给uboot添加命令 (LED)

1.在common文件夹下新建cmd_led_test.c
2.修改common/Makefile ，添加一行COBJS-y += cmd_led_test.o ，将cmd_led_test编译进uboot
3.编译
4.下载测试
U-Boot# led on
argc = 2
argv[0] is: led
argv[1] is: on
输入led on，可以发现led被亮了，我使用的是am335x GPIO3_16
U-Boot# led off
argc = 2
argv[0] is: led
argv[1] is: off
输入led off，可以发现led被熄灭

附源码cmd_led_test.c
//======================================

#define AM335X_GPIO3_BASE  0x481AE000

#define GPIO3_16_PIN 0x00010000

#define GPIO_OE 0x481AE134

#define GPIO_CLEARDATAOUT 0x481AE190

#define GPIO_SETDATAOUT 0x481AE194


#include <common.h>

#include <command.h>


static void led_on(){

    int * gpio_SETDATAOUT = (int *) GPIO_SETDATAOUT ;

    int * gpio_CLEARDATAOUT = (int *) GPIO_CLEARDATAOUT;

    int * gpio_OE = (int *) GPIO_OE;



    *gpio_OE = ~GPIO3_16_PIN;

    *gpio_SETDATAOUT = GPIO3_16_PIN;

}

static void led_off(){

    int * gpio_SETDATAOUT = (int *) GPIO_SETDATAOUT ;

    int * gpio_CLEARDATAOUT = (int *) GPIO_CLEARDATAOUT;



    int * gpio_OE = (int *) GPIO_OE;

    *gpio_OE = ~GPIO3_16_PIN;

    *gpio_CLEARDATAOUT = GPIO3_16_PIN;



}

static int do_led(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])

{

    int i = 0;

        printf("argc = %d\n",argc);

    for( i = 0; i < argc ; i++){

        printf("argv[%d] is: %s\n",i,argv[i]);

    }

    if( argc == 2){

        if( strcmp(argv[1],"on") == 0 ){

            led_on();

        }else{

            led_off();

        }

    }

    return 0;

}



U_BOOT_CMD(

    led, 2, 0, do_led,

    "led - this is a led command, light ON or OFF led2 ,which control by GPIO3_16",

    "- led - this is a led command, light ON or OFF led2 ,which control by GPIO3_16"

);