Documentation/ABI/testing/sysfs-class-rtc

   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/since_epoch
  47 Date:           March 2006
  48 KernelVersion:  2.6.17
  49 Contact:        linux-rtc@vger.kernel.org
  50 Description:
  51                 (RO) RTC-provided time as the number of seconds since the epoch
  52
  53 What:           /sys/class/rtc/rtcX/time
  54 Date:           March 2006
  55 KernelVersion:  2.6.17
  56 Contact:        linux-rtc@vger.kernel.org
  57 Description:
  58                 (RO) RTC-provided time in 24-hour notation (hh:mm:ss)
  59
  60 What:           /sys/class/rtc/rtcX/*/nvmem
  61 Date:           February 2016
  62 KernelVersion:  4.6
  63 Contact:        linux-rtc@vger.kernel.org
  64 Description:
  65                 (RW) The non volatile storage exported as a raw file, as
  66                 described in Documentation/nvmem/nvmem.txt
  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.