dtb文件16进制以D0 0D FE ED开头
#从内核中获取dtb文件（海思dtb附在内核后面）
dd if=uImage of=hisi.dtb skip=3678808 bs=1 count=20k
#dtb转dts
dtc -I dtb -O dts -o hisi.dts hisi.dtb
中断设置两种方式，其中 interrupt-controller;#interrupt-cells = <0x2>;表示其他节点引用时用两个参数
1、interrupts = <0x0 0x39 0x4>; //三个参数，共享中断类型、中断号、中断触发方式高电平
中断号配置时减32
2、interrupt-parent = <&gpio_chip0>;
interrupts = <4 0x2>; //两个参数 中断gpio号、中断触发下降沿
配置can实例，已验证
1、使用spi0.3配置CAN节点
先配置管脚复用：can芯片中断引脚配置gpio模式、spi引脚配置spi模式（
如果中断gpio没有复用正确，则只能发送一帧
）
mw 0x120F01E4 0 (gpio0_4)
mw 0x120F0148 1 (sck)
mw 0x120F014C 1 (sdo)
mw 0x120F0150 1 (sdi)
内核menuconfig增加gpio支持（class、pl061）
海思HI3531A dts部分配置，增加gpio配置、can节点配置中断gpio0_4、net->can->mcp2515
海思HI3531A
hi3531a-demb.dts文件增加
&spi_bus0{
status = “okay”;
num-cs = <4>;
spidev@0 {
compatible = “rohm,dh2228fv”;
reg = <0>;
pl022,interface = <0>;
pl022,com-mode = <0>;
spi-max-frequency = <31250000>;
};
can0: can@10 {
compatible = “microchip,mcp2515”;
reg = <3>;
clocks = <&clk16m>;
spi-max-frequency = <2000000>;
interrupt-parent = <&gpio_chip0>;
interrupts = <4 0x2>;
status = “okay”;
};
};
hi3531a.dtsi文件
根目录下：
aliases {
fmc = &fmc;
serial0 = &uart0;
serial1 = &uart1;
serial2 = &uart2;
serial3 = &uart3;
i2c0 = &i2c_bus0;
i2c1 = &i2c_bus1;
spi0 = &spi_bus0;
gpio0 = &gpio_chip0;
};
clk16m:clk16m {
compatible = “fixed-clock”;
#clock-cells = <0x0>;
clock-frequency = <16000000>;
};
soc目录下：
gpio_chip0:gpio_chip@12150000 {
compatible = “arm,pl061”, “arm,primecell”;
reg = <0x12150000 0x10000>;
interrupts = <0x0 0x39 0x4>;
clocks = <&clock HI3531A_PERIAXI_CLK>;
clock-names = “apb_pclk”;
gpio-controller;
#gpio-cells = <0x2>;
interrupt-controller;
#interrupt-cells = <0x2>;
status = “okay”;
};
2、使用gpio模拟spi配置CAN节点
gpio模拟spi，内核配置开启spi->GPIO-based bitbanging SPI Master
配置管脚复用(UBOOT命令)
mw
0x120F02F4 0
（gpio15_0）
mw
0x120F02F8 0
（gpio15_1）
mw
0x120F02FC 0
（gpio15_2）
mw 0x120F01E0 0 （gpio0_3）
dts配置
spi_bus1: spi{
compatible = “spi-gpio”;
#address-cells = <1>;
#size-cells = <0>;
gpio-sck = <&gpio_chip15 0 0>;
gpio-mosi = <&gpio_chip15 1 0>;
gpio-miso = <&gpio_chip15 2 0>;
cs-gpios = <&gpio_chip20 4 0>; //cs-gpios = <&gpio_chip20 4 0>, <&gpio_chip20 3 0>, <&gpio_chip20 2 0>, <&gpio_chip20 0 0>;
num-chipselects = <1>; //num-chipselects = <4>;
};
&spi_bus1{
status = “okay”;
can0: can@10 {
compatible = “microchip,mcp2515”;
reg = <0>;
clocks = <&clk16m>;
spi-max-frequency = <2000000>;
interrupt-parent = <&gpio_chip0>;
interrupts = <3 0x2>;
status = “okay”;
};
};
启动can0接口(ip link set can0 up)时，有报错(RTNETLINK answers: No sucrh device)，mcp251x_read_reg/mcp251x_write_reg加打印后，发现是mcp251x_open函数内mcp251x_hw_reset出错了，读寄存器值为0。
原因：
1、进入应用后，gpio引脚被其他应用重新配置了，屏蔽即可
2、还有可能原因（网上）：尝试将mcp251x_hw_reset函数内的延时增大后，就解决了。问题原因是驱动发送第一个reset指令时，芯片还未初始化完成，读到的状态不对，加大延时就解决了。
#define MCP251X_OST_DELAY_MS (20)//(5)
版权声明：本文为weixin_55163060原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。