From: Lukas Wunner <lukas@wunner.de>
To: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>,
linux-sh@vger.kernel.org, linux-kernel@vger.kernel.org,
"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
Max Filippov <jcmvbkbc@gmail.com>, Rich Felker <dalias@libc.org>,
Paul Mackerras <paulus@samba.org>,
sparclinux@vger.kernel.org, linux-api@vger.kernel.org,
Jiri Slaby <jirislaby@kernel.org>,
linux-arch@vger.kernel.org,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Helge Deller <deller@gmx.de>,
linux-doc@vger.kernel.org, linux-serial@vger.kernel.org,
Matt Turner <mattst88@gmail.com>,
linux-xtensa@linux-xtensa.org, Arnd Bergmann <arnd@arndb.de>,
Johan Hovold <johan@kernel.org>,
Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Richard Henderson <rth@twiddle.net>,
Chris Zankel <chris@zankel.net>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
linux-parisc@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-mips@vger.kernel.org, linux-alpha@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [RFC PATCH 6/7] serial: General support for multipoint addresses
Date: Sun, 6 Mar 2022 20:40:01 +0100 [thread overview]
Message-ID: <20220306194001.GD19394@wunner.de> (raw)
In-Reply-To: <20220302095606.14818-7-ilpo.jarvinen@linux.intel.com>
On Wed, Mar 02, 2022 at 11:56:05AM +0200, Ilpo Järvinen wrote:
> This patch adds generic support for serial multipoint
> addressing. Two new ioctls are added. TIOCSADDR is used to
Nit: "This patch adds..." is superfluous. Just write "Add ..."
in imperative mood.
> This change is necessary for supporting devices with RS485
> multipoint addressing [*].
If this is only used with RS485, why can't we just store the
addresses in struct serial_rs485 and use the existing TIOCSRS485
and TIOCGRS485 ioctls? There's 20 bytes of padding left in
struct serial_rs485 which you could use. No need to add more
user-space ABI.
> [*] Technically, RS485 is just an electronic spec and does not
> itself specify the 9th bit addressing mode but 9th bit seems
> at least "semi-standard" way to do addressing with RS485.
Is 9th bit addressing actually used by an Intel customer or was
it implemented just for feature completeness? I think this mode
isn't used often (I've never seen a use case myself), primarily
because it requires disabling parity.
Thanks,
Lukas
next prev parent reply other threads:[~2022-03-06 19:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220302095606.14818-1-ilpo.jarvinen@linux.intel.com>
2022-03-02 9:56 ` [RFC PATCH 5/7] serial: termbits: ADDRB to indicate 9th bit addressing mode Ilpo Järvinen
2022-03-02 9:56 ` [RFC PATCH 6/7] serial: General support for multipoint addresses Ilpo Järvinen
2022-03-06 19:40 ` Lukas Wunner [this message]
2022-03-07 9:48 ` Ilpo Järvinen
2022-03-09 19:05 ` Lukas Wunner
2022-03-10 12:29 ` Ilpo Järvinen
2022-03-10 14:09 ` Andy Shevchenko
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=20220306194001.GD19394@wunner.de \
--to=lukas@wunner.de \
--cc=James.Bottomley@HansenPartnership.com \
--cc=andriy.shevchenko@linux.intel.com \
--cc=arnd@arndb.de \
--cc=chris@zankel.net \
--cc=dalias@libc.org \
--cc=davem@davemloft.net \
--cc=deller@gmx.de \
--cc=gregkh@linuxfoundation.org \
--cc=heikki.krogerus@linux.intel.com \
--cc=ilpo.jarvinen@linux.intel.com \
--cc=ink@jurassic.park.msu.ru \
--cc=jcmvbkbc@gmail.com \
--cc=jirislaby@kernel.org \
--cc=johan@kernel.org \
--cc=linux-alpha@vger.kernel.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux-parisc@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
--cc=linux-sh@vger.kernel.org \
--cc=linux-xtensa@linux-xtensa.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mattst88@gmail.com \
--cc=paulus@samba.org \
--cc=rth@twiddle.net \
--cc=sparclinux@vger.kernel.org \
--cc=tsbogend@alpha.franken.de \
--cc=ysato@users.sourceforge.jp \
/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;
as well as URLs for NNTP newsgroup(s).