Yes, some types of passive transport, specifically facilitated diffusion, utilize a protein doorway.
Passive transport is the movement of biochemicals and other atomic or molecular substances across membranes without the need of energy input. This contrasts with active transport, which requires energy to move substances against a concentration gradient. There are several types of passive transport:
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Simple Diffusion: Movement of a solute from an area of high concentration to an area of low concentration, directly across the membrane. No protein assistance is needed.
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Osmosis: The movement of water molecules from a region of high water concentration to a region of low water concentration, through a semi-permeable membrane. While aquaporins (water channel proteins) can facilitate osmosis, osmosis can also occur without the presence of proteins.
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Facilitated Diffusion: This type does use membrane proteins to help substances cross the cell membrane. These proteins can be channel proteins or carrier proteins.
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Channel Proteins: Form a pore or channel in the membrane, allowing specific molecules or ions to flow through.
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Carrier Proteins: Bind to a specific molecule, change their shape, and then release the molecule on the other side of the membrane.
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In both cases of facilitated diffusion (channel and carrier proteins), the movement of the substance still follows the concentration gradient, meaning no energy input from the cell is required. The proteins simply "facilitate" the diffusion process. Thus, some passive transport does use a protein doorway.
