From: Hans de Goede <hdegoede@redhat.com>
To: John Stultz <john.stultz@linaro.org>
Cc: lkml <linux-kernel@vger.kernel.org>,
Yu Chen <chenyu56@huawei.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Heikki Krogerus <heikki.krogerus@linux.intel.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Chunfeng Yun <chunfeng.yun@mediatek.com>,
Felipe Balbi <balbi@kernel.org>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
Jun Li <lijun.kernel@gmail.com>,
Valentin Schneider <valentin.schneider@arm.com>,
Linux USB List <linux-usb@vger.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>
Subject: Re: [RFC][PATCH 2/3] usb: roles: Add usb role switch notifier.
Date: Fri, 18 Oct 2019 21:59:51 +0200 [thread overview]
Message-ID: <7ea7824f-abc2-4cf6-720a-3668b6286781@redhat.com> (raw)
In-Reply-To: <CALAqxLWE-8YkYmrKoP6-+2xherwsGZ8-CeUyOFe9YPQj6EuSpg@mail.gmail.com>
Hi,
On 18-10-2019 21:53, John Stultz wrote:
> On Fri, Oct 18, 2019 at 12:30 PM Hans de Goede <hdegoede@redhat.com> wrote:
>> Looking at drivers/usb/typec/tcpm/tcpci.c: tcpci_set_vconn I see that
>> there is a data struct with vendor specific callbacks and that the
>> drivers/usb/typec/tcpm/tcpci_rt1711h.c implements that.
>>
>> So you may want something similar here. But things are tricky here,
>> because when nothing is connected you want to provide Vbus for
>> the USB-A ports, which means that if someone then connects a
>> USB-A to C cable to connect the board to a PC (switching the port
>> to device mode) there will be a time when both sides are supplying
>> 5V if I remember the schedule correctly.
>
> Ok. Thanks for the pointer, I'll take a look at that to see if I can
> get it to work.
>
>> I think that the original hack might not be that bad, the whole hw
>> design seems so, erm, broken, that you probably cannot do proper
>> roleswapping anyways. So just tying Vbus to host mode might be
>> fine, the question then becomes again how can some other piece
>> of code listen to the role-switch events...
>
> So, at least in the current approach (see the v3 series), I've
> basically set the hub driver as an role-switch intermediary, sitting
> between the calls from the tcpm to the dwc3 driver. It actually works
> better then the earlier notifier method (which had some issues with
> reliably establishing the initial state on boot). Does that approach
> work for you?
That sounds like it might be a nice solution. But I have not seen the
code, I think I was not Cc-ed on v3. Do you have a patchwork or
lore.kernel.org link for me?
Regards,
Hans
next prev parent reply other threads:[~2019-10-18 20:00 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-02 23:16 [RFC][PATCH 0/3] dwc3 role-switch handling for HiKey960 John Stultz
2019-10-02 23:16 ` [RFC][PATCH 1/3] dt-bindings: usb: generic: Add role-switch-default-host binding John Stultz
2019-10-02 23:16 ` [RFC][PATCH 2/3] usb: roles: Add usb role switch notifier John Stultz
2019-10-03 9:25 ` Hans de Goede
2019-10-03 20:37 ` John Stultz
2019-10-03 20:51 ` Hans de Goede
2019-10-04 8:12 ` Heikki Krogerus
2019-10-15 5:39 ` John Stultz
2019-10-16 7:27 ` Hans de Goede
2019-10-18 5:55 ` John Stultz
2019-10-18 8:06 ` Hans de Goede
2019-10-18 18:39 ` John Stultz
2019-10-18 19:30 ` Hans de Goede
2019-10-18 19:53 ` John Stultz
2019-10-18 19:59 ` Hans de Goede [this message]
2019-10-18 20:12 ` John Stultz
2019-10-18 20:21 ` Hans de Goede
2019-10-18 20:37 ` John Stultz
2019-10-18 21:05 ` Hans de Goede
2019-10-22 5:58 ` John Stultz
2019-11-14 10:11 ` Hans de Goede
2019-11-15 0:23 ` John Stultz
2019-10-16 9:10 ` Hans de Goede
2019-10-03 11:26 ` Greg Kroah-Hartman
2019-10-03 20:45 ` John Stultz
2019-10-03 20:56 ` Hans de Goede
2019-10-03 21:33 ` John Stultz
2019-10-06 15:22 ` Hans de Goede
2019-10-15 7:03 ` John Stultz
2019-10-04 8:00 ` Heikki Krogerus
2019-10-02 23:16 ` [RFC][PATCH 3/3] usb: dwc3: Registering a role switch in the DRD code John Stultz
2019-10-15 8:25 ` Roger Quadros
2019-10-15 19:10 ` John Stultz
2019-10-16 9:24 ` Roger Quadros
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