From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nishanth Menon Subject: Re: PM: VDD2 OPPs Date: Tue, 26 Jan 2010 14:41:28 -0600 Message-ID: <4B5F5378.9020800@ti.com> References: <0C997DD87CC88A4F86C897F52650B52B02807701@MOLSON.mpc-data.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from arroyo.ext.ti.com ([192.94.94.40]:47615 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751974Ab0AZUlm (ORCPT ); Tue, 26 Jan 2010 15:41:42 -0500 In-Reply-To: <0C997DD87CC88A4F86C897F52650B52B02807701@MOLSON.mpc-data.co.uk> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Andrew Murray Cc: "linux-omap@vger.kernel.org" Andrew Murray had written, on 01/26/2010 02:34 PM, the following: > Hello, > > With regards to the OMAP2 (or at least the 3530 EVM) -the TRM and > various whitepapers suggest that they are 3 OPP levels available for > VDD2 (L3). However, from looking at the sources (linux-omap-pm / pm > branch) it seems that only 2 OPP levels are supported (@166Mhz and > @83Mhz) and used. I also notice that these rates are different to those > in a whitepaper (166, 100 and 41.5). Is there any particular reason why on OMAP34/35xx, I believe it should be s/100/83/. > only 2 OPPs are used? to my knowledge 41.5Mhz is not known to provide any performance benefits. you can also see [1] and add 41.5 (pm-wip-opp is the new branch where we are introducing opp layer. > > I understand that the OPP level of VDD2 may be set by changes to the OPP > level of VDD1 (i.e. resource34xx.c:set_opp) - and modifying VDD1's OPP > via cpufreq seems to be the only way to adjust the VDD2 OPP from > user-land - is this correct? The old /sys/power/vdd2_[opp|lock] was deprecated out. currently the control is for vdd1 OPP using cpufreq and indirect dependency for VDD2, is there a need for direct control of VDD2 freq? -- Regards, Nishanth Menon Ref: [1] http://git.kernel.org/?p=linux/kernel/git/khilman/linux-omap-pm.git;a=blob;f=arch/arm/mach-omap2/cpufreq34xx.c;h=07873e87ffc0fef97b4554efc3f17dc696cb25e3;hb=4f54a09e0ed9b2ee8e1adfe1716297792310d1c6#l46