TX2i设备树SPI驱动

默认/dev下是没有spi设备的

JetPack版本

JetPack-L4T-3.2.1-linux-x64_b23.run

下载Kernel

sudo git clone http://github.com/jetsonhacks/buildJetsonTX2Kernel.git

git checkout L4T32.2.1   //切换分支

./getKernelSources.sh   //获取源码

默认配置内核

cd /usr/src/kernel/kernel-4.4

make tegra18_defconfig

安装依赖

sudo apt-get install libncurses5-dev

配置内核

make menuconfig

模块方式加载SPI

编译内核

cd buildJetsonTX2Kernel

./makeKernel.sh

生成内核模块

反编译设备树

cd /boot/dtb    //目录下的就是当前模块使用的设备树

sudo /usr/src/kernel/kernel-4.4/scripts/dtc/dtc -I dtb -O dts -o myTX2iDeviceTree.dts tegra186-quill-p3489-1000-a00-00-ucm1.dtb

修改设备树

sudo vim myTX2iDeviceTree.dts

spi@3240000 {
    compatible = "nvidia,tegra186-spi";
    reg = <0x0 0x3240000 0x0 0x10000>;
    ...
    linux,phandle = <0x7d>;
    phandle = <0x7d>;
    spi@0 {
        compatible = "spidev";
        reg = <0x0>;
        spi-max-frequency = <0x1312D00>;
        nvidia,enable-hw-based-cs;
        nvidia,cs-setup-clk-count = <0x1e>;
        nvidia,cs-hold-clk-count = <0x1e>;
        nvidia,rx-clk-tap-delay = <0x1f>;
        nvidia,tx-clk-tap-delau = <0x0>;
    };        
};

重新编译设备树
sudo /usr/src/kernel/kernel-4.4/scripts/dtc/dtc -I dts -O dtb -o myTX2iDeviceTree.dtb myTX2iDeviceTree.dts

注：TX2i设备树反编译，也看不到设备树的修改记录

拷贝设备树

将myTX2iDeviceTree.dtb放到虚拟机的jetson/64_TX2/Linux_for_Tegr/kernel/dtb目录下

cp myTX2iDeviceTree.dtb tegra186-quill-p3489-1000-a00-00-ucm1.dtb    //覆盖原TX2i设备树文件

开发板进入Recovery模式

按住REC恢复键不放，轻点一下RST复位键

烧写设备树

cd jetson/64_TX2/Linux_for_Tegr

sudo ./flash.sh -r -k kernel-dtb jetson-tx2i mmcblk0p1    //将烧写tegra186-quill-p3489-1000-a00-00-ucm1.dtb文件

完成