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From:   Florian Eckert <fe@dev.tdt.de>
To:     Eckert.Florian@googlemail.com, gregkh@linuxfoundation.org,
        jirislaby@kernel.org, pavel@ucw.cz, lee@kernel.org,
        kabel@kernel.org, u.kleine-koenig@pengutronix.de,
        m.brock@vanmierlo.com
Cc:     linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org,
        linux-leds@vger.kernel.org
Subject: [Patch v6 6/7] leds: ledtrig-tty: make rx tx activitate configurable
Date:   Mon, 30 Oct 2023 11:04:46 +0100
Message-ID: <20231030100447.63477-7-fe@dev.tdt.de>
In-Reply-To: <20231030100447.63477-1-fe@dev.tdt.de>
References: <20231030100447.63477-1-fe@dev.tdt.de>
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Until now, the LED blinks when data is sent via the tty (rx/tx).
This is not configurable.

This change adds the possibility to make the indication for the direction
of the transmitted data independently controllable via the new rx and
tx sysfs entries.

- rx:
  Signal reception (rx) of data on the named tty device.
  If set to 0, the LED will not blink on reception.
  If set to 1 (default), the LED will blink on reception.

- tx:
  Signal transmission (tx) of data on the named tty device.
  If set to 0, the LED will not blink on transmission.
  If set to 1 (default), the LED will blink on transmission.

