android驱动学习-led次设备号(2)
跟上篇同例，只是测试LED次设备号。
内核版本：android-kernel-2.6.36
android版本：2.3.4
目的：应用上布局4个按键，分别点亮LED1~4.
------------------------------------------------------------
驱动：
#include <linux/module.h> /* For module specific items */
#include <linux/moduleparam.h> /* For new moduleparam's */
#include <linux/types.h> /* For standard types (like size_t) */
#include <linux/errno.h> /* For the -ENODEV/... values */
#include <linux/kernel.h> /* For printk/panic/... */
#include <linux/fs.h> /* For file operations */
#include <linux/ioport.h> /* For io-port access */
#include <linux/platform_device.h> /* For platform_driver framework */
#include <linux/init.h> /* For __init/__exit/... */
#include <linux/uaccess.h> /* For copy_to_user/put_user/... */
#include <linux/io.h> /* For inb/outb/... */
#include <linux/gpio.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/slab.h> /*kmalloc */
#define CMD_FLAG 'i'
#define LED_ON _IOR(CMD_FLAG,0x00000000,__u32)
#define LED_OFF _IOR(CMD_FLAG,0x00000001,__u32)
//LED1 - LED4
//gpk4 - gpk7
static int major =0;
static int minor =4;
static struct class *led_class;
struct cdev_led {
struct cdev cdev;
};
static struct cdev_led *led_dev;
//ioctl
static int led_ioctl (struct file* filp,unsigned int cmd,unsigned long argv)
{
printk(KERN_INFO "ioctl mode...\n");
int minor = iminor(filp->f_path.dentry->d_inode);
printk(KERN_INFO "minor :%d\n",minor);
switch(cmd)
{
case LED_ON:
gpio_set_value(S3C64XX_GPK(minor+4),0);
break;
case LED_OFF:
gpio_set_value(S3C64XX_GPK(minor+4),1);
break;
default:
return -EINVAL;
}
return 0;
}
//open
static int led_open(struct inode* i_node,struct file* filp)
{
printk(KERN_INFO "open mode...\n");
int err;
int minor = iminor(i_node);
printk(KERN_INFO "open minor : %d\n",minor);
err = gpio_request(S3C64XX_GPK(minor+4),"myled");
if(err<0)
{
printk(KERN_INFO "gpio request faile\n");
return err;
}
gpio_direction_output(S3C64XX_GPK(minor+4),1);
return 0;
}
//close
static void led_close(struct inode* i_node,struct file* filp)
{
printk(KERN_INFO "close mode...\n");
int minor = iminor(i_node);
gpio_free(S3C64XX_GPK(minor+4));
}
// file operations
static struct file_operations fops={
.owner = THIS_MODULE,
.open = led_open,
.unlocked_ioctl = led_ioctl,
.release = led_close
};
static void led_init_hw(struct cdev_led *dev,int minor)
{
dev_t dev_no=MKDEV(major,minor); //根据主设备号和次设备号，获取设备节点。
cdev_init( &dev->cdev,&fops);
dev->cdev.owner = THIS_MODULE;
int err = cdev_add(&dev->cdev,dev_no,1); //根据一个设备节点，加载一个设备。
if(err)
printk(KERN_INFO "error , add cdev\n");
}
static int __init led_init(void)
{
dev_t dev_no;
int result;
result = alloc_chrdev_region(&dev_no,0,minor,"myled"); //动态创建字符设备节点,有4个次设备号，就分配4个。
if(result < 0)
{
printk(KERN_INFO "alloc dev_no faile\n");
return result;
}
major = MAJOR(dev_no);
led_dev = kmalloc(4*sizeof(struct cdev_led),GFP_KERNEL);
if(!led_dev)
{
result =-ENOMEM;
goto faile_malloc;
}
memset(led_dev,0,4*(sizeof(struct cdev_led)));
int i ;
