[PATCH v5 0/2] leds: ledtrig-tty: add tty_led_mode xtension

[PATCH v5 0/2] leds: ledtrig-tty: add tty_led_mode xtension

[Florian Eckert]

Hello,

here commes v5 of this series to add additional tty_led_modes.

v5:
Changes compared to the v4 patchset with
20230220152038.3877596-1-fe@dev.tdt.de are.

Sorry for the inconvenience, but I sent the wrong patch for
ledtrig-tty.c in v4. The v5 patchset now includes all the changes I
specified in the v4 patchset.


v4:
Changes compared to the v3 patchset with
20230220093739.320478-1-fe@dev.tdt.de are.

Addressed review comments by Jiri Slaby are:

ledtrig-tty.c:
- Do not use __TTY_LED_MAX pattern us instead __TTY_LED_LAST = TTY_LED_RNG
- Move declartion and assignment into one singel line
- Use __TTY_LED_LAST pattern, to simplify tty_mode_show and
  tty_mode_store handling


v3:
Changes compared to the v2 patchset with
20230217094403.1574468-1-fe@dev.tdt.de are.

Addressed review comments by Greg K-H are:

tty.h:
- Fix first comment line and remark -%ENOTTY for the new function
  'tty_get_mget' to make a proper kernel doc.
- Add the return value -%ENOTTY again, I thought it was no longer needed.


v2:
Changes compared to the initial patchset with
20230213140638.620206-1-fe@dev.tdt.de are.

Addressed review comments by Jiri Slaby are:

tty.h:
- Fix compilation error because of wrong rebaseing
- Remove empty lines
- Use new 'tty_get_mget' in 'tty_tiocmget'

ledtrig-tty.c:
- Update commit description
- Use enum for tty_led_mod in struct ledtrig_tty_date
- Rename sysfs file from 'mode' to 'tty_led_mode'
- Change tty_led_mode show function to use loop instead of switch/case
- Change tty_led_mode store function to use loop instead of switch/case
- Check return value of function tty_get_mget

Florian Eckert (2):
  tty: new helper function tty_get_mget
  trigger: ledtrig-tty: add additional modes

 .../ABI/testing/sysfs-class-led-trigger-tty   |  16 ++
 drivers/leds/trigger/ledtrig-tty.c            | 145 ++++++++++++++++--
 drivers/tty/tty_io.c                          |  28 +++-
 include/linux/tty.h                           |   1 +
 4 files changed, 169 insertions(+), 21 deletions(-)

-- 
2.30.2

[PATCH v5 1/2] tty: new helper function tty_get_mget

[Florian Eckert]

For a given struct tty_struct, this provides the appropriate tty line
state flags needed to add more modes to the ledtrig-tty trigger.

The new function is then used to get via tty_tiocmget() the different tty
line states.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>
---
 drivers/tty/tty_io.c | 28 ++++++++++++++++++++++------
 include/linux/tty.h  |  1 +
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 3149114bf130..a068b03a0828 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2493,6 +2493,24 @@ static int send_break(struct tty_struct *tty, unsigned int duration)
 	return retval;
 }
 
+/**
+ * tty_get_mget		-	get modem status
+ * @tty: tty device
+ *
+ * Obtain the modem status bits from the tty driver if the feature
+ * is supported. Return -%ENOTTY if it is not available.
+ */
+int tty_get_mget(struct tty_struct *tty)
+{
+	int retval = -ENOTTY;
+
+	if (tty->ops->tiocmget)
+		retval = tty->ops->tiocmget(tty);
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(tty_get_mget);
+
 /**
  * tty_tiocmget		-	get modem status
  * @tty: tty device
@@ -2505,14 +2523,12 @@ static int send_break(struct tty_struct *tty, unsigned int duration)
  */
 static int tty_tiocmget(struct tty_struct *tty, int __user *p)
 {
-	int retval = -ENOTTY;
+	int retval;
 
-	if (tty->ops->tiocmget) {
-		retval = tty->ops->tiocmget(tty);
+	retval = tty_get_mget(tty);
+	if (retval >= 0)
+		retval = put_user(retval, p);
 
