Re: [PATCH] tty: serial: Fix bit order in RS485 flag definitions

[Hugo Villeneuve <hugo@hugovil.com>]

On Thu, 18 Jan 2024 13:43:50 +0100
Christoph Niedermaier <cniedermaier@dh-electronics.com> wrote:

> Since the commit 93f3350c46fa ("RS485: fix inconsistencies in the
> meaning of some variables"), the definition for bit 3 has been removed.
> But with the switch to bit shift marcos in commit 76ac8e29855b ("tty:

marcos -> macros

Hugo Villeneuve

> serial: Cleanup the bit shift with macro"), this gap wasn't preserved.
> To avoid a break in user/kernel api of the system skip bit 3 again and
> add a placeholder comment.
> 
> Signed-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
> ---
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Crescent CY Hsieh <crescentcy.hsieh@moxa.com>
> Cc: Jiri Slaby <jirislaby@kernel.org>
> Cc: Lukas Wunner <lukas@wunner.de>
> Cc: Lino Sanfilippo <l.sanfilippo@kunbus.com>
> To: linux-serial@vger.kernel.org
> To: linux-arm-kernel@lists.infradead.org
> ---
>  include/uapi/linux/serial.h | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/include/uapi/linux/serial.h b/include/uapi/linux/serial.h
> index 9086367db043..de9b4733607e 100644
> --- a/include/uapi/linux/serial.h
> +++ b/include/uapi/linux/serial.h
> @@ -145,12 +145,13 @@ struct serial_rs485 {
>  #define SER_RS485_ENABLED		_BITUL(0)
>  #define SER_RS485_RTS_ON_SEND		_BITUL(1)
>  #define SER_RS485_RTS_AFTER_SEND	_BITUL(2)
> -#define SER_RS485_RX_DURING_TX		_BITUL(3)
> -#define SER_RS485_TERMINATE_BUS		_BITUL(4)
> -#define SER_RS485_ADDRB			_BITUL(5)
> -#define SER_RS485_ADDR_RECV		_BITUL(6)
> -#define SER_RS485_ADDR_DEST		_BITUL(7)
> -#define SER_RS485_MODE_RS422		_BITUL(8)
> +/* Placeholder for bit 3: SER_RS485_RTS_BEFORE_SEND, which isn't used anymore */
> +#define SER_RS485_RX_DURING_TX		_BITUL(4)
> +#define SER_RS485_TERMINATE_BUS		_BITUL(5)
> +#define SER_RS485_ADDRB			_BITUL(6)
> +#define SER_RS485_ADDR_RECV		_BITUL(7)
> +#define SER_RS485_ADDR_DEST		_BITUL(8)
> +#define SER_RS485_MODE_RS422		_BITUL(9)
>  
>  	__u32	delay_rts_before_send;
>  	__u32	delay_rts_after_send;
> -- 
> 2.11.0
> 
>