From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladimir Zapolskiy Subject: Re: spi-imx: add support for single burst mode (8,16,32) Date: Tue, 31 May 2016 14:20:06 +0300 Message-ID: <574D7366.5050203@mentor.com> References: <574D5C2B.1000400@gtsys.com.hk> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: Fabio Estevam , To: Chris Ruehl , Return-path: In-Reply-To: <574D5C2B.1000400-CR359r9tUDPXPF5Rlphj1Q@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: On 31.05.2016 12:40, 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. > The hint comes from a discussion in the Freescale forum from 2013 where Jeff > Coffman posted his solution for a 3.x kernel. > I'd pick-up the idea behind and develop something which works "so far" with > 4.6 and linux-next > > Up front - I'm not happy using the xfer->cs_change to get set the single burst > I more likely want add a new xfer bit which allow to dedicated set a single burst. > To replace todays: > xfer[0].cs_change = 0; > with a > xfer[0].singleburst = 1; > > An other issue with is not yet solved; when I have a odd number of bytes (8 bpw) > in a transfer, its result in 3 bytes eaten on the start and 0x00 added on the > tail - Do you use PIO or DMA transfer mode? The problem description resembles a known issue within SDMA firmware (referenced as TKT238285 or ERR008517) and you should not be able to face it, if SPI controller operates in PIO mode. -- With best wishes, Vladimir -- 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