From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Howell Subject: Re: [PATCH] ARM: OMAP: mux: add config for 16xx SPI pins Date: Wed, 30 Aug 2006 08:57:18 +0800 Message-ID: <44F4E26E.4050701@northlink.com> References: <44C7D8AC.7070505@northlink.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <44C7D8AC.7070505@northlink.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-omap-open-source-bounces@linux.omap.com Errors-To: linux-omap-open-source-bounces@linux.omap.com To: Mark Howell Cc: linux-omap-open-source@linux.omap.com List-Id: linux-omap@vger.kernel.org Mark Howell wrote: > This patch adds pin mux info for the SPI master/slave interface on > OMAP16xx. Data from OMAP 1611/1612 TRM and errata. Works for me on my > 1611/H2 with current git kernel. > I have since spent some lab time with a scope and figured out that I misunderstood the pull-up config bits in the mux definition structure (they are inverted vs. what is actually written to the pull-up control registers). The patch I posted before works, but it can be better. I'll post a patch to set better default values for 16xx SPI pin mux after I get a little more lab time. I don't think this is a burning issue for anyone 'cept me, since eons had passed without anyone spec'ing these pins for 16xx SPI anyway :-) But this brings up a question... there are some other pins where I'm suspicious of the default pull-up config in mux.c, such as for the u-wire interface. Won't there be a bit of a power penalty for turning on pull-up or pull-down when it isn't necessary? Is there some established opinion or practice in this group regarding pin mux pull-up config to which I can refer? Cheers, Mark.