Hello Stefan, On Thu, Apr 19, 2018 at 05:39:16PM +0200, Stefan Agner wrote: > When using half-duplex mode (which disables receiver during txing) > the RTS signal cannot be driven low during transmission when using > i.MX UART RTS/CTS control. This seems to be a limitation of the > i.MX UART IP: The RTS (CTS_B) signal is controlled by the receiver. > When the receiver is disabled, the signal stays in UART logic idle > state which is high... > > If SER_RS485_RTS_ON_SEND is used, RTS needs to be high active during > transmission. Since this is the default state of the RTS (CTS_B) > signal when the receiver is off, half-duplex mode in this > configuration works fine. > > However, a low-active RTS signal (flag SER_RS485_RTS_ON_SEND not set) > cannot be generated when the receiver is turned off. > > Print an error if the user selects this unsupported configuration > (both SER_RS485_RTS_ON_SEND and SER_RS485_RX_DURING_TX unset) and > configure the closest working configuration (set the > SER_RS485_RX_DURING_TX flag). > > Signed-off-by: Stefan Agner <stefan@xxxxxxxx> Acked-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> Thanks Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- 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
