Re: [PATCH] net: dsa: realtek: rtl8365mb: fix mode mask calculation

Luiz Angelo Daros de Luca
2026-04-19T19:08:25Z

> The RTL8365MB_DIGITAL_INTERFACE_SELECT_MODE_MASK macro was shifting
> the 4-bit mask (0xF) by only (_extint % 2) bits instead of
> (_extint % 2) * 4. This caused the mask to overlap with the adjacent
> nibble when configuring odd-numbered external interfaces, selecting
> the wrong bits entirely.
>
> Align the shift calculation with the existing ...MODE_OFFSET macro.
>
> Signed-off-by: Abdulkader Alrezej <alrazj.abdulkader@gmail.com>
> Signed-off-by: Mieczyslaw Nalewaj <namiltd@yahoo.com>
> ---
> drivers/net/dsa/realtek/rtl8365mb.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/dsa/realtek/rtl8365mb.c b/drivers/net/dsa/realtek/rtl8365mb.c
> index ad7044b295ec..b85c99216648 100644
> --- a/drivers/net/dsa/realtek/rtl8365mb.c
> +++ b/drivers/net/dsa/realtek/rtl8365mb.c
> @@ -216,7 +216,7 @@
> (_extint) == 2 ? RTL8365MB_DIGITAL_INTERFACE_SELECT_REG1 : \
> 0x0)
> #define RTL8365MB_DIGITAL_INTERFACE_SELECT_MODE_MASK(_extint) \
> - (0xF << (((_extint) % 2)))
> + (0xF << (((_extint) % 2) * 4))
> #define RTL8365MB_DIGITAL_INTERFACE_SELECT_MODE_OFFSET(_extint) \
> (((_extint) % 2) * 4)
>

Hello Abdulkader and Mieczyslaw,

This bug has been present since the subdriver submission. I renamed
the macro (d18b59f48b318) but I didn't change the logic. Maybe we just
got luck with defaults. The patch is good. You still missed the Fixes
tag. Just add before the first Signed-off-by:

Fixes: 4af2950c50c8 ("net: dsa: realtek-smi: add rtl8365mb subdriver
for RTL8365MB-VC")

With that addiction, you can submit v2 with my Reviewed-by:

Regards,

Luiz