From nobody Sat Oct 4 17:30:11 2025 Received: from mail-ej1-f54.google.com (mail-ej1-f54.google.com [209.85.218.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 28471233149 for ; Thu, 14 Aug 2025 18:45:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.54 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755197109; cv=none; b=bYj7XvhmTwzZpZpiPjfoog4rP5VjMzraCy6V3Yb92QyVBbobp9jL5aoCT00MpQDD9ZZM7kajo8d9sTRF84tnpVZnuonvr9fYFmqX+zTIGh8Ce+jXaG4Qz5euD8N0LI/9hw0iuYmK2biiX0A0QWGUR3PZufJWyZIGV0hU3IzvVnM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755197109; c=relaxed/simple; bh=30zjWy/jj97FoKyfLjbsSZTkzTbcjQ4czjm4EU8wGs8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eiw+IZxWM93Rpp/JZn5zv4lo0ouPPdAXUR14neup9tguE6DBEPM5btjH2pLJzrmSLB1qqnTUujUs/ZfAVa2ZeSs+/yVxyQxbJ1iv6APKSoPVeP8ZNrwQabqfKsbLOddGY7WoadzgXLPfsWocj4W2vpRJOnrXfl1cMSFBsHWt+t8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=CkGSrXmp; arc=none smtp.client-ip=209.85.218.54 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="CkGSrXmp" Received: by mail-ej1-f54.google.com with SMTP id a640c23a62f3a-afcb732eee6so232559866b.0 for ; Thu, 14 Aug 2025 11:45:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1755197105; x=1755801905; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=vtcHdgDQ94Hb+lE3OrQOh7GvxJZixH0xu7gYTYaPGEQ=; b=CkGSrXmplqHUXcVQDgIfONVsgNjDIO+jubGbdS2yjZspt2hBlwpRoJg5mQTleqFB2v sHuGqA/zktvMwXextcoJGmBqk0r//nP5C7UdjekzHrvf+89Ko99iCZCLOBvXuknVZvj6 nmE4v3XKeszQ4PVBtZ/69cqv2BJ9VRG2rEh80= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1755197105; x=1755801905; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=vtcHdgDQ94Hb+lE3OrQOh7GvxJZixH0xu7gYTYaPGEQ=; b=as6AP8EIUf40/9jvLldHQq7E4LWk2nqk77V0f80k71mhW+AHT+6vGjaQPobInlopl5 gQdrJ67a92M+hNaHzCSs9wsB/MaUSZhpb+RPWOw2Zl/eIkZPEx1I0J3n0nKa7hv/nOGc nUuspKbFXrNp5Ndn8kjnWSVxyy17LNuT11qBYBpaWHn5ON6bfAVMbhFxcpTpKMWkyEQ6 XDMjHFFt+j9A+SWy2yBAm5KF6+U2iQrr+ElHFfKzrpjosDacBMhstCXcVwOXAL2bzCao surZ8Z0dcGwl5s4xg1acLhraSdH3YCftCcAoRZ6xZYklwR+SIWEBz37jFO/YuC/7BSGr LUdg== X-Forwarded-Encrypted: i=1; AJvYcCVpzgh35O8acAzMMFOAzIjn6kOApGVejCfveAHSv686v/VuyUFEpBOclCaFcImRfYHhh3qssAWp0A7Vx8o=@vger.kernel.org X-Gm-Message-State: AOJu0Yx3X45N59ItsYSG4rnw8tDjFCeuMb4MYwqFvgeKNVatjDelQvNM eEkwY4j+UuzqxOcAwWQYDNn4ocYuAQBHLvOM62et1EwugkCSOcWnnkuO6QGdbhFP/Q== X-Gm-Gg: ASbGnctzhDe2Lwg6IYPy5eaRNWrDKwo5Tw6qKcQ0+PNAlwK9DpLeW1pwOviPZitOZ/D ONgRdsoIXBcbsmDcjCukhDI++bSEbuJQqviTYsxlXtnEJg7strtiMayNQcIhiPnRBQwCxJ4oUr+ ixRpPGTiJe+uQWhGmdSLHH26Cxnyc9ap+ChBoz86P5da1WYYAkxk5nof4cm+dVazd0oSfo5+kn5 EkqAM0Q/B79AITuQnuX6hSqw2YkkjYznQZy58C2L23vpo1pmWvHBfXCVWWdz1W1FHcnhfSlcWom 0YPadwLX5U3o+Po8VjCvksKxboq90zifcfeHzI1lnEgkKmlmec+uEYy5nniLQqzBTCNhWHrOBUz kwuVpAQZZsc3DlE3xRMvrDq7Q67cbVoixhUl7ghytwk0oJC2sxsgxK+QLrkU45ER3YGPlVS1lA2 7j0GsXBMmJ5j1Z X-Google-Smtp-Source: AGHT+IHoIrfJieVmQqqm3tABVLHMdomEesJIxLp5AlDzkO4kP3URJ9mRpKR3pWGnoYuK6U7MbaKtaA== X-Received: by 2002:a17:907:2d1e:b0:ae3:5368:be85 with SMTP id a640c23a62f3a-afcb990124fmr316622966b.47.1755197105489; Thu, 14 Aug 2025 11:45:05 -0700 (PDT) Received: from akuchynski.c.googlers.com.com (37.247.91.34.bc.googleusercontent.com. [34.91.247.37]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-af91a21c0f4sm2614772466b.106.2025.08.14.11.45.