From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sascha Hauer Subject: Re: spi-imx: add support for single burst mode (8,16,32) Date: Wed, 1 Jun 2016 08:30:29 +0200 Message-ID: <20160601063029.GB11074@pengutronix.de> References: <574D5C2B.1000400@gtsys.com.hk> <20160531110608.GG31666@pengutronix.de> <574E405F.9090000@gtsys.com.hk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Fabio Estevam , Anton Bondarenko , Mark Brown , Sascha Hauer , "linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" To: Chris Ruehl Return-path: Content-Disposition: inline In-Reply-To: <574E405F.9090000-CR359r9tUDPXPF5Rlphj1Q@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: On Wed, Jun 01, 2016 at 09:54:39AM +0800, Chris Ruehl wrote: > On Tuesday, May 31, 2016 07:06 PM, Sascha Hauer wrote: > >On Tue, May 31, 2016 at 07:43:37AM -0300, Fabio Estevam wrote: > >>[Adding Sascha and Anton in Cc] > >> > >>On Tue, May 31, 2016 at 6:40 AM, Chris Ruehl wrote: > >>>Hi, > >>> > >>>as imx6 using multiple burst to send data to spi slaves and drop the > >>>chipselect between the words by default my sensor NXP MPL115A1 wasn't > >>>working. > > > >I generally recommend to use GPIO Chip selects. The SPI controller has > >its own ideas when to assert the chipselects which is hard to match (if > >possible at all) with what Linux SPI expects. See the cs-gpios device > >tree property. > > > >Sascha > > Sascha that's a good approach to fight this problem, if you have the > choice. Sadly my hardware design is finished and I can only switch to > a gpio by run wires on the finished PCB.. and that's not what I want. I'm not suggesting to change your hardware. Every chipselect pin can be configured as GPIO aswell, i.e. exchange MX6QDL_PAD_DISP0_DAT3__ECSPI3_SS0 with MX6QDL_PAD_DISP0_DAT3__GPIO4_IO24 and be done with it. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html