On Tue, 23 Sep 2025, Heiko Stuebner wrote:
> Digging deeper into how that MCU behaves, I found out it can return
> more status codes than the "@0" for "ok".
>
> The additional codes can report a failed checksum verification and
> some "general" error for the command execution.
>
> This also explains sporadic command timeout messages, I have seen
> over time, when the controller sends an error code while we expect
> a longer reply from it.
>
> So while I'm not sure yet why it reports an error, with these changes
> we at least handle the error return code in a meaningful way.
>
>
> Heiko Stuebner (4):
> mfd: qnap-mcu: Calculate the checksum on the actual number of bytes
> received
> mfd: qnap-mcu: Use EPROTO in stead of EIO on checksum errors
> mfd: qnap-mcu: Move checksum verification to its own function
> mfd: qnap-mcu: Add proper error handling for command errors
>
> drivers/mfd/qnap-mcu.c | 55 +++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 51 insertions(+), 4 deletions(-)
Note to self: patches 1-3 look good.
--
Lee Jones [李琼斯]