From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Gerlach Subject: Re: [PATCH] ARM: dts: am437x-gp-evm: Boot fixes Date: Wed, 23 Apr 2014 12:25:30 -0500 Message-ID: <5357F78A.5000406@ti.com> References: <1398192739-8901-1-git-send-email-d-gerlach@ti.com> <20140422190132.GA12204@atomide.com> <5356C8AE.3090907@ti.com> <20140423145904.GB4833@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20140423145904.GB4833@atomide.com> Sender: linux-omap-owner@vger.kernel.org To: Tony Lindgren Cc: linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, devicetree@vger.kernel.org, Rajendra Nayak , Nishanth Menon , bcousson@baylibre.com, Sekhar Nori , Lokesh Vutla List-Id: devicetree@vger.kernel.org On 04/23/2014 09:59 AM, Tony Lindgren wrote: > * Dave Gerlach [140422 12:53]: >> On 04/22/2014 02:01 PM, Tony Lindgren wrote: >>> * Dave Gerlach [140422 11:52]: >>>> This patch, along with patch here [1], fixes boot for am437x-gp-evm. The >>>> bootloader configures gpio5_7 to control the DDR3 termination regulator, >>>> the linked patch prevents that gpio bank from being reset and losing >>>> the previously configured state, and this patch binds the gpio to a >>>> regulator so the kernel is aware of the state of the gpio. >>>> >>>> [1] https://www.mail-archive.com/linux-omap@vger.kernel.org/msg102941.html >>> >>> Setting up the GPIO regulator makes sense to me. But the hack in the >>> link above is potentially a nasty time bomb for anybody trying to >>> use GPIO bank 5 on that board. >>> >>> What tests have been done that the GPIO bank behaves properly when >>> it's not reset? >> >> We've been using this configuration on this board for a while without any >> apparent issues. Also, am335x-evmsk already uses the same idea for the VTT >> regulator on board from commit 6046adb6ad701026c10adeac8d6a4138895f12e5 >> [ARM: dts: am335x-evmsk: Do not reset gpio0] and I am unaware of any issues >> with that either. > > OK. Do you have other GPIOs in use as interrupts for devices in these > banks and do they work fine? I dont see any interrupts in use from gpio5 bank but as a quick test if I add ti,no-reset-on-init to gpio3 and gpio4 I see no issue with matrix-keypad operation which uses gpios from each of those banks. > > Also, can you please test to make sure this works with the most recent > Javier's GPIO patches that had the issue of not booting on am335x-evmsk? > Yes, when using Javier's patches in addition to this patch [1], which was found to be necessary through this discussion [2], the AM437x GP EVM boots fine with linux-next with my regulator patch and gpio5 no reset patch applied. Regards, Dave [1] https://patchwork.kernel.org/patch/4041881/ [2] http://marc.info/?t=139817273800014&r=1&w=2 > Regards, > > Tony >