diff mbox series

[v8,3/3] leds: trigger: implement a tty trigger

Message ID 20201012123358.1475928-4-u.kleine-koenig@pengutronix.de
State Superseded
Headers show
Series leds: trigger: implement a tty trigger | expand

Commit Message

Uwe Kleine-König Oct. 12, 2020, 12:33 p.m. UTC 
Usage is as follows:

	myled=ledname
	tty=ttyS0

	echo tty > /sys/class/leds/$myled/trigger
	echo $tty > /sys/class/leds/$myled/ttyname

. 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                  |   9 +
 drivers/leds/trigger/Makefile                 |   1 +
 drivers/leds/trigger/ledtrig-tty.c            | 187 ++++++++++++++++++
 4 files changed, 203 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-class-led-trigger-tty
 create mode 100644 drivers/leds/trigger/ledtrig-tty.c

Comments

kernel test robot Oct. 12, 2020, 2:16 p.m. UTC | #1 
Hi "Uwe,

I love your patch! Perhaps something to improve:

[auto build test WARNING on tty/tty-testing]
[also build test WARNING on pavel-linux-leds/for-next linus/master j.anaszewski-leds/for-next v5.9 next-20201012]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Uwe-Kleine-K-nig/leds-trigger-implement-a-tty-trigger/20201012-203510
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing
config: ia64-allmodconfig (attached as .config)
compiler: ia64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/4185c273a8de0340cee6655a363f98c3737665d0
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Uwe-Kleine-K-nig/leds-trigger-implement-a-tty-trigger/20201012-203510
        git checkout 4185c273a8de0340cee6655a363f98c3737665d0
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=ia64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   drivers/leds/trigger/ledtrig-tty.c: In function 'ledtrig_tty_work':
>> drivers/leds/trigger/ledtrig-tty.c:92:7: warning: variable 'firstrun' set but not used [-Wunused-but-set-variable]
      92 |  bool firstrun = false;
         |       ^~~~~~~~

vim +/firstrun +92 drivers/leds/trigger/ledtrig-tty.c

    85	
    86	static void ledtrig_tty_work(struct work_struct *work)
    87	{
    88		struct ledtrig_tty_data *trigger_data =
    89			container_of(work, struct ledtrig_tty_data, dwork.work);
    90		struct serial_icounter_struct icount;
    91		int ret;
  > 92		bool firstrun = false;
    93	
    94		mutex_lock(&trigger_data->mutex);
    95	
    96		BUG_ON(!trigger_data->ttyname);
    97	
    98		/* try to get the tty corresponding to $ttyname */
    99		if (!trigger_data->tty) {
   100			dev_t devno;
   101			struct tty_struct *tty;
   102			int ret;
   103	
   104			firstrun = true;
   105	
   106			ret = tty_dev_name_to_number(trigger_data->ttyname, &devno);
   107			if (ret < 0)
   108				/*
   109				 * A device with this name might appear later, so keep
   110				 * retrying.
   111				 */
   112				goto out;
   113	
   114			tty = tty_kopen_shared(devno);
   115			if (IS_ERR(tty) || !tty)
   116				/* What to do? retry or abort */
   117				goto out;
   118	
   119			trigger_data->tty = tty;
   120		}
   121	
   122		ret = tty_get_icount(trigger_data->tty, &icount);
   123		if (ret) {
   124			mutex_unlock(&trigger_data->mutex);
   125			dev_info(trigger_data->tty->dev, "Failed to get icount, stopped polling\n");
   126			mutex_unlock(&trigger_data->mutex);
   127			return;
   128		}
   129	
   130		if (icount.rx != trigger_data->rx ||
   131		    icount.tx != trigger_data->tx) {
   132			led_set_brightness(trigger_data->led_cdev, LED_ON);
   133	
   134			trigger_data->rx = icount.rx;
   135			trigger_data->tx = icount.tx;
   136		} else {
   137			led_set_brightness(trigger_data->led_cdev, LED_OFF);
   138		}
   139	
   140	out:
   141		mutex_unlock(&trigger_data->mutex);
   142		schedule_delayed_work(&trigger_data->dwork, msecs_to_jiffies(100));
   143	}
   144	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Uwe Kleine-König Oct. 13, 2020, 8:37 a.m. UTC | #2 
Hello,

On Mon, Oct 12, 2020 at 10:16:59PM +0800, kernel test robot wrote:
> Hi "Uwe,

I love your test report! Perhaps something to improve: The parser of the
From: line should drop the " :-)

>    drivers/leds/trigger/ledtrig-tty.c: In function 'ledtrig_tty_work':
> >> drivers/leds/trigger/ledtrig-tty.c:92:7: warning: variable 'firstrun' set but not used [-Wunused-but-set-variable]
>       92 |  bool firstrun = false;
>          |       ^~~~~~~~

Indeed, this line should just be dropped. I won't resend yet, waiting
for some feedback first and assuming reviewers are able to interpolate
how v9 will look like :-)

