From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751245AbdAMT0P (ORCPT ); Fri, 13 Jan 2017 14:26:15 -0500 Received: from mail.kernel.org ([198.145.29.136]:41860 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750885AbdAMT0N (ORCPT ); Fri, 13 Jan 2017 14:26:13 -0500 MIME-Version: 1.0 In-Reply-To: <3bb89649-fd2a-acc6-6968-e54a00842ce2@ti.com> References: <20170104205536.15963-1-d-gerlach@ti.com> <20170104205536.15963-3-d-gerlach@ti.com> <20170109175012.sg7eze7llqq7qevd@rob-hp-laptop> <7bd282d9-df6f-f4c6-1f7f-c8ed81c78af3@ti.com> <3bb89649-fd2a-acc6-6968-e54a00842ce2@ti.com> From: Rob Herring Date: Fri, 13 Jan 2017 13:25:47 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v3 2/4] dt-bindings: Add TI SCI PM Domains To: Dave Gerlach Cc: Ulf Hansson , "Rafael J . Wysocki" , Kevin Hilman , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-pm@vger.kernel.org" , "devicetree@vger.kernel.org" , Nishanth Menon , Keerthy , Russell King , Tero Kristo , Sudeep Holla , Santosh Shilimkar , Lokesh Vutla Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 12, 2017 at 9:27 AM, Dave Gerlach wrote: > Rob, > > On 01/11/2017 03:34 PM, Rob Herring wrote: >> >> On Mon, Jan 9, 2017 at 11:57 AM, Dave Gerlach wrote: >>> >>> Rob, >>> >>> On 01/09/2017 11:50 AM, Rob Herring wrote: >>>> >>>> >>>> On Wed, Jan 04, 2017 at 02:55:34PM -0600, Dave Gerlach wrote: >>>>> >>>>> >>>>> Add a generic power domain implementation, TI SCI PM Domains, that >>>>> will hook into the genpd framework and allow the TI SCI protocol to >>>>> control device power states. >>>>> >>>>> Also, provide macros representing each device index as understood >>>>> by TI SCI to be used in the device node power-domain references. >>>>> These are identifiers for the K2G devices managed by the PMMC. >>>>> >>>>> Signed-off-by: Nishanth Menon >>>>> Signed-off-by: Dave Gerlach >>>>> --- >>>>> v2->v3: >>>>> Update k2g_pds node docs to show it should be a child of pmmc >>>>> node. >>>>> In early versions a phandle was used to point to pmmc and docs >>>>> still >>>>> incorrectly showed this. >>>>> >>>>> .../devicetree/bindings/soc/ti/sci-pm-domain.txt | 59 ++++++++++++++ >>>>> MAINTAINERS | 2 + >>>>> include/dt-bindings/genpd/k2g.h | 90 >>>>> ++++++++++++++++++++++ >>>>> 3 files changed, 151 insertions(+) >>>>> create mode 100644 >>>>> Documentation/devicetree/bindings/soc/ti/sci-pm-domain.txt >>>>> create mode 100644 include/dt-bindings/genpd/k2g.h >>>>> >>>>> diff --git a/Documentation/devicetree/bindings/soc/ti/sci-pm-domain.txt >>>>> b/Documentation/devicetree/bindings/soc/ti/sci-pm-domain.txt >>>>> new file mode 100644 >>>>> index 000000000000..4c9064e512cb >>>>> --- /dev/null >>>>> +++ b/Documentation/devicetree/bindings/soc/ti/sci-pm-domain.txt >>>>> @@ -0,0 +1,59 @@ >>>>> +Texas Instruments TI-SCI Generic Power Domain >>>>> +--------------------------------------------- >>>>> + >>>>> +Some TI SoCs contain a system controller (like the PMMC, etc...) that >>>>> is >>>>> +responsible for controlling the state of the IPs that are present. >>>>> +Communication between the host processor running an OS and the system >>>>> +controller happens through a protocol known as TI-SCI [1]. This pm >>>>> domain >>>>> +implementation plugs into the generic pm domain framework and makes >>>>> use >>>>> of >>>>> +the TI SCI protocol power on and off each device when needed. >>>>> + >>>>> +[1] Documentation/devicetree/bindings/arm/keystone/ti,sci.txt >>>>> + >>>>> +PM Domain Node >>>>> +============== >>>>> +The PM domain node represents the global PM domain managed by the >>>>> PMMC, >>>>> +which