From mboxrd@z Thu Jan 1 00:00:00 1970 From: jamesjj.liao@mediatek.com (James Liao) Date: Thu, 31 Dec 2015 13:59:26 +0800 Subject: [PATCH 2/4] soc: mediatek: Init MT8173 scpsys driver earlier In-Reply-To: <6145950.8rtkDup7QD@wuerfel> References: <1451457706-14798-1-git-send-email-jamesjj.liao@mediatek.com> <1670989.QknqqsXE3p@wuerfel> <1451470328.22426.5.camel@mtksdaap41> <6145950.8rtkDup7QD@wuerfel> Message-ID: <1451541566.10610.10.camel@mtksdaap41> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Arnd, On Wed, 2015-12-30 at 11:35 +0100, Arnd Bergmann wrote: > On Wednesday 30 December 2015 18:12:08 James Liao wrote: > > On Wed, 2015-12-30 at 09:52 +0100, Arnd Bergmann wrote: > > > On Wednesday 30 December 2015 14:41:44 James Liao wrote: > > > > Some power domain comsumers may init before module_init. > > > > So the power domain provider (scpsys) need to be initialized > > > > earlier too. > > > > > > > > Signed-off-by: James Liao > > > > --- > > > > > > > > > > Why? > > > > Some drivers use different init level to ensure they can be initialized > > before other drivers. To support these drivers, moving scpsys driver's > > initial function to subsys_init is the most easy way. > > This is just the same generic explanation that you already have. > > Please be more specific what the dependency is and why we can't rely > on deferred probing here. In our case, there is a SMI driver provide APIs to control multiple devices that attached to different power domains.Video encoder / decoder and GPU drivers are SMI users. It's not easy for SMI users to detect SMI and scpsys driver are initialized or not. A most easy way to resolve the init sequence issue is moving SMI and scpsys driver in early init stage. Do you prefer to keep scpsys driver's init in module_init? If yes, I can remove this patch in next version. Best regards, James