6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> [ Upstream commit 79d713baf63c8f23cc58b304c40be33d64a12aaf ] In some APIs we would like to assign the special value to iotype and compare against it in another places. Introduce UPIO_UNKNOWN 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@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20240304123035.758700-3-andriy.shevchenko@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Stable-dep-of: 87d80bfbd577 ("serial: 8250_dw: Don't use struct dw8250_data outside of 8250_dw") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 a7d5fa892be26..412de73547521 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 */ unsigned char quirks; /* internal quirks */ +#define UPIO_UNKNOWN ((unsigned char)~0U) /* UCHAR_MAX */ #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 */ -- 2.43.0