From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8DBAC30C62E; Thu, 23 Oct 2025 11:30:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761219008; cv=none; b=P9pZFEoG/5/nL5GGATnukkz7bIAx79tZMhTBGl0QYdB7G2JhON4umCiSWZ56qDdPJV4WznwMTlM1PwP5LZAAycQgZDDdRF/GAKtyCSypZjXBy0dLfMSQ5ExK/hNyVyuD8UZsJZLrjmgWtoNPb09soAcFjwy7oBVwuoTNXVbttME= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761219008; c=relaxed/simple; bh=XLkysNfegUvwyIevl1eKm/wT3mO3tDZSFi6ARpRRGTw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=n8T0moe5bLKgtigc7+YZruE1M5Y0hh37aGkLMFdM4AWFVhMjlIGrfvpWJPQ2aaBO+hDQXff2twpt0FWxvC2rcFQ3IDfTXXWc/nTTWM4MNkXXqRBoNdn0hGzT7qfJY2mowW6Pe4vfe4A52l1ldgOrN9gWb02unNba5LeBt4i5Pzc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IvhdcHew; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="IvhdcHew" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 513DEC4CEFF; Thu, 23 Oct 2025 11:30:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1761219005; bh=XLkysNfegUvwyIevl1eKm/wT3mO3tDZSFi6ARpRRGTw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IvhdcHewmfHAjgrwZglSVd155WrxiM4g73D6cbuvPY3vsvdnXN/GwE22hcg1dgSUO qAme1OOliteiwXZvpnXyYvTrfNY/wdnvvQGBd00WxFrDDlL+QyLaVIqWgYWo5LujOT aHqV/8zJm7ZSt8TCRKT9z8UFhoNeAC6JKxf2hhcE= Date: Thu, 23 Oct 2025 13:29:58 +0200 From: Greg Kroah-Hartman To: Chaoyi Chen Cc: Heikki Krogerus , Dmitry Baryshkov , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Vinod Koul , Kishon Vijay Abraham I , Heiko Stuebner , Sandy Huang , Andy Yan , Yubing Zhang , Frank Wang , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Amit Sunil Dhamne , Dragan Simic , Johan Jonker , Diederik de Haas , Peter Robinson , linux-usb@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-phy@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH v7 1/9] usb: typec: Add notifier functions Message-ID: <2025102308-glorified-greedy-e41c@gregkh> References: <20251023033009.90-1-kernel@airkyi.com> <20251023033009.90-2-kernel@airkyi.com> <9c52db41-14f3-41a8-9423-3efe604361aa@rock-chips.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9c52db41-14f3-41a8-9423-3efe604361aa@rock-chips.com> On Thu, Oct 23, 2025 at 07:21:31PM +0800, Chaoyi Chen wrote: > Hi Heikki, > > On 10/23/2025 5:44 PM, Heikki Krogerus wrote: > > On Thu, Oct 23, 2025 at 12:04:44PM +0300, Heikki Krogerus wrote: > > > On Thu, Oct 23, 2025 at 11:10:20AM +0300, Heikki Krogerus wrote: > > > > Hi, > > > > > > > > > diff --git a/include/linux/usb/typec_notify.h b/include/linux/usb/typec_notify.h > > > > > new file mode 100644 > > > > > index 000000000000..a3f1f3b3ae47 > > > > > --- /dev/null > > > > > +++ b/include/linux/usb/typec_notify.h > > > > > @@ -0,0 +1,17 @@ > > > > > +/* SPDX-License-Identifier: GPL-2.0 */ > > > > > + > > > > > +#ifndef __USB_TYPEC_NOTIFY > > > > > +#define __USB_TYPEC_NOTIFY > > > > > + > > > > > +#include > > > > > + > > > > > +enum usb_typec_event { > > > > > + TYPEC_ALTMODE_REGISTERED > > > > > +}; > > > > Don't you need to know when the altmode is removed? > > > I noticed that you don't because drm_dp_hpd_bridge_register() is > > > always resource managed. But I think you could still send an event > > > also when the altmode is removed already now. That way it does not > > > need to be separately added if and when it is needed. > > Hold on! Every bus has already a notifier chain. That's the one that > > we should also use. Sorry for not noticing that earlier. > > > > So let's just export the bus type in this patch - you can then use > > bus_register_notifier() in your driver: > > > > diff --git a/drivers/usb/typec/bus.c b/drivers/usb/typec/bus.c > > index a884cec9ab7e..65ded9e3cdaa 100644 > > --- a/drivers/usb/typec/bus.c > > +++ b/drivers/usb/typec/bus.c > > @@ -547,3 +547,4 @@ const struct bus_type typec_bus = { > > .probe = typec_probe, > > .remove = typec_remove, > > }; > > +EXPORT_SYMBOL_GPL(typec_bus); > > diff --git a/drivers/usb/typec/bus.h b/drivers/usb/typec/bus.h > > index 643b8c81786d..af9edb3db9d0 100644 > > --- a/drivers/usb/typec/bus.h > > +++ b/drivers/usb/typec/bus.h > > @@ -5,7 +5,6 @@ > > #include > > -struct bus_type; > > struct typec_mux; > > struct typec_retimer; > > @@ -28,7 +27,6 @@ struct altmode { > > #define to_altmode(d) container_of(d, struct altmode, adev) > > -extern const struct bus_type typec_bus; > > extern const struct device_type typec_altmode_dev_type; > > #define is_typec_altmode(_dev_) (_dev_->type == &typec_altmode_dev_type) > > diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h > > index 309251572e2e..c6fd46902fce 100644 > > --- a/include/linux/usb/typec.h > > +++ b/include/linux/usb/typec.h > > @@ -20,12 +20,15 @@ struct typec_port; > > struct typec_altmode_ops; > > struct typec_cable_ops; > > +struct bus_type; > > struct fwnode_handle; > > struct device; > > struct usb_power_delivery; > > struct usb_power_delivery_desc; > > +extern const struct bus_type typec_bus; > > + > > enum typec_port_type { > > TYPEC_PORT_SRC, > > TYPEC_PORT_SNK, > > Thank you for your detailed explanation. I noticed that there is a device_register() action in typec_register_altmode(), so we can just take advantage of this. > > > Another thing is that we need to distinguish between different devices in the notifier callback, as typec_register_altmode()/typec_register_partner()/typec_register_plug()/typec_register_cable() may all register devices. Since the data passed in bus_notify() is struct device *dev, I think we can distinguish them through `dev->type.name`? We may already have such names, "typec_alternate_mode", "typec_partner", "typec_plug" in class.c . And then extract these names as macros and put them in the typec header file. > > > Or do you have any better ideas? Thank you. Check based on the type itself, NOT on the type name, as all device types on a bus should be unique. If the structure for that is not properly exported for you to use, just export it. thanks, greg k-h