From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mika Westerberg Subject: Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices before scanning Date: Tue, 13 Jun 2017 11:48:31 +0300 Message-ID: <20170613084831.GP3187@lahna.fi.intel.com> References: <1495712248-5232-1-git-send-email-gabriele.paoloni@huawei.com> <1495712248-5232-6-git-send-email-gabriele.paoloni@huawei.com> <20170530132408.GA2556@red-moon> <20170606085553.GA20085@red-moon> <20170612155700.GA31930@red-moon> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20170612155700.GA31930@red-moon> Sender: linux-kernel-owner@vger.kernel.org To: Lorenzo Pieralisi Cc: Gabriele Paoloni , rafael@kernel.org, "Rafael J. Wysocki" , "catalin.marinas@arm.com" , "will.deacon@arm.com" , "robh+dt@kernel.org" , "frowand.list@gmail.com" , "bhelgaas@google.com" , "arnd@arndb.de" , "linux-arm-kernel@lists.infradead.org" , "mark.rutland@arm.com" , "brian.starkey@arm.com" , "olof@lixom.net" , "benh@kernel.crashing.org" , "linux-kernel@vger.kernel.org" , "linux-acpi@vger.kernel.org" , Li List-Id: linux-acpi@vger.kernel.org On Mon, Jun 12, 2017 at 04:57:00PM +0100, Lorenzo Pieralisi wrote: > I had a more in-depth look at this series and from my understanding > the problem are the following to manage the LPC bindings in ACPI. > > (1) Child devices of an LPC controller require special handling when > filling their resources (ie they need to be translated - in DT > that's guaranteed by the "isa" binding, in ACPI it has to be > done by new code) > (2) In DT systems, LPC child devices are created by the LPC bus > controller driver through an of_platform_populate() call with > the LPC controller node as the fwnode root. For ACPI to work > the same way there must be a way to prevent LPC children to > be enumerated in acpi_default_enumeration() something like > I2C does (and then the LPC driver would enumerate its children as > DT does) > > I am not sure how (1) and (2) can be managed with current ACPI bindings > and kernel code - I suspect it may be done by mirroring what's done > for I2C but I am not sure, that's why I CC'ed Mika (ie the LPC adapter > is matched as a platform device and it takes care of enumerating its > children - problem though is preventing enumeration from core ACPI code). Is there an example ASL showing how these LPC devices are currently presented in ACPI?