From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754720AbdAaBCd (ORCPT ); Mon, 30 Jan 2017 20:02:33 -0500 Received: from mail-pf0-f196.google.com ([209.85.192.196]:33679 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753682AbdAaBCb (ORCPT ); Mon, 30 Jan 2017 20:02:31 -0500 Date: Mon, 30 Jan 2017 16:59:57 -0800 From: Dmitry Torokhov To: Guenter Roeck Cc: Stephen Boyd , Russell King - ARM Linux , Michael Turquette , Viresh Kumar , Andy Shevchenko , linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] clk: add more managed APIs Message-ID: <20170131005957.GB35974@dtor-ws> References: <20170128184047.GA24957@dtor-ws> <20170128190309.GN27312@n2100.armlinux.org.uk> <20170128192207.GA38136@dtor-ws> <64ed0890-14f6-42ff-66b1-60f7b3d7d02f@roeck-us.net> <20170128233911.GO27312@n2100.armlinux.org.uk> <20170129180743.GA10917@dtor-ws> <20170130185551.GM8801@codeaurora.org> <20170130192214.GC11199@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170130192214.GC11199@roeck-us.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 30, 2017 at 11:22:14AM -0800, Guenter Roeck wrote: > On Mon, Jan 30, 2017 at 10:55:51AM -0800, Stephen Boyd wrote: > > On 01/29, Dmitry Torokhov wrote: > > > When converting a driver to managed resources it is desirable to be able to > > > manage all resources in the same fashion. This change allows managing > > > clocks in the same way we manage many other resources. > > > > Can you please add 'managing clock prepared and enabled state in > > the same way'? > > > > The current wording makes it sound like we don't have > > devm_clk_get() when we do. > > > > > > > > This adds the following managed APIs: > > > > > > - devm_clk_prepare()/devm_clk_unprepare(); > > > - devm_clk_prepare_enable()/devm_clk_disable_unprepare(). > > > > Wouldn't this be preceded by a devm_clk_get() call? Wouldn't it > > be even shorter to have the APIs > > > > devm_clk_get_and_prepare()/devm_clk_unprepare_and_put() > > devm_clk_get_and_prepare_enable()/devm_clk_disable_unprepare_and_put() > > > > instead? > > > In many cases I see > > devm_clk_get(clk1); > devm_clk_get(clk2); > clk_prepare_enable(clk1); > clk_prepare_enable(clk2); > > Sometimes the calls are intertwined with setting the clock rates. > > devm_clk_get(clk); > clk_set_rate(clk, rate); > clk_prepare_enable(clk); > > Maybe the additional calls make sense; I can imagine they would. > However, I personally would be a bit wary of changing the initialization > order of multi-clock initializations, and I am not sure how a single call > could address setting the rate ([devm_]clk_get_setrate_prepare_enable() > seems like a bit too much). > > [ On a side note, why is there no clk_get_prepare_enable() and > clk_get_prepare() ? Maybe it would be better to introduce those > together with the matching devm_ functions in a separate patch > if they are useful. ] > > > Is there any other subsystem that has similar functionality? > > Regulators? GPIOs? Resets? I'm just curious if those subsystems > > also need similar changes. > > > Ultimately yes, and most already do. If I recall correctly, I tried to > introduce devm_ functions for regulators some time ago, but that was > rejected with the comment that it would invite misuse. At the time > I accepted that; today my reaction would be to counter that pretty much > everything can be misused, and that the potential for misuse should not > penaltize all the valid use cases. I think we should ping Mark again. The only thing we are achieving is that everyone is using devm_add_action_or_reset() with wrappers around regulator_put(). As I said elsewhere, there are "always used" devices where it isn't worth it to postpone enabling regulators. Thanks. -- Dmitry