Re: [PATCH v6 6/9] dt-bindings: connector: m2: Add M.2 1620 LGA soldered down connector

[Mark Pearson]

On Mon, Mar 23, 2026, at 12:52 PM, Manivannan Sadhasivam wrote:
> On Mon, Mar 23, 2026 at 06:45:15PM +0200, Dmitry Baryshkov wrote:
>> On Mon, Mar 23, 2026 at 09:26:04PM +0530, Manivannan Sadhasivam wrote:
>> > On Mon, Mar 23, 2026 at 05:14:30PM +0200, Dmitry Baryshkov wrote:
>> > > On Mon, Mar 23, 2026 at 07:14:25PM +0530, Manivannan Sadhasivam wrote:
>> > > > On Mon, Mar 23, 2026 at 08:39:55AM -0500, Rob Herring wrote:
>> > > > > On Mon, Mar 23, 2026 at 7:16 AM Manivannan Sadhasivam <mani@xxxxxxxxxx> wrote:
>> > > > > >
>> > > > > > On Sun, Mar 22, 2026 at 06:37:13PM -0500, Rob Herring wrote:
>> > > > > > > On Tue, Mar 17, 2026 at 09:59:56AM +0530, Manivannan Sadhasivam wrote:
>> > > > > > > > Lenovo Thinkpad T14s is found to have a soldered down version of M.2 1620
>> > > > > > > > LGA connector. Though, there is no 1620 LGA form factor defined in the M.2
>> > > > > > > > spec, it looks very similar to the M.2 Key E connector. So add the
>> > > > > > > > "pcie-m2-1620-lga-connector" compatible with "pcie-m2-e-connector" fallback
>> > > > > > > > to reuse the Key E binding.
>> > > > > > >
>> > > > > > > What is LGA?
>> > > > > > >
>> > > > > >
>> > > > > > Land Grid Array
>> > > > > >
>> > > > > > > If not in the spec, is it really something generic?
>> > > > > > >
>> > > > > >
>> > > > > > Good question. Yes and No! LGA is not something that Lenovo only uses. Other
>> > > > > > vendors may also use this form factor. PCIe connectors are full of innovation as
>> > > > > > the spec gives room for hardware designers to be as innovative as possible to
>> > > > > > save the BOM cost.
>> > > > > 
>> > > > > innovation == incompatible changes
>> > > > > 
>> > > > 
>> > > > Yes, I was trying to sound nice :)
>> > > > 
>> > > > > > This is why I do not want to make it Lenovo specific. But if you prefer that, I
>> > > > > > can name it as "lenovo,pcie-m2-1620-lga-connector".
>> > > > > 
>> > > > > Depends if you think that s/w needs to know the differences. Hard to
>> > > > > say with a sample size of 1.
>> > > > > 
>> > > > 
>> > > > Sure. Will add the 'lenovo' prefix then.
>> > > 
>> > > Is it really Lenovo? Or is it some other module vendor, whose LGAs are
>> > > being used by Lenovo?
>> > > 
>> > > I remember that DB820c also used some kind of a module for the WiFi card
>> > > (which might be M.2 compatible or might not, I can't find exact docs at
>> > > this point).
>> > > 
>> > 
>> > I don't know. These kind of designs might be reused by several vendors. But
>> > considering that we should not make it generic, I'd go with Lenovo as that's
>> > the only vendor we know as of now.
>> 
>> ... and later we learn that other vendors use the same idea /pinout,
>> then nothing stops us from still telling that it's a
>> "lenovo,pcie-m2-something-lga". 
>> 
>
> How do you possibly know whether a single vendor has introduced this form factor
> or reused by multiple ones? Atleast, I don't have access to such a source to
> confirm.
>
I've not really been following this thread/patchset in detail; but want me to try and check with the T14s platform team if this device is specifically made for us (Lenovo) or not?
I doubt it is - we just don't do that usually, but I can go and ask the question if it will help resolve this (with the caveat that it could hold up the review for a bit and I may not be able to get a straight answer)

My vote (for what little it's worth) would be to make it non-Lenovo specific. Then when the same part causes issues on another vendors platform I won't get asked questions about why Lenovo is breaking <other vendor> :)

Mark