linux-kernel - Re: [RFC PATCH 2/3] usb: typec: Add product_type sysfs attribute file for partners and cables

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Message-ID: <20201119141218.GE3774817@kuha.fi.intel.com>
Date:   Thu, 19 Nov 2020 16:12:18 +0200
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     Prashant Malani <pmalani@...omium.org>
Cc:     Benson Leung <bleung@...omium.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org
Subject: Re: [RFC PATCH 2/3] usb: typec: Add product_type sysfs attribute
 file for partners and cables

Hi Prashant,

On Thu, Nov 19, 2020 at 03:11:22AM -0800, Prashant Malani wrote:
> On Thu, Nov 19, 2020 at 01:05:06PM +0200, Heikki Krogerus wrote:
> > On Wed, Nov 18, 2020 at 10:53:50AM -0800, Prashant Malani wrote:
> > > > +What:		/sys/class/typec/<port>-cable/product_type
> > > > +Date:		December 2020
> > > > +Contact:	Heikki Krogerus <heikki.krogerus@...ux.intel.com>
> > > > +Description:	USB Power Delivery Specification defines a set of product types
> > > > +		for the cables. This file will show the product type of the
> > > > +		cable if it is known. If the product type of the cable is not
> > > > +		visible to the device driver, this file will not exist.
> > > > +
> > > > +		When the cable product type is detected, uvevent is also raised
> > > > +		with PRODUCT_TYPE showing the product type of the cable.
> > > > +
> > > > +		Valid values:
> > > > +
> > > > +		========================  ==========================
> > > > +		undefined		  -
> > > > +		active			  Active Cable
> > > > +		passive			  Passive Cable
> > > > +		========================  ==========================
> > > 
> > > There exists a /sys/class/typec/<port>-cable/type attribute (connected
> > > to the "active" field in struct typec_cable [1]), which is supposed
> > > to be populated by the Type C port driver. Won't the newly introduced
> > > attribute duplicate the same information as "type"?
> > 
> > True. So we don't need add this for the cable separately. I'll just
> > modify the code so that it considers also the response to Discover
> > Identity command if we have access to it.
> > 
> > Would it be OK if we name the file "type" instead of "product_type"
> > also with the partners?
> 
> That makes the naming consistent. Sounds good to me :)

Cool. Could you test if the attached version works?

thanks,

-- 
heikki

View attachment "0001-usb-typec-Add-type-sysfs-attribute-file-for-partners.patch" of type "text/plain" (10309 bytes)