From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grygorii Strashko Subject: Re: [PATCH v4 1/2] ARM: keystone: pm: switch to use generic pm domains Date: Mon, 10 Nov 2014 19:38:14 +0200 Message-ID: <5460F806.3040305@ti.com> References: <1415631557-22897-1-git-send-email-grygorii.strashko@ti.com> <1415631557-22897-2-git-send-email-grygorii.strashko@ti.com> <5331397.OQCQmJO78C@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5331397.OQCQmJO78C@wuerfel> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Arnd Bergmann Cc: ssantosh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, "Rafael J. Wysocki" , khilman-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Rob Herring , grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Ulf Hansson , Geert Uytterhoeven , Dmitry Torokhov List-Id: devicetree@vger.kernel.org Hi Arnd, On 11/10/2014 05:06 PM, Arnd Bergmann wrote: > On Monday 10 November 2014 16:59:16 Grygorii Strashko wrote: >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/power/ti,keystone-powerdomain.txt >> @@ -0,0 +1,31 @@ >> +* TI Keystone 2 Generic PM Controller >> + >> +The TI Keystone 2 Generic PM Controller is responsible for Clock gating >> +for each controlled IP module. >> + >> +Required properties: >> +- compatible: Should be "ti,keystone-powerdomain" >> +- #power-domain-cells: Should be 0, see below: >> + >> +The PM Controller node is a PM domain as documented in >> +Documentation/devicetree/bindings/power/power_domain.txt. >> + >> +Example: >> + >> + pm_controller: pm-controller { >> + compatible = "ti,keystone-powerdomain"; >> + #power-domain-cells = <0>; >> + }; >> + >> + netcp: netcp@2090000 { >> + reg = <0x2620110 0x8>; >> + reg-names = "efuse"; >> + ... >> + #address-cells = <1>; >> + #size-cells = <1>; >> + ranges; >> + power-domains = <&pm_controller>; >> + >> + clocks = <&clkpa>, <&clkcpgmac>, <&chipclk12>; >> + dma-coherent; >> + } > > I don't get it. What keystone specific about a "ti,keystone-powerdomain" > device? It seems that the device has no registers whatsoever and the > driver doesn't really do anything that relates to the platform. That's true. but it was the only one acceptable way to enable Generic clock manipulation PM callbacks for the DT-boot case. After several unsuccessful attempts the idea to use GPD was introduced by Kevin there: https://lkml.org/lkml/2014/9/8/643 So, The Keystone 2 Generic PM Controller is just a proxy PM layer here between device and Generic clock manipulation PM callbacks. It fills per-device clock list when device is attached to GPD and ensures that all clocks from that list enabled/disabled when device is started/stopped. Regards, -grygorii -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html