On Mon, Mar 23, 2015 at 6:42 PM, Jakub Kiciński <moorray3@xxxxx> wrote: > On Mon, 23 Mar 2015 18:17:36 -0400 (EDT), Jon Ringle wrote: >> On Thu, 19 Mar 2015, Jon Ringle wrote: >> > On Wed, 18 Mar 2015, Jakub Kicinski wrote: >> > >> > > From: Jakub Kicinski <kubakici@xxxxx> >> > > >> > > Users of RS-485 can request via ioctl that RTS signals should >> > > be activated selected number of milliseconds before the actual >> > > data transmission or stay active after the transmission is >> > > finished. In sc16is7xx, however, RTS signalling is handled by >> > > the hardware and driver has no way of providing this feature. >> > > >> > > Note: this change will make the driver return -EINVAL when the >> > > feature is requested (.delay_rts_*_send are set). >> > >> > Makes sense. I removed the use of .delay_rts_before_send that my user app >> > was setting and tested it and you are correct it. >> >> I am going to have to retract this. We have some modbus peripherals that >> communicate poorly if data is sent from the controller (this driver) to >> quickly after the RTS line switches states. Putting in a delay via >> .delay_rts_befor_send helps these peripherals communicate much much better >> reliability. > > Do you have an oscilloscope and care to debug this issue a bit > further? I would love to do it myself by my electronics lab is very > limited :( > I don't have an oscilloscope -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
