小熊派驅(qū)動(dòng)開(kāi)發(fā)流程（以點(diǎn)亮LED燈為例）

原創(chuàng)

作者：Wait_Aurora 2022-02-14 14:28:57

系統(tǒng) OpenHarmony

創(chuàng)建驅(qū)動(dòng)目錄并添加驅(qū)動(dòng)源碼文件和編譯腳本–>添加驅(qū)動(dòng)配置目錄和驅(qū)動(dòng)配置文件。

??想了解更多內(nèi)容，請(qǐng)?jiān)L問(wèn)：??

??51CTO和華為官方合作共建的鴻蒙技術(shù)社區(qū)??

??https://harmonyos.51cto.com??

一、流程總覽

創(chuàng)建驅(qū)動(dòng)目錄并添加驅(qū)動(dòng)源碼文件和編譯腳本–>添加驅(qū)動(dòng)配置目錄和驅(qū)動(dòng)配置文件

二、添加驅(qū)動(dòng)文件

2.1 創(chuàng)建驅(qū)動(dòng)文件夾

在./device/st/drivers路徑下新建一個(gè)led目錄，用于存放驅(qū)動(dòng)源碼文件。

2.2 創(chuàng)建驅(qū)動(dòng)源碼文件

新建led.c文件，編寫(xiě)驅(qū)動(dòng)源碼

#include "hdf_device_desc.h" 
#include "hdf_log.h"         
#include "device_resource_if.h"
#include "osal_io.h"
#include "osal.h"
#include "osal_mem.h"
#include "gpio_if.h"

#define HDF_LOG_TAG led_driver // 打印日志所包含的標(biāo)簽，如果不定義則用默認(rèn)定義的HDF_TAG標(biāo)簽
#define LED_WRITE_READ 1       // 讀寫(xiě)操作碼1

enum LedOps {
    LED_OFF,
    LED_ON,  
    LED_TOGGLE,
};

struct Stm32Mp1ILed {
    uint32_t gpioNum;
};
static struct Stm32Mp1ILed g_Stm32Mp1ILed;
uint8_t status = 0;
// Dispatch是用來(lái)處理用戶(hù)態(tài)發(fā)下來(lái)的消息
int32_t LedDriverDispatch(struct HdfDeviceIoClient *client, int cmdCode, struct HdfSBuf *data, struct HdfSBuf *reply)
{
    uint8_t contrl;
    HDF_LOGE("Led driver dispatch");
    if (client == NULL || client->device == NULL)
    {
        HDF_LOGE("Led driver device is NULL");
        return HDF_ERR_INVALID_OBJECT;
    }

    switch (cmdCode)
    {
    /* 接收到用戶(hù)態(tài)發(fā)來(lái)的LED_WRITE_READ命令 */
    case LED_WRITE_READ:
        /* 讀取data里的數(shù)據(jù)，賦值給contrl */
        HdfSbufReadUint8(data,&contrl);                  
        switch (contrl)
        {
        /* 開(kāi)燈 */
        case LED_ON:                                            
            GpioWrite(g_Stm32Mp1ILed.gpioNum, GPIO_VAL_LOW);
            status = 1;
            break;
        /* 關(guān)燈 */
        case LED_OFF:                                           
            GpioWrite(g_Stm32Mp1ILed.gpioNum, GPIO_VAL_HIGH);
            status = 0;
            break;
        /* 狀態(tài)翻轉(zhuǎn) */
        case LED_TOGGLE:
            if(status == 0)
            {
                GpioWrite(g_Stm32Mp1ILed.gpioNum, GPIO_VAL_LOW);
                status = 1;
            }
            else
            {
                GpioWrite(g_Stm32Mp1ILed.gpioNum, GPIO_VAL_HIGH);
                status = 0;
            }                                        
            break;
        default:
            break;
        }
        /* 把LED的狀態(tài)值寫(xiě)入reply, 可被帶至用戶(hù)程序 */
        if (!HdfSbufWriteInt32(reply, status))                
        {
            HDF_LOGE("replay is fail");
            return HDF_FAILURE;
        }
        break;
    default:
        break;
    }
    return HDF_SUCCESS;
}

// 讀取驅(qū)動(dòng)私有配置
static int32_t Stm32LedReadDrs(struct Stm32Mp1ILed *led, const struct DeviceResourceNode *node)
{
    int32_t ret;
    struct DeviceResourceIface *drsOps = NULL;

    drsOps = DeviceResourceGetIfaceInstance(HDF_CONFIG_SOURCE);
    if (drsOps == NULL || drsOps->GetUint32 == NULL) {
        HDF_LOGE("%s: invalid drs ops!", __func__);
        return HDF_FAILURE;
    }
    /* 讀取led.hcs里面led_gpio_num的值 */
    ret = drsOps->GetUint32(node, "led_gpio_num", &led->gpioNum, 0); 
    if (ret != HDF_SUCCESS) {
        HDF_LOGE("%s: read led gpio num fail!", __func__);
        return ret;
    }
    return HDF_SUCCESS;
}

