From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: MIME-Version: 1.0 In-Reply-To: <979a598a-9b8f-0bcc-0de0-f1d02496515d@rock-chips.com> References: <1524471030-3527-1-git-send-email-shawn.lin@rock-chips.com> <20180427185458.6o5tlfic75gy2vqr@rob-hp-laptop> <979a598a-9b8f-0bcc-0de0-f1d02496515d@rock-chips.com> From: Ulf Hansson Date: Wed, 2 May 2018 14:46:13 +0200 Message-ID: Subject: Re: [PATCH v2 1/2] Documentation: mmc: add description for power-delay-ms Content-Type: text/plain; charset="UTF-8" To: Shawn Lin Cc: Rob Herring , Jaehoon Chung , Wolfram Sang , Adrian Hunter , "linux-mmc@vger.kernel.org" , devicetree@vger.kernel.org List-ID: On 28 April 2018 at 03:11, Shawn Lin wrote: > Hi Rob and Ulf, > > On 2018/4/28 2:54, Rob Herring wrote: >> >> On Mon, Apr 23, 2018 at 04:10:29PM +0800, Shawn Lin wrote: > > > ... > >>> +- power-delay-ms: Tunable delay waiting for I/O signalling and card >>> power supply >>> + to be stable. Default to 10ms if no available. >> >> >> How long do you need? Would changing the default to say 20ms work and >> still be short enough others don't care? > > > It varies from board-2-board, but my boards only need 2ms or less. The > hard-coded 10ms was increased from 2ms since 2009, just for fixing one > board. And nobody complained 10ms is too short(including me), so it's > fine for everybody probably. However, nobody complained it's toooo long > as well, expect me, so my best guess is either others don't care it at > all, or haven't noticed it. So the intention for this patch, is to save > the unnecessary waste for the boot-time sensitive environment, by > reducing the delay but don't break anything else. > > >> >> Can we use the same property as the mmc pwrseq binding defines: >> post-power-on-delay-ms > > > I'm fine with using post-power-on-delay-ms, but it depends on whether > using pwrseq_simple. So I need add parsing it in two places for > different prupose. Is it ok, or better idea? I don't think the parsing is an issue, but that we need to allow two different descriptions of the same property name may be a bit confusing. I would rather keep them separate, but I have no strong onion. Kind regards Uffe