From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1034906AbdAIQR4 (ORCPT ); Mon, 9 Jan 2017 11:17:56 -0500 Received: from ec2-52-27-115-49.us-west-2.compute.amazonaws.com ([52.27.115.49]:56667 "EHLO osg.samsung.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1030406AbdAIQRv (ORCPT ); Mon, 9 Jan 2017 11:17:51 -0500 Subject: Re: [PATCH 2/4] ARM: dts: exynos: Fix LAN9730 on Odroid U3 after tftpboot To: Krzysztof Kozlowski , Kukjin Kim , Anand Moon , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org References: <20170107085203.4431-1-krzk@kernel.org> <20170107085203.4431-3-krzk@kernel.org> Cc: Marek Szyprowski , Sylwester Nawrocki , Peter Chen , gregkh@linuxfoundation.org, stern@rowland.harvard.edu, ulf.hansson@linaro.org, broonie@kernel.org, sre@kernel.org, robh+dt@kernel.org, linux-usb@vger.kernel.org, linux-pm@vger.kernel.org, hverkuil@xs4all.nl, Markus Reichl From: Javier Martinez Canillas Message-ID: Date: Mon, 9 Jan 2017 13:17:38 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <20170107085203.4431-3-krzk@kernel.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Krzysztof, On 01/07/2017 05:52 AM, Krzysztof Kozlowski wrote: > The ethernet adapter LAN9730, after enabling in bootloader (e.g. for > tftpboot) requires reset during boot. Otherwise it won't come up. > > The schematics of Odroid U3 are detailed enough but after grabbing > knowledge also from other sources (like U-Boot) the overall design looks > like: > 1. LAN9730 is connected to HSIC0 and USB3503 to HSIC1 of EHCI controller. > 2. USB3503 comes with its own reset pin: gpx3-5. > 3. Reset pin of LAN9730 is pulled up to 3.3 V so it cannot be used. > 4. The supply of 3.3 V for LAN9730 is delivered from buck8. > 5. Buck8 state is a logical OR of registry value (through I2C command) > and ENB8 pin. The ENB8, not described in schematics, is in fact > gpa1-1. > 6. Missing or wrongly timed reset of LAN9730 might result in missing of > two devices: LAN9730 and USB3503. Without reset, LAN9730 will not > come up, if it was enabled by bootloader. > > To fix the issue use the generic power sequence driver and toggle the > ENB8 (buck8) pin. Reset duration of 500 us was chosen by experiments > (shortest working time was 400 us). This is an easiest way to fix the > long standing LAN9730 reset issue. > > Signed-off-by: Krzysztof Kozlowski > --- Thanks for keep pushing a fix for this long standing issue. Reviewed-by: Javier Martinez Canillas Best regards, -- Javier Martinez Canillas Open Source Group Samsung Research America