Add information on supported serial_rs485 features. In the case where RTS is lacking, RS485 cannot be enabled so provide zero rs485_supported for that case. Perhaps it would make sense to not provide rs485_config() at all in that case but such a change would have userspace visible impact/change in behavior so this patch does not attempt it. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> --- drivers/tty/serial/imx.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 9ce09b81ac9b..ba853bc9b4db 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -2200,6 +2200,14 @@ static enum hrtimer_restart imx_trigger_stop_tx(struct hrtimer *t) return HRTIMER_NORESTART; } +static const struct serial_rs485 imx_no_rs485 = {}; /* No RS485 if no RTS */ +static const struct serial_rs485 imx_rs485_supported = { + .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND | + SER_RS485_RX_DURING_TX, + .delay_rts_before_send = 1, + .delay_rts_after_send = 1, +}; + /* Default RX DMA buffer configuration */ #define RX_DMA_PERIODS 16 #define RX_DMA_PERIOD_LEN (PAGE_SIZE / 4) @@ -2279,6 +2287,11 @@ static int imx_uart_probe(struct platform_device *pdev) sport->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_IMX_CONSOLE); sport->port.ops = &imx_uart_pops; sport->port.rs485_config = imx_uart_rs485_config; + /* RTS is required to control the RS485 transmitter */ + if (sport->have_rtscts || sport->have_rtsgpio) + sport->port.rs485_supported = &imx_rs485_supported; + else + sport->port.rs485_supported = &imx_no_rs485; sport->port.flags = UPF_BOOT_AUTOCONF; timer_setup(&sport->timer, imx_uart_timeout, 0); -- 2.30.2