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# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/display/panel/panel-mipi-dbi-spi.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: MIPI DBI SPI Panel
maintainers:
- Noralf Trønnes <noralf@tronnes.org>
description: |
This binding is for display panels using a MIPI DBI compatible controller
in SPI mode.
The MIPI Alliance Standard for Display Bus Interface defines the electrical
and logical interfaces for display controllers historically used in mobile
phones. The standard defines 4 display architecture types and this binding is
for type 1 which has full frame memory. There are 3 interface types in the
standard and type C is the serial interface.
The standard defines the following interface signals for type C:
- Power:
- Vdd: Power supply for display module
- Vddi: Logic level supply for interface signals
Combined into one in this binding called: power-supply
- Interface:
- CSx: Chip select
- SCL: Serial clock
- Dout: Serial out
- Din: Serial in
- SDA: Bidrectional in/out
- D/CX: Data/command selection, high=data, low=command
Called dc-gpios in this binding.
- RESX: Reset when low
Called reset-gpios in this binding.
The type C interface has 3 options:
- Option 1: 9-bit mode and D/CX as the 9th bit
| Command | the next command or following data |
|<0><D7><D6><D5><D4><D3><D2><D1><D0>|<D/CX><D7><D6><D5><D4><D3><D2><D1><D0>|
- Option 2: 16-bit mode and D/CX as a 9th bit
| Command or data |
|<X><X><X><X><X><X><X><D/CX><D7><D6><D5><D4><D3><D2><D1><D0>|
- Option 3: 8-bit mode and D/CX as a separate interface line
| Command or data |
|<D7><D6><D5><D4><D3><D2><D1><D0>|
The panel resolution is specified using the panel-timing node properties
hactive (width) and vactive (height). The other mandatory panel-timing
properties should be set to zero except clock-frequency which can be
optionally set to inform about the actual pixel clock frequency.
If the panel is wired to the controller at an offset specify this using
hback-porch (x-offset) and vback-porch (y-offset).
allOf:
- $ref: panel-common.yaml#
- $ref: /schemas/spi/spi-peripheral-props.yaml#
properties:
compatible:
items:
- enum:
- sainsmart18
- const: panel-mipi-dbi-spi
write-only:
type: boolean
description:
Controller is not readable (ie. Din (MISO on the SPI interface) is not
wired up).
dc-gpios:
maxItems: 1
description: |
Controller data/command selection (D/CX) in 4-line SPI mode.
If not set, the controller is in 3-line SPI mode.
required:
- compatible
- reg
- width-mm
- height-mm
- panel-timing
unevaluatedProperties: false
examples:
- |
#include <dt-bindings/gpio/gpio.h>
spi {
#address-cells = <1>;
#size-cells = <0>;
display@0{
compatible = "sainsmart18", "panel-mipi-dbi-spi";
reg = <0>;
spi-max-frequency = <40000000>;
dc-gpios = <&gpio 24 GPIO_ACTIVE_HIGH>;
reset-gpios = <&gpio 25 GPIO_ACTIVE_HIGH>;
write-only;
backlight = <&backlight>;
width-mm = <35>;
height-mm = <28>;
panel-timing {
hactive = <160>;
vactive = <128>;
hback-porch = <0>;
vback-porch = <0>;
clock-frequency = <0>;
hfront-porch = <0>;
hsync-len = <0>;
vfront-porch = <0>;
vsync-len = <0>;
};
};
};
...
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