Documentation/ABI/testing/sysfs-class-pwm

   1 What:           /sys/class/pwm/
   2 Date:           May 2013
   3 KernelVersion:  3.11
   4 Contact:        H Hartley Sweeten <hsweeten@visionengravers.com>
   5 Description:
   6                 The pwm/ class sub-directory belongs to the Generic PWM
   7                 Framework and provides a sysfs interface for using PWM
   8                 channels.
   9
  10 What:           /sys/class/pwm/pwmchipN/
  11 Date:           May 2013
  12 KernelVersion:  3.11
  13 Contact:        H Hartley Sweeten <hsweeten@visionengravers.com>
  14 Description:
  15                 A /sys/class/pwm/pwmchipN directory is created for each
  16                 probed PWM controller/chip where N is the base of the
  17                 PWM chip.
  18
  19 What:           /sys/class/pwm/pwmchipN/npwm
  20 Date:           May 2013
  21 KernelVersion:  3.11
  22 Contact:        H Hartley Sweeten <hsweeten@visionengravers.com>
  23 Description:
  24                 The number of PWM channels supported by the PWM chip.
  25
  26 What:           /sys/class/pwm/pwmchipN/export
  27 Date:           May 2013
  28 KernelVersion:  3.11
  29 Contact:        H Hartley Sweeten <hsweeten@visionengravers.com>
  30 Description:
  31                 Exports a PWM channel from the PWM chip for sysfs control.
  32                 Value is between 0 and /sys/class/pwm/pwmchipN/npwm - 1.
  33
  34 What:           /sys/class/pwm/pwmchipN/unexport
  35 Date:           May 2013
  36 KernelVersion:  3.11
  37 Contact:        H Hartley Sweeten <hsweeten@visionengravers.com>
  38 Description:
  39                 Unexports a PWM channel.
  40
  41 What:           /sys/class/pwm/pwmchipN/pwmX
  42 Date:           May 2013
  43 KernelVersion:  3.11
  44 Contact:        H Hartley Sweeten <hsweeten@visionengravers.com>
  45 Description:
  46                 A /sys/class/pwm/pwmchipN/pwmX directory is created for
  47                 each exported PWM channel where X is the exported PWM
  48                 channel number.
  49
  50 What:           /sys/class/pwm/pwmchipN/pwmX/period
  51 Date:           May 2013
  52 KernelVersion:  3.11
  53 Contact:        H Hartley Sweeten <hsweeten@visionengravers.com>
  54 Description:
  55                 Sets the PWM signal period in nanoseconds.
  56
  57 What:           /sys/class/pwm/pwmchipN/pwmX/duty_cycle
  58 Date:           May 2013
  59 KernelVersion:  3.11
  60 Contact:        H Hartley Sweeten <hsweeten@visionengravers.com>
  61 Description:
  62                 Sets the PWM signal duty cycle in nanoseconds.
  63
  64 What:           /sys/class/pwm/pwmchipN/pwmX/polarity
  65 Date:           May 2013
  66 KernelVersion:  3.11
  67 Contact:        H Hartley Sweeten <hsweeten@visionengravers.com>
  68 Description:
  69                 Sets the output polarity of the PWM signal to "normal" or
  70                 "inversed".
  71
  72 What:           /sys/class/pwm/pwmchipN/pwmX/enable
  73 Date:           May 2013
  74 KernelVersion:  3.11
  75 Contact:        H Hartley Sweeten <hsweeten@visionengravers.com>
  76 Description:
  77                 Enable/disable the PWM signal.
  78                 0 is disabled
  79                 1 is enabled
  80
  81 What:           /sys/class/pwm/pwmchipN/pwmX/capture
  82 Date:           June 2016
  83 KernelVersion:  4.8
  84 Contact:        Lee Jones <lee.jones@linaro.org>
  85 Description:
  86                 Capture information about a PWM signal. The output format is a
  87                 pair unsigned integers (period and duty cycle), separated by a
  88                 single space.