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From: Rob Herring <robh@kernel.org>
To: "Heiko Stübner" <heiko@sntech.de>,
	"Jagan Teki" <jagan@amarulasolutions.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>,
	Chanwoo Choi <cw00.choi@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: Mon, 14 Sep 2020 17:15:33 -0600	[thread overview]
Message-ID: <20200914231533.GA429337@bogus> (raw)
In-Reply-To: <6955091.ERBjKZ0CLf@diego>

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.

> 
> 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
> 
> 
> 
> 

  parent reply	other threads:[~2020-09-14 23:15 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 [this message]
2020-09-15  1:17     ` Chanwoo Choi

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