From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chanwoo Choi Subject: Re: [PATCHv3 2/8] devfreq: exynos: Add documentation for generic exynos memory bus frequency driver Date: Wed, 21 Jan 2015 15:12:57 +0900 Message-ID: <54BF4369.1060900@samsung.com> References: <1420681257-3078-1-git-send-email-cw00.choi@samsung.com> <1420681257-3078-3-git-send-email-cw00.choi@samsung.com> <54BE108F.8090506@samsung.com> <54BE3E10.2080906@samsung.com> <54BF2929.3090107@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mailout3.samsung.com ([203.254.224.33]:23245 "EHLO mailout3.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750736AbbAUGNA (ORCPT ); Wed, 21 Jan 2015 01:13:00 -0500 In-reply-to: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Viresh Kumar Cc: Rob Herring , MyungJoo Ham , Kukjin Kim , Kyungmin Park , "Wysocki, Rafael J" , Mark Rutland , a.kesavan@samsung.com, Tomasz Figa , =?UTF-8?B?S3J6eXN6dG9mIEtvesWCb3dza2k=?= , Bartlomiej Zolnierkiewicz , Rob Herring , InKi Dae , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-samsung-soc@vger.kernel.org" On 01/21/2015 01:37 PM, Viresh Kumar wrote: > On 21 January 2015 at 09:50, Chanwoo Choi wrote: >> If the clock will be stayed on highest voltage, will reduce >> the considerable benefit of power-consumption. > > But this is exactly what you must be doing right now as well.. > I think I didn't make it clear enough with an example. Let me > try.. > > This is how I feel it should look like: > > memory_bus_int: memory_bus@1 { > // Regulator is shared for all below > blocks { > peri_block: memory_bus_block1 { > operating-points = < > 100000 850000 > 50000 850000>; > }; > > display_block: memory_bus_block2 { > operating-points = < > 200000 950000 > 160000 950000 > 100000 925000 > 80000 850000 > 50000 850000>; > }; > > isp_block: memory_bus_block3 { > operating-points = < > 200000 950000 > 100000 925000 > 80000 850000 > 50000 850000>; > }; > > gps_block: memory_bus_block4 { > operating-points = < > 300000 950000 > 200000 950000 > 133000 925000 > 100000 850000 > 50000 850000>; > }; > > > Now suppose these are the requirements from all the blocks > at any point of time: > - block1: 100000 850000 > - block2: 100000 925000 > - block3: 80000 850000 > - block4: 133000 925000 > > Now, all of them can control freq separately and we don't need to > worry for that. But regulator is shared between them. We can check > what's the highest voltage requested at this point of time and can > switch to that. > > i.e. 925000 in this case. And that's not the highest possible one. > And you will reach to similar conclusion with your current code as > well I believe. > OK, I understand. I'll try to update exynos memory bus according to your comment. Thanks Chanwoo From mboxrd@z Thu Jan 1 00:00:00 1970 From: cw00.choi@samsung.com (Chanwoo Choi) Date: Wed, 21 Jan 2015 15:12:57 +0900 Subject: [PATCHv3 2/8] devfreq: exynos: Add documentation for generic exynos memory bus frequency driver In-Reply-To: References: <1420681257-3078-1-git-send-email-cw00.choi@samsung.com> <1420681257-3078-3-git-send-email-cw00.choi@samsung.com> <54BE108F.8090506@samsung.com> <54BE3E10.2080906@samsung.com> <54BF2929.3090107@samsung.com> Message-ID: <54BF4369.1060900@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 01/21/2015 01:37 PM, Viresh Kumar wrote: > On 21 January 2015 at 09:50, Chanwoo Choi wrote: >> If the clock will be stayed on highest voltage, will reduce >> the considerable benefit of power-consumption. > > But this is exactly what you must be doing right now as well.. > I think I didn't make it clear enough with an example. Let me > try.. > > This is how I feel it should look like: > > memory_bus_int: memory_bus at 1 { > // Regulator is shared for all below > blocks { > peri_block: memory_bus_block1 { > operating-points = < > 100000 850000 > 50000 850000>; > }; > > display_block: memory_bus_block2 { > operating-points = < > 200000 950000 > 160000 950000 > 100000 925000 > 80000 850000 > 50000 850000>; > }; > > isp_block: memory_bus_block3 { > operating-points = < > 200000 950000 > 100000 925000 > 80000 850000 > 50000 850000>; > }; > > gps_block: memory_bus_block4 { > operating-points = < > 300000 950000 > 200000 950000 > 133000 925000 > 100000 850000 > 50000 850000>; > }; > > > Now suppose these are the requirements from all the blocks > at any point of time: > - block1: 100000 850000 > - block2: 100000 925000 > - block3: 80000 850000 > - block4: 133000 925000 > > Now, all of them can control freq separately and we don't need to > worry for that. But regulator is shared between them. We can check > what's the highest voltage requested at this point of time and can > switch to that. > > i.e. 925000 in this case. And that's not the highest possible one. > And you will reach to similar conclusion with your current code as > well I believe. > OK, I understand. I'll try to update exynos memory bus according to your comment. Thanks Chanwoo