1What:		/sys/class/rtc/
2Date:		March 2006
3KernelVersion:	2.6.17
4Contact:	[email protected]
5Description:
6		The rtc/ class subdirectory belongs to the RTC subsystem.
7
8What:		/sys/class/rtc/rtcX/
9Date:		March 2006
10KernelVersion:	2.6.17
11Contact:	[email protected]
12Description:
13		The /sys/class/rtc/rtc{0,1,2,3,...} directories correspond
14		to each RTC device.
15
16What:		/sys/class/rtc/rtcX/date
17Date:		March 2006
18KernelVersion:	2.6.17
19Contact:	[email protected]
20Description:
21		RTC-provided date in YYYY-MM-DD format
22
23What:		/sys/class/rtc/rtcX/hctosys
24Date:		September 2009
25KernelVersion:	2.6.32
26Contact:	[email protected]
27Description:
28		1 if the RTC provided the system time at boot via the
29		CONFIG_RTC_HCTOSYS kernel option, 0 otherwise
30
31What:		/sys/class/rtc/rtcX/max_user_freq
32Date:		October 2007
33KernelVersion:	2.6.24
34Contact:	[email protected]
35Description:
36		The maximum interrupt rate an unprivileged user may request
37		from this RTC.
38
39What:		/sys/class/rtc/rtcX/name
40Date:		March 2006
41KernelVersion:	2.6.17
42Contact:	[email protected]
43Description:
44		The name of the RTC corresponding to this sysfs directory
45
46What:		/sys/class/rtc/rtcX/since_epoch
47Date:		March 2006
48KernelVersion:	2.6.17
49Contact:	[email protected]
50Description:
51		RTC-provided time as the number of seconds since the epoch
52
53What:		/sys/class/rtc/rtcX/time
54Date:		March 2006
55KernelVersion:	2.6.17
56Contact:	[email protected]
57Description:
58		RTC-provided time in 24-hour notation (hh:mm:ss)
59
60What:		/sys/class/rtc/rtcX/*/nvmem
61Date:		February 2016
62KernelVersion:	4.6
63Contact:	[email protected]
64Description:
65		The non volatile storage exported as a raw file, as described in
66		Documentation/nvmem/nvmem.txt
67
68What:		/sys/class/rtc/rtcX/offset
69Date:		February 2016
70KernelVersion:	4.6
71Contact:	[email protected]
72Description:
73		The amount which the rtc clock has been adjusted in firmware.
74		Visible only if the driver supports clock offset adjustment.
75		The unit is parts per billion, i.e. The number of clock ticks
76		which are added to or removed from the rtc's base clock per
77		billion ticks. A positive value makes a day pass more slowly,
78		longer, and a negative value makes a day pass more quickly.
79
80What:		/sys/class/rtc/rtcX/wakealarm
81Date:		February 2007
82KernelVersion:	2.6.20
83Contact:	[email protected]
84Description:
85		The time at which the clock will generate a system wakeup event.
86		This is a one shot wakeup event, so must be reset after wake if
87		a daily wakeup is required. Format is seconds since the epoch by
88		default, or if there's a leading +, seconds in the future, or if
89		there is a leading +=, seconds ahead of the current alarm.
90