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=-0.8 required=3.0 tests=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 A0D9AC43603 for ; Wed, 4 Dec 2019 12:14:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7B48C20803 for ; Wed, 4 Dec 2019 12:14:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727508AbfLDMOW (ORCPT ); Wed, 4 Dec 2019 07:14:22 -0500 Received: from mail-oi1-f195.google.com ([209.85.167.195]:42398 "EHLO mail-oi1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727445AbfLDMOW (ORCPT ); Wed, 4 Dec 2019 07:14:22 -0500 Received: by mail-oi1-f195.google.com with SMTP id j22so6611565oij.9; Wed, 04 Dec 2019 04:14:21 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=gyltMSwaGXAux8Z3E1Rs/8+GQsTqCMlqwz9wEprYuxI=; b=qLWp7sO2ECMTDQgb+3QyLoEYzIQ2A9L4W+BG7LhccZqbYaUq8B7EHV9iPcm+Tt+cl1 HGC7M9qcFwgW67HyP6dLkgaML7LAiA/YlCq3LV9YMpsRIJ9X6FIAslWWm09oQuNek1k0 YfB3vfB42XYC39ua8t+OsoNEsrqZbYCMra9pw2ZpQ0br/wUqL4UnfDzw28AXqovQYtuh y40EUjh0V6pWQnXAdlYIiNVeFJvbRbeYVNbJRtrm1qwpLUIIjqTaMnXVKGeN2MxO4gAt 3spc5o1NBP+mLZiUipyfWdqawC55gypORoL5iSvxGfuVwVfM/RQts+D8/FMcZCoVoDMy FUlw== X-Gm-Message-State: APjAAAXpEQnGDfdi5t64lRwAbmdrfCcruulzaBN/5DrngQWdKUDAetRi XdVb+NUPstQD1sXy32laY45l3G8e5BqdwnFNdNA= X-Google-Smtp-Source: APXvYqw8Fs1+GeWP1j9ni3BiJ585N8x8j9pInrEEwGCzSDYGx3Bebh2yBXnZb5CHErF17b0reE6WRUv9j4VhTCJ0ntE= X-Received: by 2002:a05:6808:8ec:: with SMTP id d12mr530181oic.131.1575461661003; Wed, 04 Dec 2019 04:14:21 -0800 (PST) MIME-Version: 1.0 References: <20191203034519.5640-1-chris.brandt@renesas.com> <20191203034519.5640-5-chris.brandt@renesas.com> <20191203141944.GI1998@sirena.org.uk> <20191204112528.GQ1998@sirena.org.uk> In-Reply-To: <20191204112528.GQ1998@sirena.org.uk> From: Geert Uytterhoeven Date: Wed, 4 Dec 2019 13:14:09 +0100 Message-ID: Subject: Re: [PATCH 4/6] spi: Add SPIBSC driver To: Mark Brown Cc: Chris Brandt , Rob Herring , Mark Rutland , Geert Uytterhoeven , Michael Turquette , Stephen Boyd , linux-spi , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Linux-Renesas , linux-clk , Mason Yang , Sergei Shtylyov Content-Type: text/plain; charset="UTF-8" Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org Hi Mark, On Wed, Dec 4, 2019 at 12:25 PM Mark Brown wrote: > On Tue, Dec 03, 2019 at 07:29:45PM +0100, Geert Uytterhoeven wrote: > > On Tue, Dec 3, 2019 at 3:19 PM Mark Brown wrote: > > > > + pm_runtime_put(&pdev->dev); > > > > + pm_runtime_disable(&pdev->dev); > > > > There seems to be no purpose in the runtime PM code in this > > > driver, there's no PM operations of any kind and the driver holds > > > a runtime PM reference for the entire lifetime of the device. > > > It matters for the clock domain (assumed the module clock is not always > > marked as a critical clock). > > That seems like a problem with what the clock domains are doing > surely? The default is supposed to be that if runtime PM isn't > enabled we get the behaviour the driver is manually implementing Unfortunately not: if the driver doesn't implement Runtime PM, the default is to not do anything. Later, unused clocks will be disabled, and the device will stop functioning. > here. Besides, if this is actually impacting power management > I'd expect us to be letting the IP idle rather than holding it > powered up all the time. That would be better, definitely. However, that's just an optimization over holding it powered up all the time. 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