pdata注册i2c_client

static struct  ds90ub940_crl_sd_1 = {
    .csi2 = &ds90ub940_csi2_cfg_1,
    .i2c = {
        .board_info = {
            I2C_BOARD_INFO(CRLMODULE_NAME, 0x2c),
            .platform_data = &ds90ub940_pdata_1,
        },
        .i2c_adapter_id = 5,	
    },
};

static int isys_register_ext_subdev(struct intel_ipu4_isys *isys,
				struct intel_ipu4_isys_subdev_info *sd_info,
				bool acpi_only)
{
    struct i2c_adapter *adapter = i2c_get_adapter(sd_info->i2c.i2c_adapter_id);	// 5

    client = isys_find_i2c_subdev(adapter, sd_info);	// 默认client为NULL
    if (!client) {
        sd = v4l2_i2c_new_subdev_board(&isys->v4l2_dev, adapter,
                           &sd_info->i2c.board_info, 0);
            client = i2c_new_device(adapter, info);
    }
}