-		if (retval >= 0)
-			retval = put_user(retval, p);
-	}
 	return retval;
 }
 
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 730c3301d710..825186c0fec1 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -421,6 +421,7 @@ int tty_unthrottle_safe(struct tty_struct *tty);
 int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
 int tty_get_icount(struct tty_struct *tty,
 		struct serial_icounter_struct *icount);
+int tty_get_mget(struct tty_struct *tty);
 int is_current_pgrp_orphaned(void);
 void tty_hangup(struct tty_struct *tty);
 void tty_vhangup(struct tty_struct *tty);
-- 
2.30.2

[PATCH v5 2/2] trigger: ledtrig-tty: add additional modes

[Florian Eckert]

Add additional modes to trigger the selected LED.
The following modes are supported:

Tx/Rx:	Flash LED on data transmission (default)
CTS:	DCE Ready to accept data from the DTE.
DSR:	DCE is ready to receive and send data.
CAR:	DCE is receiving a carrier from a remote DTE.
RNG:	DCE has detected an incoming ring signal.

The mode can be changed for example with the following command:
echo "CTS" > /sys/class/leds/<led>/mode

This would turn on the LED, when the DTE(modem) signals the DCE that it
is ready to accept data.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>
---
 .../ABI/testing/sysfs-class-led-trigger-tty   |  16 ++
 drivers/leds/trigger/ledtrig-tty.c            | 145 ++++++++++++++++--
 2 files changed, 146 insertions(+), 15 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-tty b/Documentation/ABI/testing/sysfs-class-led-trigger-tty
index 2bf6b24e781b..31d62a5ae095 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>/mode
+Date:		January 2023
+KernelVersion:	6.3
+Description:
+		Specifies the operating to trigger the LED.
+		The following operating modes are supported:
+		Tx/Rx: Flash LED on data transmission (default)
+		CTS:   DCE Ready to accept data from the DTE.
+		       LED on if line is high.
+		DSR:   DCE is ready to receive and send data.
+		       LED on if line is high.
+		CAR:   DCE is receiving a carrier from a remote DTE.
+		       LED on if line is high.
+		RNG:   DCE has detected an incoming ring signal.
+		       LED on if line is high.
diff --git a/drivers/leds/trigger/ledtrig-tty.c b/drivers/leds/trigger/ledtrig-tty.c
index f62db7e520b5..7c4c171c8745 100644
--- a/drivers/leds/trigger/ledtrig-tty.c
+++ b/drivers/leds/trigger/ledtrig-tty.c
@@ -7,6 +7,15 @@
 #include <linux/tty.h>
 #include <uapi/linux/serial.h>
 
+enum tty_led_mode {
+	TTY_LED_CNT,
+	TTY_LED_CTS,
+	TTY_LED_DSR,
+	TTY_LED_CAR,
+	TTY_LED_RNG,
+	__TTY_LED_LAST = TTY_LED_RNG
+};
+
 struct ledtrig_tty_data {
 	struct led_classdev *led_cdev;
 	struct delayed_work dwork;
@@ -14,6 +23,15 @@ struct ledtrig_tty_data {
 	const char *ttyname;
 	struct tty_struct *tty;
 	int rx, tx;
+	enum tty_led_mode mode;
+};
+
+static const char * const mode[] = {
+	[TTY_LED_CNT] = "Tx/Rx", // Trasmit Data / Receive Data
+	[TTY_LED_CTS] = "CTS", // CTS Clear To Send
+	[TTY_LED_DSR] = "DSR", // DSR Data Set Ready
+	[TTY_LED_CAR] = "CAR", // CAR Data Carrier Detect (DCD)
+	[TTY_LED_RNG] = "RNG", // RNG Ring Indicator (RI)
 };
 
 static void ledtrig_tty_restart(struct ledtrig_tty_data *trigger_data)
@@ -21,6 +39,70 @@ static void ledtrig_tty_restart(struct ledtrig_tty_data *trigger_data)
 	schedule_delayed_work(&trigger_data->dwork, 0);
 }
 
