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https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
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87f33a1b8f
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>
72 lines
1.7 KiB
YAML
72 lines
1.7 KiB
YAML
# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/leds/backlight/mps,mp3309c.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: MPS MP3309C backlight
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maintainers:
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- Flavio Suligoi <f.suligoi@asem.it>
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description: |
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The Monolithic Power (MPS) MP3309C is a WLED step-up converter, featuring a
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programmable switching frequency to optimize efficiency.
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It supports two different dimming modes:
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- analog mode, via I2C commands, as default mode (32 dimming levels)
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- PWM controlled mode (optional)
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The datasheet is available at:
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https://www.monolithicpower.com/en/mp3309c.html
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allOf:
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- $ref: common.yaml#
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properties:
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compatible:
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const: mps,mp3309c
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reg:
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maxItems: 1
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pwms:
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description: if present, the backlight is controlled in PWM mode.
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maxItems: 1
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enable-gpios:
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description: GPIO used to enable the backlight in "analog-i2c" dimming mode.
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maxItems: 1
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mps,overvoltage-protection-microvolt:
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description: Overvoltage protection (13.5V, 24V or 35.5V).
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enum: [ 13500000, 24000000, 35500000 ]
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default: 35500000
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mps,no-sync-mode:
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description: disable synchronous rectification mode
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type: boolean
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required:
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- compatible
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- reg
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unevaluatedProperties: false
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examples:
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- |
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i2c {
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#address-cells = <1>;
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#size-cells = <0>;
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/* Backlight with PWM control */
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backlight_pwm: backlight@17 {
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compatible = "mps,mp3309c";
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reg = <0x17>;
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pwms = <&pwm1 0 3333333 0>; /* 300 Hz --> (1/f) * 1*10^9 */
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brightness-levels = <0 4 8 16 32 64 128 255>;
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default-brightness = <6>;
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mps,overvoltage-protection-microvolt = <24000000>;
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};
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};
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