serial: core: set missing supported flag for RX during TX GPIO

[ Upstream commit 1a33e33ca0e80d485458410f149265cdc0178cfa ]

If the RS485 feature RX-during-TX is supported by means of a GPIO set the
according supported flag. Otherwise setting this feature from userspace may
not be possible, since in uart_sanitize_serial_rs485() the passed RS485
configuration is matched against the supported features and unsupported
settings are thereby removed and thus take no effect.

Cc:  <stable@vger.kernel.org>
Fixes: 163f080eb717 ("serial: core: Add option to output RS485 RX_DURING_TX state via GPIO")
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20240103061818.564-3-l.sanfilippo@kunbus.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 021e096..bde5b60 100644 (file)
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -3630,6 +3630,8 @@ int uart_get_rs485_mode(struct uart_port *port)
        if (IS_ERR(desc))
                return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-rx-during-tx-gpios\n");
        port->rs485_rx_during_tx_gpio = desc;
+       if (port->rs485_rx_during_tx_gpio)
+               port->rs485_supported.flags |= SER_RS485_RX_DURING_TX;
 
        return 0;
 }