Linux Serial subsystem development
 help / color / mirror / Atom feed
From: Crescent CY Hsieh <crescentcy.hsieh@moxa.com>
To: Jiri Slaby <jirislaby@kernel.org>
Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
	linux-serial@vger.kernel.org
Subject: Re: [PATCH 4/4] tty: serial: 8250: Add support for MOXA PCIe boards to switch interface between RS422/RS485
Date: Tue, 3 Oct 2023 17:57:41 +0800	[thread overview]
Message-ID: <ZRvllYZS3ks+dOYc@moxa-ThinkCentre-M90t> (raw)
In-Reply-To: <92aed0d9-791f-4708-8a73-4c78457a710e@kernel.org>

On Mon, Oct 02, 2023 at 09:19:26AM +0200, Jiri Slaby wrote:
> On 02. 10. 23, 3:57, Crescent CY Hsieh wrote:
> > MOXA PCIe boards have 4 serial interfaces and don't require additional
> > stuff to switch between interfaces:
> > 
> > - RS232
> > - RS422
> > - RS485_2W (half-duplex)
> > - RS485_4W (full-duplex)
> > 
> > By using ioctl command "TIOCRS485", it can switch between default
> > interface and RS485 if supported.
> > 
> > That means, for RS422/RS485 board, it can switch between RS422 and
> > RS485 by setting the flags within struct serial_rs485.
> > 
> > However, for the RS232/RS422/RS485 board, it can only switch between
> > RS232 and RS485, there's no flag for switching interface into RS422.
> > 
> > This patch adds a flag call "SER_RS422_ENALBED" in serial.h and modifies
> 
> Hopefully not SER_RS422_ENALBED.

What if I use an existing flag within struct serial_rs485 to represent
RS422 as a workaround solution?

> > @@ -1299,7 +1299,7 @@ static int uart_get_icount(struct tty_struct *tty,
> >   #define SER_RS485_LEGACY_FLAGS	(SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \
> >   				 SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \
> > -				 SER_RS485_TERMINATE_BUS)
> > +				 SER_RS485_TERMINATE_BUS | SER_RS422_ENALBED)
> 
> So have you tested this at all?

I have tested it by switching the serial interface using TIOCSRS485
ioctl command, but it seems that I send the wrong patch which mistyping
SER_RS422_ENABLED.

---
Sincerely,
Crescent CY Hsieh

      reply	other threads:[~2023-10-03  9:57 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-02  1:56 [PATCH 0/4] tty: serial: 8250: Changes of MOXA PCIe boards in 8250_pci.c Crescent CY Hsieh
2023-10-02  1:56 ` [PATCH 1/4] tty: serial: 8250: Cleanup MOXA configurations " Crescent CY Hsieh
2023-10-02  6:51   ` Jiri Slaby
2023-10-03  7:17     ` Crescent CY Hsieh
2023-10-03  7:30       ` Greg KH
2023-10-03  9:49         ` Jiri Slaby
2023-10-02  1:57 ` [PATCH 2/4] tty: serial: 8250: Add support for MOXA Mini PCIe boards Crescent CY Hsieh
2023-10-02  7:05   ` Jiri Slaby
2023-10-03  8:17     ` Crescent CY Hsieh
2023-10-02  1:57 ` [PATCH 3/4] tty: serial: 8250: Fix MOXA RS422/RS485 PCIe boards not work by default Crescent CY Hsieh
2023-10-02  7:14   ` Jiri Slaby
2023-10-03  8:22     ` Crescent CY Hsieh
2023-10-02  1:57 ` [PATCH 4/4] tty: serial: 8250: Add support for MOXA PCIe boards to switch interface between RS422/RS485 Crescent CY Hsieh
2023-10-02  4:13   ` kernel test robot
2023-10-02  5:47   ` kernel test robot
2023-10-02  7:19   ` Jiri Slaby
2023-10-03  9:57     ` Crescent CY Hsieh [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=ZRvllYZS3ks+dOYc@moxa-ThinkCentre-M90t \
    --to=crescentcy.hsieh@moxa.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=jirislaby@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-serial@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox