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* [PATCH v6 0/4] leds: trigger: implement a tty trigger
@ 2020-02-13  9:15 Uwe Kleine-König
  2020-02-13  9:15 ` [PATCH v6 1/4] lib: new helper kstrtodev_t() Uwe Kleine-König
                   ` (3 more replies)
  0 siblings, 4 replies; 5+ messages in thread
From: Uwe Kleine-König @ 2020-02-13  9:15 UTC (permalink / raw)
  To: Jacek Anaszewski, Pavel Machek, Dan Murphy, Greg Kroah-Hartman,
	Jiri Slaby
  Cc: Uwe Kleine-König, linux-leds, linux-kernel, kernel, linux-serial

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

Hello,

This is v6 of my quest to introduce ledtriggers for UARTs. The previous
series is available at

	http://lore.kernel.org/r/20191219093947.15502-1-u.kleine-koenig@pengutronix.de

The changes compared to that are that parsing of the dev parameter is
more strict and that I set brightness directly from the kworker instead
of using led_blink_set_oneshot which makes use of another kworker. (Both
requested by Pavel Machek.)

For the former I introduced a new helper kstrtodev_t() in the spirit of
kstrtoul() to implement the stricter parsing (instead of the lax one
using plain sscanf() in v5).

Best regards
Uwe

Uwe Kleine-König (4):
  lib: new helper kstrtodev_t()
  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/leds/trigger/Kconfig                  |   7 +
 drivers/leds/trigger/Makefile                 |   1 +
 drivers/leds/trigger/ledtrig-tty.c            | 159 ++++++++++++++++++
 drivers/staging/speakup/spk_ttyio.c           |   2 +-
 drivers/tty/tty_io.c                          |  87 +++++++---
 include/linux/kdev_t.h                        |   2 +
 include/linux/kernel.h                        |   1 +
 include/linux/tty.h                           |   7 +-
 lib/kstrtox.c                                 |  46 +++++
 10 files changed, 293 insertions(+), 25 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-class-led-trigger-tty
 create mode 100644 drivers/leds/trigger/ledtrig-tty.c


base-commit: 0bf999f9c5e74c7ecf9dafb527146601e5c848b9
-- 
2.24.0


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCH v6 1/4] lib: new helper kstrtodev_t()
  2020-02-13  9:15 [PATCH v6 0/4] leds: trigger: implement a tty trigger Uwe Kleine-König
@ 2020-02-13  9:15 ` 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
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 5+ messages in thread
From: Uwe Kleine-König @ 2020-02-13  9:15 UTC (permalink / raw)
  To: Jacek Anaszewski, Pavel Machek, Dan Murphy, Greg Kroah-Hartman,
	Jiri Slaby
  Cc: linux-leds, linux-kernel, kernel, linux-serial

This function is in the same spirit as the other kstrto* functions and
uses the same calling convention. It expects the input string to be in
the format %u:%u and implements stricter parsing than sscanf as it
returns an error on trailing data (other than the usual \n).

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
---
 include/linux/kdev_t.h |  2 ++
 include/linux/kernel.h |  1 +
 lib/kstrtox.c          | 46 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+)

diff --git a/include/linux/kdev_t.h b/include/linux/kdev_t.h
index 85b5151911cf..3a5c24bd8fa4 100644
--- a/include/linux/kdev_t.h
+++ b/include/linux/kdev_t.h
@@ -4,8 +4,10 @@
 
 #include <uapi/linux/kdev_t.h>
 
+/* dev_t is 32 bit wide, 20 bits are used for MINOR, 12 for major */
 #define MINORBITS	20
 #define MINORMASK	((1U << MINORBITS) - 1)
+#define MAJORBITS	12
 
