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Date:   Thu, 24 Feb 2022 12:23:41 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Jiri Slaby <jslaby@suse.cz>
Cc:     linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/5] tty: serial: define UART_LCR_WLEN() macro
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On Thu, Feb 24, 2022 at 11:42:20AM +0100, Jiri Slaby wrote:
> On 24. 02. 22, 11:10, Greg KH wrote:
> > On Thu, Feb 24, 2022 at 10:55:54AM +0100, Jiri Slaby wrote:
> > > Define a generic UART_LCR_WLEN() macro with a size argument. It can be
> > > used to encode byte size into an LCR value. Therefore we can use it to
> > > simplify the drivers using tty_get_char_size() in the next patches.
> > > 
> > > Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> > > ---
> > >   include/uapi/linux/serial_reg.h | 1 +
> > >   1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/include/uapi/linux/serial_reg.h b/include/uapi/linux/serial_reg.h
> > > index f51bc8f36813..c9d5ff6dd4c6 100644
> > > --- a/include/uapi/linux/serial_reg.h
> > > +++ b/include/uapi/linux/serial_reg.h
> > > @@ -111,6 +111,7 @@
> > >   #define UART_LCR_WLEN6		0x01 /* Wordlength: 6 bits */
> > >   #define UART_LCR_WLEN7		0x02 /* Wordlength: 7 bits */
> > >   #define UART_LCR_WLEN8		0x03 /* Wordlength: 8 bits */
> > > +#define UART_LCR_WLEN(x)	((x) - 5)
> > 
> > I'm all for this, but why does it need to be in a uapi .h file?
> 
> I'd love to put it somewhere else. But I didn't find an appropriate place.
> Should I put it simply to
> include/linux/serial_core.h
> or
> include/linux/serial.h

This one would make sense.

> ? Or create a new:
> include/linux/serial_reg.h
> to contain only this def?

Nah, no need to create a whole .h file for a single macro :)

thanks,

greg k-h