From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [PATCH v2 1/2] devicetree: add binding for generic mmio clocksource Date: Fri, 9 Oct 2015 12:53:17 -0500 Message-ID: References: <1444232234-2133-1-git-send-email-mans@mansr.com> <20151007154727.GC28981@leverpostej> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: =?UTF-8?B?TcOlbnMgUnVsbGfDpXJk?= , Stephen Boyd Cc: Mark Rutland , Pawel Moll , Ian Campbell , Kumar Gala , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" List-Id: devicetree@vger.kernel.org +Stephen who has worked on this code. On Fri, Oct 9, 2015 at 11:19 AM, M=C3=A5ns Rullg=C3=A5rd wrote: > M=C3=A5ns Rullg=C3=A5rd writes: > >> Rob Herring writes: >> >>> On Wed, Oct 7, 2015 at 11:47 AM, M=C3=A5ns Rullg=C3=A5rd wrote: >>>> What would be a proper way to select a sched_clock source? I real= ise >>>> it's a Linux-specific thing and DT is supposed to be generic, but = the >>>> information must be provided somehow. >>> >>> The kernel already has some logic to do this. Most number of bits >>> followed by highest frequency will be the winning sched_clock. You >>> might also want to look at things like always on or not. >> >> The problem is that sched_clock_register() doesn't take a pointer to= be >> passed back to the read_sched_clock callback like most interfaces of >> this type do. This means the callback must use global variables set= up >> before the register call, but at that time there's no way of knowing >> which one will be used. If there were a way of getting a pointer to= the >> callback, it would be a simple matter of registering all instances a= nd >> letting the kernel choose which to use. > > Anyone got a comment on this? Do I have to send a patch adding this > before anyone will tell me why it's a bad idea? (That method almost > always works.) Adding a ptr to the callback seems fine to me. Rob