//驅(qū)動(dòng)對(duì)外提供的服務(wù)能力，將相關(guān)的服務(wù)接口綁定到HDF框架
int32_t HdfLedDriverBind(struct HdfDeviceObject *deviceObject)
{
    if (deviceObject == NULL)
    {
        HDF_LOGE("Led driver bind failed!");
        return HDF_ERR_INVALID_OBJECT;
    }
    static struct IDeviceIoService ledDriver = {
        .Dispatch = LedDriverDispatch,
    };
    deviceObject->service = (struct IDeviceIoService *)(&ledDriver);
    HDF_LOGD("Led driver bind success");
    return HDF_SUCCESS;
}

// 驅(qū)動(dòng)自身業(yè)務(wù)初始的接口
int32_t HdfLedDriverInit(struct HdfDeviceObject *device)
{
    struct Stm32Mp1ILed *led = &g_Stm32Mp1ILed;
    int32_t ret;

    if (device == NULL || device->property == NULL) {
        HDF_LOGE("%s: device or property NULL!", __func__);
        return HDF_ERR_INVALID_OBJECT;
    }
    /* 讀取hcs私有屬性值 */
    ret = Stm32LedReadDrs(led, device->property);
    if (ret != HDF_SUCCESS) {
        HDF_LOGE("%s: get led device resource fail:%d", __func__, ret);
        return ret;
    }
    /* 將GPIO管腳配置為輸出 */
    ret = GpioSetDir(led->gpioNum, GPIO_DIR_OUT);
    if (ret != 0)
    {
        HDF_LOGE("GpioSerDir: failed, ret %d\n", ret);
        return ret;
    }
    HDF_LOGD("Led driver Init success");
    return HDF_SUCCESS;
}

// 驅(qū)動(dòng)資源釋放的接口
void HdfLedDriverRelease(struct HdfDeviceObject *deviceObject)
{
    if (deviceObject == NULL)
    {
        HDF_LOGE("Led driver release failed!");
        return;
    }
    HDF_LOGD("Led driver release success");
    return;
}

// 定義驅(qū)動(dòng)入口的對(duì)象，必須為HdfDriverEntry（在hdf_device_desc.h中定義）類(lèi)型的全局變量
struct HdfDriverEntry g_ledDriverEntry = {
    .moduleVersion = 1,
    .moduleName = "HDF_LED",
    .Bind = HdfLedDriverBind,
    .Init = HdfLedDriverInit,
    .Release = HdfLedDriverRelease,
};

// 調(diào)用HDF_INIT將驅(qū)動(dòng)入口注冊(cè)到HDF框架中
HDF_INIT(g_ledDriverEntry);

2.3 創(chuàng)建編譯腳本文件

新建BUILD.gn文件，添加以下內(nèi)容

import("http://drivers/adapter/khdf/liteos/hdf.gni")

hdf_driver("hdf_led") {
    sources = [
    "led.c",
    ]
}

2.4 修改drivers的編譯腳本使之編譯進(jìn)內(nèi)核

在/device/st/drivers/BUILD.gn的deps中加入"led"

三、添加驅(qū)動(dòng)配置文件

驅(qū)動(dòng)配置包含兩部分，HDF框架定義的驅(qū)動(dòng)的私有配置信息和驅(qū)動(dòng)設(shè)備描述

3.1 創(chuàng)建驅(qū)動(dòng)配置文件夾

在./device/st/bearpi_hm_micro/liteos_a/hdf_config路徑下新建一個(gè)led目錄，用于存放led驅(qū)動(dòng)配置文件。

3.2 創(chuàng)建驅(qū)動(dòng)私有配置文件

在led文件夾下創(chuàng)建led_config.hcs文件，該文件為驅(qū)動(dòng)配置文件。

添加以下內(nèi)容

root {
    LedDriverConfig {
        led_gpio_num = 13;
        match_attr = "st_stm32mp157_led"; //該字段的值必須和device_info.hcs中的deviceMatchAttr值一致
    }
}

3.3 添加驅(qū)動(dòng)設(shè)備描述

在device\st\bearpi_hm_micro\liteos_a\hdf_config\device_info\device_info.hcs文件中添加以下代碼

device_led :: device { // led設(shè)備節(jié)點(diǎn)
    device0 :: deviceNode { // led驅(qū)動(dòng)的DeviceNode節(jié)點(diǎn)
        policy = 2; // policy字段是驅(qū)動(dòng)服務(wù)發(fā)布的策略，在驅(qū)動(dòng)服務(wù)管理章節(jié)有詳細(xì)介紹
        priority = 10; // 驅(qū)動(dòng)啟動(dòng)優(yōu)先級(jí)（0-200），值越大優(yōu)先級(jí)越低，建議默認(rèn)配100，優(yōu)先級(jí)相同則不保證device的加載順序
        preload = 1; // 驅(qū)動(dòng)按需加載字段
        permission = 0777; // 驅(qū)動(dòng)創(chuàng)建設(shè)備節(jié)點(diǎn)權(quán)限
        moduleName = "HDF_LED"; // 驅(qū)動(dòng)名稱(chēng)，該字段的值必須和驅(qū)動(dòng)入口結(jié)構(gòu)的moduleName值一致
        serviceName = "hdf_led"; // 驅(qū)動(dòng)對(duì)外發(fā)布服務(wù)的名稱(chēng)，必須唯一
        deviceMatchAttr = "st_stm32mp157_led"; //驅(qū)動(dòng)私有數(shù)據(jù)匹配的關(guān)鍵字，必須和驅(qū)動(dòng)私有數(shù)據(jù)配置表中的match_attr值相等
    }
}