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Martin FuzzeyandGreg Kroah-Hartman
5553d587a3
commit639949a703upstream. Since commit79d0224f6b("tty: serial: imx: Handle RS485 DE signal active high") RS485 reception no longer works after a transmission. The following scenario shows the problem: 1) Open a port in RS485 mode 2) Receive data from remote (OK) 3) Transmit data to remote (OK) 4) Receive data from remote (Nothing received) In RS485 mode, imx_uart_start_tx() calls imx_uart_stop_rx() and, when the transmission is complete, imx_uart_stop_tx() calls imx_uart_start_rx(). Since the above commit imx_uart_stop_rx() now sets the loopback bit but imx_uart_start_rx() does not clear it causing the hardware to remain in loopback mode and not receive external data. Fix this by moving the existing loopback disable code to a helper function and calling it from imx_uart_start_rx() too. Fixes:79d0224f6b("tty: serial: imx: Handle RS485 DE signal active high") Cc: stable@vger.kernel.org Signed-off-by: Martin Fuzzey <martin.fuzzey@flowbird.group> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20230616104838.2729694-1-martin.fuzzey@flowbird.group Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>