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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 5937CC388F9 for ; Tue, 27 Oct 2020 13:07:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 23EEB22384 for ; Tue, 27 Oct 2020 13:07:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2441400AbgJ0NHG (ORCPT ); Tue, 27 Oct 2020 09:07:06 -0400 Received: from muru.com ([72.249.23.125]:46866 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2441395AbgJ0NHG (ORCPT ); Tue, 27 Oct 2020 09:07:06 -0400 Received: from atomide.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id 17D1F807E; Tue, 27 Oct 2020 13:07:09 +0000 (UTC) Date: Tue, 27 Oct 2020 15:07:01 +0200 From: Tony Lindgren To: Nishanth Menon Cc: Peter Ujfalusi , t-kristo@ti.com, devicetree@vger.kernel.org, robh+dt@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] arm64: dts: ti: k3-j7200-main: Add McASP nodes Message-ID: <20201027130701.GE5639@atomide.com> References: <20201005074850.11247-1-peter.ujfalusi@ti.com> <20201005115805.d6yhykn7oc6x2tbu@charm> <5a9ed7d3-fcfd-edbf-fc34-112a7e55aa1c@ti.com> <20201005120837.75cwdmcpvzbvayq7@kinfolk> <20201026145031.ggfugctq65zvgwp2@dismiss> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201026145031.ggfugctq65zvgwp2@dismiss> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org * Nishanth Menon [201026 14:58]: > On 13:38-20201007, Peter Ujfalusi wrote: > [...] > > >>>> + status = "disabled"; > > >>> > > >>> I see that there is inconsistent usage of "disabled" in our SoC.dts > > >>> > > >>> Our generic rule has been set them to disabled in board.dtsi > > >>> McASP and DSS for existing SoC dts do not follow this.. which is a tad > > >>> confusing.. (considering that not even all uarts come out on every board > > >>> and every uart needs pinmux to function..) > > >> > > >> "keep them disabled because several required properties are not present > > >> as they are board specific." > > >> > > >> In board file the enabled mcasp must be updated with options that is > > >> required for operation. Without those option the McASP can not be > > >> initialized. > > >> > > >> I think we have been revisiting the very same discussion every time we > > >> have a new SoC with McASP... > > >> > > > > > > Yep.. This doe'snt really follow the rest of the SoC definition. [1] > > > came to mind. The McASP discussion is a variation in the debate of the > > > same. > > > > Right, saying status = "okay" to a node which is missing required > > properties (which can only be added by boards when the McASP is > > connected up) does not sound a good solution. > > How should the SW handle that? Fail the device probe and return with > > -EINVAL or eat up the error and just probe with broken configuration. > > Since the peripheral is not used, the broken configuration will not > > cause much runtime errors as there will be no runtime use of the peripheral. > > > > status of fail or fail-sss is not a good one either, their definition is: > > "Indicates that the device is not operational. A serious error was > > detected in the device, and it is unlikely to become operational without > > repair." > > > > The peripheral is fine, we are just trying to enable it without > > providing the needed properties. > > > > > I'd argue Serdes, or for that matter any IP that has a link to > > > outside-the-SoC world has the same discussion point. > > > > status = "disabled" is still the closest thing for everything which have > > external dependencies. There is not much point to enable an i2c bus > > without making sure that the signals are actually routed to the pins > > where they supposed to go. There is one reason to keep using the default status = "okay", for i2c Linux can properly idle the device on boot without dependencies to a certain boot loader version. > > Or from other pow: a board design is not based on what is _not_ > > connected to outside world, but you actually _connect_ or _enable_ > > certain peripherals to external components, connectors. > > OK, I will buy the argument that the current status thingy is a bit > overloaded and does'nt imply the correct state we need it to imply with > "fail-sss" either - I remember an argument for "fail-incomplete", but > that never happened anyways. > > Lets add this argument to the commit message and repost after testing > on 5.10-rc1 please? We should use status = "disabled" when the hardware is not accessible to the SoC. That goes for things like secure world devices, and hardware that relies on a missing external clock for example. For other things we should just stick to the default which "okay" :) Regards, Tony