内核编译常用命令
安装模块
lsmod module_test.ko
创建设备文件
mknod /dev/test c 250 0
查看设备状态
lsmod module_test.ko
查看设备注册信息(分为字符设备和块设备)
cat /proc/devices
知识补充:
#include<stdio.h> int main(void) { int i; static int j; printf(i); printf(j); } // 注意：这里如果没有指定i值，则打印出来的是随机值 // 如果定义一个静态变量而没有赋值，则打印默认为0
虚拟驱动创建流程
首先进入x210_bsp/kernel
make menuconfig
make -j4
cp arch/arm/boot/zImage /tftpboot/ -f
重启开发板查看开发板设备
ls /sys/devices/platform/
cd sys/class/leds
led_test_4编写完成后
编译不报错即可
cd /root/x210_bsp/kernel/drivers/leds/
cp /mnt/hgfs/Myshare/driver/led_test_4/leds-s5pv210.c ./
vi Makefile->
obj-$(CONFIG_LEDS_S5PV210) += leds-s5pv210.o
vi Kconfig更改依赖（添加以下文件）
config LEDS_S5PV210 tristate "LED Support for S5PV210" help This option enables support for on-chip LED drivers found on Marvell Semiconductor 88PM8606 PMIC.
进入到x210_bsp/kernel
执行make menuconfig
可以发现生成了新的配置（Device Drivers-> LED_Support），使能这个
执行make编译
cp arch/arm/boot/zImage /tftpboot/ -f
secureCRT：
cd sys/class/leds
进入LED1,执行
echo 1 > brightness // 灯亮
echo 0 > brightness //灯灭
最后附上源代码：
leds-s5pv210.c
#include <linux/module.h> #include <linux/init.h> #include <linux/fs.h> #include <asm/uaccess.h> #include <mach/gpio-bank.h> #include <mach/regs-gpio.h> #include <linux/ioport.h> #include <asm/io.h> #include <linux/cdev.h> #include <linux/device.h> #include <mach/gpio.h> #include <linux/leds.h> #define GPIO_LED1 S5PV210_GPJ0(3) #define GPIO_LED2 S5PV210_GPJ0(4) #define GPIO_LED3 S5PV210_GPJ0(5) #define X210_LED_OFF 1 #define X210_LED_ON 0 struct led_classdev mydev1; struct led_classdev mydev2; struct led_classdev mydev3; void s5pv210_led1_set(struct led_classdev *led_cdev,enum led_brightness value) { printk(KERN_INFO "s5pv210_led1_set\n"); if(value == LED_OFF) { gpio_set_value(GPIO_LED1,X210_LED_OFF); } else { gpio_set_value(GPIO_LED1,X210_LED_ON); } } void s5pv210_led2_set(struct led_classdev *led_cdev,enum led_brightness value) { printk(KERN_INFO "s5pv210_led2_set\n"); if(value == LED_OFF) { gpio_set_value(GPIO_LED2,X210_LED_OFF); } else { gpio_set_value(GPIO_LED2,X210_LED_ON); } } void s5pv210_led3_set(struct led_classdev *led_cdev,enum led_brightness value) { printk(KERN_INFO "s5pv210_led3_set\n"); if(value == LED_OFF) { gpio_set_value(GPIO_LED3,X210_LED_OFF); } else { gpio_set_value(GPIO_LED3,X210_LED_ON); } } static int __init s5pv210_led_init(void) { int ret = -1; // 申请GPIO if(gpio_request(GPIO_LED1,"led1_gpj0.3")) { printk(KERN_ERR "gpio_request failed.\n"); } else { gpio_direction_output(GPIO_LED1,1); } mydev1.name = "led1"; mydev1.brightness = 0; mydev1.brightness_set = s5pv210_led1_set; ret = led_classdev_register(NULL,&mydev1); if(ret < 0) { printk(KERN_ERR "led_classdev_register failed.\n"); return ret; } mydev2.name = "led2"; mydev2.brightness = 0; mydev2.brightness_set = s5pv210_led2_set; ret = led_classdev_register(NULL,&mydev2); if(ret < 0) { printk(KERN_ERR "led_classdev_register failed.\n"); return ret; } mydev3.name = "led3"; mydev3.brightness = 0; mydev3.brightness_set = s5pv210_led3_set; ret = led_classdev_register(NULL,&mydev3); if(ret < 0) { printk(KERN_ERR "led_classdev_register failed.\n"); return ret; } return 0; } static void __exit s5pv210_led_exit(void) { led_classdev_unregister(&mydev1); led_classdev_unregister(&mydev2); led_classdev_unregister(&mydev3); gpio_free(GPIO_LED1); gpio_free(GPIO_LED2); gpio_free(GPIO_LED3); } module_init(s5pv210_led_init); module_exit(s5pv210_led_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("WYQ"); MODULE_DESCRIPTION("module_test");
Makefile
#KERN_VER = $(shell uname -r) #KERN_DIR = /lib/modules/$(KERN_VER)/build KERN_DIR = /root/x210_bsp/kernel obj-m += leds-s5pv210.o all: make -C $(KERN_DIR) M=`pwd` modules .PHONY:clean clean: make -C $(KERN_DIR) M=`pwd` modules clean
