(defparameter *backlight-root* #P"/sys/class/backlight/")

(defclass backlight-device ()
  ((device-name :accessor backlight-device-name
                :initarg :device-name)
   (max-brightness :type (integer 0)
                   :attribute "max_brightness"
                   :parser parse-integer
                   :reader backlight-max-brightness
                   :constp t)
   (brightness :type (integer 0)
               :parser parse-integer
               :attribute "brightness"
               :accessor backlight-brightness))
  (:metaclass sysfs-class))

(defun make-backlight-device-from-pathname (pathname)
  (make-instance 'backlight-device
                 :sysfs-base-directory pathname
                 :device-name (lastcar (pathname-directory pathname))))

(defun backlight-devices ()
  (mapcar #'make-backlight-device-from-pathname
          (uiop:subdirectories *backlight-root*)))