OpenHarmony：全流程讲解如何编写ADC平台驱动以及应用程序 原创 精华

#include "adc_config.hcs"

root {
    device_info {
        platform :: host {
            device_adc :: device {
                device0 :: deviceNode {                         // ADC控制器信息描述
                    policy = 2;                                 // 对外发布服务，必须为2，用于定义ADC管理器的服务
                    priority = 50;
                    permission = 0644;
                    moduleName = "HDF_PLATFORM_ADC_MANAGER";    // 这与drivers/hdf_core/framework/support/platform/src/adc/adc_core.c的g_adcManagerEntry.moduleName对应，它主要负责ADC的管理
                    serviceName = "HDF_PLATFORM_ADC_MANAGER";
                }
                device1 :: deviceNode {
                    policy = 0;                                 // 等于0，不需要发布服务
                    priority = 55;                              // 驱动驱动优先级
                    permission = 0644;                          // 驱动创建设备节点权限
                    moduleName = "linux_adc_adapter";           // 用于指定驱动名称，必须是linux_adc_adapter
                    deviceMatchAttr = "linux_adc_adapter";      // 用于配置控制器私有数据，必须与adc_config.hcs中对应控制器保持一致
                }
            }
        }
    }
}
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root {
    platform {
        adc_config {
            match_attr = "linux_adc_adapter";       // 与device_info.hcs的deviceMatchAttr的值一致
            template adc_device {                   // 必须与//drivers/hdf_core/adapter/khdf/linux/platform/adc/adc_iio_adapter.c的配置树定义保持一致
                deviceNum = 0;                      // 设备号标识
                channelNum = 8;                     // ADC通道数量
                driver_channel0_name = "";          // 通道0在linux文件系统路径
                driver_channel1_name = "";          // 通道1在linux文件系统路径
                driver_channel2_name = "";          // 通道2在linux文件系统路径
                driver_channel3_name = "";          // 通道3在linux文件系统路径
                driver_channel4_name = "";          // 通道4在linux文件系统路径
                driver_channel5_name = "";          // 通道5在linux文件系统路径
                driver_channel6_name = "";          // 通道6在linux文件系统路径
                driver_channel7_name = "";          // 通道7在linux文件系统路径
                scanMode = 0;                       // 扫描模式（必要，但无意义）
                rate = 1000;                        // 转换速率（必要，但无意义）
            }
            device_0 :: adc_device {
                deviceNum = 0;
                channelNum = 8;
                driver_channel0_name = "/sys/bus/iio/devices/iio:device0/in_voltage0_raw";
                driver_channel1_name = "/sys/bus/iio/devices/iio:device0/in_voltage1_raw";
                driver_channel2_name = "/sys/bus/iio/devices/iio:device0/in_voltage2_raw";
                driver_channel3_name = "/sys/bus/iio/devices/iio:device0/in_voltage3_raw";
                driver_channel4_name = "/sys/bus/iio/devices/iio:device0/in_voltage4_raw";
                driver_channel5_name = "/sys/bus/iio/devices/iio:device0/in_voltage5_raw";
                driver_channel6_name = "/sys/bus/iio/devices/iio:device0/in_voltage6_raw";
                driver_channel7_name = "/sys/bus/iio/devices/iio:device0/in_voltage7_raw";
            }
        }
    }
}
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#include "../../samples/b04_platform_device_adc/config/device_info.hcs"
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CONFIG_DRIVERS_HDF_PLATFORM_ADC=y
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#include "adc_if.h"                 // ADC标准接口头文件
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int main(int argc, char* argv[])
{
    DevHandle handle = NULL;
    int32_t ret;
    uint32_t value;

    // 解析参数
    parse_opt(argc, argv);
    printf("adc_device: %d\n", m_adc_device);
    printf("adc_channel: %d\n", m_adc_channel);

    // 打开ADC设备
    handle = AdcOpen(m_adc_device);
    if (handle == NULL) {
        PRINT_ERROR("AdcOpen failed\n");
        return -1;
    }

    // 进行AD转换并读取转换结果
    ret = AdcRead(handle, m_adc_channel, &value);
    if (ret != 0) {
        PRINT_ERROR("AdcRead failed and ret = %d\n", ret);
        AdcClose(handle);
        return -1;
    }

    printf("Adc Device(%d), Channel(%d) read successful and value = %d\n", m_adc_device, m_adc_channel, value);

    // 关闭ADC设备
    AdcClose(handle);

    return 0;
}
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import("//build/ohos.gni")
import("//drivers/hdf_core/adapter/uhdf2/uhdf.gni")

print("samples: compile rk3568_adc_test")
ohos_executable("rk3568_adc_test") {
  sources = [ "adc_test.c" ]
  include_dirs = [
    "$hdf_framework_path/include",
    "$hdf_framework_path/include/core",
    "$hdf_framework_path/include/osal",
    "$hdf_framework_path/include/platform",
    "$hdf_framework_path/include/utils",
    "$hdf_uhdf_path/osal/include",
    "$hdf_uhdf_path/ipc/include",
    "//base/hiviewdfx/hilog/interfaces/native/kits/include",
    "//third_party/bounds_checking_function/include",
  ]

  deps = [
    "$hdf_uhdf_path/platform:libhdf_platform",
    "$hdf_uhdf_path/utils:libhdf_utils",
    "//base/hiviewdfx/hilog/interfaces/native/innerkits:libhilog",
  ]

  cflags = [
    "-Wall",
    "-Wextra",
    "-Werror",
    "-Wno-format",
    "-Wno-format-extra-args",
  ]

  subsystem_name = "applications"
  part_name = "product_rk3568"
  install_enable = true
}
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"b04_platform_device_adc/app:rk3568_adc_test",
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hb set -root .
hb set
# 选择lockzhiner下的rk3568编译分支。
hb build -f
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# rk3568_adc_test -d 0 -c 5
../../vendor/lockzhiner/rk3568/samples/b21_platform_device_adc/app/adc_test.c, main, 103, info: adc_device: 0
../../vendor/lockzhiner/rk3568/samples/b21_platform_device_adc/app/adc_test.c, main, 104, info: adc_channel: 5
Adc Device(0), Channel(5) read successful and value = 955
#
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