From: Chanwoo Choi <cw00.choi@samsung.com>
To: "Rob Herring" <robh@kernel.org>,
"Heiko Stübner" <heiko@sntech.de>,
"Jagan Teki" <jagan@amarulasolutions.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>,
Tom Cubie <tom@radxa.com>,
devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-amarula@amarulasolutions.com
Subject: Re: [PATCH 0/3] extcon: Add Type-C Virtual PD
Date: Tue, 15 Sep 2020 10:17:39 +0900 [thread overview]
Message-ID: <ce889395-d4f8-b8bb-0288-54f3628d8a02@samsung.com> (raw)
In-Reply-To: <20200914231533.GA429337@bogus>
Hi Rob,
On 9/15/20 8:15 AM, Rob Herring wrote:
> On Fri, Sep 04, 2020 at 11:23:21PM +0200, Heiko Stübner wrote:
>> Hi Jagan,
>>
>> Am Freitag, 4. September 2020, 21:18:27 CEST schrieb Jagan Teki:
>>> USB Type-C protocol supports various modes of operations
>>> includes PD, USB3, and Altmode. If the platform design
>>> supports a Type-C connector then configuring these modes
>>> can be done via enumeration.
>>>
>>> However, there are some platforms that design these modes
>>> of operations as separate protocol connectors like design
>>> Display Port from on-chip USB3 controller. So accessing
>>> Type-C Altmode Display Port via onboard Display Port
>>> connector instead of a Type-C connector.
>>>
>>> These kinds of platforms require an explicit extcon driver
>>> in order to handle Power Delivery and Port Detection.
>>>
>>> This series support this Type-C Virtual PD and enable the
>>> same in ROCK Pi 4C SBC.
>>>
>>> Any inputs?
>>
>> I tend to disagree on the design via an extcon.
>
> I don't accept new extcon bindings or users of it either. It's a
> poorly thought out collection of Linux driver properties. Use the usb
> connector binding.
I agree the prior binding format of extcon with 'extcon' property name
is not proper. So, I'll try to bind new style. But, I have a question.
Do you have the objection of the use of extcon like 'users of it either'
of your comment?
>
>>
>> That the Rockchip rk3399 currently carries that extcon thingy is unfortunate
>> and only works for ChromeOS devices based on the rk3399.
>>
>> The kernel now has a real type-c framework so we should not extend this
>> extcon hack any further, because that will make it even harder to roll back
>> later. Also simply because other Rockchip boards currently can't really make
>> use of type-c due to this, as they use the fsusb302 phys directly connected.
>>
>> ChromeOS actually spend some time to make the cros-ec pd part of the type-c
>> framework if I remember correctly, so a viable battle plan would be to:
>>
>> (1) move the Rockchip type-c phy driver to actually be part of the type-c
>> framework, with the extcon being a deprecated fallback for old DTs.
>> (2) implement your gpio-altmode as part of the type-c framework
>> (which may even already exist)
>>
>>
>> In short, please don't extend the rk3399 type-c extcon hack.
>>
>> Thanks
>> Heiko
>>
>>
>>
>>
>
>
--
Best Regards,
Chanwoo Choi
Samsung Electronics
prev parent reply other threads:[~2020-09-15 1:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 19:18 [PATCH 0/3] extcon: Add Type-C Virtual PD Jagan Teki
2020-09-04 19:18 ` [PATCH 1/3] dt-bindings: extcon: Document Type-C Virtual PD driver Jagan Teki
2020-09-04 19:18 ` [PATCH 2/3] extcon: Add " Jagan Teki
2020-09-04 19:18 ` [PATCH 3/3] arm64: dts: rk3399-rock-pi-4c: Enable Display Port Jagan Teki
2020-09-04 21:23 ` [PATCH 0/3] extcon: Add Type-C Virtual PD Heiko Stübner
2020-09-09 13:56 ` Jagan Teki
2020-09-14 23:15 ` Rob Herring
2020-09-15 1:17 ` Chanwoo Choi [this message]
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