【Rayeager PX2】PX2上使用GPIO口的例程

時間 2019-11-11

標籤 Rayeager PX2 px2 使用 gpio 例程欄目 CSS 简体版

原文原文鏈接

以前樓主在論壇中已經分享了簡單驅動的編寫，如今樓主再來教剛接觸板子的新手們如何引用調用GPIO，不過這裏樓主並無將GPIO口的函數封裝成庫，而後在eclipse上調用，樓主這邊的例子，只是簡單的用adb工具進入板中，而後用一個測試程序使用端口，有興趣想要在安卓界面調用端口的，能夠參考樓主以前寫的那編jni調用的帖子。node

首先咱們依舊來簡單地說下步驟，linux

1.在/kernel/drivers下建個文件夾，本身建立並添加Kconfig和makefile，內容以下，app

2.在該目錄下寫個gpio驅動，內容在最後eclipse

3.返回drivers目錄，在目錄下修改Kconfig和makefile,修改內容以下函數

4.進入內核，打開已寫好的驅動。工具

驅動內容以下，測試

/***********************************************************************************ui

* driver for GPIO接口

* ip

**********************************************************************************/

#include <linux/miscdevice.h>

#include <linux/input.h>

#include <linux/clk.h>

#include <linux/delay.h>

#include <asm/io.h>

#include <asm/uaccess.h>

#include <linux/module.h>

#include <linux/init.h>

#include <mach/gpio.h>

#include <linux/gpio.h>

#define DEVICE_NAME "rkpx2_GPIO" //定義設備名

#define RKPX2_GPIO_MAJOR 101 //定義設備號

static struct class *dev_class//定義設備結構體

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

{

int i

int err

i=0

err = gpio_request(RK30_PIN4_PD1, "GPIO4_D1")//申請端口gpio4_1，成功返回0,失敗返回負的錯誤值

if(err)

{

printk(KERN_ERR "RK_PX2 failed to request GPIO4_D1 \n")

return err

}//若申請失敗，則報錯，而後推出，

err = gpio_request(RK30_PIN4_PD2, "GPIO4_D2")//申請端口gpio4_2，成功返回0,失敗返回負的錯誤值

if(err)

{

printk(KERN_ERR "RK_PX2 failed to request GPIO4_D2 \n")

return err

}

err = gpio_request(RK30_PIN4_PD3, "GPIO4_D3")//申請端口gpio4_3，成功返回0,失敗返回負的錯誤值

if(err)

{

printk(KERN_ERR "RK_PX2 failed to request GPIO4_D3 \n")

return err

}

err = gpio_request(RK30_PIN4_PD4, "GPIO4_D4")//申請端口gpio4_4，成功返回0,失敗返回負的錯誤值

if(err)

{

printk(KERN_ERR "RK_PX2 failed to request GPIO4_D4 \n")

return err

}

printk(KERN_INFO "RK_PX2 GPIO opened 4 !\n")

gpio_direction_output(RK30_PIN4_PD1,1)//決定GPIO的方向，爲輸出

gpio_direction_output(RK30_PIN4_PD2,1)

gpio_direction_output(RK30_PIN4_PD3,1)

gpio_direction_output(RK30_PIN4_PD4,1)

return 0

}

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

{

gpio_free(RK30_PIN4_PD1)

gpio_free(RK30_PIN4_PD2)

gpio_free(RK30_PIN4_PD3)

gpio_free(RK30_PIN4_PD4) //釋放端口，

printk(KERN_INFO "RK_PX2 GPIO driver successfully close\n")

return 0

}

static int gpio_read(struct file *file, char *buffer, size_t size, loff_t *pos) //從內核中讀取GPIO引腳的值

{

int ret

char key_buf[4]

if (gpio_get_value(RK30_PIN4_PD1)==0){

key_buf[0]=0

}else{

key_buf[0]=1

}

if (gpio_get_value(RK30_PIN4_PD2)==0){

key_buf[1]=0

}else{

key_buf[1]=1

}

if (gpio_get_value(RK30_PIN4_PD3)==0){

key_buf[2]=0

}else{

key_buf[2]=1

}

if (gpio_get_value(RK30_PIN4_PD4)==0){

key_buf[3]=0

}else{

key_buf[3]=1

}

ret=copy_to_user(buffer,key_buf,4)//拷貝數據到用戶區，成功爲 0,失敗爲字節數

return ret

}

static long gpio_ioctl(struct file *file ,unsigned int cmd,unsigned long arg){

switch(cmd){//改變引腳的電平值

case 00: gpio_set_value(RK30_PIN4_PD1,0)

