From patchwork Mon Oct 12 12:33:56 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: 269839 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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 861BCC43467 for ; Mon, 12 Oct 2020 12:34:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4245D20757 for ; Mon, 12 Oct 2020 12:34:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388500AbgJLMeL (ORCPT ); Mon, 12 Oct 2020 08:34:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48900 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388503AbgJLMeL (ORCPT ); Mon, 12 Oct 2020 08:34:11 -0400 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 9F0CCC0613D5 for ; Mon, 12 Oct 2020 05:34:10 -0700 (PDT) Received: from pty.hi.pengutronix.de ([2001:67c:670:100:1d::c5]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kRx1f-0001Ex-N7; Mon, 12 Oct 2020 14:34:03 +0200 Received: from ukl by pty.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1kRx1c-0007So-Tr; Mon, 12 Oct 2020 14:34:00 +0200 From: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= To: Jacek Anaszewski , Pavel Machek , Dan Murphy , Greg Kroah-Hartman , Jiri Slaby Cc: Johan Hovold , linux-leds@vger.kernel.org, linux-serial@vger.kernel.org, kernel@pengutronix.de, linux-kernel@vger.kernel.org Subject: [PATCH v8 1/3] tty: rename tty_kopen() and add new function tty_kopen_shared() Date: Mon, 12 Oct 2020 14:33:56 +0200 Message-Id: <20201012123358.1475928-2-u.kleine-koenig@pengutronix.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201012123358.1475928-1-u.kleine-koenig@pengutronix.de> References: <20201012123358.1475928-1-u.kleine-koenig@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 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 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 --- drivers/accessibility/speakup/spk_ttyio.c | 2 +- drivers/tty/tty_io.c | 56 +++++++++++++++-------- include/linux/tty.h | 5 +- 3 files changed, 42 insertions(+), 21 deletions(-) diff --git a/drivers/accessibility/speakup/spk_ttyio.c b/drivers/accessibility/speakup/spk_ttyio.c index a831ff64f8ba..991b21017a01 100644 --- a/drivers/accessibility/speakup/spk_ttyio.c +++ b/drivers/accessibility/speakup/spk_ttyio.c @@ -149,7 +149,7 @@ 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 ceed72c9a88f..8aede3d2c1e0 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1871,22 +1871,7 @@ 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; @@ -1901,7 +1886,7 @@ 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) { @@ -1919,7 +1904,42 @@ 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 for in-kernel use. Compared to + * tty_kopen_exclusive() above it doesn't ensure to be the only user. + * + * 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 a99e9b8e4e31..c867d6fe67c4 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -413,7 +413,8 @@ 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); @@ -438,7 +439,7 @@ 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) { } From patchwork Mon Oct 12 12:33:57 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: 269838 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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 17606C433E7 for ; Mon, 12 Oct 2020 12:34:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D933520757 for ; Mon, 12 Oct 2020 12:34:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388546AbgJLMeW (ORCPT ); Mon, 12 Oct 2020 08:34:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48906 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388503AbgJLMeL (ORCPT ); Mon, 12 Oct 2020 08:34:11 -0400 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 66CE8C0613D1 for ; Mon, 12 Oct 2020 05:34:11 -0700 (PDT) Received: from pty.hi.pengutronix.de ([2001:67c:670:100:1d::c5]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kRx1f-0001Ey-N6; Mon, 12 Oct 2020 14:34:03 +0200 Received: from ukl by pty.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1kRx1d-0007Sr-49; Mon, 12 Oct 2020 14:34:01 +0200 From: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= To: Jacek Anaszewski , Pavel Machek , Dan Murphy , Greg Kroah-Hartman , Jiri Slaby Cc: Johan Hovold , linux-leds@vger.kernel.org, linux-serial@vger.kernel.org, kernel@pengutronix.de, linux-kernel@vger.kernel.org Subject: [PATCH v8 2/3] tty: new helper function tty_get_icount() Date: Mon, 12 Oct 2020 14:33:57 +0200 Message-Id: <20201012123358.1475928-3-u.kleine-koenig@pengutronix.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201012123358.1475928-1-u.kleine-koenig@pengutronix.de> References: <20201012123358.1475928-1-u.kleine-koenig@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 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 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 --- 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 8aede3d2c1e0..9dc1cac7aab7 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -2486,15 +2486,36 @@ 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 c867d6fe67c4..3ac812b347de 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -497,6 +497,8 @@ 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); From patchwork Mon Oct 12 12:33:58 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: 287338 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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 E707BC433DF for ; Mon, 12 Oct 2020 12:34:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AACEC20757 for ; Mon, 12 Oct 2020 12:34:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388506AbgJLMeL (ORCPT ); Mon, 12 Oct 2020 08:34:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388500AbgJLMeL (ORCPT ); Mon, 12 Oct 2020 08:34:11 -0400 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 2905EC0613D1 for ; Mon, 12 Oct 2020 05:34:10 -0700 (PDT) Received: from pty.hi.pengutronix.de ([2001:67c:670:100:1d::c5]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kRx1f-0001F7-N6; Mon, 12 Oct 2020 14:34:03 +0200 Received: from ukl by pty.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1kRx1d-0007Su-AC; Mon, 12 Oct 2020 14:34:01 +0200 From: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= To: Jacek Anaszewski , Pavel Machek , Dan Murphy , Greg Kroah-Hartman , Jiri Slaby Cc: Johan Hovold , linux-leds@vger.kernel.org, linux-serial@vger.kernel.org, kernel@pengutronix.de, linux-kernel@vger.kernel.org Subject: [PATCH v8 3/3] leds: trigger: implement a tty trigger Date: Mon, 12 Oct 2020 14:33:58 +0200 Message-Id: <20201012123358.1475928-4-u.kleine-koenig@pengutronix.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201012123358.1475928-1-u.kleine-koenig@pengutronix.de> References: <20201012123358.1475928-1-u.kleine-koenig@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 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 Reported-by: kernel test robot Reported-by: kernel test robot --- .../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 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//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 +#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; + + 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 "); +MODULE_DESCRIPTION("UART LED trigger"); +MODULE_LICENSE("GPL v2");