Linux-Serial Archive on lore.kernel.org
 help / color / Atom feed
From: "Uwe Kleine-König" <uwe@kleine-koenig.org>
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: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel@pengutronix.de, linux-serial@vger.kernel.org
Subject: [PATCH v6 4/4] leds: trigger: implement a tty trigger
Date: Thu, 13 Feb 2020 10:16:00 +0100
Message-ID: <20200213091600.554-5-uwe@kleine-koenig.org> (raw)
In-Reply-To: <20200213091600.554-1-uwe@kleine-koenig.org>

From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Usage is as follows:

	myled=ledname
	tty=ttyS0

	echo tty > /sys/class/leds/$myled/trigger
	cat /sys/class/tty/$tty/dev > /sys/class/leds/$myled/dev

. When this new trigger is active it periodically checks the tty's
statistics and when it changed since the last check the led is flashed
once.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 .../ABI/testing/sysfs-class-led-trigger-tty   |   6 +
 drivers/leds/trigger/Kconfig                  |   7 +
 drivers/leds/trigger/Makefile                 |   1 +
 drivers/leds/trigger/ledtrig-tty.c            | 159 ++++++++++++++++++
 4 files changed, 173 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-class-led-trigger-tty
 create mode 100644 drivers/leds/trigger/ledtrig-tty.c

diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-tty b/Documentation/ABI/testing/sysfs-class-led-trigger-tty
new file mode 100644
index 000000000000..f56f9721c317
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-trigger-tty
@@ -0,0 +1,6 @@
+What:		/sys/class/leds/<led>/dev
+Date:		Dec 2019
+KernelVersion:	5.6
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Specifies $major:$minor of the triggering tty
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index ce9429ca6dde..40ff08c93f56 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -144,4 +144,11 @@ config LEDS_TRIGGER_AUDIO
 	  the audio mute and mic-mute changes.
 	  If unsure, say N
 
+config LEDS_TRIGGER_TTY
+	tristate "LED Trigger for TTY devices"
+	depends on TTY
+	help
+	  This allows LEDs to be controlled by activity on ttys which includes
+	  serial devices like /dev/ttyS0.
+
 endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile
index 733a83e2a718..25c4db97cdd4 100644
--- a/drivers/leds/trigger/Makefile
+++ b/drivers/leds/trigger/Makefile
@@ -15,3 +15,4 @@ obj-$(CONFIG_LEDS_TRIGGER_PANIC)	+= ledtrig-panic.o
 obj-$(CONFIG_LEDS_TRIGGER_NETDEV)	+= ledtrig-netdev.o
 obj-$(CONFIG_LEDS_TRIGGER_PATTERN)	+= ledtrig-pattern.o
 obj-$(CONFIG_LEDS_TRIGGER_AUDIO)	+= ledtrig-audio.o
+obj-$(CONFIG_LEDS_TRIGGER_TTY)		+= ledtrig-tty.o
diff --git a/drivers/leds/trigger/ledtrig-tty.c b/drivers/leds/trigger/ledtrig-tty.c
new file mode 100644
index 000000000000..e1be93c3026f
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-tty.c
@@ -0,0 +1,159 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/delay.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <uapi/linux/serial.h>
+
+struct ledtrig_tty_data {
+	struct led_classdev *led_cdev;
+	struct delayed_work dwork;
+	struct tty_struct *tty;
+	dev_t device;
+	int rx, tx;
+};
+
+static void ledtrig_tty_halt(struct ledtrig_tty_data *trigger_data)
+{
+	cancel_delayed_work_sync(&trigger_data->dwork);
+}
+
+static void ledtrig_tty_restart(struct ledtrig_tty_data *trigger_data)
+{
+	schedule_delayed_work(&trigger_data->dwork, 0);
+}
+
+static ssize_t dev_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct ledtrig_tty_data *trigger_data = led_trigger_get_drvdata(dev);
+	ssize_t len = 0;
+
+	if (trigger_data->tty)
+		len = sprintf(buf, "%d:%d\n", MAJOR(trigger_data->device),
+			      MINOR(trigger_data->device));
+
+	return len;
+}
+
+static ssize_t dev_store(struct device *dev,
+			 struct device_attribute *attr, const char *buf,
+			 size_t size)
+{
+	struct ledtrig_tty_data *trigger_data = led_trigger_get_drvdata(dev);
+	struct tty_struct *tty;
+	dev_t d;
+	int ret;
+
+	if (size == 0 || (size == 1 && buf[0] == '\n')) {
+		tty = NULL;
+	} else {
+		ret = kstrtodev_t(buf, &d);
+		if (ret < 0)
+			return ret;
+
+		tty = tty_kopen_shared(d);
+		if (IS_ERR(tty))
+			return PTR_ERR(tty);
+	}
+
+	ledtrig_tty_halt(trigger_data);
+
+	tty_kref_put(trigger_data->tty);
+	trigger_data->tty = tty;
+	trigger_data->device = d;
+
+	if (tty) {
+		struct serial_icounter_struct icount;
+		ret = tty_get_icount(trigger_data->tty, &icount);
+		if (!ret) {
+			trigger_data->tx = icount.tx;
+			trigger_data->rx = icount.rx;
+		}
+
+		ledtrig_tty_restart(trigger_data);
+	}
+
+	return size;
+}
+static DEVICE_ATTR_RW(dev);
+
+static void ledtrig_tty_work(struct work_struct *work)
+{
+	struct ledtrig_tty_data *trigger_data =
+		container_of(work, struct ledtrig_tty_data, dwork.work);
+	struct serial_icounter_struct icount;
+	int ret;
+
+	if (!trigger_data->tty) {
+		led_set_brightness(trigger_data->led_cdev, LED_OFF);
+		return;
+	}
+
+	ret = tty_get_icount(trigger_data->tty, &icount);
+	if (ret)
+		return;
+
+	while (icount.rx != trigger_data->rx ||
+	       icount.tx != trigger_data->tx) {
+		led_set_brightness(trigger_data->led_cdev, LED_ON);
+
+		msleep(100);
+
+		led_set_brightness(trigger_data->led_cdev, LED_OFF);
+
+		trigger_data->rx = icount.rx;
+		trigger_data->tx = icount.tx;
+
+		ret = tty_get_icount(trigger_data->tty, &icount);
+		if (ret)
+			return;
+	}
+
+	schedule_delayed_work(&trigger_data->dwork, msecs_to_jiffies(100));
+}
+
+static struct attribute *ledtrig_tty_attrs[] = {
+	&dev_attr_dev.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(ledtrig_tty);
+
+static int ledtrig_tty_activate(struct led_classdev *led_cdev)
+{
+	struct ledtrig_tty_data *trigger_data;
+
+	trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
+	if (!trigger_data)
+		return -ENOMEM;
+
+	led_set_trigger_data(led_cdev, trigger_data);
+
+	INIT_DELAYED_WORK(&trigger_data->dwork, ledtrig_tty_work);
+	trigger_data->led_cdev = led_cdev;
+
+	return 0;
+}
+
+static void ledtrig_tty_deactivate(struct led_classdev *led_cdev)
+{
+	struct ledtrig_tty_data *trigger_data = led_get_trigger_data(led_cdev);
+
+	cancel_delayed_work_sync(&trigger_data->dwork);
+
+	kfree(trigger_data);
+}
+
+struct led_trigger ledtrig_tty = {
+	.name = "tty",
+	.activate = ledtrig_tty_activate,
+	.deactivate = ledtrig_tty_deactivate,
+	.groups = ledtrig_tty_groups,
+};
+module_led_trigger(ledtrig_tty);
+
+MODULE_AUTHOR("Uwe Kleine-König <u.kleine-koenig@pengutronix.de>");
+MODULE_DESCRIPTION("UART LED trigger");
+MODULE_LICENSE("GPL v2");
-- 
2.24.0