+static ssize_t ledtrig_tty_mode_show(char *buf, enum tty_led_mode tty_mode)
+{
+	int len = 0;
+	int i;
+
+	for (i = 0; i <= __TTY_LED_LAST; i++) {
+		bool hit = tty_mode == i;
+		bool last = i == __TTY_LED_LAST;
+
+		len += sysfs_emit_at(buf, len, "%s%s%s%s",
+				  hit ? "[" : "",
+				  mode[i],
+				  hit ? "]" : "",
+				  last ? "" : " ");
+	}
+
+	len += sysfs_emit_at(buf, len, "\n");
+
+	return len;
+}
+
+static ssize_t tty_led_mode_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	struct ledtrig_tty_data *trigger_data = led_trigger_get_drvdata(dev);
+	enum tty_led_mode tty_mode;
+
+	mutex_lock(&trigger_data->mutex);
+	tty_mode = trigger_data->mode;
+	mutex_unlock(&trigger_data->mutex);
+
+	return ledtrig_tty_mode_show(buf, tty_mode);
+}
+
+static ssize_t tty_led_mode_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);
+	ssize_t ret = size;
+	enum tty_led_mode tty_mode = __TTY_LED_LAST;
+	int i;
+
+	/* Check for new line in string*/
+	if (size > 0 && buf[size - 1] == '\n')
+		size -= 1;
+
+	for (i = 0; i <= __TTY_LED_LAST; i++)
+		if (strncmp(buf, mode[i], size) == 0) {
+			tty_mode = i;
+			break;
+		}
+
+	if (i > __TTY_LED_LAST)
+		return -EINVAL;
+
+	mutex_lock(&trigger_data->mutex);
+	trigger_data->mode = tty_mode;
+	mutex_unlock(&trigger_data->mutex);
+
+	return ret;
+}
+static DEVICE_ATTR_RW(tty_led_mode);
+
 static ssize_t ttyname_show(struct device *dev,
 			    struct device_attribute *attr, char *buf)
 {
@@ -76,6 +158,18 @@ static ssize_t ttyname_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(ttyname);
 
+static void ledtrig_tty_flags(struct ledtrig_tty_data *trigger_data,
+		unsigned int flag)
+{
+	unsigned int status;
+
+	status = tty_get_mget(trigger_data->tty);
+	if (status & flag)
+		led_set_brightness_sync(trigger_data->led_cdev, LED_ON);
+	else
+		led_set_brightness_sync(trigger_data->led_cdev, LED_OFF);
+}
+
 static void ledtrig_tty_work(struct work_struct *work)
 {
 	struct ledtrig_tty_data *trigger_data =
@@ -113,21 +207,38 @@ static void ledtrig_tty_work(struct work_struct *work)
 		trigger_data->tty = tty;
 	}
 
-	ret = tty_get_icount(trigger_data->tty, &icount);
-	if (ret) {
-		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_sync(trigger_data->led_cdev, LED_ON);
-
-		trigger_data->rx = icount.rx;
-		trigger_data->tx = icount.tx;
-	} else {
-		led_set_brightness_sync(trigger_data->led_cdev, LED_OFF);
+	switch (trigger_data->mode) {
+	case TTY_LED_CTS:
+		ledtrig_tty_flags(trigger_data, TIOCM_CTS);
+		break;
+	case TTY_LED_DSR:
+		ledtrig_tty_flags(trigger_data, TIOCM_DSR);
+		break;
+	case TTY_LED_CAR:
+		ledtrig_tty_flags(trigger_data, TIOCM_CAR);
+		break;
+	case TTY_LED_RNG:
+		ledtrig_tty_flags(trigger_data, TIOCM_RNG);
+		break;
+	case TTY_LED_CNT:
+	default:
+		ret = tty_get_icount(trigger_data->tty, &icount);
+		if (ret) {
+			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_sync(trigger_data->led_cdev, LED_ON);
+
+			trigger_data->rx = icount.rx;
+			trigger_data->tx = icount.tx;
+		} else {
+			led_set_brightness_sync(trigger_data->led_cdev, LED_OFF);
+		}
+		break;
 	}
 
 out:
@@ -137,6 +248,7 @@ static void ledtrig_tty_work(struct work_struct *work)
 
 static struct attribute *ledtrig_tty_attrs[] = {
 	&dev_attr_ttyname.attr,
+	&dev_attr_tty_led_mode.attr,
 	NULL
 };
 ATTRIBUTE_GROUPS(ledtrig_tty);
@@ -149,6 +261,9 @@ static int ledtrig_tty_activate(struct led_classdev *led_cdev)
 	if (!trigger_data)
 		return -ENOMEM;
 