 #define MAJOR(dev)	((unsigned int) ((dev) >> MINORBITS))
 #define MINOR(dev)	((unsigned int) ((dev) & MINORMASK))
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 0d9db2a14f44..9cf694c5d2c3 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -410,6 +410,7 @@ int __must_check kstrtos16(const char *s, unsigned int base, s16 *res);
 int __must_check kstrtou8(const char *s, unsigned int base, u8 *res);
 int __must_check kstrtos8(const char *s, unsigned int base, s8 *res);
 int __must_check kstrtobool(const char *s, bool *res);
+int __must_check kstrtodev_t(const char *s, dev_t *res);
 
 int __must_check kstrtoull_from_user(const char __user *s, size_t count, unsigned int base, unsigned long long *res);
 int __must_check kstrtoll_from_user(const char __user *s, size_t count, unsigned int base, long long *res);
diff --git a/lib/kstrtox.c b/lib/kstrtox.c
index 1006bf70bf74..e1b896635c6a 100644
--- a/lib/kstrtox.c
+++ b/lib/kstrtox.c
@@ -19,6 +19,7 @@
 #include <linux/export.h>
 #include <linux/types.h>
 #include <linux/uaccess.h>
+#include <linux/kdev_t.h>
 #include "kstrtox.h"
 
 const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
@@ -367,6 +368,51 @@ int kstrtobool(const char *s, bool *res)
 }
 EXPORT_SYMBOL(kstrtobool);
 
+/**
+ * kstrtodev_t - convert a string in format %u:%u to a dev_t
+ * @s: input string
+ * @res: result
+ *
+ * This is the reverse of print_dev_t. The first number is interpreted as major,
+ * the second as minor.
+ */
+int kstrtodev_t(const char *s, dev_t *res)
+{
+	unsigned long long _res;
+	unsigned int ma, mi;
+	int rv;
+
+	rv = _parse_integer(s, 10, &_res);
+	if (rv < 0)
+		return rv;
+	if (rv & KSTRTOX_OVERFLOW || _res >= (1U << MAJORBITS))
+		return -ERANGE;
+	ma = _res;
+
+	s += rv;
+
+	if (*s++ != ':')
+		return -EINVAL;
+
+	rv = _parse_integer(s, 10, &_res);
+	if (rv < 0)
+		return rv;
+	if (rv & KSTRTOX_OVERFLOW || _res >= (1U << MINORBITS))
+		return -ERANGE;
+	mi = _res;
+
+	s += rv;
+
+	if (*s == '\n')
+		s++;
+	if (*s)
+		return -EINVAL;
+
+	*res = MKDEV(ma, mi);
+	return 0;
+}
+EXPORT_SYMBOL(kstrtodev_t);
+
 /*
  * Since "base" would be a nonsense argument, this open-codes the
  * _from_user helper instead of using the helper macro below.
-- 
2.24.0


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCH v6 2/4] tty: rename tty_kopen() and add new function tty_kopen_shared()
  2020-02-13  9:15 [PATCH v6 0/4] leds: trigger: implement a tty trigger Uwe Kleine-König
  2020-02-13  9:15 ` [PATCH v6 1/4] lib: new helper kstrtodev_t() Uwe Kleine-König
@ 2020-02-13  9:15 ` 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 ` [PATCH v6 4/4] leds: trigger: implement a tty trigger Uwe Kleine-König
  3 siblings, 0 replies; 5+ messages in thread
From: Uwe Kleine-König @ 2020-02-13  9:15 UTC (permalink / raw)
  To: Jacek Anaszewski, Pavel Machek, Dan Murphy, Greg Kroah-Hartman,
	Jiri Slaby
  Cc: Uwe Kleine-König, linux-leds, linux-kernel, kernel, linux-serial

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

Introduce a new function tty_kopen_shared() that yields a struct
tty_struct. The semantic difference to tty_kopen() is that the tty is
expected to be used already. So rename tty_kopen() to
tty_kopen_exclusive() for clearness, adapt the single user and put the
common code in a new static helper function.

tty_kopen_shared is to be used to implement an LED trigger for tty
devices in one of the next patches.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/staging/speakup/spk_ttyio.c |  2 +-
 drivers/tty/tty_io.c                | 58 ++++++++++++++++++++---------
 include/linux/tty.h                 |  5 ++-
 3 files changed, 44 insertions(+), 21 deletions(-)

diff --git a/drivers/staging/speakup/spk_ttyio.c b/drivers/staging/speakup/spk_ttyio.c
index 5a9eff08cb96..e9db06eae875 100644
--- a/drivers/staging/speakup/spk_ttyio.c
+++ b/drivers/staging/speakup/spk_ttyio.c
@@ -147,7 +147,7 @@ static int spk_ttyio_initialise_ldisc(struct spk_synth *synth)
 	if (ret)
 		return ret;
 
