Merge tag 'backlight-next-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight

Pull backlight updates from Lee Jones:
 "Core Framework:
   - Remove unused/obsolete code/comments

  New Functionality:
   - Allow less granular brightness specification for high-res PWMs; pwm_bl
   - Align brightness {inc,dec}rements with that perceived by the human-eye; pwm_bl

  Fix-ups:
   - Prepare for the introduction of -Wimplicit-fall-through; adp8860_bl

  Bug Fixes:
   - Fix uninitialised variable; pwm_bl"

* tag 'backlight-next-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  backlight: pwm_bl: Fix uninitialized variable
  backlight: adp8860: Mark expected switch fall-through
  backlight: Remove obsolete comment for ->state
  dt-bindings: pwm-backlight: Move brightness-levels to optional
  backlight: pwm_bl: Compute brightness of LED linearly to human eye
  dt-bindings: pwm-backlight: Add a num-interpolation-steps property
  backlight: pwm_bl: Linear interpolation between brightness-levels

include/linux/backlight.h

@@ -79,7 +79,6 @@ struct backlight_properties {
 	/* Backlight type */
 	enum backlight_type type;
 	/* Flags used to signal drivers of state changes */
-	/* Upper 4 bits are reserved for driver internal use */
 	unsigned int state;
 
 #define BL_CORE_SUSPENDED	(1 << 0)	/* backlight is suspended */