[PATCH v10 0/3] leds: trigger: implement a tty trigger - Uwe Kleine-König

From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Jacek Anaszewski <jacek.anaszewski@gmail.com>,
	Pavel Machek <pavel@ucw.cz>, Dan Murphy <dmurphy@ti.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org, linux-leds@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel@pengutronix.de,
	"Johan Hovold" <johan@kernel.org>,
	"Uwe Kleine-König" <uwe@kleine-koenig.org>
Subject: [PATCH v10 0/3] leds: trigger: implement a tty trigger
Date: Fri, 18 Dec 2020 11:42:43 +0100	[thread overview]
Message-ID: <20201218104246.591315-1-u.kleine-koenig@pengutronix.de> (raw)

From: Uwe Kleine-König <uwe@kleine-koenig.org>

Hello,

here comes v10 of this series. Changes compared to v9 sent with
Message-Id: 20201018204022.910815-1-u.kleine-koenig@pengutronix.de in
October:

 - Bump date and kernel version in ABI doc
 - Fix double unlock in error path; found by Pavel
 - Don't stop the workqueue in ttyname_store() to
   fix error behaviour on memory allocation failure.
   Now it continues with the previous configuration instead of
   stopping. Also found by Pavel.

Unaddressed review comments by Pavel are:

 - Unused assignment to len in ttyname_show
   This is wrong
 - "Poll every 100 msec... Hmm.... Okay, I guess?"
   Yes, I think there is no way around this given the trigger uses
   polling. There is no easy way to get notified instead.
 - "Are you sure about LED_ON [in the worker]? It should use current
   brightness selected by brightness file..."
   I found no consistent behaviour in other triggers. ledtrig-gpio
   implements a dedicated "desired_brightness" sysfs file, several use
   led_cdev->blink_brightness (via led_trigger_blink_oneshot),
   ledtrig-cpu uses led_trigger_event with LED_FULL.
 - "How is [the data initialized in ledtrig_tty_activate()] protected
   from concurrent access from sysfs?"
   I think there is no need to protect this. But I'm not sure I
   understood the question correctly, so please recheck and if needed
   point out the problem you see in more detail.

Uwe Kleine-König (3):
  tty: rename tty_kopen() and add new function tty_kopen_shared()
  tty: new helper function tty_get_icount()
  leds: trigger: implement a tty trigger

 .../ABI/testing/sysfs-class-led-trigger-tty   |   6 +
 drivers/accessibility/speakup/spk_ttyio.c     |   2 +-
 drivers/leds/trigger/Kconfig                  |   9 +
 drivers/leds/trigger/Makefile                 |   1 +
 drivers/leds/trigger/ledtrig-tty.c            | 188 ++++++++++++++++++
 drivers/tty/tty_io.c                          |  85 ++++++--
 include/linux/tty.h                           |   7 +-
 7 files changed, 273 insertions(+), 25 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-class-led-trigger-tty
 create mode 100644 drivers/leds/trigger/ledtrig-tty.c

-- 
2.29.2