Doug / smarc-fsl-linux-kernel

Download as
Browse Code ยป

Commit ea3d1606fd32059461309099e8856c6652888a79

Authored by Matthew Garrett
Committed by Linus Torvalds
1 parent dac94d9ec9
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

rtc: document the sysfs interface 

The sysfs interface to the RTC class drivers is currently undocumented.
Add some basic documentation defining the semantics of the fields.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 1 changed file with 22 additions and 0 deletions Side-by-side Diff

Documentation/rtc.txt
Diff comments   View file @ ea3d160
... ... @@ -135,6 +135,28 @@
135 135 the system clock from the discrete RTC, but use the integrated one for all
136 136 other tasks, because of its greater functionality.
137 137  
  138 +SYSFS INTERFACE
  139 +---------------
  140 +
  141 +The sysfs interface under /sys/class/rtc/rtcN provides access to various
  142 +rtc attributes without requiring the use of ioctls. All dates and times
  143 +are in the RTC's timezone, rather than in system time.
  144 +
  145 +date: RTC-provided date
  146 +max_user_freq: The maximum interrupt rate an unprivileged user may request
  147 + from this RTC.
  148 +name: The name of the RTC corresponding to this sysfs directory
  149 +since_epoch: The number of seconds since the epoch according to the RTC
  150 +time: RTC-provided time
  151 +wakealarm: The time at which the clock will generate a system wakeup
  152 + event. This is a one shot wakeup event, so must be reset
  153 + after wake if a daily wakeup is required. Format is either
  154 + seconds since the epoch or, if there's a leading +, seconds
  155 + in the future.
  156 +
  157 +IOCTL INTERFACE
  158 +---------------
  159 +
138 160 The ioctl() calls supported by /dev/rtc are also supported by the RTC class
139 161 framework. However, because the chips and systems are not standardized,
140 162 some PC/AT functionality might not be provided. And in the same way, some