From mboxrd@z Thu Jan 1 00:00:00 1970 From: clemens.gruber@pqgruber.com (Clemens Gruber) Date: Sat, 7 Jan 2017 21:59:30 +0100 Subject: imx: RS-485 problems during TX, maybe DMA related In-Reply-To: References: <20170104160024.GA13442@archie.localdomain> <20170106225026.GA3804@archie.localdomain> <20170107134557.GA12299@archie.localdomain> <20170107153434.GA13307@archie.localdomain> Message-ID: <20170107205930.GA12367@archie.localdomain> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Sat, Jan 07, 2017 at 02:48:03PM -0200, Fabio Estevam wrote: > On Sat, Jan 7, 2017 at 1:34 PM, Clemens Gruber > wrote: > > Hi Fabio, > > > > On Sat, Jan 07, 2017 at 12:57:10PM -0200, Fabio Estevam wrote: > >> The MX6QDL_PAD_CSI0_DAT16__UART4_CTS_B option is only valid in dte mode. > > > > Ah, the input select is limited in that way, I see. > > > > You wrote that you tried rts-gpios. > > What about setting cts-gpios to gpio6 2 in the DT? > > > > Or can you remux RX and TX to be switched to work in dte mode? > > I managed to get RS485 in half-duplex working with rts-gios. Will send > a patch shortly. Great! Did you observe the same effect I described, with the doubling of characters in the front and the leftovers from previous transmissions at the end? Thanks, Clemens