for(i=0;i<minor;i++)
{
led_init_hw(&led_dev[i],i); //创建4个设备。
}
led_class = class_create(THIS_MODULE,"myled");
for(i=0;i<minor;i++)
{
device_create(led_class,NULL,MKDEV(major,i),NULL,"myled%d",i);
}
return 0;
faile_malloc:
return result;
}
static void __exit led_exit(void)
{
dev_t dev_no = MKDEV(major,0);
int i;
for(i=0;i<minor;i++)
cdev_del(&((led_dev+i)->cdev));
unregister_chrdev_region(dev_no,4);
kfree(led_dev);
device_destroy(led_class,dev_no);
class_destroy(led_class);
}
module_init(led_init);
module_exit(led_exit);
MODULE_AUTHOR("koliy <[email protected]>");
MODULE_DESCRIPTION("ARM test led minor");
MODULE_LICENSE("GPL");
Makefile：
KERN_DIR = /android/linux-2.6.36-android
all:
make -C $(KERN_DIR) M=`pwd` modules
clean:
make -C $(KERN_DIR) M=`pwd` clean
obj-m += android_led.o
================================================================
接下来布局好android的应用层按键，这里就简单贴上，主要是怎么调用JNI接口。
在这里说下，类名和JNI接口函数名称不要带'_'符号，因JNI会转换成' . '，造成java调用不到JNI接口。
package sz.ics.arm.test;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
public class Minor extends Activity implements OnClickListener {
private Button bt_led1_on,bt_led1_off;
private Button bt_led2_on,bt_led2_off;
private Button bt_led3_on,bt_led3_off;
private Button bt_led4_on,bt_led4_off;
private Button bt_led_exit;
private static final int LED_ON = 0;
private static final int LED_OFF = 1;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
findID();
setOnclick();
// Minor_ledActivity p = new Minor_ledActivity();
}
private void findID()
{
bt_led1_on = (Button)findViewById(R.id.led1_on);
bt_led1_off = (Button)findViewById(R.id.led1_off);
bt_led2_on = (Button)findViewById(R.id.led2_on);
bt_led2_off = (Button)findViewById(R.id.led2_off);
bt_led3_on = (Button)findViewById(R.id.led3_on);
bt_led3_off = (Button)findViewById(R.id.led3_off);
bt_led4_on = (Button)findViewById(R.id.led4_on);
bt_led4_off = (Button)findViewById(R.id.led4_off);
bt_led_exit =(Button)findViewById(R.id.led_exit);
}
private void setOnclick()
{
bt_led1_on.setOnClickListener(this);
bt_led1_off.setOnClickListener(this);
bt_led2_on.setOnClickListener(this);
bt_led2_off.setOnClickListener(this);
bt_led3_on.setOnClickListener(this);
bt_led3_off.setOnClickListener(this);
bt_led4_on.setOnClickListener(this);
bt_led4_off.setOnClickListener(this);
bt_led_exit.setOnClickListener(this);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
try{
switch(v.getId()){
case R.id.led1_on:{
Minor p =new Minor();
int err = p.ledopen("/dev/myled0");
if(err < 0)
{
setTitle("don't open.");
finish();
}
setTitle("open");
p.ledioctl(LED_ON);
break;
}
case R.id.led1_off:{
Minor p =new Minor();
p.ledioctl(LED_OFF);
p.ledclose("/dev/myled0");
break;
}
case R.id.led2_on:{
int err = this.ledopen("/dev/myled1");
if(err < 0)
{
Toast.makeText(this, "error! don't load lib", Toast.LENGTH_LONG);
finish();
}
this.ledioctl(LED_ON);
break;
}
case R.id.led2_off:{
this.ledioctl(LED_OFF);
this.ledclose("/dev/myled1");
break;
}
case R.id.led3_on:{
