Linux-Serial Archive on lore.kernel.org
 help / color / Atom feed
From: Heiko Stuebner <heiko@sntech.de>
To: gregkh@linuxfoundation.org
Cc: jslaby@suse.com, andriy.shevchenko@linux.intel.com,
	matwey.kornilov@gmail.com, linux-serial@vger.kernel.org,
	linux-kernel@vger.kernel.org, heiko@sntech.de, lukas@wunner.de,
	christoph.muellner@theobroma-systems.com,
	giulio.benetti@micronovasrl.com
Subject: [PATCH RFC v2 0/7] serial: 8250: Add rs485 emulation to 8250_dw
Date: Thu, 26 Mar 2020 00:14:15 +0100
Message-ID: <20200325231422.1502366-1-heiko@sntech.de> (raw)

This series tries to revive the work of Giulio Benetti from 2018 [0]
which seemed to have stalled at that time.

The board I needed that on also had the additional caveat that it
uses non-standard pins for DE/RE so needed gpio mctrl layer as well
and even more special needed to control the RE pin manually not as
part of it being connected to the DE signal as seems to be the standard.

The first 3 patches are taken from Lukas Wunner's repository
with work he wants to submit after 5.7-rc1.
Patches needed adaptions from their 4.19 base of course,
so no guarantes I did that correctly ;-) .
I just need the change in the rs485_mode handling as base.

So as suggested by Andy this series is meant as a base for discussions
to show how my 8250_dw rs485 support fits onto the more recent codebase
and find more issues earlier.


Changes in v2:
- move to recent rs485 improvements in tty-next
- added a capability for TEMT interrupt presence
- external gpio for optional receiver-enable handling
- timeout polling via the generic readx_poll_timeout

Changes from the 2018 submission include:
- add timeout when waiting for fifos to clear using a new helper
- move on-boot enablement of the rs485 mode to after registering
  the port. This saves having to copy the em485 struct as done
  originally, which also ran into spinlock-debug warnings when testing
  and also makes it actually possible to use the mctrl gpio layer
  for non-standard gpios.


*** BLURB HERE ***

Giulio Benetti (2):
  serial: 8250: Handle implementations not having TEMT interrupt using
    em485
  serial: 8250_dw: add em485 support

Heiko Stuebner (2):
  dt-bindings: serial: Add binding for rs485 receiver enable GPIO
  serial: 8250: Support separate rs485 rx-enable GPIO

Lukas Wunner (3):
  serial: Allow uart_get_rs485_mode() to return errno
  dt-bindings: serial: Add binding for rs485 bus termination GPIO
  serial: 8250: Support rs485 bus termination GPIO

 .../devicetree/bindings/serial/rs485.yaml     |  8 ++++
 drivers/tty/serial/8250/8250.h                |  1 +
 drivers/tty/serial/8250/8250_bcm2835aux.c     |  2 +-
 drivers/tty/serial/8250/8250_core.c           |  4 +-
 drivers/tty/serial/8250/8250_dw.c             |  3 ++
 drivers/tty/serial/8250/8250_of.c             |  2 +
 drivers/tty/serial/8250/8250_omap.c           |  2 +-
 drivers/tty/serial/8250/8250_port.c           | 41 +++++++++++++++---
 drivers/tty/serial/ar933x_uart.c              |  6 ++-
 drivers/tty/serial/atmel_serial.c             |  6 ++-
 drivers/tty/serial/fsl_lpuart.c               |  5 ++-
 drivers/tty/serial/imx.c                      |  6 ++-
 drivers/tty/serial/omap-serial.c              |  4 +-
 drivers/tty/serial/serial_core.c              | 43 ++++++++++++++++++-
 drivers/tty/serial/stm32-usart.c              |  8 ++--
 include/linux/serial_core.h                   |  4 +-
 16 files changed, 124 insertions(+), 21 deletions(-)

-- 
2.24.1


             reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-25 23:14 Heiko Stuebner [this message]
2020-03-25 23:14 ` [PATCH DON'T APPLY v2 1/7] serial: Allow uart_get_rs485_mode() to return errno Heiko Stuebner
2020-03-25 23:14 ` [PATCH DON'T APPLY v2 2/7] dt-bindings: serial: Add binding for rs485 bus termination GPIO Heiko Stuebner
2020-03-25 23:14 ` [PATCH DON'T APPLY v2 3/7] serial: 8250: Support " Heiko Stuebner
2020-03-25 23:14 ` [PATCH v2 4/7] serial: 8250: Handle implementations not having TEMT interrupt using em485 Heiko Stuebner
2020-03-25 23:47   ` Giulio Benetti
2020-03-26  0:05     ` Heiko Stübner
2020-03-26  2:02       ` Giulio Benetti
2020-03-25 23:14 ` [PATCH v2 5/7] dt-bindings: serial: Add binding for rs485 receiver enable GPIO Heiko Stuebner
2020-03-25 23:14 ` [PATCH v2 6/7] serial: 8250: Support separate rs485 rx-enable GPIO Heiko Stuebner
2020-03-25 23:14 ` [PATCH v2 7/7] serial: 8250_dw: add em485 support Heiko Stuebner

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=20200325231422.1502366-1-heiko@sntech.de \
    --to=heiko@sntech.de \
    --cc=andriy.shevchenko@linux.intel.com \
    --cc=christoph.muellner@theobroma-systems.com \
    --cc=giulio.benetti@micronovasrl.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=jslaby@suse.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-serial@vger.kernel.org \
    --cc=lukas@wunner.de \
    --cc=matwey.kornilov@gmail.com \
    /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

Linux-Serial Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-serial/0 linux-serial/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-serial linux-serial/ https://lore.kernel.org/linux-serial \
		linux-serial@vger.kernel.org
	public-inbox-index linux-serial

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-serial


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git