Bluetooth device tree configuration

Article purpose

本文介绍如何配置“蓝牙” 将外围设备“(或与框架关联的外围设备)”分配给 Linux^® OS.

使用 设备树机制 执行配置。

在我们的平台上选择的蓝牙配套芯片是赛普拉斯(Cypress)芯片

Bluetooth DT bindings documentation

The Bluetooth 树绑定由以下部分组成：

• STM32 USART设备树绑定
• 用作从属设备所连接的主机USART设备的子节点 的Cypress设备。

Bluetooth DT configuration

此硬件描述是STM32微处理器设备树文件（扩展名为.dtsi）和板设备树文件（扩展名为.dts）的组合。有关设备树文件拆分的说明，请参见设备树

Bluetooth DT configuration (STM32 level)

USART外设节点位于``stm32mp157c.dtsi

• 这是一组属性，对于给定的STM32器件而言可能不变，例如：寄存器地址，时钟，复位...

在 Serial TTY device tree configuration中说明了USART DT配置。

Bluetooth DT configuration (board level)

The USART peripheral node is located in stm32mp151.dtsi

    This is a set of properties that may not vary for given STM32 device, such as: registers address, clock, reset...

The USART DT configuration is explained in [Description for the STM32MP15-Ecosystem-v1.1.0 revision]

&usart2 {
       ... 
       st,hw-flow-ctrl;                                       /* enable hardware flow control */
       ...
       bluetooth {                                            /* node of Bluetooth companion chip */         
               shutdown-gpios = <&gpioz 6 GPIO_ACTIVE_HIGH>;  /* GPIO specifier, used to enable the BT module */
               compatible = "brcm,bcm43438-bt";
               max-speed = <3000000>;
       };
};

USART的特定属性：

• st,hw-flow-ctrl:bool标志以启用硬件流控制

[Description for the STM32MP15-Ecosystem-v1.0.0 and previous revisions]

&usart2 {
       ... 
       st,hw-flow-ctrl;                            /* enable hardware flow control */
       ...
       bluetooth {                                 /* node of Bluetooth companion chip */
               pinctrl-names = "default";          
               pinctrl-0 = <&btreg>;               /* GPIO to power up or down the internal companion chip regulators */
               compatible = "brcm,bcm43438-bt";
               max-speed = <3000000>;
       };
};

USART的特定属性：

• btreg: GPIO，用于打开或关闭蓝牙部分使用的内部CYW4343W稳压器
• st,hw-flow-ctrl: bool标志以启用硬件流控制

How to configure Bluetooth using CubeMX

The STM32CubeMX tool can be used to configure the STM32MPU device and get the corresponding platform configuration device tree files.
The STM32CubeMX may not support all the properties described in the above DT bindings documentation paragraph. If so, the tool inserts user sections in the generated device tree. These sections can then be edited to add some properties and they are preserved from one generation to another. Refer to STM32CubeMX user manual for further information.

References