1What:		/sys/class/rtc/
2Date:		March 2006
3KernelVersion:	2.6.17
4Contact:	linux-rtc@vger.kernel.org
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:	linux-rtc@vger.kernel.org
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:	linux-rtc@vger.kernel.org
20Description:
21		(RO) RTC-provided date in YYYY-MM-DD format
22
23What:		/sys/class/rtc/rtcX/hctosys
24Date:		September 2009
25KernelVersion:	2.6.32
26Contact:	linux-rtc@vger.kernel.org
27Description:
28		(RO) 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:	linux-rtc@vger.kernel.org
35Description:
36		(RW) 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:	linux-rtc@vger.kernel.org
43Description:
44		(RO) 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:	linux-rtc@vger.kernel.org
50Description:
51		(RO) 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:	linux-rtc@vger.kernel.org
57Description:
58		(RO) RTC-provided time in 24-hour notation (hh:mm:ss)
59
60What:		/sys/class/rtc/rtcX/*/nvmem
61Date:		February 2016
62KernelVersion:	4.6
63Contact:	linux-rtc@vger.kernel.org
64Description:
65		(RW) The non volatile storage exported as a raw file, as
66		described in Documentation/nvmem/nvmem.txt
67
68What:		/sys/class/rtc/rtcX/offset
69Date:		February 2016
70KernelVersion:	4.6
71Contact:	linux-rtc@vger.kernel.org
72Description:
73		(RW) The amount which the rtc clock has been adjusted in
74		firmware. Visible only if the driver supports clock offset
75		adjustment. The unit is parts per billion, i.e. The number of
76		clock ticks which are added to or removed from the rtc's base
77		clock per billion ticks. A positive value makes a day pass more
78		slowly, longer, and a negative value makes a day pass more
79		quickly.
80
81What:		/sys/class/rtc/rtcX/wakealarm
82Date:		February 2007
83KernelVersion:	2.6.20
84Contact:	linux-rtc@vger.kernel.org
85Description:
86		(RW) The time at which the clock will generate a system wakeup
87		event. This is a one shot wakeup event, so must be reset after
88		wake if a daily wakeup is required. Format is seconds since the
89		epoch by default, or if there's a leading +, seconds in the
90		future, or if there is a leading +=, seconds ahead of the
91		current alarm.
92