Re: [PATCH v1 02/14] serial: core: Add UPIO_UNSET constant for unset port type

Jiri Slaby
2024-02-22T06:58:36Z

On 21. 02. 24, 19:31, Andy Shevchenko wrote:
> In some APIs we would like to assign the special value to iotype
> and compare against it in another places. Introduce UPIO_UNSET
> for this purpose.
>
> Note, we can't use 0, because it's a valid value for IO port access.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
> include/linux/serial_core.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> index 2d2ec99eca93..2b0526ae1fac 100644
> --- a/include/linux/serial_core.h
> +++ b/include/linux/serial_core.h
> @@ -470,6 +470,7 @@ struct uart_port {
>
> unsigned char iotype; /* io access style */
>
> +#define UPIO_UNSET ((unsigned char)~0U) /* UCHAR_MAX */

Perhaps making the var u8 and this U8_MAX then? It would make more sense
to me.

> #define UPIO_PORT (SERIAL_IO_PORT) /* 8b I/O port access */
> #define UPIO_HUB6 (SERIAL_IO_HUB6) /* Hub6 ISA card */
> #define UPIO_MEM (SERIAL_IO_MEM) /* driver-specific */

thanks,
--
js
suse labs