Re: [PATCH v2 1/4] dt-bindings: connector: Add PCIe M.2 Mechanical Key M connector

[Manivannan Sadhasivam]

On Sun, Nov 09, 2025 at 07:34:09PM +0100, Sebastian Reichel wrote:
> Hi,
> 
> On Sat, Nov 08, 2025 at 08:53:19AM +0530, Manivannan Sadhasivam wrote:
> > Add the devicetree binding for PCIe M.2 Mechanical Key M connector defined
> > in the PCI Express M.2 Specification, r4.0, sec 5.3. This connector
> > provides interfaces like PCIe and SATA to attach the Solid State Drives
> > (SSDs) to the host machine along with additional interfaces like USB, and
> > SMB for debugging and supplementary features. At any point of time, the
> > connector can only support either PCIe or SATA as the primary host
> > interface.
> > 
> > The connector provides a primary power supply of 3.3v, along with an
> > optional 1.8v VIO supply for the Adapter I/O buffer circuitry operating at
> > 1.8v sideband signaling.
> > 
> > The connector also supplies optional signals in the form of GPIOs for fine
> > grained power management.
> > 
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxxxxxxxx>
> > ---
> >  .../bindings/connector/pcie-m2-m-connector.yaml    | 122 +++++++++++++++++++++
> >  1 file changed, 122 insertions(+)
> 
> I would expect something similar to usb-connector.yaml, i.e. m2-connector.yaml,
> which then defines
> 
> compatible:
>   enum:
>     - m2-a-connector
>     - m2-b-connector
>     - m2-e-connector
>     - m2-m-connector

The interfaces of each Key greatly varies as per the spec. So I was planning to
use a separate schema for each one of them to avoid clutter.

> 
> (also not sure if we need the PCIe prefix, it just seems to make the
> name longer)
> 

The M.2 card is always connected to the PCIe connector even if the interface
could use something else other than PCIe. So having the 'pcie' prefix seems
logical to me.

- Mani

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