-	tty = tty_kopen(dev);
+	tty = tty_kopen_exclusive(dev);
 	if (IS_ERR(tty))
 		return PTR_ERR(tty);
 
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index a1453fe10862..b718666ce73c 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -1875,22 +1875,7 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
 	return driver;
 }
 
-/**
- *	tty_kopen	-	open a tty device for kernel
- *	@device: dev_t of device to open
- *
- *	Opens tty exclusively for kernel. Performs the driver lookup,
- *	makes sure it's not already opened and performs the first-time
- *	tty initialization.
- *
- *	Returns the locked initialized &tty_struct
- *
- *	Claims the global tty_mutex to serialize:
- *	  - concurrent first-time tty initialization
- *	  - concurrent tty driver removal w/ lookup
- *	  - concurrent tty removal from driver table
- */
-struct tty_struct *tty_kopen(dev_t device)
+static struct tty_struct *tty_kopen(dev_t device, int shared)
 {
 	struct tty_struct *tty;
 	struct tty_driver *driver;
@@ -1905,7 +1890,7 @@ struct tty_struct *tty_kopen(dev_t device)
 
 	/* check whether we're reopening an existing tty */
 	tty = tty_driver_lookup_tty(driver, NULL, index);
-	if (IS_ERR(tty))
+	if (IS_ERR(tty) || shared)
 		goto out;
 
 	if (tty) {
@@ -1923,7 +1908,44 @@ struct tty_struct *tty_kopen(dev_t device)
 	tty_driver_kref_put(driver);
 	return tty;
 }
-EXPORT_SYMBOL_GPL(tty_kopen);
+
+/**
+ *	tty_kopen_exclusive	-	open a tty device for kernel
+ *	@device: dev_t of device to open
+ *
+ *	Opens tty exclusively for kernel. Performs the driver lookup,
+ *	makes sure it's not already opened and performs the first-time
+ *	tty initialization.
+ *
+ *	Returns the locked initialized &tty_struct
+ *
+ *	Claims the global tty_mutex to serialize:
+ *	  - concurrent first-time tty initialization
+ *	  - concurrent tty driver removal w/ lookup
+ *	  - concurrent tty removal from driver table
+ */
+struct tty_struct *tty_kopen_exclusive(dev_t device)
+{
+	return tty_kopen(device, 0);
+}
+EXPORT_SYMBOL_GPL(tty_kopen_exclusive);
+
+/**
+ *	tty_kopen_shared	-	open a tty device for shared in-kernel use
+ *	@device: dev_t of device to open
+ *
+ *	Opens an already existing tty
+ *	rnel. Performs the driver lookup,
+ *	makes sure it's not already opened and performs the first-time
+ *	tty initialization.
+ *
+ *	Locking is identical to tty_kopen() above.
+ */
+struct tty_struct *tty_kopen_shared(dev_t device)
+{
+	return tty_kopen(device, 1);
+}
+EXPORT_SYMBOL_GPL(tty_kopen_shared);
 
 /**
  *	tty_open_by_driver	-	open a tty device
diff --git a/include/linux/tty.h b/include/linux/tty.h
index bfa4e2ee94a9..d0bcf3226fb2 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -411,7 +411,8 @@ extern struct tty_struct *get_current_tty(void);
 /* tty_io.c */
 extern int __init tty_init(void);
 extern const char *tty_name(const struct tty_struct *tty);
-extern struct tty_struct *tty_kopen(dev_t device);
+extern struct tty_struct *tty_kopen_exclusive(dev_t device);
+extern struct tty_struct *tty_kopen_shared(dev_t device);
 extern void tty_kclose(struct tty_struct *tty);
 extern int tty_dev_name_to_number(const char *name, dev_t *number);
 extern int tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout);
@@ -436,7 +437,7 @@ static inline int __init tty_init(void)
 { return 0; }
 static inline const char *tty_name(const struct tty_struct *tty)
 { return "(none)"; }
-static inline struct tty_struct *tty_kopen(dev_t device)
+static inline struct tty_struct *tty_kopen_exclusive(dev_t device)
 { return ERR_PTR(-ENODEV); }
 static inline void tty_kclose(struct tty_struct *tty)
 { }
-- 
2.24.0


