From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Boibessot Subject: Re: SPI: Add SPI driver for most known i.MX SoCs Date: Sun, 21 Jun 2009 15:10:21 +0200 Message-ID: <4A3E313D.8020008@free.fr> References: <20090504214307.GN15603@pengutronix.de> <4A24DF22.4040601@free.fr> <20090602172259.GB32355@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: quoted-printable Cc: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-arm-kernel-xIg/pKzrS19vn6HldHNs0ANdhmdF6hFW@public.gmane.org To: Sascha Hauer Return-path: In-Reply-To: <20090602172259.GB32355-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-spi.vger.kernel.org Hi Sascha, Sascha Hauer a =E9crit : > On Tue, Jun 02, 2009 at 10:13:22AM +0200, Julien Boibessot wrote: > = >> I don't know yet if it's related to bitbang but I would say that your = >> driver is 2x slowier that current inkernel one. >> = > > Have you checked that the driver gets the baudrate correct? If it is > maybe my driver produces more interrupts than the in kernel driver. > Maybe you could produce a defined workload with both drivers and compare > the outputs of /proc/interrupts afterwards. > = Clock seems ok. The problem is the "setup" time between 2 transfers. We use an ADC (MAX1027) from which we try to get the data as fast as = possible (successive SPI read transfers of 16 bytes) and the time = between 2 transfers was quite doubled when switching to your new driver. I will try to spend more time to check that after the summer holidays ;-). Regards, Julien ---------------------------------------------------------------------------= --- Are you an open source citizen? Join us for the Open Source Bridge conferen= ce! Portland, OR, June 17-19. Two days of sessions, one day of unconference: $2= 50. Need another reason to go? 24-hour hacker lounge. Register today! http://ad.doubleclick.net/clk;215844324;13503038;v?http://opensourcebridge.= org