Best regards
Uwe
kernel test robot Oct. 15, 2020, 10:32 p.m. UTC | #3 
Hi "Uwe,

I love your patch! Perhaps something to improve:

[auto build test WARNING on tty/tty-testing]
[also build test WARNING on pavel-linux-leds/for-next linus/master j.anaszewski-leds/for-next v5.9 next-20201015]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Uwe-Kleine-K-nig/leds-trigger-implement-a-tty-trigger/20201012-203510
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing
config: openrisc-randconfig-s031-20201015 (attached as .config)
compiler: or1k-linux-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.3-rc1-dirty
        # https://github.com/0day-ci/linux/commit/4185c273a8de0340cee6655a363f98c3737665d0
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Uwe-Kleine-K-nig/leds-trigger-implement-a-tty-trigger/20201012-203510
        git checkout 4185c273a8de0340cee6655a363f98c3737665d0
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=openrisc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


"sparse warnings: (new ones prefixed by >>)"
>> drivers/leds/trigger/ledtrig-tty.c:177:20: sparse: sparse: symbol 'ledtrig_tty' was not declared. Should it be static?

Please review and possibly fold the followup patch.

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

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..5c53ce3ede36
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-trigger-tty
@@ -0,0 +1,6 @@ 
+What:		/sys/class/leds/<led>/ttyname
+Date:		Jul 2020
+KernelVersion:	5.8
+Contact:	linux-leds@vger.kernel.org
+Description:
+		Specifies the tty device name of the triggering tty
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index ce9429ca6dde..b77a01bd27f4 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -144,4 +144,13 @@  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.
+
+	  When build as a module this driver will be called ledtrig-tty.
+
 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..806548e33cd8
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-tty.c
@@ -0,0 +1,187 @@ 
+// 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 mutex mutex;
+	const char *ttyname;
+	struct tty_struct *tty;
+	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 ttyname_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;
+
+	mutex_lock(&trigger_data->mutex);
+
+	if (trigger_data->ttyname)
+		len = sprintf(buf, "%s\n", trigger_data->ttyname);
+
+	mutex_unlock(&trigger_data->mutex);
+
+	return len;
+}
+
+static ssize_t ttyname_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);
+	char *ttyname;
+	ssize_t ret = size;
+
+	ledtrig_tty_halt(trigger_data);
+
+	mutex_lock(&trigger_data->mutex);
+
+	if (size > 0 && buf[size - 1] == '\n')
+		size -= 1;
+
+	if (size) {
+		ttyname = kmemdup_nul(buf, size, GFP_KERNEL);
+		if (!ttyname) {
+			ret = -ENOMEM;
+			goto out_unlock;
+		}
+	} else {
+		ttyname = NULL;
+	}
+
+	kfree(trigger_data->ttyname);
+	tty_kref_put(trigger_data->tty);
+	trigger_data->tty = NULL;
+
+	trigger_data->ttyname = ttyname;
+
+out_unlock:
+	mutex_unlock(&trigger_data->mutex);
+
+	if (ttyname)
+		ledtrig_tty_restart(trigger_data);
+
+	return ret;
+}
+static DEVICE_ATTR_RW(ttyname);
+
+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;
+	bool firstrun = false;
+
+	mutex_lock(&trigger_data->mutex);
+
+	BUG_ON(!trigger_data->ttyname);
+
+	/* try to get the tty corresponding to $ttyname */
+	if (!trigger_data->tty) {
+		dev_t devno;
+		struct tty_struct *tty;
+		int ret;
+
+		firstrun = true;
+
+		ret = tty_dev_name_to_number(trigger_data->ttyname, &devno);
+		if (ret < 0)
+			/*
+			 * A device with this name might appear later, so keep
+			 * retrying.
+			 */
+			goto out;
+
+		tty = tty_kopen_shared(devno);
+		if (IS_ERR(tty) || !tty)
+			/* What to do? retry or abort */
+			goto out;
+
+		trigger_data->tty = tty;
+	}
+
+	ret = tty_get_icount(trigger_data->tty, &icount);
+	if (ret) {
+		mutex_unlock(&trigger_data->mutex);
+		dev_info(trigger_data->tty->dev, "Failed to get icount, stopped polling\n");
+		mutex_unlock(&trigger_data->mutex);
+		return;
+	}
+
+	if (icount.rx != trigger_data->rx ||
+	    icount.tx != trigger_data->tx) {
+		led_set_brightness(trigger_data->led_cdev, LED_ON);
+
+		trigger_data->rx = icount.rx;
+		trigger_data->tx = icount.tx;
+	} else {
+		led_set_brightness(trigger_data->led_cdev, LED_OFF);
+	}
+
+out:
+	mutex_unlock(&trigger_data->mutex);
+	schedule_delayed_work(&trigger_data->dwork, msecs_to_jiffies(100));
+}
+
+static struct attribute *ledtrig_tty_attrs[] = {
+	&dev_attr_ttyname.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;
+	mutex_init(&trigger_data->mutex);
+
+	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");