From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bo Shen Date: Mon, 22 Jul 2013 09:59:21 +0800 Subject: [U-Boot] [PATCH] arm: at91sam9n12: change EBI IO to high drive mode In-Reply-To: <51EB16FB.8010500@googlemail.com> References: <1374052458-3326-1-git-send-email-voice.shen@atmel.com> <20130719121338.GE18359@bill-the-cat> <51EB16FB.8010500@googlemail.com> Message-ID: <51EC91F9.700@atmel.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Andreas, On 07/21/2013 07:02 AM, Andreas Bie?mann wrote: > To answer the second question we can have a look at the specs. I can > presume by looking at the specs that we need to switch the drive > strength for the data I/O pins to higher level for this board to fix the > problem mentioned in the commit message. You have to know that this > specific part (configuring EBI for NAND access) is copied from board to > board (yes, another point to consolidate in near future). And this > specific part is copied over from at91samx5ek which seems to work with > lower drive strength. Unfortunately the concrete limit of EBI > capacitance is not specified in specs for at91sam9n12 nor at91sam9x35 > devices. More distracting this parameter (EBI_DRIVE) seems to have > different reset values in at91sam9n12 and atsam9x35 devices, at least > the specs say so ... Atmel guys, please have a look on that and update > your specs! > Especially fill the TBD field in at91sam9n12 spec p. 311 (EBI_DRIVE in > CCFG_EBICSA) in version 11063I?ATARM?17-Apr-13. And possibly check why > there is EBI_DRIVE default to 'low' for 9x5 and default to 'high' for > 9n12. There is also another bug in the specs, when you have to decide > between 'high' and 'low' you cant say the 'low' is required for > 'capacitance < TBD pF' and 'high' is required for 'capacitance < TBD > pF', presumably the 'high' part should be chosen for 'capacitance > TBD pF'. Thank for this information, I will check this with our colleagues. Thanks again. > So from my point of view this patch fixes an existing bug in a new board > introduced in this releases MW. It uses a fairly new SoC which is first > used in this new board. Therefore > > Acked-by: Andreas Bie?mann > > And Tom, please apply this patch directly. > > Best regards > > Andreas Bie?mann Best Regards, Bo Shen