#ifndef ANDROID_HELLO_INTERFACE_H
#define ANDROID_HELLO_INTERFACE_H
#include <hardware/hardware.h>

__BEGIN_DECLS

/*定义模块ID*/
#define HELLO_HARDWARE_MODULE_ID "hello"

/*硬件模块结构体*/
struct hello_module_t {
 struct hw_module_t common;
};

/*硬件接口结构体*/
struct hello_device_t {
 struct hw_device_t common;
 int fd;
 int (*set_val)(struct hello_device_t* dev, int val);
 int (*get_val)(struct hello_device_t* dev, int* val);
};

__END_DECLS

#endif

#define LOG_TAG "HelloStub"

#include <hardware/hardware.h>
#include <hardware/hello.h>
#include <fcntl.h>
#include <errno.h>
#include <cutils/log.h>
#include <cutils/atomic.h>

#define DEVICE_NAME "/dev/hello"
#define MODULE_NAME "Hello"
#define MODULE_AUTHOR "shyluo@gmail.com"

/*设备打开和关闭接口*/
static int hello_device_open(const struct hw_module_t* module, const char* name, struct hw_device_t** device);
static int hello_device_close(struct hw_device_t* device);

/*设备访问接口*/
static int hello_set_val(struct hello_device_t* dev, int val);
static int hello_get_val(struct hello_device_t* dev, int* val);

/*模块方法表*/
static struct hw_module_methods_t hello_module_methods = {
 open: hello_device_open
};

/*模块实例变量*/
struct hello_module_t HAL_MODULE_INFO_SYM = {
 common: {
  tag: HARDWARE_MODULE_TAG,
  version_major: 1,
  version_minor: 0,
  id: HELLO_HARDWARE_MODULE_ID,
  name: MODULE_NAME,
  author: MODULE_AUTHOR,
  methods: &hello_module_methods,
 }
};

static int hello_device_open(const struct hw_module_t* module, const char* name, struct hw_device_t** device) {
 struct hello_device_t* dev;dev = (struct hello_device_t*)malloc(sizeof(struct hello_device_t));
 
 if(!dev) {
  LOGE("Hello Stub: failed to alloc space");
  return -EFAULT;
 }

 memset(dev, 0, sizeof(struct hello_device_t));
 dev->common.tag = HARDWARE_DEVICE_TAG;
 dev->common.version = 0;
 dev->common.module = (hw_module_t*)module;
 dev->common.close = hello_device_close;
 dev->set_val = hello_set_val;dev->get_val = hello_get_val;

 if((dev->fd = open(DEVICE_NAME, O_RDWR)) == -1) {
  LOGE("Hello Stub: failed to open /dev/hello -- %s.", strerror(errno));free(dev);
  return -EFAULT;
 }

 *device = &(dev->common);
 LOGI("Hello Stub: open /dev/hello successfully.");

 return 0;

static int hello_device_close(struct hw_device_t* device) {
 struct hello_device_t* hello_device = (struct hello_device_t*)device;

 if(hello_device) {
  close(hello_device->fd);
  free(hello_device);
 }
 
 return 0;
}

static int hello_set_val(struct hello_device_t* dev, int val) {
 LOGI("Hello Stub: set value %d to device.", val);

 write(dev->fd, &val, sizeof(val));

 return 0;
}

static int hello_get_val(struct hello_device_t* dev, int* val) {
 if(!val) {
  LOGE("Hello Stub: error val pointer");
  return -EFAULT;
 }

 read(dev->fd, val, sizeof(*val));

 LOGI("Hello Stub: get value %d from device", *val);

 return 0;
}