in this case is the single implementation as documented by the >>>>> generic >>>>> +PM domain bindings in >>>>> Documentation/devicetree/bindings/power/power_domain.txt. >>>>> +Because this relies on the TI SCI protocol to communicate with the >>>>> PMMC >>>>> it >>>>> +must be a child of the pmmc node. >>>>> + >>>>> +Required Properties: >>>>> +-------------------- >>>>> +- compatible: should be "ti,sci-pm-domain" >>>>> +- #power-domain-cells: Must be 0. >>>>> + >>>>> +Example (K2G): >>>>> +------------- >>>>> + pmmc: pmmc { >>>>> + compatible = "ti,k2g-sci"; >>>>> + ... >>>>> + >>>>> + k2g_pds: k2g_pds { >>>>> + compatible = "ti,sci-pm-domain"; >>>>> + #power-domain-cells = <0>; >>>>> + }; >>>>> + }; >>>>> + >>>>> +PM Domain Consumers >>>>> +=================== >>>>> +Hardware blocks that require SCI control over their state must provide >>>>> +a reference to the sci-pm-domain they are part of and a unique device >>>>> +specific ID that identifies the device. >>>>> + >>>>> +Required Properties: >>>>> +-------------------- >>>>> +- power-domains: phandle pointing to the corresponding PM domain node. >>>>> +- ti,sci-id: index representing the device id to be passed oevr SCI to >>>>> + be used for device control. >>>> >>>> >>>> >>>> As I've already stated before, this goes in power-domain cells. When you >>>> have a single thing (i.e. node) that controls multiple things, then you >>>> you need to specify the ID for each of them in phandle args. This is how >>>> irqs, gpio, clocks, *everything* in DT works. >>> >>> >>> >>> You think the reasoning for doing it this way provided by both Ulf and >>> myself on v2 [1] is not valid then? >>> >>> From Ulf: >>> >>> To me, the TI SCI ID, is similar to a "conid" for any another "device >>> resource" (like clock, pinctrl, regulator etc) which we can describe >>> in DT and assign to a device node. The only difference here, is that >>> we don't have common API to fetch the resource (like clk_get(), >>> regulator_get()), but instead we fetches the device's resource from >>> SoC specific code, via genpd's device ->attach() callback. >> >> >> Sorry, but that sounds like a kernel problem to me and has nothing to >> do with DT bindings. >> >>> From me: >>> >>> Yes, you've pretty much hit it on the head. It is not an index into a >>> list >>> of genpds but rather identifies the device *within* a single genpd. It is >>> a >>> property specific to each device that resides in a ti-sci-genpd, not a >>> mapping describing which genpd the device belongs to. The generic power >>> domain binding is concerned with mapping the device to a specific genpd, >>> which is does fine for us, but we have a sub mapping for devices that >>> exist >>> inside a genpd which, we must describe as well, hence the ti,sci-id. >>> >>> >>> So to summarize, the genpd framework does interpret the phandle arg as an >>> index into multiple genpds, just as you've said other frameworks do, but >>> this is not what I am trying to do, we have multiple devices within this >>> *single* genpd, hence the need for the ti,sci-id property. >> >> >> Fix the genpd framework rather than work around it in DT. > > > I still disagree that this has nothing to do with DT bindings, as the > current DT binding represents something different already. I am trying to > extend it to give me additional information needed for our platforms. Are > you saying that we should break what the current DT binding already > represents to mean something else? No idea because what's the current binding? From the patch, looks like a new binding to me. Rob