Hi! > Send out a morse code by using LEDs. > > This is useful especially on embedded systems without displays to tell the > user about error conditions and status information. > > The trigger will be called "morse" > > The string to be send is written into the file morse_string and sent out > with a workqueue. Supported are letters and digits. > > With the file dot_unit the minimal time unit can be adjusted in > milliseconds. > > Signed-off-by: Andreas Klinger <ak@xxxxxxxxxxxxx> Can we get more general "pattern" trigger? Some LEDs can do that in hardware, and it is more general than plain morse. Ouch and it already was implemented :-). Patch is in attachment. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
From rteysseyre@xxxxxxxxx Fri Mar 20 15:40:22 2015 Return-Path: <rteysseyre@xxxxxxxxx> X-Original-To: pavel@xxxxxxxxxxxxxxxxxxxxxxxx Delivered-To: pavel@xxxxxxxxxxxxxxxxxxxxxxxx Received: from jabberwock.ucw.cz (jabberwock.ucw.cz [46.255.230.98]) by atrey.karlin.mff.cuni.cz (Postfix) with ESMTP id 3275281ECB for <pavel@xxxxxxxxxxxxxxxxxxxxxxxx>; Fri, 20 Mar 2015 15:40:22 +0100 (CET) Received: by jabberwock.ucw.cz (Postfix) id 3053A1C00FF; Fri, 20 Mar 2015 15:40:22 +0100 (CET) Delivered-To: pavel@xxxxxxxxxxxxxxxxx Received: from mail-wg0-f46.google.com (mail-wg0-f46.google.com [74.125.82.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (not verified)) by jabberwock.ucw.cz (Postfix) with ESMTPS id 18EB61C00F9 for <pavel@xxxxxx>; Fri, 20 Mar 2015 15:40:22 +0100 (CET) Received: by wgbcc7 with SMTP id cc7so91022009wgb.0 for <pavel@xxxxxx>; Fri, 20 Mar 2015 07:40:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=subject:from:to:cc:content-type:date:message-id:mime-version :content-transfer-encoding; bh=UdT+u6nHVkpFGm2AqZ0XFePjLX83mCQTkcoTCraWWvc=; b=b9VbjaS+0McMAtdeSJv1Lhb6RDg/noWghgIsbIZD/DpMnIXJ05Dyi160Jx28uS0YzT zyPmtmEv3IrnmkcCp7g6S6f04ATgi9q3tI+5qooaQS65V7bRtlpcTMoB8KEA38SsBtap 8Ng+65MHchSpmGyR/h0WxVg934ieNpySSLCQ/vSUu2lOxi0SLmyr93KqfZXQ6Yk5FCA3 QOcCuiXpcLfmGbLwR2YT0uu3/60LOmWL6xt+J/bkWjo38qwqtH5phoa5ydjcUy5MZJSZ tn4qM8mQ8YH9EUJ+VjcxQX4nYdY+Mf3tsnSOieHNzUVt+2z1GmLcDi1Jfe8MtyPh8+9m dp+w== X-Received: by 10.194.108.137 with SMTP id hk9mr118158926wjb.112.1426862421666; Fri, 20 Mar 2015 07:40:21 -0700 (PDT) Received: from [192.168.244.132] (fs-141-0-203-237.fullsave.info. [141.0.203.237]) by mx.google.com with ESMTPSA id ha10sm6624401wjc.37.2015.03.20.07.40.20 (version=SSLv3 cipher=RC4-SHA bits=128/128); Fri, 20 Mar 2015 07:40:20 -0700 (PDT) Subject: [PATCH v2] leds: Add arbitrary pattern trigger From: =?ISO-8859-1?Q?Rapha=EBl?= Teysseyre <rteysseyre@xxxxxxxxx> To: Pavel Machek <pavel@xxxxxx> Cc: Joe Xue <lgxue@xxxxxxxxxxx>, Bryan Wu <cooloney@xxxxxxxxx>, "rpurdie@xxxxxxxxx" <rpurdie@xxxxxxxxx>, Linux LED Subsystem <linux-leds@xxxxxxxxxxxxxxx>, lkml <linux-kernel@xxxxxxxxxxxxxxx> Content-Type: text/plain; charset="UTF-8" Date: Fri, 20 Mar 2015 15:42:02 +0100 Message-ID: <1426862522.48232.3.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.32.3 (2.32.3-34.el6) Content-Transfer-Encoding: 8bit X-CRM114-Status: Good ( pR: 191.7191 ) Status: RO Content-Length: 17146 Hi all, Following your comments about [PATCH] leds: Add arbitrary pattern trigger, here is a revised version of this patch. This is intended for embedded systems without screen or network access to show a status (or error) code to a human. It's been tested on an ARM architecture (Xilinx Zynq 7010 SoC, which CPU is a dual ARM Cortex-A9), with a