From patchwork Fri Dec 18 10:42:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= X-Patchwork-Id: 346155 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D2BA5C2D0E4 for ; Fri, 18 Dec 2020 10:43:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A2BAB23AA7 for ; Fri, 18 Dec 2020 10:43:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389129AbgLRKnh (ORCPT ); Fri, 18 Dec 2020 05:43:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389126AbgLRKng (ORCPT ); Fri, 18 Dec 2020 05:43:36 -0500 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 34587C061282 for ; Fri, 18 Dec 2020 02:42:55 -0800 (PST) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kqDDk-00006y-RO; Fri, 18 Dec 2020 11:42:48 +0100 Received: from ukl by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1kqDDk-0004hW-8X; Fri, 18 Dec 2020 11:42:48 +0100 From: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= To: Jacek Anaszewski , Pavel Machek , Dan Murphy , Greg Kroah-Hartman , Jiri Slaby Cc: linux-serial@vger.kernel.org, linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@pengutronix.de, Johan Hovold Subject: [PATCH v10 3/3] leds: trigger: implement a tty trigger Date: Fri, 18 Dec 2020 11:42:46 +0100 Message-Id: <20201218104246.591315-4-u.kleine-koenig@pengutronix.de> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201218104246.591315-1-u.kleine-koenig@pengutronix.de> References: <20201218104246.591315-1-u.kleine-koenig@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-serial@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org 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 --- .../ABI/testing/sysfs-class-led-trigger-tty | 6 + drivers/leds/trigger/Kconfig | 9 + drivers/leds/trigger/Makefile | 1 + drivers/leds/trigger/ledtrig-tty.c | 188 ++++++++++++++++++ 4 files changed, 204 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..2bf6b24e781b --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-led-trigger-tty @@ -0,0 +1,6 @@ +What: /sys/class/leds//ttyname +Date: Dec 2020 +KernelVersion: 5.10 +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..c1e87c0d23c3 --- /dev/null +++ b/drivers/leds/trigger/ledtrig-tty.c @@ -0,0 +1,188 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include +#include +#include + +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; + bool running; + + 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; + } + + mutex_lock(&trigger_data->mutex); + + running = trigger_data->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 && !running) + 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; + + mutex_lock(&trigger_data->mutex); + + if (!trigger_data->ttyname) { + /* exit without rescheduling */ + mutex_unlock(&trigger_data->mutex); + return; + } + + /* try to get the tty corresponding to $ttyname */ + if (!trigger_data->tty) { + dev_t devno; + struct tty_struct *tty; + int ret; + + 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) { + 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); +} + +static 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 "); +MODULE_DESCRIPTION("UART LED trigger"); +MODULE_LICENSE("GPL v2");