Re: [PATCH 0/3] extcon: Add Type-C Virtual PD

Hi Heiko,

On Sat, Sep 5, 2020 at 2:53 AM Heiko Stübner [off-list ref] wrote:

Hi Jagan,

Am Freitag, 4. September 2020, 21:18:27 CEST schrieb Jagan Teki:

quoted

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.

Okay, are you disagree with the extcon extension for fusb chips
routing or entire rk3399 designs?

I totally agree with this point of bypassing extcon for the designs
which has fusb302 chips. My only concern is about designs that don't
have fusb chips - for example rock-pi-4. Designs that do have fusb302
chips, has dynamic possibilities to identify data roles, like
detecting Altmode DP via Type-C connector whereas designs that don't
have fusb302 or any type-c chip need static identification of data
role, polarity, and ss for detecting direct DP port ie where
virtual-pd is useful.

Look like we have two potential issues of handling DP on rk3399 here,
let me know if you think these non-type-c chips designs also possible
to detect w/o extcon?

Jagan.

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