printk("GPIO_D1 is low!\n")

break

case 01: gpio_set_value(RK30_PIN4_PD1,1)

printk("GPIO_D1 is high!\n")

break

case 10: gpio_set_value(RK30_PIN4_PD2,0)

printk("GPIO_D2 is low!\n")

break

case 11: gpio_set_value(RK30_PIN4_PD2,1)

printk("GPIO_D2 is high!\n")

break

case 20: gpio_set_value(RK30_PIN4_PD3,0)

printk("GPIO_D3 is low!\n")

break

case 21: gpio_set_value(RK30_PIN4_PD3,1)

printk("GPIO_D3 is high!\n")

break

case 30: gpio_set_value(RK30_PIN4_PD4,0)

printk("GPIO_D4 is low!\n")

break

case 31: gpio_set_value(RK30_PIN4_PD4,1)

printk("GPIO_D4 is high!\n")

break

}

return 0

}

/*驅動接口設置*/

static struct file_operations dev_fops = {

.owner = THIS_MODULE,

//.unlocked_ioctl = tq210_gpio_ioctl,

.open = gpio_open,

.release = gpio_close,

.read = gpio_read,

.unlocked_ioctl = gpio_ioctl,

}

/*初始化設備，配置對應的IO，以及註冊設備*/

static int __init dev_init(void)

{

int ret

ret=0

ret = register_chrdev(RKPX2_GPIO_MAJOR,"rkpx2_GPIO",&dev_fops)//註冊

if (ret<0) {

printk("rkpx2 GPIO for test unable to get major%d \n",ret)

return ret

}

dev_class = class_create(THIS_MODULE,"rkpx2_GPIO")//初始化

if (IS_ERR(dev_class)){

unregister_chrdev(RKPX2_GPIO_MAJOR,"rkpx2_GPIO")

return PTR_ERR(dev_class)

}

device_create(dev_class,NULL,MKDEV(RKPX2_GPIO_MAJOR,0),NULL,"rkpx2_GPIO")//建立設備

printk(KERN_INFO "RKPX2 GPIO driver successfully probed!\n")

return ret

}

/*註銷設備*/

static void __exit dev_exit(void)

{

//misc_deregister(&dev_misc)

gpio_free(RK30_PIN4_PD1)

gpio_free(RK30_PIN4_PD2)

gpio_free(RK30_PIN4_PD3)

gpio_free(RK30_PIN4_PD4)

printk(KERN_INFO "RKPX2 gpio driver successfully exit\n")

}

module_init(dev_init)

module_exit(dev_exit)

MODULE_AUTHOR("Rayeager cyl")

MODULE_DESCRIPTION("rkpx2 gpio Driver")

MODULE_LICENSE("GPL")

而後測試程序內容以下：

#include <stdio.h>

#include <stdlib.h>

#include <fcntl.h>

#include <string.h>

#define DEVICE_NAME "/dev/rkpx2_GPIO"

#define LED_OFF 0

#define LED_ON 1

int main(int argc,char **argv){

int fd

int ret

int flag

int pin

int ch

printf("\n start test gpio_drivers\n")

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

fd=open(DEVICE_NAME,O_RDWR)

if (fd==-1){

printf("open devices %s error\n",DEVICE_NAME)

}

printf("input the pin you want to operate")

scanf("%d",&pin)

printf("\n")

printf("it will be set ?(1=on or 0=off):")

scanf("%d",&ch)

switch(pin){

case 0: (ch==1?ioctl(fd,1):ioctl(fd,2))break

case 1: (ch==1?ioctl(fd,3):ioctl(fd,4))break

case 2: (ch==1?ioctl(fd,5):ioctl(fd,6))break

case 3: (ch==1?ioctl(fd,7):ioctl(fd,8))break

}

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

fd=open(DEVICE_NAME,O_RDWR)

close(fd)

}

return 0

}

Android.mk的內容

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_SRC_FILES:=\

test.c

LOCAL_MODULE:=gpioapp

include$(BUILD_EXECUTABLE)

編譯測試程序的方法:在源碼任意位置建個目錄，把Android.mk和測試程序全扔進去，而後執行mm（如今根目錄執行source build/envsetup.sh）

實際操做，過程就不說了，親測可行，正常操做的端口爲GPIO4_1234

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