linux-kernel - Re: [PATCH v10 01/11] usb: typec: Add notifier functions

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Message-ID: <aSbyCR-vFo3mvZ3u@kuha>
Date: Wed, 26 Nov 2025 14:26:49 +0200
From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To: Chaoyi Chen <chaoyi.chen@...k-chips.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Chaoyi Chen <kernel@...kyi.com>,
	Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
	Peter Chen <hzpeterchen@...il.com>,
	Luca Ceresoli <luca.ceresoli@...tlin.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, Vinod Koul <vkoul@...nel.org>,
	Kishon Vijay Abraham I <kishon@...nel.org>,
	Heiko Stuebner <heiko@...ech.de>, Sandy Huang <hjc@...k-chips.com>,
	Andy Yan <andy.yan@...k-chips.com>,
	Yubing Zhang <yubing.zhang@...k-chips.com>,
	Frank Wang <frank.wang@...k-chips.com>,
	Andrzej Hajda <andrzej.hajda@...el.com>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Robert Foss <rfoss@...nel.org>,
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
	Jonas Karlman <jonas@...boo.se>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	Amit Sunil Dhamne <amitsd@...gle.com>,
	Dragan Simic <dsimic@...jaro.org>, Johan Jonker <jbx6244@...il.com>,
	Diederik de Haas <didi.debian@...ow.org>,
	Peter Robinson <pbrobinson@...il.com>, linux-usb@...r.kernel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-phy@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org,
	linux-rockchip@...ts.infradead.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH v10 01/11] usb: typec: Add notifier functions

Wed, Nov 26, 2025 at 07:51:33PM +0800, Chaoyi Chen kirjoitti:
> On 11/26/2025 7:44 PM, Greg Kroah-Hartman wrote:
> > On Wed, Nov 26, 2025 at 11:42:43AM +0200, Heikki Krogerus wrote:
> >> Wed, Nov 26, 2025 at 09:46:19AM +0800, Chaoyi Chen kirjoitti:
> >>> On 11/25/2025 7:49 PM, Greg Kroah-Hartman wrote:
> >>>>> +static umode_t typec_is_visible(struct kobject *kobj, struct attribute *attr, int n)
> >>>>> +{
> >>>>> +	if (is_typec_port(kobj_to_dev(kobj)->parent))
> >>>>
> >>>> Why look at the parent?  Doesn't the device have a type that should show
> >>>> this?
> >>>>
> >>>> Otherwise, looks good to me.
> >>>
> >>> They have same deivce type "typec_altmode_dev_type".
> >>> The parent device has a different device type to distinguish between
> >>> port device and partner device.
> >>
> >> I was already wondering would it make sense to provide separate device
> >> types for the port, and also plug, alternate modes, but I'm not sure
> >> if that's the right thing to do.
> >>
> >> There is a plan to register an "altmode" also for the USB4 mode,
> >> which of course is not an alternate mode. So USB4 will definitely need a
> >> separate device type.
> >>
> >> So if we supply separate device types for the port, plug and partner
> >> alternate modes, we need to supply separate device types for port, plug
> >> and partner USB4 mode as well.
> >>
> >> We certainly can still do that, but I'm just not sure if it makes
> >> sense?
> >>
> >> I'll prepare a new version for this and include a separate patch where
> >> instead of defining separate device types for the port and plug
> >> alternate modes I'll just supply helpers is_port_alternate_mode() and
> >> is_plug_alternate_mode().
> > 
> > That feels like it would be better in the long run as it would be
> > easier to "match" on the device type.
> >
> 
> It make sense. But now can we first use the current "match" device type
> operation and then modify them later?

Let's do this right from the beginning. Here's a version with the
dedicated device types.

-- 
heikki

View attachment "0001-usb-typec-Set-the-bus-also-for-the-port-and-plug-alt.patch" of type "text/plain" (6535 bytes)