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCH v6 3/4] tty: new helper function tty_get_icount()
  2020-02-13  9:15 [PATCH v6 0/4] leds: trigger: implement a tty trigger Uwe Kleine-König
  2020-02-13  9:15 ` [PATCH v6 1/4] lib: new helper kstrtodev_t() 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
@ 2020-02-13  9:15 ` Uwe Kleine-König
  2020-02-13  9:16 ` [PATCH v6 4/4] leds: trigger: implement a tty trigger Uwe Kleine-König
  3 siblings, 0 replies; 5+ messages in thread
From: Uwe Kleine-König @ 2020-02-13  9:15 UTC (permalink / raw)
  To: Jacek Anaszewski, Pavel Machek, Dan Murphy, Greg Kroah-Hartman,
	Jiri Slaby
  Cc: Uwe Kleine-König, linux-leds, linux-kernel, kernel, linux-serial

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

For a given struct tty_struct this yields the corresponding statistics
about sent and received characters (and some more) which is needed to
implement an LED trigger for tty devices.

The new function is then used to simplify tty_tiocgicount().

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/tty/tty_io.c | 29 +++++++++++++++++++++++++----
 include/linux/tty.h  |  2 ++
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index b718666ce73c..3e74e6cec1a6 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2492,15 +2492,36 @@ static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
 	return tty->ops->tiocmset(tty, set, clear);
 }
 
+/**
+ *	tty_get_icount		-	get tty statistics
+ *	@tty: tty device
+ *	@icount: output parameter
+ *
+ *	Gets a copy of the tty's icount statistics.
+ *
+ *	Locking: none (up to the driver)
+ */
+int tty_get_icount(struct tty_struct *tty,
+		   struct serial_icounter_struct *icount)
+{
+	memset(icount, 0, sizeof(*icount));
+
+	if (tty->ops->get_icount)
+		return tty->ops->get_icount(tty, icount);
+	else
+		return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(tty_get_icount);
+
 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
 {
-	int retval = -EINVAL;
 	struct serial_icounter_struct icount;
-	memset(&icount, 0, sizeof(icount));
-	if (tty->ops->get_icount)
-		retval = tty->ops->get_icount(tty, &icount);
+	int retval;
+
+	retval = tty_get_icount(tty, &icount);
 	if (retval != 0)
 		return retval;
+
 	if (copy_to_user(arg, &icount, sizeof(icount)))
 		return -EFAULT;
 	return 0;
diff --git a/include/linux/tty.h b/include/linux/tty.h
index d0bcf3226fb2..40ea5c409619 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -495,6 +495,8 @@ extern void tty_unthrottle(struct tty_struct *tty);
 extern int tty_throttle_safe(struct tty_struct *tty);
 extern int tty_unthrottle_safe(struct tty_struct *tty);
 extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
+extern int tty_get_icount(struct tty_struct *tty,
+			  struct serial_icounter_struct *icount);
 extern int is_current_pgrp_orphaned(void);
 extern void tty_hangup(struct tty_struct *tty);
 extern void tty_vhangup(struct tty_struct *tty);
-- 
2.24.0


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCH v6 4/4] leds: trigger: implement a tty trigger
  2020-02-13  9:15 [PATCH v6 0/4] leds: trigger: implement a tty trigger Uwe Kleine-König
                   ` (2 preceding siblings ...)
  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
  3 siblings, 0 replies; 5+ messages in thread
From: Uwe Kleine-König @ 2020-02-13  9:16 UTC (permalink / raw)
  To: Jacek Anaszewski, Pavel Machek, Dan Murphy, Greg Kroah-Hartman,
	Jiri Slaby
  Cc: Uwe Kleine-König, linux-leds, linux-kernel, kernel, linux-serial

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


^ permalink raw reply	[flat|nested] 5+ messages in thread

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Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-02-13  9:15 [PATCH v6 0/4] leds: trigger: implement a tty trigger Uwe Kleine-König
2020-02-13  9:15 ` [PATCH v6 1/4] lib: new helper kstrtodev_t() 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
2020-02-13  9:15 ` [PATCH v6 3/4] tty: new helper function tty_get_icount() Uwe Kleine-König
2020-02-13  9:16 ` [PATCH v6 4/4] leds: trigger: implement a tty trigger Uwe Kleine-König

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