On Wed, Nov 01, 2023 at 02:44:04PM +0800, Crescent CY Hsieh wrote: > 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) A new flag is "legacy"? > > 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); Why is this ratelimited? What would cause lots of repeats of this? > + 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) Why the extra blank line before this? And why isn't it using the proper BIT() type macro instead (yeah, the others are not, I understand...) Also, what userspace code is going to use this? How is it tested? thanks, greg k-h