+	/* set default mode */
+	trigger_data->mode = TTY_LED_CNT;
+
 	led_set_trigger_data(led_cdev, trigger_data);
 
 	INIT_DELAYED_WORK(&trigger_data->dwork, ledtrig_tty_work);
-- 
2.30.2

Re: [PATCH v5 2/2] trigger: ledtrig-tty: add additional modes

[kernel test robot]

Hi Florian,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on tty/tty-testing]
[also build test WARNING on tty/tty-next tty/tty-linus staging/staging-testing staging/staging-next staging/staging-linus pavel-leds/for-next linus/master v6.2 next-20230221]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Florian-Eckert/tty-new-helper-function-tty_get_mget/20230221-162126
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing
patch link:    https://lore.kernel.org/r/20230221081901.15557-3-fe%40dev.tdt.de
patch subject: [PATCH v5 2/2] trigger: ledtrig-tty: add additional modes
reproduce:
        # https://github.com/intel-lab-lkp/linux/commit/445b7555bccd279bf106995ee42f5dbef2e97c8b
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Florian-Eckert/tty-new-helper-function-tty_get_mget/20230221-162126
        git checkout 445b7555bccd279bf106995ee42f5dbef2e97c8b
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        make htmldocs

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202302220740.2RKDHnof-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> Documentation/ABI/testing/sysfs-class-led-trigger-tty:9: WARNING: Unexpected indentation.
>> Documentation/ABI/testing/sysfs-class-led-trigger-tty:9: WARNING: Block quote ends without a blank line; unexpected unindent.

vim +9 Documentation/ABI/testing/sysfs-class-led-trigger-tty

   > 9	Date:		January 2023

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests

Re: [PATCH v5 2/2] trigger: ledtrig-tty: add additional modes

[Florian Eckert]

On 2023-02-22 01:02, kernel test robot wrote:
> Hi Florian,
> 
> Thank you for the patch! Perhaps something to improve:
> 
> [auto build test WARNING on tty/tty-testing]
> [also build test WARNING on tty/tty-next tty/tty-linus
> staging/staging-testing staging/staging-next staging/staging-linus
> pavel-leds/for-next linus/master v6.2 next-20230221]
> [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#_base_tree_information]
> 
> url:
> https://github.com/intel-lab-lkp/linux/commits/Florian-Eckert/tty-new-helper-function-tty_get_mget/20230221-162126
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
> tty-testing
> patch link:    
> https://lore.kernel.org/r/20230221081901.15557-3-fe%40dev.tdt.de
> patch subject: [PATCH v5 2/2] trigger: ledtrig-tty: add additional 
> modes
> reproduce:
>         #
> https://github.com/intel-lab-lkp/linux/commit/445b7555bccd279bf106995ee42f5dbef2e97c8b
>         git remote add linux-review 
> https://github.com/intel-lab-lkp/linux
>         git fetch --no-tags linux-review
> Florian-Eckert/tty-new-helper-function-tty_get_mget/20230221-162126
>         git checkout 445b7555bccd279bf106995ee42f5dbef2e97c8b
>         make menuconfig
>         # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS,
> CONFIG_WARN_ABI_ERRORS
>         make htmldocs
> 
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <lkp@intel.com>
> | Link:
> https://lore.kernel.org/oe-kbuild-all/202302220740.2RKDHnof-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
>>> Documentation/ABI/testing/sysfs-class-led-trigger-tty:9: WARNING: 
>>> Unexpected indentation.
>>> Documentation/ABI/testing/sysfs-class-led-trigger-tty:9: WARNING: 
>>> Block quote ends without a blank line; unexpected unindent.
> 
> vim +9 Documentation/ABI/testing/sysfs-class-led-trigger-tty
> 
>    > 9	Date:		January 2023

I apologies for the question! But I don't know what the test buildbot 
here wants from me.
I've looked at the other files and I can't find anything that stands 
out.

