查看“Linux内核-蓝牙驱动移植”的源代码

==实验原理==
FS-MP1A开发板蓝牙采用AP6236，WIFI蓝牙二合一芯片。蓝牙部分通过usart3与SoC进行数据交互。<br>

[[Image:59-1-1-1.png]] <br>

蓝牙部分移需要配置usart3的设备树与AP_CK32KO管脚，可参考stm32mp157c-dk2.dts中的相关配置。<br>

[[Image:59-1-1-2.png]] <br>

[[Image:59-1-1-3.png]] <br>

查看原理图得出AP6236数据管脚与STM32MP157A的管脚对应关系如下：

{|class="wikitable"
|-
! 原理图网络编号 !! 对应管脚 !! 管脚功能 !! 管脚功能码
|-
| BT_UART_TX 
| PD8 
| USART3_TX
| AF7
|-
| BT_UART_RX 
| PD9 
| USART3_RX
| AF7
|-
| BT_UART_CTS 
| PD11 
| USART3_CTS
| AF7
|-
| BT_UART_RTS 
| PD12 
| USART3_RTS
| AF7
|-
| BT_WIFI_RST
| PD13 
| IO
| ANALOG
|-
| AP_CK32KO 
| PI8 
| RTC_OUT2
| ANALOG
|}
*WiFi设备树节点<br>

参考文档：
<pre><nowiki>
Documentation/devicetree/bindings/net/broadcom-bluetooth.txt
Documentation/devicetree/bindings/serial/st,stm32-usart.txt
</nowiki></pre>
内核中ST对STM32MP15x系列芯片的设备树资源了做了定义，可参见：
 arch/arm/boot/dts/stm32mp151.dtsi
stm32mp151中usart3定义如下：
<pre><nowiki>
usart3: serial@4000f000 {
    compatible = "st,stm32h7-uart";
    reg = <0x4000f000 0x400>;
    interrupts-extended = <&exti 28 IRQ_TYPE_LEVEL_HIGH>;
    clocks = <&rcc USART3_K>;
    resets = <&rcc USART3_R>;
    wakeup-source;
    power-domains = <&pd_core>;
    dmas = <&dmamux1 45 0x400 0x5>,
           <&dmamux1 46 0x400 0x1>;
    dma-names = "rx", "tx";
    status = "disabled";
};
</nowiki></pre>
上述代码只对usart3做了基本的初始化，并没有针对不同的硬件设计做适配，所以需结合硬件补全设备树节点信息。<br>

参考文档或stm32mp157f-dk2.dts对于usart2设备节点的描述，增加usart3内容如下：
<pre><nowiki>
&usart3 {
    pinctrl-names = "default", "sleep", "idle";
    pinctrl-0 = <&usart3_pins_bt>;
    pinctrl-1 = <&usart3_idle_pins_bt>;
    pinctrl-2 = <&usart3_sleep_pins_bt>;
    uart-has-rtscts; 
    status = "okay";
        
    bluetooth {
        pinctrl-names = "default";
        pinctrl-0 = <&btreg0>;
        compatible = "brcm,bcm43438-bt";
        max-speed = <3000000>;
        vbat-supply = <&v3v3>;
        vddio-supply = <&v3v3>;
    };
};
</nowiki></pre>
这里用到了一个btreg0管脚用于控制AP6236蓝牙模块的硬件复位，stm32mp15-pinctrl.dtsi没有对于btreg0管脚的描述，需要增加如下内容描述：
<pre><nowiki>
btreg0: bt_reg_on-0 {
    pins {
        pinmux = <STM32_PINMUX('D', 13, GPIO)>;
        drive-push-pull;
        bias-pull-up;
        output-high;
        slew-rate = <0>;
    };
};
</nowiki></pre>
同时stm32mp15-pinctrl.dtsi对于usart3的描述与FS-MP1A所使用管脚不一致，所以无法直接使用，需参考其增加如下内容：
<pre><nowiki>
usart3_pins_bt: usart3-bt-0 {
    pins1 {
       pinmux = <STM32_PINMUX('D', 8, AF7)>, /* USART3_TX */
              <STM32_PINMUX('D', 12, AF7)>; /* USART3_RTS */
       bias-disable;
       drive-push-pull;
       slew-rate = <0>;
    };
    pins2 {
       pinmux = <STM32_PINMUX('D', 9, AF7)>, /* USART3_RX */
              <STM32_PINMUX('D', 11, AF7)>; /* USART3_CTS_NSS */
       bias-disable;
    }; 
};

usart3_idle_pins_bt: usart3-idle-bt-0 {
    pins1 {
        pinmux = <STM32_PINMUX('D', 8, ANALOG)>, /* USART3_TX */
               <STM32_PINMUX('D', 12, ANALOG)>, /* USART3_RTS */
               <STM32_PINMUX('D', 11, ANALOG)>; /* USART3_CTS_NSS */
    };
    pins2 {
        pinmux = <STM32_PINMUX('D', 9, AF7)>; /* USART3_RX */
        bias-disable;
    };
};

usart3_sleep_pins_bt: usart3-sleep-bt-0 {
    pins {
         pinmux = <STM32_PINMUX('D', 8, ANALOG)>, /* USART3_TX */
                <STM32_PINMUX('D', 12, ANALOG)>, /* USART3_RTS */
                <STM32_PINMUX('D', 11, ANALOG)>, /* USART3_CTS_NSS */
                <STM32_PINMUX('D', 9, ANALOG)>; /* USART3_RX */
    };
};
</nowiki></pre>
*RTC节点<br>

AP6236需要使用一个外部输入的32.768Hz的时钟源，因此我们需要使能RTC的外部32.768Hz功能<br>

参考文档：
 Documentation/devicetree/bindings/rtc/st,stm32-rtc.txt
内核中ST对STM32MP15x系列芯片的设备树资源了做了定义，可参见：
 arch/arm/boot/dts/stm32mp151.dtsi
stm32mp151中rtc定义如下：
<pre><nowiki>
rtc: rtc@5c004000 {
    compatible = "st,stm32mp1-rtc";
    reg = <0x5c004000 0x400>;
    clocks = <&scmi0_clk CK_SCMI0_RTCAPB>,
         <&scmi0_clk CK_SCMI0_RTC>;
    clock-names = "pclk", "rtc_ck";
    interrupts-extended = <&exti 19 IRQ_TYPE_LEVEL_HIGH>;
    status = "disabled";
};
</nowiki></pre>
上述代码只对rtc做了基本的初始化，并没有针对不同的硬件设计做适配，所以需结合硬件补全设备树节点信息。<br>

参考stm32mp157f-dk2.dts对于rtc设备节点的描述，需增加内容如下：
<pre><nowiki>
rtc {
 	  st,lsco = <RTC_OUT2_RMP>;
 	  pinctrl-0 = <&rtc_out2_rmp_pins_a>;
 	  pinctrl-names = "default";
   status = "okay";
};
</nowiki></pre>

==实验目的==
熟悉基于Linux操作系统下的蓝牙设备驱动移植配置过程。

==实验平台==
==实验步骤==