From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2DAA8C43458 for ; Thu, 9 Jul 2026 10:53:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ltJYKu5vBBdVeOMLhjGQdQTTAHldNEHzZRaL7sIwTaE=; b=X2hwRJSYj0oEdGy0BYsLuPb8D6 vZT2FPAzMHm6h0eKIywpKLfAIYdOnrHS48c3HM2py9WkBnvSYa/Ep8RDtZQj0Z+hwkeNqLG02NzLv N08Gll4kzAyea2Z5tbYNqiK7MM4oumSoq2XQPtJd4BI1fTrcycNC0sU9BE6TzDR6yxzJORpxJcfXG Usk0xetQqmv6hOJ7vfYI8R146LltEwOr2QRloE90wie1zkRBHI5yCziYpqi3l2yFZL38SD4NV9MEO dEa8Ox9wzsLuJVFW++c9QiFZPqBmPX5MV1ag053NxFMQ8DDkZ17IPmCaDISPT4RPRhIkMeBjAb9KN P+7VDwOg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1whmNq-000000021vp-3aMU; Thu, 09 Jul 2026 10:53:34 +0000 Received: from mgamail.intel.com ([198.175.65.15]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1whmNm-000000021k4-2mJj; Thu, 09 Jul 2026 10:53:32 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1783594411; x=1815130411; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=PvwFawp2iYCKug7OnZ1L1tsF9gscNjwbC5sgQMjyLUA=; b=QDuRPSD8Rqfx8wPcKp6OVfoVDvFLjjul8A2RwDt42cVSeBvsF7oYoU5a 6qdoU4K5UL+coUPadkGI9V/MV226CokdnNik0yz/YO29ZrEcKLtUJBoWE wW/lH256Jx/phBU1/BzNSbRHb3xO3azLclkyDMnZtfsf8p5EPu7EKd28F D0zWvAJyTO7Szw7Bgf+fiQFOB2qQd3rI/flr6p+1n/ZbiwgiM9GJbc/oC LMTqfw08Vbw7hl/5bOhW5tMSMl9enyTXV+a9wIPkLH/wrrUZhvQ5Mm0tn Cg7EgsqjysqXGIOtvFu7U9xVqqfrfLbk7d1MZAWSQiIcZNk2NPKVppdNk A==; X-CSE-ConnectionGUID: bK8D+EXIR8C3DLuiO7QFYA== X-CSE-MsgGUID: 0izMqrgFRpakW8SAZvuQzg== X-IronPort-AV: E=McAfee;i="6800,10657,11841"; a="87956674" X-IronPort-AV: E=Sophos;i="6.25,154,1779174000"; d="scan'208";a="87956674" Received: from orviesa004.jf.intel.com ([10.64.159.144]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Jul 2026 03:53:30 -0700 X-CSE-ConnectionGUID: XV2lQsU2QUK3dikQ6J3nQg== X-CSE-MsgGUID: PFp2vzNHSaa1nuO8WaAUaw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,154,1779174000"; d="scan'208";a="258420526" Received: from ettammin-mobl3.ger.corp.intel.com (HELO localhost) ([10.245.245.235]) by orviesa004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Jul 2026 03:53:24 -0700 Date: Thu, 9 Jul 2026 13:53:22 +0300 From: Andy Shevchenko To: Chen-Yu Tsai Cc: Bartosz Golaszewski , Greg Kroah-Hartman , Daniel Scally , Heikki Krogerus , Sakari Ailus , "Rafael J. Wysocki" , Danilo Krummrich , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Matthias Brugger , AngeloGioacchino Del Regno , linux-acpi@vger.kernel.org, driver-core@lists.linux.dev, linux-pm@vger.kernel.org, linux-usb@vger.kernel.org, devicetree@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Manivannan Sadhasivam , Alan Stern , Bartosz Golaszewski Subject: Re: [PATCH v4 09/14] usb: hub: Power on connected M.2 E-key connectors with power sequencing API Message-ID: References: <20260709095726.704448-1-wenst@chromium.org> <20260709095726.704448-10-wenst@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260709095726.704448-10-wenst@chromium.org> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260709_035330_775008_5A5EC43B X-CRM114-Status: GOOD ( 35.61 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Jul 09, 2026 at 05:57:14PM +0800, Chen-Yu Tsai wrote: > The new M.2 E-key connector can have a USB connection. For the USB device > on this connector to work, its power must be enabled and the W_DISABLE2# > signal deasserted. The connector driver handles this and provides a > toggle over the power sequencing API. > > This feature currently only supports a directly connected (no mux in > between) M.2 E-key connector. Existing USB connector types are not > covered. The USB A connector was recently added to the onboard devices > driver. USB B