From mboxrd@z Thu Jan 1 00:00:00 1970 From: Viresh Kumar Subject: Re: [PATCH 1/3] PM / OPP: Add "opp-supported-hw" binding Date: Tue, 3 Nov 2015 07:42:54 +0530 Message-ID: <20151103021254.GM3639@ubuntu> References: <2d52388bd7d3cc546ac3ab5afeb47bfcb3012213.1446167359.git.viresh.kumar@linaro.org> <20151030214907.GJ19782@codeaurora.org> <20151031021612.GU3716@ubuntu> <20151102192144.GQ19782@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20151102192144.GQ19782@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org To: Stephen Boyd Cc: Rafael Wysocki , robh+dt@kernel.org, lee.jones@linaro.org, linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org, mark.rutland@arm.com, pawel.moll@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, nm@ti.com, devicetree@vger.kernel.org, open list , "Rafael J. Wysocki" List-Id: devicetree@vger.kernel.org On 02-11-15, 11:21, Stephen Boyd wrote: > Ah I see that after looking at the previous thread. Perhaps we > can add such information into the documentation so that people > aren't misled into thinking they're limited to 32 bits? What about these changes: diff --git a/Documentation/devicetree/bindings/opp/opp.txt b/Documentation/devicetree/bindings/opp/opp.txt index 96892057586a..b6ca2239838b 100644 --- a/Documentation/devicetree/bindings/opp/opp.txt +++ b/Documentation/devicetree/bindings/opp/opp.txt @@ -123,11 +123,15 @@ properties. - opp-suspend: Marks the OPP to be used during device suspend. Only one OPP in the table should have this. -- opp-supported-hw: User defined array containing a hierarchy of hardware - version numbers, supported by the OPP. For example: a platform with hierarchy - of three levels of versions (A, B and C), this field should be like , - where X corresponds to Version hierarchy A, Y corresponds to version hierarchy - B and Z corresponds to version hierarchy C. +- opp-supported-hw: This enables us to select only a subset of OPPs from the + larger OPP table, based on what version of the hardware we are running on. We + still can't have multiple nodes with the same opp-hz value in OPP table. + + Its an user defined array containing a hierarchy of hardware version numbers, + supported by the OPP. For example: a platform with hierarchy of three levels + of versions (A, B and C), this field should be like , where X + corresponds to Version hierarchy A, Y corresponds to version hierarchy B and Z + corresponds to version hierarchy C. Each level of hierarchy is represented by a 32 bit value, and so there can be only 32 different supported version per hierarchy. i.e. 1 bit per version. A @@ -135,6 +139,10 @@ properties. level. And a value of 0x00000000 will disable the OPP completely, and so we never want that to happen. + If 32 values aren't sufficient for a version hierarchy, than that version + hierarchy can be contained in multiple 32 bit values. i.e. in the + above example, Z1 & Z2 refer to the version hierarchy Z. + - status: Marks the node enabled/disabled. -- viresh