From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiko Stuebner Subject: Re: [PATCH] arm64: dts: mt8173: add clock_null Date: Thu, 18 Jun 2015 18:15:03 +0200 Message-ID: <2333431.ttvjElY3ps@phil> References: <1434605351-64592-1-git-send-email-eddie.huang@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1434605351-64592-1-git-send-email-eddie.huang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+glpam-linux-mediatek=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, James Liao , Sascha Hauer , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Matthias Brugger , Eddie Huang , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org Am Donnerstag, 18. Juni 2015, 13:29:11 schrieb Eddie Huang: > Add clk_null, which represents clocks that can not / need not > controlled by software. > There are many clocks' parent set to clk_null. Devicetree is supposed to describe hardware, and ideally not what software does with it. If the clock simply cannot be controlled by software, it will still have a rate and I think it should probably be modelled - similarly we sometimes have fixed regulators that also are not software controllable. While it might be ok to define dummy clocks as a temporary stopgap, these should definitly be marked as such. This clk_null at least sounds like there is no plan to replace this with a real solution at some point. And of course a bit of context would be cool, to know which type of clocks this actually replaces. Heiko > Signed-off-by: James Liao > Signed-off-by: Eddie Huang > --- > Base on 4.1-rc1 > > Change-Id: I4db9b40d07e28f54f7bae9b676316cbd6a962124 > --- > arch/arm64/boot/dts/mediatek/mt8173.dtsi | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/arch/arm64/boot/dts/mediatek/mt8173.dtsi > b/arch/arm64/boot/dts/mediatek/mt8173.dtsi index 924fdb6..4798f44 100644 > --- a/arch/arm64/boot/dts/mediatek/mt8173.dtsi > +++ b/arch/arm64/boot/dts/mediatek/mt8173.dtsi > @@ -81,6 +81,12 @@ > cpu_on = <0x84000003>; > }; > > + clk_null: clk_null { > + compatible = "fixed-clock"; > + clock-frequency = <0>; > + #clock-cells = <0>; > + }; > + > uart_clk: dummy26m { > compatible = "fixed-clock"; > clock-frequency = <26000000>;