151	*/
152	if (yrs > 169) {
153	spin_unlock_irqrestore(&rtc_lock, flags);
154	return -EINVAL;
155	}
156
157	if (yrs >= 100)
158	yrs -= 100;
159
160	if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
161	\|\| RTC_ALWAYS_BCD) {
162	sec = bin2bcd(sec);
163	min = bin2bcd(min);
164	hrs = bin2bcd(hrs);
165	day = bin2bcd(day);
166	mon = bin2bcd(mon);
167	yrs = bin2bcd(yrs);
168	century = bin2bcd(century);
169	}
170
171	save_control = CMOS_READ(RTC_CONTROL);
172	CMOS_WRITE((save_control\|RTC_SET), RTC_CONTROL);
173	save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
174	CMOS_WRITE((save_freq_select\|RTC_DIV_RESET2), RTC_FREQ_SELECT);
175
176	#ifdef CONFIG_MACH_DECSTATION
177	CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
178	#endif
179	CMOS_WRITE(yrs, RTC_YEAR);
180	CMOS_WRITE(mon, RTC_MONTH);
181	CMOS_WRITE(day, RTC_DAY_OF_MONTH);
182	CMOS_WRITE(hrs, RTC_HOURS);
183	CMOS_WRITE(min, RTC_MINUTES);
184	CMOS_WRITE(sec, RTC_SECONDS);
185	#ifdef CONFIG_ACPI
186	if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
187	acpi_gbl_FADT.century)
188	CMOS_WRITE(century, acpi_gbl_FADT.century);
189	#endif
190
191	CMOS_WRITE(save_control, RTC_CONTROL);
192	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
193
194	spin_unlock_irqrestore(&rtc_lock, flags);
195
196	return 0;
197	}
198	EXPORT_SYMBOL_GPL(mc146818_set_time);