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Aug 2025 11:45:05 -0700 (PDT) From: Andrei Kuchynski To: Heikki Krogerus , Abhishek Pandit-Subedi , Benson Leung , Jameson Thies , Tzung-Bi Shih , linux-usb@vger.kernel.org, chrome-platform@lists.linux.dev Cc: Guenter Roeck , Greg Kroah-Hartman , Dmitry Baryshkov , "Christian A. Ehrhardt" , Venkat Jayaraman , linux-kernel@vger.kernel.org, Andrei Kuchynski Subject: [PATCH v1 4/5] usb: typec: Implement alternate mode priority handling Date: Thu, 14 Aug 2025 18:44:54 +0000 Message-ID: <20250814184455.723170-5-akuchynski@chromium.org> X-Mailer: git-send-email 2.51.0.rc1.163.g2494970778-goog In-Reply-To: <20250814184455.723170-1-akuchynski@chromium.org> References: <20250814184455.723170-1-akuchynski@chromium.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This patch introduces APIs to manage the priority of USB Type-C alternate modes. These APIs allow for setting and retrieving a priority number for each mode. If a new priority value conflicts with an existing mode's priority, the priorities of the conflicting mode and all subsequent modes are automatically incremented to ensure uniqueness. Signed-off-by: Andrei Kuchynski --- drivers/usb/typec/Makefile | 2 +- drivers/usb/typec/class.h | 1 + drivers/usb/typec/mode_selection.c | 127 +++++++++++++++++++++++++++++ drivers/usb/typec/mode_selection.h | 8 ++ include/linux/usb/typec_altmode.h | 9 ++ 5 files changed, 146 insertions(+), 1 deletion(-) create mode 100644 drivers/usb/typec/mode_selection.c create mode 100644 drivers/usb/typec/mode_selection.h diff --git a/drivers/usb/typec/Makefile b/drivers/usb/typec/Makefile index 7a368fea61bc..8a6a1c663eb6 100644 --- a/drivers/usb/typec/Makefile +++ b/drivers/usb/typec/Makefile @@ -1,6 +1,6 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_TYPEC) +=3D typec.o -typec-y :=3D class.o mux.o bus.o pd.o retimer.o +typec-y :=3D class.o mux.o bus.o pd.o retimer.o mode_selection.o typec-$(CONFIG_ACPI) +=3D port-mapper.o obj-$(CONFIG_TYPEC) +=3D altmodes/ obj-$(CONFIG_TYPEC_TCPM) +=3D tcpm/ diff --git a/drivers/usb/typec/class.h b/drivers/usb/typec/class.h index f05d9201c233..c6467e576569 100644 --- a/drivers/usb/typec/class.h +++ b/drivers/usb/typec/class.h @@ -82,6 +82,7 @@ struct typec_port { struct device *usb3_dev; =20 bool alt_mode_override; + struct list_head mode_list; }; =20 #define to_typec_port(_dev_) container_of(_dev_, struct typec_port, dev) diff --git a/drivers/usb/typec/mode_selection.c b/drivers/usb/typec/mode_se= lection.c new file mode 100644 index 000000000000..8a54639b86bf --- /dev/null +++ b/drivers/usb/typec/mode_selection.c @@ -0,0 +1,127 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2025 Google LLC. + */ + +#include +#include +#include +#include "mode_selection.h" +#include "class.h" + +static const char * const mode_names[TYPEC_ALTMODE_MAX] =3D { + [TYPEC_ALTMODE_DP] =3D "DisplayPort", + [TYPEC_ALTMODE_TBT] =3D "Thunderbolt3", + [TYPEC_ALTMODE_USB4] =3D "USB4", +}; + +static const int default_priorities[TYPEC_ALTMODE_MAX] =3D { + [TYPEC_ALTMODE_DP] =3D 2, + [TYPEC_ALTMODE_TBT] =3D 1, + [TYPEC_ALTMODE_USB4] =3D 0, +}; + +static inline enum typec_mode_type typec_svid_to_altmode(const u16 svid) +{ + switch (svid) { + case USB_TYPEC_DP_SID: + return TYPEC_ALTMODE_DP; + case USB_TYPEC_TBT_SID: + return TYPEC_ALTMODE_TBT; + case USB_TYPEC_USB4_SID: + return TYPEC_ALTMODE_USB4; + } + return TYPEC_ALTMODE_MAX; +} + +/** + * struct mode_selection_state - State tracking for a specific Type-C mode + * @mode: The type of mode this instance represents + * @priority: The mode