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/range 47Date: January 2018 48KernelVersion: 4.16 49Contact: linux-rtc@vger.kernel.org 50Description: 51 Valid time range for the RTC, as seconds from epoch, formatted 52 as [min, max] 53 54What: /sys/class/rtc/rtcX/since_epoch 55Date: March 2006 56KernelVersion: 2.6.17 57Contact: linux-rtc@vger.kernel.org 58Description: 59 (RO) RTC-provided time as the number of seconds since the epoch 60 61What: /sys/class/rtc/rtcX/time 62Date: March 2006 63KernelVersion: 2.6.17 64Contact: linux-rtc@vger.kernel.org 65Description: 66 (RO) RTC-provided time in 24-hour notation (hh:mm:ss) 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