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/offset 61Date: February 2016 62KernelVersion: 4.6 63Contact: linux-rtc@vger.kernel.org 64Description: 65 (RW) The amount which the rtc clock has been adjusted in 66 firmware. Visible only if the driver supports clock offset 67 adjustment. The unit is parts per billion, i.e. The number of 68 clock ticks which are added to or removed from the rtc's base 69 clock per billion ticks. A positive value makes a day pass more 70 slowly, longer, and a negative value makes a day pass more 71 quickly. 72 73What: /sys/class/rtc/rtcX/wakealarm 74Date: February 2007 75KernelVersion: 2.6.20 76Contact: linux-rtc@vger.kernel.org 77Description: 78 (RW) The time at which the clock will generate a system wakeup 79 event. This is a one shot wakeup event, so must be reset after 80 wake if a daily wakeup is required. Format is seconds since the 81 epoch by default, or if there's a leading +, seconds in the 82 future, or if there is a leading +=, seconds ahead of the 83 current alarm. 84