priority. Lower values indicate a more preferred mo= de. + * @list: List head to link this mode state into a prioritized list. + */ +struct mode_selection_state { + enum typec_mode_type mode; + int priority; + struct list_head list; +}; + +/* -----------------------------------------------------------------------= --- */ +/* port 'mode_priorities' attribute */ + +int typec_mode_set_priority(struct typec_altmode *adev, const int priority) +{ + struct typec_port *port =3D to_typec_port(adev->dev.parent); + const enum typec_mode_type mode =3D typec_svid_to_altmode(adev->svid); + struct mode_selection_state *ms_target =3D NULL; + struct mode_selection_state *ms, *tmp; + + if (mode >=3D TYPEC_ALTMODE_MAX || !mode_names[mode]) + return -EOPNOTSUPP; + + list_for_each_entry_safe(ms, tmp, &port->mode_list, list) { + if (ms->mode =3D=3D mode) { + ms_target =3D ms; + list_del(&ms->list); + break; + } + } + + if (!ms_target) { + ms_target =3D kzalloc(sizeof(struct mode_selection_state), GFP_KERNEL); + if (!ms_target) + return -ENOMEM; + ms_target->mode =3D mode; + INIT_LIST_HEAD(&ms_target->list); + } + + if (priority >=3D 0) + ms_target->priority =3D priority; + else + ms_target->priority =3D default_priorities[mode]; + + while (ms_target) { + struct mode_selection_state *ms_peer =3D NULL; + + list_for_each_entry(ms, &port->mode_list, list) + if (ms->priority >=3D ms_target->priority) { + if (ms->priority =3D=3D ms_target->priority) + ms_peer =3D ms; + break; + } + + list_add_tail(&ms_target->list, &ms->list); + ms_target =3D ms_peer; + if (ms_target) { + ms_target->priority++; + list_del(&ms_target->list); + } + } + + return 0; +} + +int typec_mode_get_priority(struct typec_altmode *adev, int *priority) +{ + struct typec_port *port =3D to_typec_port(adev->dev.parent); + const enum typec_mode_type mode =3D typec_svid_to_altmode(adev->svid); + struct mode_selection_state *ms; + + list_for_each_entry(ms, &port->mode_list, list) + if (ms->mode =3D=3D mode) { + *priority =3D ms->priority; + return 0; + } + + return -EOPNOTSUPP; +} + +void typec_mode_selection_destroy(struct typec_port *port) +{ + struct mode_selection_state *ms, *tmp; + + list_for_each_entry_safe(ms, tmp, &port->mode_list, list) { + list_del(&ms->list); + kfree(ms); + } +} diff --git a/drivers/usb/typec/mode_selection.h b/drivers/usb/typec/mode_se= lection.h new file mode 100644 index 000000000000..69adfcf39d7c --- /dev/null +++ b/drivers/usb/typec/mode_selection.h @@ -0,0 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include +#include + +int typec_mode_set_priority(struct typec_altmode *adev, const int priority= ); +int typec_mode_get_priority(struct typec_altmode *adev, int *priority); +void typec_mode_selection_destroy(struct typec_port *port); diff --git a/include/linux/usb/typec_altmode.h b/include/linux/usb/typec_al= tmode.h index b3c0866ea70f..318858fc7bec 100644 --- a/include/linux/usb/typec_altmode.h +++ b/include/linux/usb/typec_altmode.h @@ -145,6 +145,15 @@ enum { =20 #define TYPEC_MODAL_STATE(_state_) ((_state_) + TYPEC_STATE_MODAL) =20 +#define USB_TYPEC_USB4_SID 0xff00 + +enum typec_mode_type { + TYPEC_ALTMODE_DP =3D 0, + TYPEC_ALTMODE_TBT, + TYPEC_ALTMODE_USB4, + TYPEC_ALTMODE_MAX, +}; + struct typec_altmode *typec_altmode_get_plug(struct typec_altmode *altmode, enum typec_plug_index index); void typec_altmode_put_plug(struct typec_altmode *plug); --=20 2.51.0.rc0.215.g125493bb4a-goog