一、配置GPIO读

在视频14的基础上做

1.利用拨码开关来实现GPIO输入

所以AP_SLEEP对应GPC0_3，然后在drivers/gpio/gpio-exynos4.c中对应EXYNOS4_GPC0(0)

XEINT6→GPX0_6→EXYNOS4_GPX0(6)

读寄存器手册分析流程：

1. 设置寄存器为输入　　GPC0CON

2. 读寄存器值　　　　　GPC0DAT

3. 不上拉，不下拉　　　GPC0PUD

2.GPIO的输入需要哪些函数，从archarmplat-samsunggpio-config.c中找

• 申请gpio_request

• 读寄存器gpio_get_value

• 设置GPIO为输入模式s3c_gpio_cfgpin  S3C_GPIO_INPUT

• 设置上拉下拉s3c_gpio_setpull S3C_GPIO_PULL_NONE

• 释放GPIO gpio_free

3.平台文件中设备注册

 在文件arch/arm/mach-exynos/mach-itop4412.c中：

    struct platform_device s3c_device_read_gpio_ctl = {
        .name   = "read_gpio_ctl",
        .id     = -1,
    };

　　&s3c_device_read_gpio_ctl,

在init_lcd_type函数中request了GPIO。所以在get_lcd_type需要释放GPIO

    gpio_free(EXYNOS4_GPC0(3));
    gpio_free(EXYNOS4_GPX0(6));

4.Makefile修改

Makefile

TARGET_NAME = read_gpio

APP_NAME = app_read_gpio

obj-m += $(TARGET_NAME).o

KDIR := /home/topeet/chen/kernel-3.0/iTop4412_Kernel_3.0

PWD ?= $(shell pwd)

all:app

    make -C $(KDIR) M=$(PWD) modules

app:$(APP_NAME)

    arm-none-linux-gnueabi-gcc $(APP_NAME).c -o $(APP_NAME) -static

clean:

    rm -rf *.o *.ko *.mod.c *.symvers *.order

    .$(TARGET_NAME)* $(APP_NAME)

5.驱动的修改

read_gpio.c

#include

#include

/*驱动注册的头文件，包含驱动的结构体和注册和卸载的函数*/

#include

/*注册杂项设备头文件*/

#include

/*注册设备节点的文件结构体*/

#include

/*Linux中申请GPIO的头文件*/

#include

/*三星平台的GPIO配置函数头文件*/

/*三星平台EXYNOS系列平台，GPIO配置参数宏定义头文件*/

#include

#include

/*三星平台4412平台，GPIO宏定义头文件*/

#include

#define DRIVER_NAME "read_gpio_ctl"

#define DEVICE_NAME "read_gpio_ctl"

MODULE_LICENSE("Dual BSD/GPL");

MODULE_AUTHOR("TOPEET");

static long read_gpio_ioctl( struct file *files, unsigned int cmd, unsigned long arg)

{

    printk("cmd is %d,arg is %dn",cmd,arg);

    if(cmd > 1){

        printk(KERN_EMERG "cmd is 0 or 1n");

    }

    if(arg > 1){

        printk(KERN_EMERG "arg is only 1n");

    }

    //if cmd is 0, return GPC(3)>>switch3

    //if cmd is 1, return GPX(6)>>switch4

    if(cmd == 0) {

        return gpio_get_value(EXYNOS4_GPC0(3));

    }

    if(cmd == 1) {

        return gpio_get_value(EXYNOS4_GPX0(6));

    }

    return 0;

}

static int read_gpio_release(struct inode *inode, struct file *file)

{

    printk(KERN_EMERG "read_gpio releasen");

    return 0;

}

static int read_gpio_open(struct inode *inode, struct file *file)

{

    printk(KERN_EMERG "read_gpio openn");

    return 0;

}

static struct file_operations read_gpio_ops = {

    .owner = THIS_MODULE,

    .open = read_gpio_open,

    .release = read_gpio_release,

    .unlocked_ioctl = read_gpio_ioctl,

};

static  struct miscdevice read_gpio_dev = {

    .minor = MISC_DYNAMIC_MINOR,

    .name = DEVICE_NAME,

    .fops = &read_gpio_ops,

};

static int read_gpio_probe(struct platform_device *pdv)

{

    int ret;

    printk(KERN_EMERG "tinitializedn");

    ret = gpio_request(EXYNOS4_GPC0(3),"Switch3");

    if(ret < 0){

        printk(KERN_EMERG "gpio_request EXYNOS4_GPL2(0) failed!n");

        return ret;

    } else {

        s3c_gpio_cfgpin(EXYNOS4_GPC0(3), S3C_GPIO_INPUT);

        s3c_gpio_setpull(EXYNOS4_GPC0(3), S3C_GPIO_PULL_NONE);

    }

    ret = gpio_request(EXYNOS4_GPX0(6),"Switch4");

    if(ret < 0){

        printk(KERN_EMERG "gpio_request EXYNOS4_GPL2(0) failed!n");

        return ret;

