WLAN device tree configuration

Article purpose

本文的目的是解释在将外围设备(或与框架关联的外围设备)分配给 Linux^® OS时，如何配置WLAN.

使用device tree 机制执行配置，该机制提供了SDIO总线上连接的WLAN外围设备的硬件描述。

本文的目的是解释赛普拉斯WLAN / BT配套芯片device tree node

DT bindings documentation

The WLAN tree bindings are composed by :

• SDIO link configuration

• WLAN device configuration

DT configuration

This hardware description is a combination of the STM32 microprocessor device tree files (.dtsi extension) and board device tree files (.dts extension). See the Device tree for an explanation of the device tree file split.

DT configuration (STM32 level)

The companion chip uses the SDIO link so the DT is based on the SDMMC peripheral node which is located in stm32mp157c.dtsi

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

The SDMMC DT configuration is explained at SDMMC device tree configuration

This device tree part is related to STM32 microprocessors. It must be kept as is, without being modified by the end-user.

DT configuration (board level)

Part of the device tree is used to describe the WLAN hardware used on a given board. The DT node ("sdmmc2") must be filled in:

• mmc-pwrseq: phandle to the MMC power sequence node
• keep-power-in-suspend: preserves the card power during a suspend/resume cycle

&sdmmc2 {
       ...
       vmmc-supply = <&v3v3>;
       mmc-pwrseq = <&wifi_pwrseq>;                 /* phandle to the MMC power sequence node */
       ...
       keep-power-in-suspend;                       /* preserves the card power during a suspend/resume cycle */
       brcmf: bcrmf@1 {                             /* node of WLAN companion chip */
          reg = <1>;
          compatible = "brcm,bcm4329-fmac";
       }
}

References