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

Florian Fainelli
2024-02-21T18:47:20Z

On 2/21/24 10:31, 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 */

Nit: I would name this UPIO_UNKNOWN, or UPIO_NOTSET, unset means to me
that it was previously set and we undid that action, whereas unknown or
not set means we never did.
--
Florian