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 X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2B48AC4742C for ; Thu, 29 Oct 2020 22:52:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C590720639 for ; Thu, 29 Oct 2020 22:52:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="ZktCDXVV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725898AbgJ2Wwf (ORCPT ); Thu, 29 Oct 2020 18:52:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59094 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725379AbgJ2Wwf (ORCPT ); Thu, 29 Oct 2020 18:52:35 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B2A2C0613CF; Thu, 29 Oct 2020 15:52:18 -0700 (PDT) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 7963F50E; Thu, 29 Oct 2020 23:52:13 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1604011933; bh=vzSndNEC2+VUkDZk9LxMGrAa8RXHZZppKTDuEiYcZCk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZktCDXVVdoN8DxlaC77AznsLYPn/9Hx06ldF8z7ULe/ZP+AR1hxO+PKXStPS3Zgcz ntNoeqSbaqTCsFMCEPAQaz1WG2RSgQwmOx9RM7X03nJaBSjDGxK9jVAbSDPNDOmayu 7eTfoKkE4WvGfj/ukwXsTNfPgEpNLosjVs8lEbqc= Date: Fri, 30 Oct 2020 00:51:24 +0200 From: Laurent Pinchart To: Andy Shevchenko Cc: Dan Scally , Linux Kernel Mailing List , Linux Media Mailing List , Linus Walleij , prabhakar.mahadev-lad.rj@bp.renesas.com, "Krogerus, Heikki" , Dmitry Torokhov , laurent.pinchart+renesas@ideasonboard.com, kieran.bingham+renesas@ideasonboard.com, Jacopo Mondi , Rob Herring , "David S. Miller" , Rasmus Villemoes , Sergey Senozhatsky , Steven Rostedt , Petr Mladek , Mauro Carvalho Chehab , Tian Shu Qiu , Bingbu Cao , Sakari Ailus , Yong Zhi , "Rafael J. Wysocki" , Greg Kroah-Hartman , Tsuchiya Yuto Subject: Re: [RFC PATCH v3 9/9] ipu3-cio2: Add functionality allowing software_node connections to sensors on platforms designed for Windows Message-ID: <20201029225124.GI15024@pendragon.ideasonboard.com> References: <20201019225903.14276-1-djrscally@gmail.com> <20201019225903.14276-10-djrscally@gmail.com> <20201024012411.GT5979@pendragon.ideasonboard.com> <20201024093702.GA3939@pendragon.ideasonboard.com> <20201026161050.GQ4077@smile.fi.intel.com> <20201029201918.GD15024@pendragon.ideasonboard.com> <20201029212930.GE15024@pendragon.ideasonboard.com> <20201029222215.GI4077@smile.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20201029222215.GI4077@smile.fi.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andy, On Fri, Oct 30, 2020 at 12:22:15AM +0200, Andy Shevchenko wrote: > On Thu, Oct 29, 2020 at 11:29:30PM +0200, Laurent Pinchart wrote: > > On Thu, Oct 29, 2020 at 10:26:56PM +0200, Andy Shevchenko wrote: > > > On Thu, Oct 29, 2020 at 10:21 PM Laurent Pinchart wrote: > > > > On Mon, Oct 26, 2020 at 06:10:50PM +0200, Andy Shevchenko wrote: > > > > > On Sat, Oct 24, 2020 at 12:37:02PM +0300, Laurent Pinchart wrote: > > > > > > On Sat, Oct 24, 2020 at 09:50:07AM +0100, Dan Scally wrote: > > > > > > > On 24/10/2020 02:24, Laurent Pinchart wrote: > > > > > > > > On Mon, Oct 19, 2020 at 11:59:03PM +0100, Daniel Scally wrote: > > > > > > > > > > > > >> + adev = acpi_dev_get_first_match_dev(supported_devices[i], NULL, -1); > > > > > > > > > > > > > > > > What if there are multiple sensor of the same model ? > > > > > > > > > > > > > > Hmm, yeah, that would be a bit of a pickle. I guess the newer > > > > > > > smartphones have multiple sensors on the back, which I presume are the > > > > > > > same model. So that will probably crop up at some point. How about > > > > > > > instead I use bus_for_each_dev() and in the applied function check if > > > > > > > the _HID is in the supported list? > > > > > > > > > > > > Sounds good to me. > > > > > > > > > > > > > >> + if (!adev) > > > > > > > >> + continue; > > > > > > > > > > Please, don't. > > > > > > > > > > If we have so weird ACPI tables it must be w/a differently. The all, even badly > > > > > formed, ACPI tables I have seen so far are using _UID to distinguish instance > > > > > of the device (see second parameter to the above function). > > > > > > > > > > If we meet the very broken table I would like rather to know about, then > > > > > silently think ahead what could be best. > > > > > > > > > > I.o.w. don't change this until we will have a real example of the problematic > > > > > firmware. > > > > > > > > I'm not sure to follow you. Daniel's current code loops over all the > > > > supported HID (as stored in the supported_devices table), and then gets > > > > the first ACPI device for each of them. If multiple ACPI devices exist > > > > with the same HID, we need to handle them all, so enumerating all ACPI > > > > devices and checking whether their HID is one we handle seems to be the > > > > right option to me. > > > > > > Devices with the same HID should be still different by another > > > parameter in ACPI. The above mentioned call just uses the rough > > > estimation for relaxed conditions. If you expect more than one device > > > with the same HID how do you expect to distinguish them? The correct > > > way is to use _UID. It may be absent, or set to a value. And this > > > value should be unique (as per U letter in UID abbreviation). That > > > said, the above is good enough till we find the firmware with the > > > above true (several devices with the same HID). Until then the code is > > > fine. > > > > I expect those devices with the same _HID to have different _UID values, > > yes. On the systems I've seen so far, that assumption is not violated, > > and I don't think we need to already plan how we will support systems > > where multiple devices would have the same _HID and _UID (within the > > same scope). There's no disagreement there. > > > > My point is that supported_devices stores HID values, and doesn't care > > about UID. The code loops over supported_devices, and for each entry, > > calls acpi_dev_get_first_match_dev() and process the ACPI devices > > returned by that call. We thus process at most one ACPI device per HID, > > which isn't right. > > In this case we probably need something like > > struct acpi_device * > acpi_dev_get_next_match_dev(struct acpi_device *adev, > const char *hid, const char *uid, s64 hrv) > { > struct device *start = adev ? &adev->dev : NULL; > ... > dev = bus_find_device(&acpi_bus_type, start, &match, acpi_dev_match_cb); > ... > } > > in drivers/acpi/utils.c and > > static inline struct acpi_device * > acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv) > { > return acpi_dev_get_next_match_dev(NULL, hid, uid, hrv); > } > > in include/linux/acpi.h. > > Then we may add > > #define for_each_acpi_dev_match(adev, hid, uid, hrv) \ > for (adev = acpi_dev_get_first_match_dev(hid, uid, hrv); \ > adev; \ > adev = acpi_dev_get_next_match_dev(adev, hid, uid, hrv)) What the cio2-bridge code needs is indeed for each hid in supported hids: for each acpi device that is compatible with hid: ... which could also be expressed as for each acpi device: if acpi device hid is in supported hids: ... I don't mind either option, I'll happily follow the preference of the ACPI maintainers. -- Regards, Laurent Pinchart