代码示例_平台总线

---

#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/miscdevice.h>

#include <asm/io.h>
#include <asm/uaccess.h>


static void *led_reg_base;
static struct miscdevice  led_misc;

//实现设备操作接口
int led_plat_drv_open(struct inode *inode, struct file *filp)
{

    printk("--------^_^ %s------------
",__FUNCTION__);
    // 对寄存器进行初始化
    unsigned long value = __raw_readl(led_reg_base);
    value &= ~(0xff<<12);
    value |= (0x11<<12); //配置成输出功能
    __raw_writel(value, led_reg_base);

    return 0;
}
ssize_t led_plat_drv_write(struct file *filp, const char __user *buf, size_t size, loff_t *flags)
{
    int ret;
    printk("--------^_^ %s------------
",__FUNCTION__);

    unsigned int  value;
    //应用空间数据转换为内核空间数据
    ret = copy_from_user(&value, buf, size);
    if(ret != 0){
        printk("copy_from_user error!
");
        return -EFAULT;
    }

    

    if(value)
    {
        // 将led亮起来
        __raw_writel(__raw_readl(led_reg_base + 4) | (0x3<<3), led_reg_base + 4);
    }else
    {
        __raw_writel(__raw_readl(led_reg_base + 4) &~(0x3<<3), led_reg_base + 4);
    }


    return size;
}

int led_plat_drv_close(struct inode *inode, struct file *filp)
{
    printk("--------^_^ %s------------
",__FUNCTION__);

    __raw_writel(__raw_readl(led_reg_base + 4) &~(0x3<<3), led_reg_base + 4);
    
    return 0;
}



const struct file_operations plat_led_fops = {
    .open = led_plat_drv_open,
    .write = led_plat_drv_write,
    .release = led_plat_drv_close,

};

int led_pdrv_probe(struct platform_device *pdev)
{
    printk("-----------%s-----------
", __FUNCTION__);


    //任务1---与应用交互
    // register_chrdev() , class_create, device_create, fops
    // 或一种写法---用一个函数搞定上面所有函数
    led_misc.name = "plat_led";  // /dev/plat_led
    led_misc.minor = 120;  // 主设备号默认为10， 次设备自由定义--MISC_DYNAMIC_MINOR(255)由系统分配
    led_misc.fops = &plat_led_fops;
    misc_register(&led_misc);
    

    //任务2---与硬件交互---先要获取资源， ioremap/request_irq()
    //参数1--从哪个pdev中获取
    //参数2--资源的类型
    //参数3--同种资源的第几个
    struct resource *mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

    //获取地址资源就需要进行地址映射
    led_reg_base = ioremap(mem_res->start,  resource_size(mem_res));



    return 0;
}
int led_pdrv_remove(struct platform_device *pdev)
{
    printk("-----------%s-----------
", __FUNCTION__);
    
    iounmap(led_reg_base);
    misc_deregister(&led_misc);
    
    return 0;
}


const struct platform_device_id led_id_table[] = {
        {"s5pv210_led", 0x123}, //第二个值随便写
        {"exynos4_led", 0x124},
        {"s5p6818_led", 0x444},
};


struct platform_driver led_pdrv = {
    .probe = led_pdrv_probe,
    .remove = led_pdrv_remove,
    .driver = { //父类一定要初始化
        .name = "samsung_led_drv", // 一定要初始化--自定义
    },
    .id_table = led_id_table,

};

static int __init plat_led_drv_init(void)
{

    //注册一个pdrv
    return platform_driver_register(&led_pdrv);

}

static void __exit plat_led_drv_exit(void)
{

    platform_driver_unregister(&led_pdrv);
}


module_init(plat_led_drv_init);
module_exit(plat_led_drv_exit);
MODULE_LICENSE("GPL");

---

#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>


#define GPC0_REG_BASE 0xE0200060
#define GPC0_SIZE 8

struct resource     led_res[] = {
    [0] = {
        .start = GPC0_REG_BASE,
        .end = GPC0_REG_BASE + GPC0_SIZE - 1,
        .flags = IORESOURCE_MEM,
    },
    //以下代码为演示如何定义多个资源--led硬件实际没有
    [1] = {
        .start = 0x666,
        .end = 0x666,
        .name = "fake_irq",
        .flags = IORESOURCE_IRQ,
    },
    [2] = {
        .start = 0x12345678,
        .end = 0x12345678 + 0x8 - 1,
        .name = "fake_mem",
        .flags = IORESOURCE_MEM,
    },
};


//主要用于解决rmmod的有警告
void    led_pdev_release(struct device *dev) //pdev从总线移除系统自动调用
{


}


struct platform_device  led_pdev = {
    .name = "s5pv210_led",
    .id = -1,
    .dev = {
        .release = led_pdev_release,
    },
    .num_resources = ARRAY_SIZE(led_res),
    .resource = led_res,
};


static int __init plat_led_dev_init(void)
{

    //注册一个pdev
    return platform_device_register(&led_pdev);

}

static void __exit plat_led_dev_exit(void)
{

    platform_device_unregister(&led_pdev);
}


module_init(plat_led_dev_init);
module_exit(plat_led_dev_exit);
MODULE_LICENSE("GPL");

---

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

int main(void)
{

    int fd;
    int on;

    fd = open("/dev/plat_led",O_RDWR);
    if(fd < 0)
    {
        perror("open");
        exit(1);
    }

    
    while(1)
    {
        
        on = 1;
        write(fd,&on,sizeof(on));
        sleep(1);

        
        on = 0;
        write(fd,&on,sizeof(on));
        sleep(1);
    }

    close(fd);
    return 0;
}

---

CROSS_COMPILE = arm-none-linux-gnueabi-
CC = $(CROSS_COMPILE)gcc

#指定内核源码路径
KERNEL_DIR = /home/farsight/s5pv210/kernel/driver/linux-3.0.8
CUR_DIR = $(shell pwd)

MYAPP = plat_led_app

MODULE = plat_led_dev
MODULE2 = plat_led_drv

all:
    #让make进入内核源码编译，同时将当前目录中的c程序作为内核模块一起编译
    make -C $(KERNEL_DIR) M=$(CUR_DIR) modules
ifneq ($(MYAPP), )    
    $(CC)  -o $(MYAPP) $(MYAPP).c
endif

clean:
    #删除上面编译生成的文件
    make -C $(KERNEL_DIR) M=$(CUR_DIR) clean
    rm -rf $(MYAPP)

install:
    cp *.ko $(MYAPP) /opt/rootfs/drv_module

#指定当前目录下哪个文件作为内核模块编
obj-m += $(MODULE).o
obj-m += $(MODULE2).o