Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752413AbbLNBiF (ORCPT ); Sun, 13 Dec 2015 20:38:05 -0500 Received: from galahad.ideasonboard.com ([185.26.127.97]:39120 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751797AbbLNBgo (ORCPT ); Sun, 13 Dec 2015 20:36:44 -0500 From: Laurent Pinchart To: Geert Uytterhoeven Cc: Simon Horman , Geert Uytterhoeven , Greg Kroah-Hartman , Magnus Damm , Yoshinori Sato , Laurent Pinchart , "linux-serial@vger.kernel.org" , Linux-sh list , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 17/25] serial: sh-sci: Correct SCIF type on R-Car for BRG Date: Sun, 13 Dec 2015 21:18:24 +0200 Message-ID: <2202629.UfeqFbQ39W@avalon> User-Agent: KMail/4.14.8 (Linux/4.1.12-gentoo; KDE/4.14.8; x86_64; ; ) In-Reply-To: References: <1447958344-836-1-git-send-email-geert+renesas@glider.be> <1865922.WzPYzesBTg@avalon> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3275 Lines: 76 Hi Geert, On Thursday 10 December 2015 10:21:27 Geert Uytterhoeven wrote: > On Fri, Nov 20, 2015 at 4:33 PM, Laurent Pinchart wrote: > > On Friday 20 November 2015 16:30:22 Geert Uytterhoeven wrote: > >> On Fri, Nov 20, 2015 at 3:52 PM, Laurent Pinchart wrote: > >>> On Friday 20 November 2015 08:46:56 Geert Uytterhoeven wrote: > >>>> On Thu, Nov 19, 2015 at 9:55 PM, Laurent Pinchart wrote: > >>>>> On Thursday 19 November 2015 19:38:56 Geert Uytterhoeven wrote: > >>>>>> The "renesas,scif" compatible value is currently used for the SCIF > >>>>>> variant in all Renesas SoCs of the R-Car family. However, the > >>>>>> variant used in the R-Car family is not the common "SH-4(A)" > >>>>>> variant, but a derivative with added "Baud Rate Generator for > >>>>>> External Clock" (BRG), which is also present in sh7734. > >>>>> > >>>>> Time to introduce a "renesas,scif-rcar" compatible string ? ;-) > >>>>> > >>>>> As the only DT-enabled platform to have a different SCIF type is > >>>>> r7s72100 we could also consider just switching the regtype to > >>>>> SCIx_SH4_SCIF_BRG_REGTYPE for the generic "renesas,scif" entry as > >>>>> it's listed after the "renesas,scif- r7s72100" entry. That might > >>>>> cause an issue if we want to enable DT on arch/sh though, but even if > >>>>> that happens due to the J-Core processors I'd be surprised to see the > >>>>> old Renesas SH platforms being moved to DT. > >>>> > >>>> I thought about that, but you never know in which out-of-tree BSP it > >>>> ended up being used, too. So better safe than sorry. > >>> > >>> Out-of-tree should be banned :-) > >>> > >>> More seriously, I suppose you wouldn't be thrilled by the idea of a > >>> "renesas,scif-rcar-gen2" ? > >> > >> Nope. Note that it's also used in R-Car Gen 1 and Gen 3, and sh7734. > > > > Yes, but it would at least cover the whole Gen2 family that behaves the > > same way. And wouldn't preclude adding "renesas,scif-rcar-gen1". That's > > two compat strings only. > > In light of all the recent "add fallback compatibility strings" patch series > from Simon, perhaps I should reconsider, and just match against three (new) > family-specific compatible values: > > "renesas,scif-rcar-gen1" > "renesas,scif-rcar-gen2" > "renesas,scif-rcar-gen3" > > instead of the 8 (and more coming) SoC-specific compatible values? > > Following that scheme means we will have to add many compatible values > to the existing dtsis. I.e. every SCIx device node (there are more than 100) > will have 3, like > > scif0: serial@e6e60000 { > compatible = "renesas,scif-r8a7791", > "renesas,scif-rcar-gen2", "renesas,scif"; > > Not having the SoC-specific ones in the driver won't cause an issue when > using an old DTS with a new kernel: you can't use the new BRG features > without adding the extra clocks to the DTS anyway, so you can add the > family-specific compatible value when doing that update. > > Simon, what do you think? Needless to say I agree :-) -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/