On Wed, 8 Nov 2023, Crescent CY Hsieh wrote: > Add "SER_RS485_MODE_RS422" flag to struct serial_rs485, so that serial > port can switch interface into RS422 if supported by using ioctl command > "TIOCSRS485". > > By treating RS422 as a mode of RS485, which means while enabling RS422 > there are two flags need to be set (SER_RS485_ENABLED and > SER_RS485_MODE_RS422), it would make things much easier. For example > some places that checks for "SER_RS485_ENABLED" won't need to be rewritten. > > There are only two things need to be noticed: > > - While enabling RS422, other RS485 flags should not be set. > - RS422 doesn't need to deal with termination, so while disabling RS485 > or enabling RS422, uart_set_rs485_termination() shall return. > > Signed-off-by: Crescent CY Hsieh <crescentcy.hsieh@xxxxxxxx> > > --- > Changes from v2 to v3: > - Remove "SER_RS422_ENABLED" flag from legacy flags. > - Revise "SER_RS422_ENABLED" into "SER_RS485_MODE_RS422". > - Remove the code which checks the conflicts between SER_RS485_ENABLED > and SER_RS422_ENABLED. > - Add return check in uart_set_rs485_termination(). > > Changes from v1 to v2: > - Revise the logic that checks whether RS422/RS485 are enabled > simultaneously. > > v2: https://lore.kernel.org/all/20231101064404.45711-1-crescentcy.hsieh@xxxxxxxx/ > v1: https://lore.kernel.org/all/20231030053632.5109-1-crescentcy.hsieh@xxxxxxxx/ > > --- > --- a/include/uapi/linux/serial.h > +++ b/include/uapi/linux/serial.h > @@ -137,17 +137,19 @@ 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_RS485_MODE_RS422 - Enable RS422. Requires %SER_RS485_ENABLED. > */ > struct serial_rs485 { > __u32 flags; > -#define SER_RS485_ENABLED (1 << 0) > -#define SER_RS485_RTS_ON_SEND (1 << 1) > -#define SER_RS485_RTS_AFTER_SEND (1 << 2) > -#define SER_RS485_RX_DURING_TX (1 << 4) > -#define SER_RS485_TERMINATE_BUS (1 << 5) > -#define SER_RS485_ADDRB (1 << 6) > -#define SER_RS485_ADDR_RECV (1 << 7) > -#define SER_RS485_ADDR_DEST (1 << 8) > +#define SER_RS485_ENABLED BIT(0) > +#define SER_RS485_RTS_ON_SEND BIT(1) > +#define SER_RS485_RTS_AFTER_SEND BIT(2) > +#define SER_RS485_RX_DURING_TX BIT(3) > +#define SER_RS485_TERMINATE_BUS BIT(4) > +#define SER_RS485_ADDRB BIT(5) > +#define SER_RS485_ADDR_RECV BIT(6) > +#define SER_RS485_ADDR_DEST BIT(7) > +#define SER_RS485_MODE_RS422 BIT(8) Is BIT() allowed in uapi headers these days? -- i.
