1What: /sys/class/pwm/ 2Date: May 2013 3KernelVersion: 3.11 4Contact: H Hartley Sweeten <hsweeten@visionengravers.com> 5Description: 6 The pwm/ class sub-directory belongs to the Generic PWM 7 Framework and provides a sysfs interface for using PWM 8 channels. 9 10What: /sys/class/pwm/pwmchipN/ 11Date: May 2013 12KernelVersion: 3.11 13Contact: H Hartley Sweeten <hsweeten@visionengravers.com> 14Description: 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 19What: /sys/class/pwm/pwmchipN/npwm 20Date: May 2013 21KernelVersion: 3.11 22Contact: H Hartley Sweeten <hsweeten@visionengravers.com> 23Description: 24 The number of PWM channels supported by the PWM chip. 25 26What: /sys/class/pwm/pwmchipN/export 27Date: May 2013 28KernelVersion: 3.11 29Contact: H Hartley Sweeten <hsweeten@visionengravers.com> 30Description: 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 34What: /sys/class/pwm/pwmchipN/unexport 35Date: May 2013 36KernelVersion: 3.11 37Contact: H Hartley Sweeten <hsweeten@visionengravers.com> 38Description: 39 Unexports a PWM channel. 40 41What: /sys/class/pwm/pwmchipN/pwmX 42Date: May 2013 43KernelVersion: 3.11 44Contact: H Hartley Sweeten <hsweeten@visionengravers.com> 45Description: 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 50What: /sys/class/pwm/pwmchipN/pwmX/period 51Date: May 2013 52KernelVersion: 3.11 53Contact: H Hartley Sweeten <hsweeten@visionengravers.com> 54Description: 55 Sets the PWM signal period in nanoseconds. 56 57What: /sys/class/pwm/pwmchipN/pwmX/duty_cycle 58Date: May 2013 59KernelVersion: 3.11 60Contact: H Hartley Sweeten <hsweeten@visionengravers.com> 61Description: 62 Sets the PWM signal duty cycle in nanoseconds. 63 64What: /sys/class/pwm/pwmchipN/pwmX/polarity 65Date: May 2013 66KernelVersion: 3.11 67Contact: H Hartley Sweeten <hsweeten@visionengravers.com> 68Description: 69 Sets the output polarity of the PWM signal to "normal" or 70 "inversed". 71 72What: /sys/class/pwm/pwmchipN/pwmX/enable 73Date: May 2013 74KernelVersion: 3.11 75Contact: H Hartley Sweeten <hsweeten@visionengravers.com> 76Description: 77 Enable/disable the PWM signal. 78 0 is disabled 79 1 is enabled 80 81What: /sys/class/pwm/pwmchipN/pwmX/capture 82Date: June 2016 83KernelVersion: 4.8 84Contact: Lee Jones <lee.jones@linaro.org> 85Description: 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. 89