From: "mka@chromium.org" <mka@chromium.org>
To: "Linyu Yuan (QUIC)" <quic_linyyuan@quicinc.com>
Cc: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"Tao Wang (Consultant) (QUIC)" <quic_wat@quicinc.com>,
"balbi@kernel.org" <balbi@kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"dianders@chromium.org" <dianders@chromium.org>,
"frowand.list@gmail.com" <frowand.list@gmail.com>,
"hadess@hadess.net" <hadess@hadess.net>,
"krzk@kernel.org" <krzk@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"mathias.nyman@intel.com" <mathias.nyman@intel.com>,
"michal.simek@xilinx.com" <michal.simek@xilinx.com>,
"peter.chen@kernel.org" <peter.chen@kernel.org>,
"ravisadineni@chromium.org" <ravisadineni@chromium.org>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"rogerq@kernel.org" <rogerq@kernel.org>,
"stern@rowland.harvard.edu" <stern@rowland.harvard.edu>,
"swboyd@chromium.org" <swboyd@chromium.org>
Subject: Re: 回复: 回复: Re: [PATCH v20 3/5] usb: misc: Add onboard_usb_hub driver
Date: Tue, 1 Mar 2022 08:33:22 -0800 [thread overview]
Message-ID: <Yh5K0u3jp4jTXCPi@google.com> (raw)
In-Reply-To: <DM8PR02MB8198F2BFE9E933CC8F2C148BE3029@DM8PR02MB8198.namprd02.prod.outlook.com>
On Tue, Mar 01, 2022 at 02:30:00AM +0000, Linyu Yuan (QUIC) wrote:
> > From: mka@chromium.org <mka@chromium.org>
> > Sent: Tuesday, March 1, 2022 2:29 AM
> > To: Linyu Yuan (QUIC) <quic_linyyuan@quicinc.com>
> > Cc: gregkh@linuxfoundation.org; Tao Wang (Consultant) (QUIC)
> > <quic_wat@quicinc.com>; balbi@kernel.org; devicetree@vger.kernel.org;
> > dianders@chromium.org; frowand.list@gmail.com; hadess@hadess.net;
> > krzk@kernel.org; linux-kernel@vger.kernel.org; linux-usb@vger.kernel.org;
> > mathias.nyman@intel.com; michal.simek@xilinx.com;
> > peter.chen@kernel.org; ravisadineni@chromium.org; robh+dt@kernel.org;
> > rogerq@kernel.org; stern@rowland.harvard.edu; swboyd@chromium.org
> > Subject: Re: 回复: 回复: Re: [PATCH v20 3/5] usb: misc: Add
> > onboard_usb_hub driver
> >
> > >
> > > Hi Greg and mka,
> > >
> > > Let's make it clear that we are talking about once this driver is approved
> > into usb tree,
> > > If we use different USB HUB which have VID/PID not defined in this driver,
> > > We need to update this driver.
> > >
> > > But if we defined VID/PID in device tree(for a specific board, manufacture
> > should know VID/PID from HUB it used),
> > > dynamic parsed by the driver, then we don't need to change this driver
> > (increase VID/PID table).
> >
> > As per my earlier reply, the kernel/USB core uses the VID:PID reported
> > by the USB device, the compatible string in the device tree is purely
> > informational. That's not something that could be changed by this
> > driver.
> I can't fully understand this comment, could you please share step if we want to add a new HUB support, what should we do ? nothing ?
Add the VID:PID and compatible strings to onboard_usb_hub.c, analogous
to those for the RTS5411 and RTS5414. More work will be needed if the
hub needs a special power up or power down sequence (multiple regulators,
GPIOs, ...)
> If do nothing, can we remove id_table from onboard_hub_usbdev_driver ?
> >
> > And even if the VID:PID from the device tree was used: how is the
> > kernel supposed to know that the onboard_hub driver should be
> > probed for a given VID:PID from the device tree, without listing
> > the VID:PID (or compatible string) in the driver (which is what
> > you seem to seek to avoid)?
> In my opinion, if it need update VID/PID table in this driver to support a new HUB,
> we can parse VID/PID from device tree and create dynamic VID/PID entry to id_table of onboard_hub_usbdev_driver.
>
> Hope you can understand what I said.
Not really.
I doubt that what you are suggesting would work. The easiest thing
to convince people would probably be to send a patch (based on this
one) with a working implementation of your idea.
next prev parent reply other threads:[~2022-03-01 16:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <SA1PR02MB86067ACF0C96F18B7306D208903A9@SA1PR02MB8606.namprd02.prod.outlook.com>
[not found] ` <SA1PR02MB860660B6F33011E5A97F7930903A9@SA1PR02MB8606.namprd02.prod.outlook.com>
2022-02-22 16:37 ` 回复: Re: [PATCH v20 3/5] usb: misc: Add onboard_usb_hub driver mka
2022-02-23 7:40 ` 回复: " Tao Wang (Consultant) (QUIC)
2022-02-23 7:56 ` gregkh
2022-02-28 3:08 ` Linyu Yuan (QUIC)
2022-02-28 18:28 ` mka
2022-03-01 2:30 ` Linyu Yuan (QUIC)
2022-03-01 16:33 ` mka [this message]
2022-03-02 5:14 ` Linyu Yuan (QUIC)
2022-03-04 16:47 ` mka
2022-03-07 1:24 ` Linyu Yuan (QUIC)
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