The two properties:
- max-brightness
- default brightness
are not really required, so they can be removed from the "required"
section.
The "max-brightness" is no longer used in the current version
of the driver (it was used only in the first version).
The "default-brightness", if omitted in the DT, is managed by the
device driver, using a default value. This value depends on the dimming
mode used:
- for the "analog mode", via I2C commands, this value is fixed by
hardware (=31)
- while in case of pwm mode the default used is the last value of the
brightness-levels array.
Also the brightness-levels array is not required:
- in "analog mode", via I2C commands, the brightness-level array is
fixed by hardware (0..31).;
- in pwm dimming mode, the driver uses a default array of 0..255 and
the "default-brightness" is the last one, which is "255"
NOTE: there are no compatibility problems with the previous version,
since the device driver has not yet been included in any kernel.
Only this dt-binding yaml file is already included in the current
v6.7.0-rc1 kernel version.
No developer may have used it.
Other changes:
- improve the backlight working mode description, in the "description"
section
- update the example, removing the "max-brightness" and introducing the
"brightess-levels" property
Signed-off-by: Flavio Suligoi <f.suligoi@asem.it>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20231116105319.957600-2-f.suligoi@asem.it
Signed-off-by: Lee Jones <lee@kernel.org>
The Monolithic Power (MPS) MP3309C is a WLED step-up converter, featuring a
programmable switching frequency to optimize efficiency.
The brightness can be controlled either by I2C commands (called "analog"
mode) or by a PWM input signal (PWM mode).
This driver supports both modes.
For device driver details, please refer to:
- drivers/video/backlight/mp3309c_bl.c
The datasheet is available at:
- https://www.monolithicpower.com/en/mp3309c.html
Signed-off-by: Flavio Suligoi <f.suligoi@asem.it>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230925122609.78849-1-f.suligoi@asem.it
Signed-off-by: Lee Jones <lee@kernel.org>
