Re: [PATCH v4 1/7] dt-bindings: phy: Add PHY_TYPE_DSI and PHY_TYPE_CSI definitions

[楊智成]

Hi Krzysztof,

Thanks for the review.

(from the review of 2/7)

> Please link/show the upstream DTS using simultaneously transmitter and
> receiver, where the consumer does not know with whom is it talking to.

I grepped the tree and found a device tree that has simultaneously
transmitter and receiver. In the arch/arm/boot/dts/samsung/*,
exynos4412-midas.dtsi enables csis_0, and exynos4412-galaxy-s3.dtsi, which
includes it, enables dsi_0. Both consumers are declared in exynos4.dtsi,
on the same phy node:

    dsi_0:  phys = <&mipi_phy 1>;
    csis_0: phys = <&mipi_phy 0>;

Tracing that back, the provider is
Documentation/devicetree/bindings/phy/samsung,mipi-video-phy.yaml and
drivers/phy/samsung/phy-exynos-mipi-video.c.
It registers several struct phy in one node, and the binding says:

      For samsung,s5pv210-mipi-video-phy compatible PHYs the second cell in the
      PHY specifier identifies the PHY and its meaning is as follows::
        0 - MIPI CSIS 0,
        1 - MIPI DSIM 0,
        2 - MIPI CSIS 1,
        3 - MIPI DSIM 1.

Resuming from the cover letter in v4, I treat this phy as one tx phy and one
rx phy. Maybe I can follow this pattern and introduce phy 0 and phy 1 in
rockchip,rk3588-mipi-dcphy.yaml, and add an enum for
SAMSUNG_MIPI_DCPHY_TX/RX in the driver. The binding would then say:

      Two cells select the mode and then one of the two PHYs that the
      block contains:
        0 - the transmitter, for a MIPI DSI host
        1 - the receiver, for a MIPI CSI-2 host

      A single cell is equivalent to a second cell of 0.

In this way, I don't need to add PHY_TYPE_CSI/DSI to
include/dt-bindings/phy/phy.h.
And I think this will not go against the discussion in v2, where Michael pointed
out that DSI and CSI are standard protocols and should not be named in
a Rockchip
specific header, and suggested introducing PHY_TYPE_CSI/DSI:

> How is that Rockchip specific? As you state above this is either MIPI
> CSI or MIPI DSI, two perfectly standard protocols.
>
> @all Would it be reasonable to introduce PHY_TYPE_CSI and PHY_TYPE_DSI?

https://lore.kernel.org/r/82da3622-9c3a-454c-87bc-fb4ec7adb68d@xxxxxxxxxxxxx

> Where is any DTS using it? I did a search and no results of upstream
> posting.

The user will be rk3588-base.dtsi. It adds csi0/1, which connect back
to the existing vicap_mipi0/1 ports. It also sets #phy-cells
and the dsi consumers to the shape that comes out of this review; with v4
that would have been #phy-cells = <2> and PHY_TYPE_CSI/DSI.

I thought the dts should wait until the binding and driver were settled,
so I did not post it. I will add it in v5.

Thanks,
Jason

Krzysztof Kozlowski <krzk@xxxxxxxxxx> 於 2026年8月27日週四 下午7:46寫道：
>
> On Fri, Aug 21, 2026 at 08:02:29PM +0800, Jason Yang wrote:
> > A MIPI D-PHY or C-PHY can be a transmitter (DSI) or a receiver (CSI),
> > and in some PHY blocks both work at the same time. The existing
> > PHY_TYPE_DPHY and PHY_TYPE_CPHY cannot tell whether a consumer wants
> > the transmitter or the receiver.
>
> The consumer knows this already, no? Imagine consumer of the phy is some
> ISP receiving data over CSI for given port, thus consumer cannot
> transmit over that link.
>
> All this seems redundant.
>
> >
> > Add PHY_TYPE_DSI and PHY_TYPE_CSI, so that a binding can select both
> > D-PHY or C-PHY and transmitter or receiver. They do not replace
> > PHY_TYPE_DPHY/PHY_TYPE_CPHY, which remain the right choice where a cell
> > selects the mode. The first user is the Rockchip RK3588 MIPI DC-PHY
> > binding.
> >
> > Suggested-by: Michael Riesch <michael.riesch@xxxxxxxxxxxxx>
> > Link: https://lore.kernel.org/r/82da3622-9c3a-454c-87bc-fb4ec7adb68d@xxxxxxxxxxxxx
> > Signed-off-by: Jason Yang <jason98166@xxxxxxxxx>
>
> Where is any DTS using it? I did a search and no results of upstream
> posting.
>
> > ---
> >  include/dt-bindings/phy/phy.h | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/include/dt-bindings/phy/phy.h b/include/dt-bindings/phy/phy.h
> > index 979b5dfd8353..8ee3f88e6d80 100644
> > --- a/include/dt-bindings/phy/phy.h
> > +++ b/include/dt-bindings/phy/phy.h
> > @@ -24,6 +24,8 @@
> >  #define PHY_TYPE_CPHY                11
> >  #define PHY_TYPE_USXGMII     12
> >  #define PHY_TYPE_XAUI                13
> > +#define PHY_TYPE_DSI         14
> > +#define PHY_TYPE_CSI         15
>
> DSI and CSI does not look like types of PHY...
>
> Best regards,
> Krzysztof
>