From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH 1/5] ARM: OMAP2+: gpmc: Print error message in set_gpmc_timing_reg() Date: Wed, 29 Oct 2014 07:13:24 -0700 Message-ID: <20141029141323.GY2542@atomide.com> References: <1413895309-9152-1-git-send-email-rogerq@ti.com> <1413895309-9152-2-git-send-email-rogerq@ti.com> <20141028222349.GV2542@atomide.com> <5450AA4D.9040708@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mho-02-ewr.mailhop.org ([204.13.248.72]:36308 "EHLO mho-02-ewr.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932927AbaJ2OOj (ORCPT ); Wed, 29 Oct 2014 10:14:39 -0400 Content-Disposition: inline In-Reply-To: <5450AA4D.9040708@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Roger Quadros Cc: pekon@pek-sem.com, javier@dowhile0.org, linux-omap@vger.kernel.org, Sekhar Nori * Roger Quadros [141029 01:51]: > On 10/29/2014 12:23 AM, Tony Lindgren wrote: > > * Roger Quadros [141021 05:43]: > >> Simplify set_gpmc_timing_reg() and always print error message > >> if the requested timing cannot be achieved due to a too fast > >> GPMC functional clock, irrespective if whether DEBUG is defined > >> or not. This should help us debug timing configuration issues, > >> which were otherwise simply not being displayed in the kernel log. > > > > I think some newer versions of GPMC have a divider in the > > GPMC_CONFIG regs somewhere but we're not currently using it. > > Probably does not affect this patch, just FYI. > > Right, we don't use it. In the future it could be a possibility that the GPMC > driver scales the clock as necessary by using the GPMC_FCLK divider > to accommodate slower devices. But then again, who needs slower devices? ;) I think some devices need such slow timings that we're already hitting the issue with 200MHz L3 on 37xx connected to a SMSC LAN9220 at least. With LAN9221 this is not an issue with faster timings. Anyways, I think the issue is out of the way now with LAN9220 and GPMC_FCLK divider support can be added later on as needed. Regards, Tony