From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lina Iyer Subject: Re: [PATCH v4 03/10] of/irq: document properties for wakeup interrupt parent Date: Mon, 15 Apr 2019 15:11:47 -0600 Message-ID: <20190415211147.GB16124@codeaurora.org> References: <20190313211844.29416-1-ilina@codeaurora.org> <20190313211844.29416-4-ilina@codeaurora.org> <20190318174236.072f0a95@why.wild-wind.fr.eu.org> <20190404155838.GD10883@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Marc Zyngier Cc: swboyd@chromium.org, evgreen@chromium.org, linux-kernel@vger.kernel.org, rplsssn@codeaurora.org, linux-arm-msm@vger.kernel.org, thierry.reding@gmail.com, bjorn.andersson@linaro.org, dianders@chromium.org, linus.walleij@linaro.org, Rob Herring List-Id: linux-arm-msm@vger.kernel.org On Mon, Apr 15 2019 at 06:42 -0600, Marc Zyngier wrote: >On 04/04/2019 16:58, Lina Iyer wrote: >> On Mon, Mar 18 2019 at 11:54 -0600, Marc Zyngier wrote: >>> On Wed, 13 Mar 2019 15:18:37 -0600 >>> Lina Iyer wrote: >>> >>> Please do Cc Rob when posting DT related patches. >>> >>>> Some interrupt controllers in a SoC, are always powered on and have a >>>> select interrupts routed to them, so that they can wakeup the SoC from >>>> suspend. Add wakeup-parent DT property to refer to these interrupt >>>> controllers. >>>> >>>> If the interrupts routed to the wakeup parent are not sequential, than a >>>> map needs to exist to associate the same interrupt line on multiple >>>> interrupt controllers. Providing this map in every driver is cumbersome. >>>> Let's add this in the device tree and document the properties to map the >>>> interrupt specifiers >>>> >>>> Signed-off-by: Lina Iyer >>>> --- >>>> Changes in v4: >>>> - Added this documentation >>>> --- >>>> .../interrupt-controller/interrupts.txt | 39 +++++++++++++++++++ >>>> 1 file changed, 39 insertions(+) >>>> >>>> diff --git a/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt b/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt >>>> index 8a3c40829899..917b598317f5 100644 >>>> --- a/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt >>>> +++ b/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt >>>> @@ -108,3 +108,42 @@ commonly used: >>>> sensitivity = <7>; >>>> }; >>>> }; >>>> + >>>> +3) Interrupt wakeup parent >>>> +-------------------------- >>>> + >>>> +Some interrupt controllers in a SoC, are always powered on and have a select >>>> +interrupts routed to them, so that they can wakeup the SoC from suspend. These >>>> +interrupt controllers do not fall into the category of a parent interrupt >>>> +controller and can be specified by the "wakeup-parent" property and contain a >>>> +single phandle referring to the wakeup capable interrupt controller. >>>> + >>>> + Example: >>>> + wakeup-parent = <&pdc_intc>; >>>> + >>>> + >>>> +4) Interrupt mapping >>>> +-------------------- >>>> + >>>> +Sometimes interrupts may be detected by more than one interrupt controller >>>> +(depending on which controller is active). The interrupt controllers may not >>>> +be in hierarchy and therefore the interrupt controller driver is required to >>>> +establish the relationship between the same interrupt at different interrupt >>>> +controllers. If these interrupts are not sequential then a map needs to be >>>> +specified to help identify these interrupts. >>>> + >>>> +Mapping the interrupt specifiers in the device tree can be done using the >>>> +"irqdomain-map" property. The property contains interrupt specifier at the >>>> +current interrupt controller followed by the interrupt specifier at the mapped >>>> +interrupt controller. >>>> + >>>> + irqdomain-map = >>>> + >>>> +The optional properties "irqdomain-map-mask" and "irqdomain-map-pass-thru" may >>>> +be provided to help interpret the valid bits of the incoming and mapped >>>> +interrupt specifiers respectively. >>>> + >>>> + Example: >>>> + irqdomain-map = <22 0 &intc 36 0>, <24 0 &intc 37 0>; >>>> + irqdomain-map-mask = <0xff 0>; >>>> + irqdomain-map-pass-thru = <0 0xff>; >>> >>> >>> This doesn't quite explain how the mask and pass-thru properties are >>> used. I guess that the mask is used to define the 'useful bits' on the >>> incoming side, but pass-thru puzzles me. In your example, does it mean >>> that incoming lines map to outgoing interrupt <0 0>? >>> >> Sorry about the late reply. >> >> How about this to go with the rest of the documentation - >> >> In the above example, the input interrupt specifier map-mask <0xff 0> applied >> on the incoming interrupt specifier of the map <22 0>, <24 0>, returns the >> input interrupt 22, 24 etc. The second argument being irq type is immaterial >> from the map and is used from the incoming request instead. The pass-thru >> specifier parses the output interrupt specifier from the rest of the unparsed >> argments from the map <&intc 36 0>, <&intc 37 0> etc to return the output >> interrupt 36, 37 etc. > >I think you need to add #interrupt-cells in your example, which is >otherwise hard to interpret. > Ok. Thanks, will add. --Lina