Android硬件访问服务(一)

#define IMX_GPIO_NR(port, index)		((((port)-1)*32)+((index)&31))
static int led_major = 211;
struct led_gpio_desc {
    int gpio;
    char *name;
};
static struct led_gpio_desc led_gpio [] = {
    {
        .gpio = IMX_GPIO_NR(3, 21),
        .name = "led4",
    },
    {
        .gpio = IMX_GPIO_NR(3, 22),
        .name = "led5",
    },
    {
        .gpio = IMX_GPIO_NR(3, 23),
        .name = "led6",
    },

};
static int led_gpio_open(struct inode *inode , struct file *filp)
{
    int ret;
    int i;

    for (i = 0; i < 3; i++) {
        if (gpio_is_valid(led_gpio[i].gpio)){
            ret = gpio_request(led_gpio[i].gpio, led_gpio[i].name);
            if (ret) {
                printk(KERN_ERR "led gpio request failed.\n");
                return -1;
            }
        }
    }
    return 0;
}
static long led_gpio_ctrl (struct file *file, unsigned int cmd, unsigned long args)
{
    gpio_direction_output(led_gpio[args].gpio, cmd);
    return 0;
}
static const struct file_operations led_gpio_fops = {
    .owner = THIS_MODULE,
    .open = led_gpio_open,
    .unlocked_ioctl = led_gpio_ctrl,

};
static int led_gpio_init(void)
{
    int ret;
    ret = register_chrdev(led_major, "led_gpio", &led_gpio_fops);
    if (ret < 0) {
        printk(KERN_ERR "led_gpio: can't get major %d.\n", led_major);
        return ret;
    }
}
static void led_gpio_exit(void)
{
    unregister_chrdev(led_major, "led_gpio");
}

#include <jni.h>  /* /usr/lib/jvm/java-1.7.0-openjdk-amd64/include/ */
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <android/log.h>  /* liblog */

 #define  TAG "LedGPIO"
// 定义info信息
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,TAG,__VA_ARGS__)
// 定义debug信息
#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG, TAG, __VA_ARGS__)
// 定义error信息
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,TAG,__VA_ARGS__)

#if 0
typedef struct {
    char *name;          /* Java里调用的函数名 */
    char *signature;    /* JNI字段描述符, 用来表示Java里调用的函数的参数和返回值类型 */
    void *fnPtr;          /* C语言实现的本地函数 */
} JNINativeMethod;
#endif
static jint fd = 0;
jint led_open(JNIEnv *env, jobject cls)
{
	fd = open("/dev/gpiodev", O_RDWR);
	if (fd < 0)
	{
		LOGE("open /dev/gpiodev error\n");
		return -1;
	}
	LOGD("native open\n");
	return 0;
}
void led_close(JNIEnv *env, jobject cls)
{
	close(fd);
	LOGD("native close\n");
}
jint led_ctrl(JNIEnv *env, jobject cls, jint which, jint status)
{
	LOGD("native ctrl which = %d, status = %d\n", which, status);
	ioctl(fd, status, which);
	return 0;
}
static const JNINativeMethod methods[] = {
	{"ledOpen", "()I", (void *)led_open},
	{"ledClose", "()V", (void *)led_close},
	{"ledCtrl", "(II)I", (void *)led_ctrl},
};
/* System.loadLibrary */
JNIEXPORT jint JNICALL
JNI_OnLoad(JavaVM *jvm, void *reserved)
{
	JNIEnv *env;
	jclass cls;

	if ((*jvm)->GetEnv(jvm, (void **)&env, JNI_VERSION_1_4)) {
		return JNI_ERR; /* JNI version not supported */
	}
	cls = (*env)->FindClass(env, "com/example/jason/led_gpio/led_ctrl");
	if (cls == NULL) {
		return JNI_ERR;
	}

	/* 2. map java hello <-->c c_hello */
	if ((*env)->RegisterNatives(env, cls, methods, sizeof(methods)/sizeof(methods[0])) < 0)
		return JNI_ERR;

	return JNI_VERSION_1_4;
}