From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH] ARM: shmobile: r8a73a4: Move pfc node to work around probe ordering bug Date: Mon, 9 Feb 2015 10:29:19 -0800 Message-ID: <20150209182918.GA2531@atomide.com> References: <1423254173-31852-1-git-send-email-geert+renesas@glider.be> <20150209162428.GG25235@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-sh-owner@vger.kernel.org To: Geert Uytterhoeven Cc: Geert Uytterhoeven , Simon Horman , Magnus Damm , Rob Herring , Grant Likely , Laurent Pinchart , Thierry Reding , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Linux-sh list , "linux-kernel@vger.kernel.org" List-Id: devicetree@vger.kernel.org * Geert Uytterhoeven [150209 09:17]: > On Mon, Feb 9, 2015 at 5:24 PM, Tony Lindgren wrote: > > * Geert Uytterhoeven [150206 12:26]: > >> Notes: > >> - It seems several people tried to solve this in the core OF probing > >> code before, but the final solution never went in? > >> - This can be reproduced on other SoCs (e.g. sh73a0 and r8a7740) by > >> moving their pfc nodes before their interrupt controller nodes. > >> - This patch is against my working tree, so it doesn't apply to > >> Simon's repository, but you get the idea.... > > > > No issues with the patch, but here are few comments on the core > > reasons (without looking at the code in this case) that might help > > fix similar issues. > > > > In all the cases I've seen these errors are caused by non-standard > > custom initcall levels for drivers like i2c bus. The real solution > > is to initialize drivers later with standard module_init, and stop > > the race to the bottom with custom initcall levels. > > > > If there is legacy board specific platofrm init code that needs > > i2c gpios early, that code can probably be moved to initialize > > later on. > > In this case no i2c is involved. The drivers for both pinctrl > (renesas,pfc-r8a73a4) and irqchip (renesas,irqc) are registered > at the same level: > - postcore_initcall(sh_pfc_init); > - postcore_initcall(irqc_init); > Hence the system uses the "natural" order from within the DTS, > and decided to instantiate the pfc before the irqchip. OK > > Also, there should not be any need for custom driver initcall > > levels from Linux generic framework point of view as for example > > irqchip implementing drivers work just fine as a loadable module. > > As long as no other device that's instantiated earlier references that > irqchip? Right :) And deferred probe won't still remove the warning in that case. From what I remember, that's a valid warning from irq framework point of view. Regards, Tony