From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Zik Saleeba" Subject: Re: PXA270 SSPSFRM gates chip select ? Date: Tue, 12 Feb 2008 16:24:03 +1100 Message-ID: <33e9dd1c0802112124y5ae8dd39ua9078f2b3878a018@mail.gmail.com> References: <20080211174339.73ca7ed5.merrij3@rpi.edu> <33e9dd1c0802111454k5deeaa38o9d21cee610b79da7@mail.gmail.com> <200802111851.10155.david-b@pacbell.net> <47B11178.6090904@whoi.edu> <33e9dd1c0802111948u2256d0adj8caa478073795d78@mail.gmail.com> <47B12406.9040208@whoi.edu> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: David Brownell , spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, stephen-nl6u4wocdmy51APUEpUfAkEOCMrvLtNR@public.gmane.org To: "Ned Forrester" Return-path: In-Reply-To: <47B12406.9040208-/d+BM93fTQY@public.gmane.org> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-spi.vger.kernel.org On Feb 12, 2008 3:43 PM, Ned Forrester wrote: > > I thought you might be doing lots of little transfers; that would > explain your need. Is each transfer in a separate message, because you > have to interact with every transfer, or can you put several transfers > in one message, to be executed without higher level interaction? Yes, good idea. Unfortunately the transfers are of the form "how many bytes are waiting" followed by "please send x bytes" so they need to be separate transfers. > Does your pxa2xx_spi.c contain the function > "set_dma_burst_and_threshold()"? If it does, you have Stephen's > 12/7/06 patch. Yes thanks, I have that function. > Actually, it is scheduled from each of the xx_error_stop() and > xx_transfer_complete() routines, which all run in interrupt context. Yep sorry - picked that one up in my followup email as I'm sure you've already seen. > You might want to check the kernel config parameters for your system and > make sure that the timer ticks are at least 1000HZ. I notice that mine > is set by default (by Gumstix perhaps) to be a tickless system (dynamic > ticks): > > CONFIG_TICK_ONESHOT=y > CONFIG_NO_HZ=y > CONFIG_HIGH_RES_TIMERS=y > > I don't know if this helps; it is just the way mine is set. I'll give it a try. Thanks. Cheers, Zik ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/