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一、程序简介

该程序是基于OpenHarmony标准系统编写的基础外设类：RGB LED。

目前已在凌蒙派-RK3568开发板跑通。详细资料请参考官网：https://gitee.com/Lockzhiner-Electronics/lockzhiner-rk3568-openharmony/tree/master/samples/b02_hdf_rgb_led。

详细资料请参考OpenHarmony官网：

• GPIO平台驱动开发
• GPIO应用程序开发

二、硬件设计

RGB LED灯整体硬件电路如下图所示,硬件电路中包含了三个GPIO控制管脚控制RGB　LED灯，低电平点亮LED灯，高电平熄灭LED灯。电路简单，这边不对此进行多余的说明。

三、程序解析

1、目录结构

b02_hdf_rgb_led
├── config              # HDF资源配置文件目录├── config.hcs      # 接口IO配置文件├── device_info.hcs # 设备信息配置文件
├── drivers             # 内核HDF驱动程序目录├── rgb_led_drv.c   # 内核HDF驱动程序├── Makefile        # 内核HDF驱动编译脚本
├── figures             # MD文档图片
├── BUILD.gn            # GN文件
├── rgb_led.c           # 应用层控制程序

2、内核HDF驱动程序

（1）接口函数

• 函数名：HdfRgbLedDriverInit.
• 功能说明：HDF初始化注册，读取HDF资源配置文件，获取三色灯控制GPIO管脚。

int32_t HdfRgbLedDriverInit(struct HdfDeviceObject *deviceObject)
{if (deviceObject == NULL) {HDF_LOGE("g_rgbLedDriverEntry: %s failed", __func__);return HDF_ERR_INVALID_OBJECT;}struct DeviceResourceIface *CfgOps = NULL;CfgOps = DeviceResourceGetIfaceInstance(HDF_CONFIG_SOURCE);if (CfgOps == NULL || CfgOps->GetUint32 == NULL) {HDF_LOGE("%s: DeviceResourceGetIfaceInstance failed", __func__);return HDF_FAILURE;}if (CfgOps->GetUint32(deviceObject->property, "rgb_led_version", &g_rgbLedCfg.rgb_led_version, 0) != HDF_SUCCESS) {HDF_LOGE("%s: read rgb_led_version failed", __func__);return HDF_FAILURE;}if (CfgOps->GetUint32(deviceObject->property, "rgb_led_red", &g_rgbLedCfg.rgb_led_red, 0) != HDF_SUCCESS) {g_rgbLedCfg.rgb_led_version = 0;HDF_LOGE("%s: read rgb_led_red failed", __func__);return HDF_FAILURE;}if (CfgOps->GetUint32(deviceObject->property, "rgb_led_green", &g_rgbLedCfg.rgb_led_green, 0) != HDF_SUCCESS) {g_rgbLedCfg.rgb_led_version = 0;HDF_LOGE("%s: read rgb_led_green failed", __func__);return HDF_FAILURE;}if (CfgOps->GetUint32(deviceObject->property, "rgb_led_blue", &g_rgbLedCfg.rgb_led_blue, 0) != HDF_SUCCESS) {g_rgbLedCfg.rgb_led_version = 0;HDF_LOGE("%s: read rgb_led_blue failed", __func__);return HDF_FAILURE;}HDF_LOGI("g_rgbLedDriverEntry: %s success", __func__);return HDF_SUCCESS;
}

• 函数名：HdfRgbLedDriverRelease。
• 功能说明：HDF去注册。

void HdfRgbLedDriverRelease(struct HdfDeviceObject *deviceObject)
{if (deviceObject == NULL) {HDF_LOGE("g_rgbLedDriverEntry: %s failed", __func__);return;}HDF_LOGI("g_rgbLedDriverEntry: %s success", __func__);return;
}

• 函数名：HdfRgbLedDriverBind。
• 功能说明：HDF绑定解析函数。

int32_t HdfRgbLedDriverBind(struct HdfDeviceObject *deviceObject)
{if (deviceObject == NULL) {HDF_LOGE("g_rgbLedDriverEntry: %s failed", __func__);return HDF_ERR_INVALID_OBJECT;}static struct IDeviceIoService ledDriverServ = {.Dispatch = rgbLedDriverDispatch,};deviceObject->service = (struct IDeviceIoService *)(&ledDriverServ);HDF_LOGI("g_rgbLedDriverEntry: %s success NodeName[%s]", __func__,deviceObject->property->name);return HDF_SUCCESS;
}

