Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753113AbbDGUc1 (ORCPT ); Tue, 7 Apr 2015 16:32:27 -0400 Received: from mail-wg0-f50.google.com ([74.125.82.50]:33377 "EHLO mail-wg0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750862AbbDGUcZ (ORCPT ); Tue, 7 Apr 2015 16:32:25 -0400 MIME-Version: 1.0 In-Reply-To: <1428432239-4114-5-git-send-email-lee.jones@linaro.org> References: <1428432239-4114-1-git-send-email-lee.jones@linaro.org> <1428432239-4114-5-git-send-email-lee.jones@linaro.org> From: Rob Herring Date: Tue, 7 Apr 2015 15:32:02 -0500 Message-ID: Subject: Re: [PATCH v6 4/4] clk: dt: Introduce binding for always-on clock support To: Lee Jones Cc: "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , Mike Turquette , kernel@stlinux.com, Stephen Boyd , Geert Uytterhoeven Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3445 Lines: 73 On Tue, Apr 7, 2015 at 1:43 PM, Lee Jones wrote: > Signed-off-by: Lee Jones Please use get_maintainers.pl in the future. Acked-by: Rob Herring > --- > .../devicetree/bindings/clock/clock-bindings.txt | 38 ++++++++++++++++++++++ > 1 file changed, 38 insertions(+) > > diff --git a/Documentation/devicetree/bindings/clock/clock-bindings.txt b/Documentation/devicetree/bindings/clock/clock-bindings.txt > index 06fc6d5..daf3323 100644 > --- a/Documentation/devicetree/bindings/clock/clock-bindings.txt > +++ b/Documentation/devicetree/bindings/clock/clock-bindings.txt > @@ -44,6 +44,44 @@ For example: > clocks by index. The names should reflect the clock output signal > names for the device. > > +clock-always-on: Some hardware contains bunches of clocks which must never be > + turned off. If drivers a) fail to obtain a reference to any > + of these or b) give up a previously obtained reference > + during suspend, the common clk framework will attempt to > + disable them and a platform can fail irrecoverably as a > + result. Usually the only way to recover from these failures > + is to reboot. > + > + To avoid either of these two scenarios from catastrophically > + disabling an otherwise perfectly healthy running system, > + clocks can be identified as always-on using this property > + from inside a clocksource's node. > + > + This property is not to be abused. It is only to be used to > + protect platforms from being crippled by gated clocks, not > + as a convenience function to avoid using the framework > + correctly inside device drivers. > + > + Expected values are hardware clock indices. If the > + clock-indices property (see below) is used, then supplied > + values must correspond to one of the listed identifiers. > + Using the clock-indices example below, hardware clock <2> > + is missing, therefore it is considered invalid to then > + list clock <2> as an always-on clock. > + > +For example: > + > + oscillator { > + #clock-cells = <1>; > + clock-output-names = "ckil", "ckih"; > + clock-always-on = <0>, <1>; > + }; > + > +- this node defines a device with two clock outputs, just as in the > + example above. The only difference being that 'ckil' and 'ckih' > + are now identified as an always-on clocks, so the framework will > + know to never attempt to gate them. > + > clock-indices: If the identifying number for the clocks in the node > is not linear from zero, then this allows the mapping of > identifiers into the clock-output-names array. > -- > 1.9.1 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- 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/