Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932756AbcCRNCu (ORCPT ); Fri, 18 Mar 2016 09:02:50 -0400 Received: from mail-io0-f193.google.com ([209.85.223.193]:34664 "EHLO mail-io0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932306AbcCRNCr (ORCPT ); Fri, 18 Mar 2016 09:02:47 -0400 MIME-Version: 1.0 In-Reply-To: <56EBF8E0.8020700@ti.com> References: <1458224359-32665-1-git-send-email-jonathanh@nvidia.com> <1458224359-32665-15-git-send-email-jonathanh@nvidia.com> <56EBD4E5.1060002@nvidia.com> <56EBDEFA.30102@nvidia.com> <56EBF8E0.8020700@ti.com> Date: Fri, 18 Mar 2016 14:02:46 +0100 X-Google-Sender-Auth: QFWGBAEBBx6RA7D7Zlj_nx8Aw0s Message-ID: Subject: Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document From: Geert Uytterhoeven To: Grygorii Strashko Cc: Jon Hunter , Thomas Gleixner , Jason Cooper , Marc Zyngier , =?UTF-8?Q?Beno=C3=AEt_Cousson?= , Tony Lindgren , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Stephen Warren , Thierry Reding , Kevin Hilman , Lars-Peter Clausen , Linus Walleij , linux-tegra@vger.kernel.org, "linux-omap@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3187 Lines: 74 Hi Grygorii, On Fri, Mar 18, 2016 at 1:47 PM, Grygorii Strashko wrote: > On 03/18/2016 02:05 PM, Geert Uytterhoeven wrote: >> On Fri, Mar 18, 2016 at 11:56 AM, Jon Hunter wrote: >>> On 18/03/16 10:52, Geert Uytterhoeven wrote: >>>> On Fri, Mar 18, 2016 at 11:13 AM, Jon Hunter wrote: >>>>> On 18/03/16 09:13, Geert Uytterhoeven wrote: >>>>>> On Thu, Mar 17, 2016 at 3:19 PM, Jon Hunter wrote: >>>>>>> Commit afbbd2338176 ("irqchip/gic: Document optional Clock and Power >>>>>>> Domain properties") documented optional clock and power-dmoain properties >>>>>>> for the ARM GIC. Currently, there are no users of these and for the >>>>>>> Tegra210 Audio GIC (based upon the GIC-400) there are two clocks, a >>>>>>> functional clock and interface clock, that need to be enabled. >>>>>> >>>>>> The reason that there are no users for this is twofold: >>>>>> 1. The GIC driver doesn't have Runtime PM support yet, >>>>>> 2. There was no clean way to prevent the GIC's clock from being disabled. >>>>>> Due to this, adding the clocks to the DTSes would mean that they will be >>>>>> disabled during boot up as unused clocks, leading to a system lock-up. >>>>>> >>>>>> I had hoped your series would fix part 1. I gave it a try on r8a7791/koelsch, >>>>>> but unfortunately it seems the platform driver only supports non-root >>>>>> controllers, while the r8a7791 GIC is the primary one... >>>>> >>>>> Can you try making the following change ... >>>> >>>> Thanks! I gave it a try, but no difference. >>> >>> I assume you added the appropriate compatible flag? Any more details you >> >> Doh... bad assumption... Silly me. >> >>> can share about why it is not working? Is it not registered early enough? >> >> With >> >> + { .compatible = "arm,gic-400", }, >> >> the kernel no longer crashes due to accessing the GIC registers while the >> GIC module clock is disabled. >> >> However, the system doesn't boot completely, and time outs on SPI transfers >> make me believe interrupts are not working. >> Both with and without "the following change". >> > > Is my assumption correct that you are trying to enable RPM for primary GIC controller? That's correct. > If yes it may help to take a look on clocksource drivers which use early_platform_device/driver > sh_cmt.c sh_mtu2.c sh_tmu.c > > The primary interrupt controller is initialized very early init_IRQ->irqchip_init->of_irq_init() > (IRQCHIP_DECLARE) and, at least as i can see from st_xxx code, the same case is valid for > clocksource devices and it was solved using early_platform_device/drive staff. The GIC now depends on the clock driver, which may be a real platform driver, not initialized from CLK_OF_DECLARE(). Or do you mean to make the clock driver an early platform driver? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds