Re: [PATCH v4 1/3] dt-bindings: vendor-prefixes: Add 'ltr' as deprecated vendor prefix

[Shreeya Patel]

On 24/05/22 21:17, Rob Herring wrote:
> On Mon, May 23, 2022 at 08:27:56PM +0530, Shreeya Patel wrote:
> > On 18/05/22 22:02, Rob Herring wrote:
> > > On Tue, May 17, 2022 at 04:07:33PM +0530, Shreeya Patel wrote:
> > > > On 16/05/22 22:30, Rob Herring wrote:
> > > > > On Wed, May 11, 2022 at 03:10:22PM +0530, Shreeya Patel wrote:
> > > > > > 'liteon' is the correct vendor prefix for devices released by
> > > > > > LITE-ON Technology Corp. But one of the released device which uses
> > > > > > ltr216a light sensor exposes the vendor prefix name as 'ltr' through
> > > > > > ACPI.
> > > > > ACPI? NAK.
> > > > >
> > > > > There are no cases of 'ltr' for DT, so fix ACPI.
> > > > Hi Rob,
> > > >
> > > > Yes, we understand there are no cases of 'ltr', but we have released devices
> > > > which uses this string for probing the ltrf216a light sensor driver ( x86
> > > > with DT )
> > > That's not what your commit message says.
> > >
> > > Even if this is DT based, given an undocumented vendor string is used,
> > > it seems doubtful the rest of the binding would match upstream. What
> > > about the rest of the DTB? Got a pointer to it or want to publish it?
> > >
> > > > If we don't document this in vendor-prefixes.yaml, then the following
> > > > warning
> > > > is generated.
> > > >
> > > > WARNING: DT compatible string vendor "ltr" appears un-documented -- check
> > > > ./Documentation/devicetree/bindings/vendor-prefixes.yaml 364: FILE:
> > > > drivers/iio/light/ltrf216a.c:313: + { .compatible = "ltr,ltrf216a" },
> > > >
> > > >
> > > > Can you suggest us what would be the right way to fix this warning if not
> > > > documenting
> > > > in vendor-prefixes.yaml?
> > > Fix the DT. We don't accept bindings simply because they are already
> > > used in the field. If this was the only issue, it would be fine, but I
> > > suspect it's the tip of the iceberg.
> >
> > Hi Rob,
> >
> > To make things more clear, following is the modalias info of the device.
> >
> > (B+)(root@linux iio:device0)# cat
> > /sys/bus/i2c/devices/i2c-PRP0001\:01/modalias
> > of:NltrfTCltr,ltrf216a
> >
> > It's a dt namespace on an ACPI based device. We used an of_device_id table
> > to be able to probe the driver
> > using the vendor prefix and compatible string.
> Again, it's ACPI so I don't care. If someone cares about using DT
> bindings in ACPI they can step up and help maintain them. It's not a DT
> vs. ACPI thing, but just that I can only maintain so much and have to
> draw the line somewhere.
>
> > But when we compile the driver, we get the following warning and hence we
> > documented it in vendor-prefixes.yaml
> > and also added a complete device tree file [Patch 3/3] just to get rid of
> > the warning. In real life we are not using
> > the device tree file at all.
> >
> > WARNING: DT compatible string vendor "ltr" appears un-documented -- check
> > ./Documentation/devicetree/bindings/vendor-prefixes.yaml 364: FILE:
> > drivers/iio/light/ltrf216a.c:313: + { .compatible = "ltr,ltrf216a" },
> So, is someone telling you to fix this?


So will it be right to just keep the warning and remove this patch?
Is there a way you know to silent this warning?


Thanks,
Shreeya Patel

> > There are many existing devices used by people which has the vendor prefix
> > name as 'ltr'
> > and it won't be possible to change that hence we are trying to upstream it.
> There are millions if not billions of DT based devices using
> undocumented bindings. If those used "ltr,ltrf216a", I wouldn't accept
> it either.
>
> Rob