• 函数名：rgbLedDriverDispatch。
• 功能说明：解析函数，解析应用层下发的命令，执行命令对应操作，RGB_LED_WRITE控制三色灯亮灭。

int32_t rgbLedDriverDispatch(struct HdfDeviceIoClient *client, int32_t cmdId,struct HdfSBuf *dataBuf, struct HdfSBuf *replyBuf)
{int32_t result = HDF_FAILURE;int32_t rgbLedMode = 0;if (client == NULL || client->device == NULL) {HDF_LOGE("driver device is NULL");return HDF_ERR_INVALID_OBJECT;}if (g_rgbLedCfg.rgb_led_version != RGB_LED_VERSION) {HDF_LOGE("driver rgb_led_version not match");return HDF_FAILURE;}switch (cmdId) {case RGB_LED_WRITE:result = HdfSbufReadInt32(dataBuf, &rgbLedMode);if (result) {HDF_LOGI("%s: mode:[0x%X][%s%s%s]", __func__, rgbLedMode,(rgbLedMode&RGB_LED_RED_BIT)?"R":"-",(rgbLedMode&RGB_LED_GREEN_BIT)?"G":"-",(rgbLedMode&RGB_LED_BLUE_BIT)?"B":"-");LedGpioCtrl(g_rgbLedCfg.rgb_led_red, (rgbLedMode&RGB_LED_RED_BIT)?LED_ON:LED_OFF);LedGpioCtrl(g_rgbLedCfg.rgb_led_green, (rgbLedMode&RGB_LED_GREEN_BIT)?LED_ON:LED_OFF);LedGpioCtrl(g_rgbLedCfg.rgb_led_blue, (rgbLedMode&RGB_LED_BLUE_BIT)?LED_ON:LED_OFF);}break;default:HDF_LOGE("%s: receiving unknown command", __func__);break;}return result;
}

• 函数名：LedGpioCtrl。
• 功能说明：LED GPIO控制函数，低电平点亮LED，高电平熄灭LED。

static int32_t LedGpioCtrl(uint16_t gpio, int32_t mode)
{uint16_t level = GPIO_VAL_HIGH;if (HDF_SUCCESS != GpioSetDir(gpio, GPIO_DIR_OUT)) {HDF_LOGE("%s: GpioSetDir failed", __func__);return HDF_FAILURE;}if (mode == LED_ON) {level = GPIO_VAL_LOW;} else if (mode == LED_OFF) {level = GPIO_VAL_HIGH;}if (HDF_SUCCESS != GpioWrite(gpio, level)) {HDF_LOGE("%s: GpioWrite failed", __func__);return HDF_FAILURE;}return HDF_SUCCESS;
}

3、应用层程序

（1）应用层代码分析

程序启动后获取命令行参数，如果命令行不带参数，RGB三色灯运行跑马灯；如果命令行带参数，根据传入的参数的低三位映射点亮对应的红灯、绿灯和蓝灯；通过HdfIoServiceBind绑定RGB三色灯HDF服务，获取HDF空间缓冲区，向缓冲区写入需要控制的RGB三色灯低三位数据，通过RGB_LED_WRITE命令下发到HDF驱动中，从而控制RGB三色灯亮灭。程序运行结束，回收HDF空间缓冲区和HDF服务。

int main(int argc, char* argv[])
{int ret = HDF_SUCCESS;int32_t mode = -1;if (argc == ARGS_NUM) {mode = atoi(argv[1]);/*low-3bits*/mode &= 0x7;HILOG_INFO(LOG_APP, "[%s] main enter: mode[%s%s%s][0x%X]",LOG_TAG,(mode&RGB_LED_BLUE_BIT)?"B":"-",(mode&RGB_LED_GREEN_BIT)?"G":"-",(mode&RGB_LED_RED_BIT)?"R":"-",mode);printf("RGB mode[%s%s%s][0x%X]\n",(mode&RGB_LED_BLUE_BIT)?"B":"-",(mode&RGB_LED_GREEN_BIT)?"G":"-",(mode&RGB_LED_RED_BIT)?"R":"-",mode);} else {HILOG_INFO(LOG_APP, "[%s] main enter: auto test RGB LED", LOG_TAG);printf("auto test RGB LED\n");}struct HdfIoService *serv = HdfIoServiceBind(RGB_LED_SERVICE_NAME);if (serv == NULL) {HILOG_ERROR(LOG_APP, "get service %s failed", RGB_LED_SERVICE_NAME);return -1;}struct HdfSBuf *data = HdfSbufObtainDefaultSize();if (data == NULL) {HILOG_ERROR(LOG_APP, "obtain data failed");return -1;}if (mode == -1) {mode = 0x8;while (mode) {HdfSbufFlush(data);if (!HdfSbufWriteInt32(data, --mode)) {HILOG_ERROR(LOG_APP, "write data failed");return -1;}ret = serv->dispatcher->Dispatch(&serv->object, RGB_LED_WRITE, data, NULL);sleep(1);}} else {if (!HdfSbufWriteInt32(data, mode)) {HILOG_ERROR(LOG_APP, "write data failed");return -1;}ret = serv->dispatcher->Dispatch(&serv->object, RGB_LED_WRITE, data, NULL);}HdfSbufRecycle(data);HdfIoServiceRecycle(serv);HILOG_INFO(LOG_APP, "[%s] main exit.", LOG_TAG);return ret;
}

四、运行程序

系统启动后，命令行运行命令：

rgb_led

五、运行结果

运行结果：

# rgb_led
auto test RGB LED# rgb_led 1
RGB mode[--R][0x1]
# rgb_led 2
RGB mode[-G-][0x2]
# rgb_led 3
RGB mode[-GR][0x3]
# rgb_led 4
RGB mode[B--][0x4]
# rgb_led 5
RGB mode[B-R][0x5]
# rgb_led 6
RGB mode[BG-][0x6]
# rgb_led 7
RGB mode[BGR][0x7]