From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH v3 0/4] clk: st: New always-on clock domain Date: Mon, 2 Mar 2015 08:30:19 +0000 Message-ID: <20150302083019.GD31325@x1> References: <1424799222-9301-1-git-send-email-lee.jones@linaro.org> <87385r3uk9.fsf@free.fr> <20150227214941.GB12821@x1> <87sidq3ox8.fsf@free.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <87sidq3ox8.fsf@free.fr> Sender: linux-kernel-owner@vger.kernel.org To: Robert Jarzmik Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, mturquette@linaro.org, sboyd@codeaurora.org, kernel@stlinux.com, devicetree@vger.kernel.org List-Id: devicetree@vger.kernel.org On Sat, 28 Feb 2015, Robert Jarzmik wrote: > Lee Jones writes: >=20 > >> I wonder why there is a need for a new clock when CLK_IGNORE_UNUSE= D does > >> exist. What is the usecase that is covered by this patchset which = is not used by > >> CLK_IGNORE_UNUSED clock flag ? > >>=20 > >> And if that reason exists, I'd like to find it in the commit messa= ge. > > > > The problem is applying that flag in a generic way. > > > > However, I guess you haven't seen this [1] yet? > > > > [1] https://lkml.org/lkml/2015/2/27/548 > I have. >=20 > And yet : > 1) This won't go in a _commit_ message (as opposed to cover-letter).= Moreover Did you read rest of the set, or just the cover-letter? I referenced 0/0 because it is the thread parent and from there you can drill down into the commits where I believe there is adequate explanation in each. If you could be more specific and tell me which commit you think requires more explanation, I'd be happy to take a look. > it doesn't specify which usecase is not covered by CLK_IGNORE_UNU= SED, it > says, up to my understanding, that is it another way to have to > CLK_IGNORE_UNUSED flag applied. Well that is exactly what we're doing. Is there an issue with that? This is a way to do it at a platform level. It means we can support multiple platforms where clocksources have been switched around without writing new driver code in drivers/clk/st. If you have something else in mind, let me know. > 2) I still fail to see why this is necessary > IOW why declaring the mandatory always-on clocks with the proper = flag should > be augmented with a new clock list. Isn't the existing flag the g= eneric way > ? I'm not sure what you mean by this, would you be able to expland a little? > I might not understand the real motivation behind that of course, tha= t's why I'm > asking. Please bear in mind that we don't supply our clocks statically. All of the information is extracted from DT, so if the always-on information does reside in there, where do you propose it comes from? We could just write this code inside our own driver and apply the CLK_IGNORE_UNUSED at a local level, but that's not the generic solution I am searching for. --=20 Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org =E2=94=82 Open source software for ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog