Re: [PATCH] staging: greybus: uart: document c_cflag handling in set_termios

[Greg KH]

On Sun, Apr 19, 2026 at 08:56:32AM +0530, Debjeet Banerjee wrote:
> gb_tty_set_termios() derives UART line configuration from a subset of
> termios->c_cflag bits, namely CSIZE, CSTOPB, PARENB, PARODD, CMSPAR,
> CRTSCTS, CLOCAL and CBAUD. Other c_cflag bits are not interpreted by
> the driver and are not represented in the Greybus UART protocol
> messages.
> 
> The existing FIXME suggests clearing unsupported bits from termios.
> However, the driver already limits its behavior to the supported subset
> when constructing line coding, and unused bits are effectively ignored.
> No invalid or unsupported values are propagated to the hardware.
> 
> Replace the FIXME with a comment documenting which c_cflag bits are
> consumed by the driver and clarifying that other bits are ignored.

Ignoring is fine, but shouldn't the bits be cleared to let userspace
know about this?  I think that's why we wrote that FIXME all so long
ago.

thanks,

greg k-h