--
Regards Florian

Re: [PATCH v5 2/2] trigger: ledtrig-tty: add additional modes

[Jiri Slaby]

On 22. 02. 23, 7:07, Florian Eckert wrote:
> 
> 
> On 2023-02-22 01:02, kernel test robot wrote:
>> Hi Florian,
>>
>> Thank you for the patch! Perhaps something to improve:
>>
>> [auto build test WARNING on tty/tty-testing]
>> [also build test WARNING on tty/tty-next tty/tty-linus
>> staging/staging-testing staging/staging-next staging/staging-linus
>> pavel-leds/for-next linus/master v6.2 next-20230221]
>> [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#_base_tree_information]
>>
>> url:
>> https://github.com/intel-lab-lkp/linux/commits/Florian-Eckert/tty-new-helper-function-tty_get_mget/20230221-162126
>> base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
>> tty-testing
>> patch link: 
>> https://lore.kernel.org/r/20230221081901.15557-3-fe%40dev.tdt.de
>> patch subject: [PATCH v5 2/2] trigger: ledtrig-tty: add additional modes
>> reproduce:
>>         #
>> https://github.com/intel-lab-lkp/linux/commit/445b7555bccd279bf106995ee42f5dbef2e97c8b
>>         git remote add linux-review 
>> https://github.com/intel-lab-lkp/linux
>>         git fetch --no-tags linux-review
>> Florian-Eckert/tty-new-helper-function-tty_get_mget/20230221-162126
>>         git checkout 445b7555bccd279bf106995ee42f5dbef2e97c8b
>>         make menuconfig
>>         # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS,
>> CONFIG_WARN_ABI_ERRORS
>>         make htmldocs
>>
>> If you fix the issue, kindly add following tag where applicable
>> | Reported-by: kernel test robot <lkp@intel.com>
>> | Link:
>> https://lore.kernel.org/oe-kbuild-all/202302220740.2RKDHnof-lkp@intel.com/
>>
>> All warnings (new ones prefixed by >>):
>>
>>>> Documentation/ABI/testing/sysfs-class-led-trigger-tty:9: WARNING: 
>>>> Unexpected indentation.
>>>> Documentation/ABI/testing/sysfs-class-led-trigger-tty:9: WARNING: 
>>>> Block quote ends without a blank line; unexpected unindent.
>>
>> vim +9 Documentation/ABI/testing/sysfs-class-led-trigger-tty
>>
>>    > 9    Date:        January 2023
> 
> I apologies for the question! But I don't know what the test buildbot 
> here wants from me.
> I've looked at the other files and I can't find anything that stands out.

sphinx is always misleading.

It's the indentation of all "LED on if ...".

-- 
js
suse labs

Re: [PATCH v5 2/2] trigger: ledtrig-tty: add additional modes

[Jiri Slaby]

On 22. 02. 23, 8:16, Jiri Slaby wrote:
>>> vim +9 Documentation/ABI/testing/sysfs-class-led-trigger-tty
>>>
>>>    > 9    Date:        January 2023
>>
>> I apologies for the question! But I don't know what the test buildbot 
>> here wants from me.
>> I've looked at the other files and I can't find anything that stands out.
> 
> sphinx is always misleading.
> 
> It's the indentation of all "LED on if ...".

So this should work:

                 Specifies the operating to trigger the LED.
                 The following operating modes are supported:

                 * Tx/Rx: Flash LED on data transmission (default)
                 * CTS:   DCE Ready to accept data from the DTE.
                   LED on if line is high.
                 * DSR:   DCE is ready to receive and send data.
                   LED on if line is high.
                 * CAR:   DCE is receiving a carrier from a remote DTE.
                   LED on if line is high.
                 * RNG:   DCE has detected an incoming ring signal.
                   LED on if line is high.

-- 
js
suse labs