From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [v2 1/4] ARM: tegra20: create a DT header defining CLK IDs Date: Fri, 15 Feb 2013 09:45:45 -0700 Message-ID: <511E6639.1090909@wwwdotorg.org> References: <1360868369-20093-1-git-send-email-hdoyu@nvidia.com> <1360868369-20093-2-git-send-email-hdoyu@nvidia.com> <511D45E0.1080105@wwwdotorg.org> <20130215092407.GO3073@tbergstrom-lnx.Nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130215092407.GO3073-Rysk9IDjsxmJz7etNGeUX8VPkgjIgRvpAL8bYrjMMd8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" To: Peter De Schrijver Cc: Russell King , "linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Rob Herring , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , Hiroshi Doyu List-Id: linux-tegra@vger.kernel.org On 02/15/2013 02:24 AM, Peter De Schrijver wrote: > On Thu, Feb 14, 2013 at 09:15:28PM +0100, Stephen Warren wrote: >> On 02/14/2013 11:59 AM, Hiroshi Doyu wrote: >>> To replace magic number in tegra_car: >>> >>> - clocks = <&tegra_car 28>; >>> + clocks = <&tegra_car CLK_HOST1X>; >> >>> diff --git a/arch/arm/boot/dts/tegra20-car.h b/arch/arm/boot/dts/tegra20-car.h >> >> Sorry, forgot a couple small comments the last time around. >> >> This file should probably have some header indicating which binding it >> describes, rather like the GPIO header in my patch series. >> >>> +#define CLK_CPU 0 >> >> I'd suggest naming that TEGRA20_CLK_CPU, so that the various different >> clock headers don't conflict. It's not too likely that more than one of >> the /Tegra/ clock headers will be included at once, but it doesn't seem >> that unlikely that a board file could end up having a Tegra clock header >> included plus various other clock headers for some other chip that has >> some clock outputs. >> > > I would suggest removing this clock. It's not actually implemented in the CCF > and rather useless. If you would gate the CPU clock from the CPU by writing to > this register, how would you ungate it? :) Note that this would gate the clock > to all CPUs. (Note that my comment was re: all clocks, not just that one clock) Can't the PMC or flow-controller ungate the clock based on some event? Either way, that clock definition exists in HW, right? So I don't think there's actually any harm in including the definition in the binding even if we never implement/use it.