Re: [PATCH 02/18] dt-bindings: usb: usb-hcd: Add "wireless" maximum-speed property value

From: Serge Semin <Sergey.Semin@baikalelectronics.ru>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Serge Semin <fancer.lancer@gmail.com>,
	Mathias Nyman <mathias.nyman@intel.com>,
	Felipe Balbi <balbi@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>,
	Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru>,
	Andy Gross <agross@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Manu Gautam <mgautam@codeaurora.org>,
	Roger Quadros <rogerq@ti.com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	Neil Armstrong <narmstrong@baylibre.com>,
	Kevin Hilman <khilman@baylibre.com>, <linux-usb@vger.kernel.org>,
	<devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 02/18] dt-bindings: usb: usb-hcd: Add "wireless" maximum-speed property value
Date: Tue, 13 Oct 2020 00:19:05 +0300
Message-ID: <20201012211905.6x4lfj4phxit5zi4@mobilestation> (raw)
In-Reply-To: <20201012154150.GA1565332@kroah.com>

On Mon, Oct 12, 2020 at 05:41:50PM +0200, Greg Kroah-Hartman wrote:
> On Sun, Oct 11, 2020 at 08:53:33PM +0300, Serge Semin wrote:
> > On Sun, Oct 11, 2020 at 04:42:36PM +0200, Greg Kroah-Hartman wrote:
> > > On Sun, Oct 11, 2020 at 01:41:05AM +0300, Serge Semin wrote:
> > > > It appears that the "maximum-speed" property can also accept the
> > > > "wireless" value. Add it to the enumeration of the possible property
> > > > values then.
> > > > 
> > > > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> > > > ---
> > > >  Documentation/devicetree/bindings/usb/usb-hcd.yaml | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > 
> > > > diff --git a/Documentation/devicetree/bindings/usb/usb-hcd.yaml b/Documentation/devicetree/bindings/usb/usb-hcd.yaml
> > > > index 815de24127db..e1a82a2b3295 100644
> > > > --- a/Documentation/devicetree/bindings/usb/usb-hcd.yaml
> > > > +++ b/Documentation/devicetree/bindings/usb/usb-hcd.yaml
> > > > @@ -28,7 +28,7 @@ properties:
> > > >       isn't passed via DT, USB controllers should default to their maximum HW
> > > >       capability.
> > > >     $ref: /schemas/types.yaml#/definitions/string
> > > > -   enum: ["low-speed", "full-speed", "high-speed", "super-speed",
> > > > +   enum: ["low-speed", "full-speed", "high-speed", "wireless", "super-speed",
> > > >            "super-speed-plus"]
> > > 
> > 
> > > Are you sure?  wireless usb has been removed from the kernel, where do
> > > you see a user of this?  If it's still in there, we need to just drop
> > > it.
> > 
> > My decision on suggesting this patch has been based purely on the speed types
> > the USB core API supports and what usb_get_maximum_speed() can return.
> > USB_SPEED_WIRELESS type is one of the possible return values. As I can see
> > aside the rest of the USB speeds the wireless speed is also defined
> > in the kernel USB subsystem. Moreover it is used in some kernel drivers.
> > (See the USB_SPEED_WIRELESS enumeration constant usage.)
> > Are you sure that the wireless speed support has been really removed?
> 

> All of the drivers that implement and support this should have been
> removed.  Code in the USB core is probably not removed, but patches are
> gladly welcome.
> 
> Please do not add new wireless support as it is not going to happen,
> because there are no wireless devices in the world.

Ok. Thanks for clarification. I'll drop this patch then.

-Sergey

> 
> thanks,
> 
> greg k-h