1 What: /sys/class/rtc/ 2 Date: March 2006 3 KernelVersion: 2.6.17 4 Contact: linux-rtc@vger.kernel.org 5 Description: 6 The rtc/ class subdirectory belongs to the RTC subsystem. 7 8 What: /sys/class/rtc/rtcX/ 9 Date: March 2006 10 KernelVersion: 2.6.17 11 Contact: linux-rtc@vger.kernel.org 12 Description: 13 The /sys/class/rtc/rtc{0,1,2,3,...} directories correspond 14 to each RTC device. 15 16 What: /sys/class/rtc/rtcX/date 17 Date: March 2006 18 KernelVersion: 2.6.17 19 Contact: linux-rtc@vger.kernel.org 20 Description: 21 (RO) RTC-provided date in YYYY-MM-DD format 22 23 What: /sys/class/rtc/rtcX/hctosys 24 Date: September 2009 25 KernelVersion: 2.6.32 26 Contact: linux-rtc@vger.kernel.org 27 Description: 28 (RO) 1 if the RTC provided the system time at boot via the 29 CONFIG_RTC_HCTOSYS kernel option, 0 otherwise 30 31 What: /sys/class/rtc/rtcX/max_user_freq 32 Date: October 2007 33 KernelVersion: 2.6.24 34 Contact: linux-rtc@vger.kernel.org 35 Description: 36 (RW) The maximum interrupt rate an unprivileged user may request 37 from this RTC. 38 39 What: /sys/class/rtc/rtcX/name 40 Date: March 2006 41 KernelVersion: 2.6.17 42 Contact: linux-rtc@vger.kernel.org 43 Description: 44 (RO) The name of the RTC corresponding to this sysfs directory 45 46 What: /sys/class/rtc/rtcX/range 47 Date: January 2018 48 KernelVersion: 4.16 49 Contact: linux-rtc@vger.kernel.org 50 Description: 51 Valid time range for the RTC, as seconds from epoch, formatted 52 as [min, max] 53 54 What: /sys/class/rtc/rtcX/since_epoch 55 Date: March 2006 56 KernelVersion: 2.6.17 57 Contact: linux-rtc@vger.kernel.org 58 Description: 59 (RO) RTC-provided time as the number of seconds since the epoch 60 61 What: /sys/class/rtc/rtcX/time 62 Date: March 2006 63 KernelVersion: 2.6.17 64 Contact: linux-rtc@vger.kernel.org 65 Description: 66 (RO) RTC-provided time in 24-hour notation (hh:mm:ss) 67 68 What: /sys/class/rtc/rtcX/offset 69 Date: February 2016 70 KernelVersion: 4.6 71 Contact: linux-rtc@vger.kernel.org 72 Description: 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 81 What: /sys/class/rtc/rtcX/wakealarm 82 Date: February 2007 83 KernelVersion: 2.6.20 84 Contact: linux-rtc@vger.kernel.org 85 Description: 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