int err = this.ledopen("/dev/myled2");
if(err < 0)
{
Toast.makeText(this, "error! don't load lib", Toast.LENGTH_LONG);
finish();
}
this.ledioctl(LED_ON);
break;
}
case R.id.led3_off:{
this.ledioctl(LED_OFF);
this.ledclose("/dev/myled2");
break;
}
case R.id.led4_on:{
int err = this.ledopen("/dev/myled3");
if(err < 0)
{
Toast.makeText(this, "error! don't load lib", Toast.LENGTH_LONG);
finish();
}
this.ledioctl(LED_ON);
break;
}
case R.id.led4_off:{
this.ledioctl(LED_OFF);
this.ledclose("/dev/myled3");
break;
}
case R.id.led_exit:{
finish();
break;
}
default:
{
finish();
return ;
}
}
}catch(Exception e)
{
e.printStackTrace();
}
}
/*
* load lib
*/
static {
try{
System.loadLibrary("led");
}catch(Exception e){
e.printStackTrace();
}
}
public native int ledopen(String dev);
public native void ledclose(String dev);
public native int ledioctl(int cmd);
}
JNI：对JNI方法不了解的请到我的第一篇去下载JNI学习资料。
/*
* Copyright 2009 Cedric Priscal
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <termios.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <jni.h>
#include <dirent.h>
int fd =0;
#define CMD_FLAG 'i'
#define LED_ON _IOR(CMD_FLAG,0x00000000,__u32)
#define LED_OFF _IOR(CMD_FLAG,0x00000001,__u32)
#include "android/log.h"
static const char *TAG="led-jni";
#define LOGI(fmt, args...) __android_log_print(ANDROID_LOG_INFO, TAG, fmt, ##args)
#define LOGD(fmt, args...) __android_log_print(ANDROID_LOG_DEBUG, TAG, fmt, ##args)
#define LOGE(fmt, args...) __android_log_print(ANDROID_LOG_ERROR, TAG, fmt, ##args)
/* * Class: minor_led
* Method: led_open
* Signature: ([java/lang/string)I
*/
JNIEXPORT jint JNICALL
Java_sz_ics_arm_test_Minor_ledopen(JNIEnv*env,jobject obj,jstring dev)
{
LOGI("entry open---> ");
char dev_name[128];
int len=(*env)->GetStringLength(env,dev);
(*env)->GetStringUTFRegion(env,dev,0,len,dev_name); //不涉及内存操作
LOGI("%s\n",dev_name);
dev_name[len]='\0';
fd = open(dev_name,O_RDWR);
if(fd<0)
{
LOGI("Don't open %s\n",dev_name);
return -1;
}
return 0;
}
/** Class minor_led
* Method: led_close
* Signature: ([java/lang/string)V
*/
JNIEXPORT void JNICALL
Java_sz_ics_arm_test_Minor_ledclose(JNIEnv*env,jobject obj,jstring dev)
{
LOGI("entry close---> ");
const char * dev_name;
dev_name =(*env)->GetStringUTFChars(env,dev,NULL); //涉及内存操作，需另外malloc、strcpy之后，再操作返回值，耗时费力
if(dev_name == NULL){
LOGI("Don't get %s\n",dev_name);
return;
}
LOGI(" get %s\n",dev_name);
(*env)->ReleaseStringUTFChars(env,dev,dev_name);
close(fd);
}
/** Class minor_led
* Method: led_ioctl
* Signature: (I)I
*/
JNIEXPORT jint JNICALL
Java_sz_ics_arm_test_Minor_ledioctl(JNIEnv* env,jobject obj,jint cmd)
{
LOGI("entry ioctl---> ");
if(cmd>0)
ioctl(fd,LED_OFF,NULL);
else
ioctl(fd,LED_ON,NULL);
return 0;
}
上文提到，生成libxx.so通过NDK工具来生成，所以编写
Android.mk 文件
LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) TARGET_PLATFORM := android-3 LOCAL_MODULE := led LOCAL_SRC_FILES := led.c LOCAL_LDLIBS := -llog include $(BUILD_SHARED_LIBRARY)
最后把应用工程包放进NDK里编译，具体步骤看上篇博文。