xref: /linux-6.15/include/linux/mc146818rtc.h (revision f96cffd7)
1 /* mc146818rtc.h - register definitions for the Real-Time-Clock / CMOS RAM
2  * Copyright Torsten Duwe <[email protected]> 1993
3  * derived from Data Sheet, Copyright Motorola 1984 (!).
4  * It was written to be part of the Linux operating system.
5  */
6 /* permission is hereby granted to copy, modify and redistribute this code
7  * in terms of the GNU Library General Public License, Version 2 or later,
8  * at your option.
9  */
10 
11 #ifndef _MC146818RTC_H
12 #define _MC146818RTC_H
13 
14 #include <asm/io.h>
15 #include <linux/rtc.h>			/* get the user-level API */
16 #include <asm/mc146818rtc.h>		/* register access macros */
17 #include <linux/bcd.h>
18 #include <linux/delay.h>
19 
20 #ifdef __KERNEL__
21 #include <linux/spinlock.h>		/* spinlock_t */
22 extern spinlock_t rtc_lock;		/* serialize CMOS RAM access */
23 
24 /* Some RTCs extend the mc146818 register set to support alarms of more
25  * than 24 hours in the future; or dates that include a century code.
26  * This platform_data structure can pass this information to the driver.
27  *
28  * Also, some platforms need suspend()/resume() hooks to kick in special
29  * handling of wake alarms, e.g. activating ACPI BIOS hooks or setting up
30  * a separate wakeup alarm used by some almost-clone chips.
31  */
32 struct cmos_rtc_board_info {
33 	void	(*wake_on)(struct device *dev);
34 	void	(*wake_off)(struct device *dev);
35 
36 	u32	flags;
37 #define CMOS_RTC_FLAGS_NOFREQ	(1 << 0)
38 	int	address_space;
39 
40 	u8	rtc_day_alarm;		/* zero, or register index */
41 	u8	rtc_mon_alarm;		/* zero, or register index */
42 	u8	rtc_century;		/* zero, or register index */
43 };
44 #endif
45 
46 /**********************************************************************
47  * register summary
48  **********************************************************************/
49 #define RTC_SECONDS		0
50 #define RTC_SECONDS_ALARM	1
51 #define RTC_MINUTES		2
52 #define RTC_MINUTES_ALARM	3
53 #define RTC_HOURS		4
54 #define RTC_HOURS_ALARM		5
55 /* RTC_*_alarm is always true if 2 MSBs are set */
56 # define RTC_ALARM_DONT_CARE 	0xC0
57 
58 #define RTC_DAY_OF_WEEK		6
59 #define RTC_DAY_OF_MONTH	7
60 #define RTC_MONTH		8
61 #define RTC_YEAR		9
62 
63 /* control registers - Moto names
64  */
65 #define RTC_REG_A		10
66 #define RTC_REG_B		11
67 #define RTC_REG_C		12
68 #define RTC_REG_D		13
69 
70 /**********************************************************************
71  * register details
72  **********************************************************************/
73 #define RTC_FREQ_SELECT	RTC_REG_A
74 
75 /* update-in-progress  - set to "1" 244 microsecs before RTC goes off the bus,
76  * reset after update (may take 1.984ms @ 32768Hz RefClock) is complete,
77  * totalling to a max high interval of 2.228 ms.
78  */
79 # define RTC_UIP		0x80
80 # define RTC_DIV_CTL		0x70
81    /* divider control: refclock values 4.194 / 1.049 MHz / 32.768 kHz */
82 #  define RTC_REF_CLCK_4MHZ	0x00
83 #  define RTC_REF_CLCK_1MHZ	0x10
84 #  define RTC_REF_CLCK_32KHZ	0x20
85    /* 2 values for divider stage reset, others for "testing purposes only" */
86 #  define RTC_DIV_RESET1	0x60
87 #  define RTC_DIV_RESET2	0x70
88   /* Periodic intr. / Square wave rate select. 0=none, 1=32.8kHz,... 15=2Hz */
89 # define RTC_RATE_SELECT 	0x0F
90 
91 /**********************************************************************/
92 #define RTC_CONTROL	RTC_REG_B
93 # define RTC_SET 0x80		/* disable updates for clock setting */
94 # define RTC_PIE 0x40		/* periodic interrupt enable */
95 # define RTC_AIE 0x20		/* alarm interrupt enable */
96 # define RTC_UIE 0x10		/* update-finished interrupt enable */
97 # define RTC_SQWE 0x08		/* enable square-wave output */
98 # define RTC_DM_BINARY 0x04	/* all time/date values are BCD if clear */
99 # define RTC_24H 0x02		/* 24 hour mode - else hours bit 7 means pm */
100 # define RTC_DST_EN 0x01	/* auto switch DST - works f. USA only */
101 
102 /**********************************************************************/
103 #define RTC_INTR_FLAGS	RTC_REG_C
104 /* caution - cleared by read */
105 # define RTC_IRQF 0x80		/* any of the following 3 is active */
106 # define RTC_PF 0x40
107 # define RTC_AF 0x20
108 # define RTC_UF 0x10
109 
110 /**********************************************************************/
111 #define RTC_VALID	RTC_REG_D
112 # define RTC_VRT 0x80		/* valid RAM and time */
113 /**********************************************************************/
114 
115 #ifndef ARCH_RTC_LOCATION	/* Override by <asm/mc146818rtc.h>? */
116 
117 #define RTC_IO_EXTENT	0x8
118 #define RTC_IO_EXTENT_USED	0x2
119 #define RTC_IOMAPPED	1	/* Default to I/O mapping. */
120 
121 #else
122 #define RTC_IO_EXTENT_USED      RTC_IO_EXTENT
123 #endif /* ARCH_RTC_LOCATION */
124 
125 unsigned int mc146818_get_time(struct rtc_time *time);
126 int mc146818_set_time(struct rtc_time *time);
127 
128 #endif /* _MC146818RTC_H */
129