Add "SER_RS422_ENABLED" flag within struct serial_rs485, so that serial port can switching interface into RS422 if supported by using ioctl command "TIOCSRS485". In case of interfaces confliction, add checks within uart_sanitize_serial_rs485() such that only one of RS422/RS485 is set. Signed-off-by: Crescent CY Hsieh <crescentcy.hsieh@xxxxxxxx> --- Changes in v2: - Revise the logic that checks whether RS422/RS485 are enabled simultaneously. v1: https://lore.kernel.org/all/20231030053632.5109-1-crescentcy.hsieh@xxxxxxxx/ --- drivers/tty/serial/serial_core.c | 19 +++++++++++++++++-- include/uapi/linux/serial.h | 4 ++++ 2 files changed, 21 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 831d03361..54a104c52 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1305,7 +1305,7 @@ static int uart_get_icount(struct tty_struct *tty, #define SER_RS485_LEGACY_FLAGS (SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \ SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \ - SER_RS485_TERMINATE_BUS) + SER_RS485_TERMINATE_BUS | SER_RS422_ENABLED) static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485) { @@ -1371,11 +1371,26 @@ static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs4 { u32 supported_flags = port->rs485_supported.flags; - if (!(rs485->flags & SER_RS485_ENABLED)) { + if (!(rs485->flags & (SER_RS485_ENABLED | SER_RS422_ENABLED))) { memset(rs485, 0, sizeof(*rs485)); return; } + /* Pick sane setting if the user enables both interfaces */ + if (rs485->flags & SER_RS485_ENABLED && rs485->flags & SER_RS422_ENABLED) { + dev_warn_ratelimited(port->dev, + "%s (%d): Invalid serial interface setting, using RS485 instead\n", + port->name, port->line); + rs485->flags &= ~SER_RS422_ENABLED; + } + + /* Clear other bits and return if RS422 is enabled */ + if (rs485->flags & SER_RS422_ENABLED) { + memset(rs485, 0, sizeof(*rs485)); + rs485->flags |= SER_RS422_ENABLED; + return; + } + /* Pick sane settings if the user hasn't */ if ((supported_flags & (SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND)) && !(rs485->flags & SER_RS485_RTS_ON_SEND) == diff --git a/include/uapi/linux/serial.h b/include/uapi/linux/serial.h index 53bc1af67..427609fd5 100644 --- a/include/uapi/linux/serial.h +++ b/include/uapi/linux/serial.h @@ -137,6 +137,8 @@ struct serial_icounter_struct { * * %SER_RS485_ADDRB - Enable RS485 addressing mode. * * %SER_RS485_ADDR_RECV - Receive address filter (enables @addr_recv). Requires %SER_RS485_ADDRB. * * %SER_RS485_ADDR_DEST - Destination address (enables @addr_dest). Requires %SER_RS485_ADDRB. + * + * * %SER_RS422_ENABLED - RS422 enabled. */ struct serial_rs485 { __u32 flags; @@ -149,6 +151,8 @@ struct serial_rs485 { #define SER_RS485_ADDR_RECV (1 << 7) #define SER_RS485_ADDR_DEST (1 << 8) +#define SER_RS422_ENABLED (1 << 9) + __u32 delay_rts_before_send; __u32 delay_rts_after_send; -- 2.34.1