connectors have historically been managed by the USB > gadget or dual-role device controller drivers. USB C connectors are > handled by TCPM drivers. > > The power sequencing API does not know whether a power sequence provider > is not needed or not available yet, so we only request it for connectors > that we know need it, which at this time is just the E-key connector. > > On the USB side, the port firmware node (if present) is tied to the > usb_port device. This device is used to acquire the power sequencing > descriptor. This allows the provider to tell the different ports on one > hub apart. > > This feature is not implemented in the onboard USB devices driver. The > power sequencing API expects the consumer device to make the request, > but there is no device node to instantiate a platform device to tie > the driver to. The connector is not a child node of the USB host or > hub, and the graph connection is from a USB port to the connector. > And the connector itself already has a driver. > > Power sequencing is not directly enabled in the connector driver as > that would completely decouple the timing of it from the USB subsystem. > It would not be possible for the USB subsystem to toggle the power > for a power cycle or to disable the port. > > Also rewrite the existing set_bit() and clear_bit() branches with > assign_bit() to make it cleaner. ... > int usb_hub_set_port_power(struct usb_device *hdev, struct usb_hub *hub, > int port1, bool set) > { > + struct usb_port *pwrseq_port = hub->ports[port1 - 1]; > int ret; > > + ret = usb_hub_set_port_pwrseq(pwrseq_port, set); > + if (ret) > + return ret; > + > if (set) > ret = set_port_feature(hdev, port1, USB_PORT_FEAT_POWER); > else > ret = usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_POWER); > > - if (ret) > + if (ret) { > + usb_hub_set_port_pwrseq(pwrseq_port, !set); > return ret; > + } > - if (set) > - set_bit(port1, hub->power_bits); > - else > - clear_bit(port1, hub->power_bits); > + assign_bit(port1, hub->power_bits, set); I just realised that this change doesn't affect any functionality neither before nor after the core of this patch. With that being said, I think you may split this small piece to a separate patch to avoid unneeded churn here. I will give a tag to that patch immediately I see it. > return 0; > } ... > - return ret; > + /* stub functions return error */ > + if (!IS_ENABLED(CONFIG_POWER_SEQUENCING)) > + return ret; > + > + if (!port->pwrseq) > + return ret; > + > + return ret && pwrseq_power_is_on(port->pwrseq); Perhaps /* stub functions return error */ if (IS_ENABLED(CONFIG_POWER_SEQUENCING) && port->pwrseq) return ret && pwrseq_power_is_on(port->pwrseq); return ret; ? This will also make better visibility of what you meant in the comment above. > } ... > +static bool port_pwrseq_is_supported(struct usb_port *port_dev) > +{ > + struct device *dev = &port_dev->dev; > + struct fwnode_handle *port = dev->fwnode; Use dev_fwnode(). Also it make sense to add a blank line here to keep __free()-defined variables coupled with the checks (and hence scope). > + struct fwnode_handle *ep __free(fwnode_handle) = > + fwnode_graph_get_next_port_endpoint(port, NULL); > + if (!ep) > + return false; > + > + struct fwnode_handle *remote __free(fwnode_handle) = > + fwnode_graph_get_remote_port_parent(ep); > + if (!remote) > + return false; > + > + if (!fwnode_device_is_compatible(remote, "pcie-m2-e-connector")) { > + dev_dbg(dev, "remote endpoint %pfw is not a supported connector", remote); > + return false; > + } > + > + return true; > +} -- With Best Regards, Andy Shevchenko