Re: [PATCH v3 1/5] dt-bindings: phy: Add PHY_TYPE_DSI and PHY_TYPE_CSI definitions

[Krzysztof Kozlowski <krzk@kernel.org>]

On 12/08/2026 14:24, 楊智成 wrote:
> Thanks for the review.
> 
>> I read above, but still do not get why TYPE_DPHY/CPHY is not enough.
>> Isn't DPHY implying it is DSI?
> 
> I see your point, and I did not explain this clearly enough in the previous
> version.
> 
> D-PHY only describes the electrical layer, and both MIPI DSI and MIPI CSI-2
> can run on top of it. A CSI-2 receiver's PHY is a D-PHY just as much as a
> DSI transmitter's is, so PHY_TYPE_DPHY alone does not tell us which one the
> consumer is asking for.
> 
> That is the problem here. The RK3588 DC-PHY exposes both a transmitter and
> a receiver from a single PHY block, which can be used by two independent
> consumers at the same time. This is not a theoretical concern: on this
> board a DSI panel is scanning out while the same PHY receives CSI-2 frames
> from a camera. With only the electrical layer to identify the PHY, both
> consumers would end up with the same phandle cell:
> 
> dsi@fde20000 {
> phys = <&mipidcphy0 PHY_TYPE_DPHY>; /* wants the TX */
> };
> 
> csi2@fdd10000 {
> phys = <&mipidcphy0 PHY_TYPE_DPHY>; /* wants the RX */
> };
> 
> There is then nothing in .of_xlate() to distinguish the two requests.
> 
> I will make this clearer in the v4 commit message and include the example
> above so that the reasoning is easier to follow.
> 
> For context, v2 described the direction with a Rockchip-private
> RK_DCPHY_DIR_* enum. Michael Riesch suggested using generic constants
> instead [1], and Vinod agreed [2].
> 
> [1] https://lore.kernel.org/r/82da3622-9c3a-454c-87bc-fb4ec7adb68d@collabora.com
> [2] https://lore.kernel.org/r/anSuxfeitSqmSHNr@vaman
> 
>> Your tag goes the last.
> 
> Sure, I will fix this in v4. The Signed-off-by tag will come last, and I
> will check the whole series again.

LLM-pasted and LLM-feeding answer again.

Best regards,
Krzysztof