    } else {

        s3c_gpio_cfgpin(EXYNOS4_GPX0(6), S3C_GPIO_INPUT);

        s3c_gpio_setpull(EXYNOS4_GPX0(6), S3C_GPIO_PULL_NONE);

    }

    misc_register(&read_gpio_dev);

    return 0;

}

static int read_gpio_remove(struct platform_device *pdv)

{    

    printk(KERN_EMERG "tremoven");

    gpio_free(EXYNOS4_GPC0(3));

    gpio_free(EXYNOS4_GPX0(6));

    misc_deregister(&read_gpio_dev);

    return 0;

}

static void read_gpio_shutdown(struct platform_device *pdv)

{

    ;

}

static int read_gpio_suspend(struct platform_device *pdv,pm_message_t pmt)

{

    return 0;

}

static int read_gpio_resume(struct platform_device *pdv)

{

    return 0;

}

struct platform_driver read_gpio_driver = {

    .probe = read_gpio_probe,

    .remove = read_gpio_remove,

    .shutdown = read_gpio_shutdown,

    .suspend = read_gpio_suspend,

    .resume = read_gpio_resume,

    .driver = {

        .name = DRIVER_NAME,

        .owner = THIS_MODULE,

    }

};

static int read_gpio_init(void)

{

    int DriverState;

    printk(KERN_EMERG "read_gpio enter!n");

    DriverState = platform_driver_register(&read_gpio_driver);

    printk(KERN_EMERG "tDriverState is %dn",DriverState);

    return 0;

}

static void read_gpio_exit(void)

{

    printk(KERN_EMERG "read_gpio exit!n");

    platform_driver_unregister(&read_gpio_driver);    

}

module_init(read_gpio_init);

module_exit(read_gpio_exit);

应用程序：

app_read_gpio

#include

#include

#include

#include

#include

#include

#include

#define GPIOS 32

int main(int argc, char *argv[])

{

        int fd, i, cmd = 2;

        char *read_gpio = "/dev/read_gpio_ctl";

        char *cmd0 = "0";

        char *cmd1 = "1";

        printf("argv[0] is %s;argv[1] is %s;n", argv[0], argv[1]);

        if(strcmp(argv[1], cmd0) == 0) {

                cmd = 0;

        }

        if(strcmp(argv[1], cmd1) == 0) {

                cmd = 1;

        }

        if((fd = open(read_gpio, O_RDWR|O_NDELAY)) < 0) {

                printf("APP open %s failedn", read_gpio);

        } else {

                printf("APP open %s success!n", read_gpio);

                printf("%d io value is %dn", cmd, ioctl(fd, cmd, 0));

        }

        close(fd);

}

测试结果：

[root@iTOP-4412]# ./app_read_gpio 1                                                                        

argv[0] is ./app_[  312.514145] read_gpio open

[  312.516876] cmd is 1,arg is 0

[  312.519870] read_gpio release

read_gpio;argv[1] is 1;

APP open /dev/read_gpio_ctl success!

1 io value is 0

[root@iTOP-4412]# ./app_read_gpio 0                                                                        

argv[0] is ./app_[  314.786489] read_gpio open

[  314.789131] cmd is 0,arg is 0

[  314.792307] read_gpio release

read_gpio;argv[1] is 0;

APP open /dev/read_gpio_ctl success!

0 io value is 0

[root@iTOP-4412]# ./app_read_gpio 1                                                                        

argv[0] is ./app_[  321.786146] read_gpio open

[  321.788790] cmd is 1,arg is 0

[  321.791899] read_gpio release

read_gpio;argv[1] is 1;

APP open /dev/read_gpio_ctl success!

1 io value is 1

[root@iTOP-4412]# ./app_read_gpio 0                                                                        

argv[0] is ./app_[  323.449833] read_gpio open

[  323.452526] cmd is 0,arg is 0

[  323.455489] read_gpio release

read_gpio;argv[1] is 0;

APP open /dev/read_gpio_ctl success!

0 io value is 1

二、ioremap控制GPIO寄存器

上面使用的是直接通过软件转换好了的，其实内核也是可以自己做转化的。

自己实现物理地址到虚拟地址的转化，iounmap和ioremap函数可以实现物理地址到虚拟地址的转化

1.硬件

•  原理图部分

• datasheet物理地址

• GPL2CON = 0x1100 0000 + 0x0100 = 0x1100 0100

• GPL2DAT = 0x1100 0000 + 0x0104 = 0x1100 0104

• GPL2PUD = 0x1100 0000 + 0x0108 = 0x1100 0108

• 寄存器不一定是32位的，也有16位或8位的

2.软件

ioremap_leds.c

#include

#include

#include

MODULE_LICENSE("Dual BSD/GPL");

MODULE_AUTHOR("Topeet");

//用于存放虚拟地址和物理地址

volatile unsigned long virt_addr, phys_addr;