From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Szyprowski Subject: Re: [PATCH 1/2] power: reset: add driver for Hardkernel's Odroid boards Date: Tue, 27 Jan 2015 09:16:23 +0100 Message-ID: <54C74957.2000600@samsung.com> References: <1414588409-8065-1-git-send-email-m.szyprowski@samsung.com> <20150122010631.GL13715@earth.universe> <54C05373.60308@samsung.com> <54C22C5A.9050701@samsung.com> <20150125143207.GD2719@earth.universe> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <20150125143207.GD2719@earth.universe> Sender: linux-pm-owner@vger.kernel.org To: Sebastian Reichel Cc: Joonyoung Shim , linux-pm@vger.kernel.org, devicetree@vger.kernel.org, linux-samsung-soc@vger.kernel.org, Kukjin Kim , Tobias Jakobi , Daniel Drake , Dmitry Eremin-Solenikov , David Woodhouse List-Id: devicetree@vger.kernel.org Hello, On 2015-01-25 15:32, Sebastian Reichel wrote: > On Fri, Jan 23, 2015 at 12:11:22PM +0100, Marek Szyprowski wrote: >> Frankly, I analyzed this case once again and I came to conclusion >> that there is no need to make a separate reset driver for Odroid >> boards. There is nothing special, specific to whole board about >> this gpio. It is rather a property of MMC host controller and eMMC >> card that is connected to it. When only gpio toggling code is >> moved to reset handler registered from mmc controller, the board >> properly performs reboot with a generic exynos4 code. > OK, so I guess this will be fixed independently via mmc subsystem. I've posted an updated patch. > >> The poweroff code in above driver is just a generic Exynos4 code, >> so again there is no need to duplicate it. > OK. It seems there is a driver for that in arch/arm/mach-exynos. > Otherwise I would have suggest to create something like > syscon-reboot for shutdown. > >> By moving the code to mmc driver, the same approach can be used for other >> Odroid boards (XU/XU3) and maybe even other boards which need manual >> resetting of eMMC cards to properly perform reboot procedure. > I suggest to start a new thread for discussing this, which includes > linux-mmc. It might be interesting to provide some more details about > eMMC_nDET, since MMC already contain a reset signal (which seems to > be used according to the odroid schematics I found). My fault. The documentation for this initial driver was incorrect. The reboot fix has noting to eMMC_nDET signal. It should be eMMC nreset, which is routed directly to SoC GPIO line with external pull-up resistor. I really have no idea why I wrote eMMC_nDET instead of nreset. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland