From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaehoon Chung Subject: Re: [PATCH 1/2] mmc: sdhci: Added set_power sdhci_ops handler. Date: Fri, 24 May 2013 13:02:58 +0900 Message-ID: <519EE672.9060508@samsung.com> References: <1369244832-23868-1-git-send-email-eu@felipetonello.com> <1369244832-23868-2-git-send-email-eu@felipetonello.com> <2537252.KzShHU8h54@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mailout2.samsung.com ([203.254.224.25]:44137 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751079Ab3EXECw (ORCPT ); Fri, 24 May 2013 00:02:52 -0400 In-reply-to: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Guennadi Liakhovetski Cc: Felipe Ferreri Tonello , linux-mmc@vger.kernel.org, ben-linux@fluff.org, cjb@laptop.org, arnd@arndb.de, linux-kernel@vger.kernel.org On 05/23/2013 04:25 PM, Guennadi Liakhovetski wrote: > On Wed, 22 May 2013, Felipe Ferreri Tonello wrote: > >> Hi Guennadi, >> >> On Wednesday, May 22, 2013 10:30:40 PM Guennadi Liakhovetski wrote: >>> On Wed, 22 May 2013, Felipe F. Tonello wrote: >>>> From: "Felipe F. Tonello" >>>> >>>> This is useful for power managment purposes if a sdhci child host wants to >>>> turn off some other peripheral also. >>> >>> Sorry, could you elaborate a bit? In what situations is it exactly useful? >>> And why cannot the regulator API be used there? >> >> Sorry about that. >> >> One example that I can think of is when you have a wifi module connected as a >> mmc card via sdio. So you can register a callback function in your machine >> source code to turn on/off the wifi module based on the mmc host power. > > Ok, understand. Your second patch in this series adds such a callback in > your SDHCI host driver and there it just calls a platform callback. I > don't think this is a good idea. First, we want to go away from platform > callbacks, because they are incompatible with DT. Second, because the > proper solution IMHO would be for your platform to export a regulator, and > the SDHCI core driver already includes regulator support. We can use the regulator framework. i think this callback function didn't need. Best Regards, Jaehoon Chung > >> I've seen this implementation in others mmc hosts, such as omap. > > Which, however, doesn't yet mean, it's a good idea :) > > Thanks > Guennadi > --- > Guennadi Liakhovetski, Ph.D. > Freelance Open-Source Software Developer > http://www.open-technology.de/ > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >