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On ARM platforms, each particular board is described by its own Device Tree file. In our case, the STM32MP157 Discovery Kit 2 is described by the Device Tree file arch/arm/boot/dts/stm32mp157c-dk2.dts in the Linux kernel source code. This human-readable source file, with a .dts extension, is compiled during the Linux kernel build process into a machine-readable binary file, with a .dtb extension.
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// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
/*
* Copyright (C) STMicroelectronics 2019 - All Rights Reserved
* Author: Alexandre Torgue <alexandre.torgue@st.com> for STMicroelectronics.
*/
/dts-v1/;
#include "stm32mp157.dtsi"
#include "stm32mp15xc.dtsi"
#include "stm32mp15-pinctrl.dtsi"
#include "stm32mp15xxac-pinctrl.dtsi"
#include "stm32mp15xx-dkx.dtsi"
/ {
model = "STMicroelectronics STM32MP157C-DK2 Discovery Board";
compatible = "st,stm32mp157c-dk2", "st,stm32mp157";
aliases {
ethernet0 = ðernet0;
serial0 = &uart4;
serial1 = &usart3;
serial2 = &uart7;
serial3 = &usart2;
};
chosen {
stdout-path = "serial0:115200n8";
};
};
&cryp1 {
status = "okay";
};
&dsi {
status = "okay";
phy-dsi-supply = <®18>;
ports {
port@0 {
reg = <0>;
dsi_in: endpoint {
remote-endpoint = <<dc_ep1_out>;
};
};
port@1 {
reg = <1>;
dsi_out: endpoint {
remote-endpoint = <&panel_in>;
};
};
};
panel@0 {
compatible = "orisetech,otm8009a";
reg = <0>;
reset-gpios = <&gpioe 4 GPIO_ACTIVE_LOW>;
power-supply = <&v3v3>;
status = "okay";
port {
panel_in: endpoint {
remote-endpoint = <&dsi_out>;
};
};
};
};
&i2c1 {
touchscreen@38 {
compatible = "focaltech,ft6236";
reg = <0x38>;
interrupts = <2 2>;
interrupt-parent = <&gpiof>;
interrupt-controller;
touchscreen-size-x = <480>;
touchscreen-size-y = <800>;
status = "okay";
};
};
<dc {
status = "okay";
port {
ltdc_ep1_out: endpoint@1 {
reg = <1>;
remote-endpoint = <&dsi_in>;
};
};
};
&usart2 {
pinctrl-names = "default", "sleep", "idle";
pinctrl-0 = <&usart2_pins_c>;
pinctrl-1 = <&usart2_sleep_pins_c>;
pinctrl-2 = <&usart2_idle_pins_c>;
status = "disabled";
}; |
This stm32mp157c-dk2.dts describes the hardware of our Discovery Kit 2 platform. In fact, it only describes what is specific to the Discovery Kit 2: the display panel, the touchscreen, the WiFi and Bluetooth chip. Everything else is common with the Discovery Kit 1 platform, which is why the stm32mp157c-dk2.dts file includes the arm/boot/dts/stm32mp157a-dk1.dtsfile. Indeed, stm32mp157a-dk1.dts describes the hardware on the Discovery Kit 1, which is the same as the Discovery Kit 2, without the display, touchscreen and WiFi/Bluetooth chip.
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