This new sysfs entry are on by default. Thus the trigger behaves as
before this change.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>
---
 .../ABI/testing/sysfs-class-led-trigger-tty   |  16 +++
 drivers/leds/trigger/ledtrig-tty.c            | 124 ++++++++++++++++--
 2 files changed, 130 insertions(+), 10 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-tty b/Docu=
mentation/ABI/testing/sysfs-class-led-trigger-tty
index 2bf6b24e781b..504dece151b8 100644
--- a/Documentation/ABI/testing/sysfs-class-led-trigger-tty
+++ b/Documentation/ABI/testing/sysfs-class-led-trigger-tty
@@ -4,3 +4,19 @@ KernelVersion:	5.10
 Contact:	linux-leds@vger.kernel.org
 Description:
 		Specifies the tty device name of the triggering tty
+
+What:		/sys/class/leds/<led>/rx
+Date:		February 2024
+KernelVersion:	6.8
+Description:
+		Signal reception (rx) of data on the named tty device.
+		If set to 0, the LED will not blink on reception.
+		If set to 1 (default), the LED will blink on reception.
+
+What:		/sys/class/leds/<led>/tx
+Date:		February 2024
+KernelVersion:	6.8
+Description:
+		Signal transmission (tx) of data on the named tty device.
+		If set to 0, the LED will not blink on transmission.
+		If set to 1 (default), the LED will blink on transmission.
diff --git a/drivers/leds/trigger/ledtrig-tty.c b/drivers/leds/trigger/le=
dtrig-tty.c
index 3badf74fa420..1a40a78bf1ee 100644
--- a/drivers/leds/trigger/ledtrig-tty.c
+++ b/drivers/leds/trigger/ledtrig-tty.c
@@ -17,6 +17,19 @@ struct ledtrig_tty_data {
 	const char *ttyname;
 	struct tty_struct *tty;
 	int rx, tx;
+	bool mode_rx;
+	bool mode_tx;
+};
+
+/* Indicates which state the LED should now display */
+enum led_trigger_tty_state {
+	TTY_LED_BLINK,
+	TTY_LED_DISABLE,
+};
+
+enum led_trigger_tty_modes {
+	TRIGGER_TTY_RX =3D 0,
+	TRIGGER_TTY_TX,
 };
=20
 static int ledtrig_tty_waitforcompletion(struct device *dev)
@@ -86,12 +99,82 @@ static ssize_t ttyname_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(ttyname);
=20
+static ssize_t ledtrig_tty_attr_show(struct device *dev, char *buf,
+				     enum led_trigger_tty_modes attr)
+{
+	struct ledtrig_tty_data *trigger_data =3D led_trigger_get_drvdata(dev);
+	int completion;
+	bool state;
+
+	reinit_completion(&trigger_data->sysfs);
+	completion =3D ledtrig_tty_waitforcompletion(dev);
+	if (completion < 0)
+		return completion;
+
+	switch (attr) {
+	case TRIGGER_TTY_RX:
+		state =3D trigger_data->mode_rx;
+		break;
+	case TRIGGER_TTY_TX:
+		state =3D trigger_data->mode_tx;
+		break;
+	}
+
+	return sysfs_emit(buf, "%u\n", state);
+}
+
+static ssize_t ledtrig_tty_attr_store(struct device *dev, const char *bu=
f,
+				      size_t size, enum led_trigger_tty_modes attr)
+{
+	struct ledtrig_tty_data *trigger_data =3D led_trigger_get_drvdata(dev);
+	int completion;
+	bool state;
+	int ret;
+
+	ret =3D kstrtobool(buf, &state);
+	if (ret)
+		return ret;
+
+	reinit_completion(&trigger_data->sysfs);
+	completion =3D ledtrig_tty_waitforcompletion(dev);
+	if (completion < 0)
+		return completion;
+
+	switch (attr) {
+	case TRIGGER_TTY_RX:
+		trigger_data->mode_rx =3D state;
+		break;
+	case TRIGGER_TTY_TX:
+		trigger_data->mode_tx =3D state;
+		break;
+	}
+
+	return size;
+}
+
+#define DEFINE_TTY_TRIGGER(trigger_name, trigger) \
+	static ssize_t trigger_name##_show(struct device *dev, \
+		struct device_attribute *attr, char *buf) \
+	{ \
+		return ledtrig_tty_attr_show(dev, buf, trigger); \
+	} \
+	static ssize_t trigger_name##_store(struct device *dev, \
+		struct device_attribute *attr, const char *buf, size_t size) \
+	{ \
+		return ledtrig_tty_attr_store(dev, buf, size, trigger); \
+	} \
+	static DEVICE_ATTR_RW(trigger_name)
+
+DEFINE_TTY_TRIGGER(rx, TRIGGER_TTY_RX);
+DEFINE_TTY_TRIGGER(tx, TRIGGER_TTY_TX);
+
 static void ledtrig_tty_work(struct work_struct *work)
 {
 	struct ledtrig_tty_data *trigger_data =3D
 		container_of(work, struct ledtrig_tty_data, dwork.work);
-	struct serial_icounter_struct icount;
 	struct led_classdev *led_cdev =3D trigger_data->led_cdev;
+	enum led_trigger_tty_state state =3D TTY_LED_DISABLE;
+	unsigned long interval =3D LEDTRIG_TTY_INTERVAL;
 	int ret;
=20
 	if (!trigger_data->ttyname)
@@ -119,21 +202,36 @@ static void ledtrig_tty_work(struct work_struct *wo=
rk)
 		trigger_data->tty =3D tty;
 	}
=20
-	ret =3D tty_get_icount(trigger_data->tty, &icount);
-	if (ret)
-		goto out;
+	if (trigger_data->mode_rx || trigger_data->mode_tx) {
+		struct serial_icounter_struct icount;
=20
-	if (icount.rx !=3D trigger_data->rx ||
-	    icount.tx !=3D trigger_data->tx) {
-		unsigned long interval =3D LEDTRIG_TTY_INTERVAL;
+		ret =3D tty_get_icount(trigger_data->tty, &icount);
+		if (ret)
+			goto out;
=20
-		led_blink_set_oneshot(led_cdev, &interval, &interval, 0);
+		if (trigger_data->mode_tx && (icount.tx !=3D trigger_data->tx)) {
+			trigger_data->tx =3D icount.tx;
+			state =3D TTY_LED_BLINK;
+		}
=20
-		trigger_data->rx =3D icount.rx;
-		trigger_data->tx =3D icount.tx;
+		if (trigger_data->mode_rx && (icount.rx !=3D trigger_data->rx)) {
+			trigger_data->rx =3D icount.rx;
+			state =3D TTY_LED_BLINK;
+		}
 	}
=20
 out:
+	switch (state) {
+	case TTY_LED_BLINK:
+		led_blink_set_oneshot(led_cdev, &interval, &interval, 0);
+		break;
+	case TTY_LED_DISABLE:
+		fallthrough;
+	default:
+		led_set_brightness(led_cdev, LED_OFF);
+		break;
+	}
+
 	complete_all(&trigger_data->sysfs);
 	schedule_delayed_work(&trigger_data->dwork,
 			      msecs_to_jiffies(LEDTRIG_TTY_INTERVAL * 2));
@@ -141,6 +239,8 @@ static void ledtrig_tty_work(struct work_struct *work=
)
=20
 static struct attribute *ledtrig_tty_attrs[] =3D {
 	&dev_attr_ttyname.attr,
+	&dev_attr_rx.attr,
+	&dev_attr_tx.attr,
 	NULL
 };
 ATTRIBUTE_GROUPS(ledtrig_tty);
@@ -153,6 +253,10 @@ static int ledtrig_tty_activate(struct led_classdev =
*led_cdev)
 	if (!trigger_data)
 		return -ENOMEM;
=20
+	/* Enable default rx/tx mode */
+	trigger_data->mode_rx =3D true;
+	trigger_data->mode_tx =3D true;
+
 	led_set_trigger_data(led_cdev, trigger_data);
=20
 	INIT_DELAYED_WORK(&trigger_data->dwork, ledtrig_tty_work);
--=20
2.30.2