  parent reply index

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-13  9:15 [PATCH v6 0/4] " Uwe Kleine-König
2020-02-13  9:15 ` [PATCH v6 1/4] lib: new helper kstrtodev_t() Uwe Kleine-König
2020-02-19 19:50   ` Andy Shevchenko
2020-02-20  7:49     ` Uwe Kleine-König
2020-02-20 10:22       ` Andy Shevchenko
2020-02-20 10:57         ` Uwe Kleine-König
2020-02-20 11:46           ` Andy Shevchenko
2020-02-20 11:57             ` Andy Shevchenko
2020-02-20 14:01             ` Uwe Kleine-König
2020-02-21  8:42               ` Andy Shevchenko
2020-02-21 10:53                 ` Uwe Kleine-König
2020-02-13  9:15 ` [PATCH v6 2/4] tty: rename tty_kopen() and add new function tty_kopen_shared() Uwe Kleine-König
2020-02-19 13:21   ` Johan Hovold
2020-02-19 16:37     ` Uwe Kleine-König
2020-02-19 17:17       ` Johan Hovold
2020-02-20 11:04         ` Uwe Kleine-König
2020-02-25  8:55           ` Johan Hovold
2020-02-25  9:05             ` Uwe Kleine-König
2020-02-13  9:15 ` [PATCH v6 3/4] tty: new helper function tty_get_icount() Uwe Kleine-König
2020-02-13  9:16 ` Uwe Kleine-König [this message]
2020-02-19 10:52   ` [PATCH v6 4/4] leds: trigger: implement a tty trigger Johan Hovold
2020-02-19 11:03     ` Uwe Kleine-König
2020-02-19 11:19       ` Johan Hovold
2020-02-19 12:48         ` Johan Hovold
2020-02-19 10:40 ` [PATCH v6 0/4] " Greg Kroah-Hartman
2020-02-26 14:02   ` Pavel Machek

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=20200213091600.554-5-uwe@kleine-koenig.org \
    --to=uwe@kleine-koenig.org \
    --cc=dmurphy@ti.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=jacek.anaszewski@gmail.com \
    --cc=jslaby@suse.com \
    --cc=kernel@pengutronix.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-leds@vger.kernel.org \
    --cc=linux-serial@vger.kernel.org \
    --cc=pavel@ucw.cz \
    --cc=u.kleine-koenig@pengutronix.de \
    /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