Re: [PATCH v1 5/6] dt-bindings: phy: tegra: Document Nvidia Tegra XMM6260 PHY

[Svyatoslav Ryhel]

пт, 15 трав. 2026 р. о 11:20 Krzysztof Kozlowski <krzk@xxxxxxxxxx> пише:
>
> On Mon, May 11, 2026 at 04:57:00PM +0300, Svyatoslav Ryhel wrote:
> > Document the XMM6260 PHY used by various devices based on the Nvidia Tegra
> > SoC, describing its usage
> >
> > Signed-off-by: Svyatoslav Ryhel <clamor95@xxxxxxxxx>
> > ---
> >  .../bindings/phy/nvidia,tegra-xmm6260.yaml    | 58 +++++++++++++++++++
> >  1 file changed, 58 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/phy/nvidia,tegra-xmm6260.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/phy/nvidia,tegra-xmm6260.yaml b/Documentation/devicetree/bindings/phy/nvidia,tegra-xmm6260.yaml
> > new file mode 100644
> > index 000000000000..0346433c9772
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/phy/nvidia,tegra-xmm6260.yaml
> > @@ -0,0 +1,58 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/phy/nvidia,tegra-xmm6260.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Nvidia Tegra PHY for XMM6260 modem
>
> XMM6260 is Infineon modem, so any combination with nvidia,tegra is very
> confusing.
>

May you please suggest how to adjust the name then? Thank you.

> > +
> > +description:
> > +  A hardware configuration used in Tegra SoCs to provide proper interaction
> > +  between the application processor and the modem, as well as control over
> > +  one of the SoC's USB lines for the modem.
> > +
> > +maintainers:
> > +  - Svyatoslav Ryhel <clamor95@xxxxxxxxx>
> > +
> > +properties:
> > +  compatible:
> > +    const: nvidia,tegra-xmm6260
>
> Also here.
>
> What sort of phy is this? So far looks more like a software construct.
>

Infineon XMM6260 does not work as an ordinary USB modem, it is a
standalone CPU which just exposes itself to AP via USB. In order to do
so, it has to have control over a USB bus of AP which is dedicated to
it. In case of Tegra - XMM6260 interaction it looks like this: second
Tegra USB controller is set into HSIC mode and is dedicated solely to
the modem, modem controls this USB bus. Then the main XMM6260 driver
performs power and init sequence and once it is ready it calls phy to
register controller. Phy has its own supply, controls USB controller
de/register and using enable GPIO sends signal to modem to proceed.
Additionally, since some XMM626 versions have a few steps to setup
exposing different USB devices, phy handles controller reinit for each
step. If treat XMM6260 as an simple USB modem it will never init.

One more benefit of having PHY is that modem driver itself is generic
and PHY handles SoC specific configurations required by the modem.
Since this modem was used on a variety of different SoC's (Exynos and
OMAP for example) they can reuse modem's driver and provide only PHY
which handles modem interactions with the USB bus.

> Best regards,
> Krzysztof
>