non-mainline kernel (xilinx-v2014.4, based of a 3.17.0 kernel). Unfortunately, I don't have other hardware to test it on. It compiles fine in a 3.19.0-rc1 source tree. Additional testing and comments would be appreciated. Changes since version 1: - Fixed typos in documentation and comments. - Fixed MODULE_LICENSE string. - No more mutex in atomic context. - Return EINVAL when invalid patterns are written to the "pattern" attribute. Add a new led trigger supporting arbitrary patterns. This is useful for embedded systems with no screen or network access. Export two sysfs attributes: "pattern", and "repeat". When "repeat"=-1, repeat the pattern indefinitely. Otherwise, repeat it the specified number of times. "pattern" specifies the pattern as comma separated couples of "brightness duration" values. See detailled documentation in patch. Signed-off-by: Raphaël Teysseyre <rteysseyre@xxxxxxxxx> --- Documentation/leds/ledtrig-pattern.txt | 86 +++++++ drivers/leds/trigger/Kconfig | 10 + drivers/leds/trigger/Makefile | 1 + drivers/leds/trigger/ledtrig-pattern.c | 432 ++++++++++++++++++++++++++++++++ 4 files changed, 529 insertions(+), 0 deletions(-) create mode 100644 Documentation/leds/ledtrig-pattern.txt create mode 100644 drivers/leds/trigger/ledtrig-pattern.c diff --git a/Documentation/leds/ledtrig-pattern.txt b/Documentation/leds/ledtrig-pattern.txt new file mode 100644 index 0000000..579295e --- /dev/null +++ b/Documentation/leds/ledtrig-pattern.txt @@ -0,0 +1,86 @@ +LED Pattern Trigger +=================== + +This is a LED trigger allowing arbitrary pattern execution. It can do gradual +dimming. This trigger can be configured to repeat the pattern a number of +times or indefinitely. This is intended as a way of communication for embedded +systems with no screen. + +The trigger can be activated from user space on LED class devices as shown +below: + + echo pattern > trigger + +This adds the following sysfs attributes to the LED: + + pattern - specifies the pattern. See syntax below. + + repeat - number of times the pattern must be repeated. + writing -1 to this file will make the pattern + repeat indefinitely. + +The pattern will be restarted each time a new value is written to +the pattern or repeat attribute. When dimming, the LED brightness +is set every 50 ms. + +pattern syntax: +The pattern is specified in the pattern attribute with an array of comma- +separated "brightness/length in miliseconds" values. The two components +of each value are to be separated by a space. + +For example, assuming the driven LED supports +intensity value from 0 to 255: + + echo 0 1000, 255 2000 > pattern + +Or: + + echo 0 1000, 255 2000, > pattern + +Will make the LED go gradually from zero-intensity to max (255) intensity +in 1000 milliseconds, then back to zero intensity in 2000 milliseconds: + +LED brightness + ^ +255-| / \ / \ / + | / \ / \ / + | / \ / \ / + | / \ / \ / + 0-| / \/ \/ + +---0----1----2----3----4----5----6------------> time (s) + + + +To make the LED go instantly from one brigntess value to another, +use zero-time lengths. For example: + + echo 0 1000, 0 0, 255 2000, 255 0 > pattern + +Will make the LED stay off for one second, then stay at max brightness +for two seconds: + +LED brightness + ^ +255-| +---------+ +---------+ + | | | | | + | | | | | + | | | | | + 0-| -----+ +----+ +---- + +---0----1----2----3----4----5----6------------> time (s) + + +Notes: + +Patterns with invalid syntax are reported with EINVAL, the +resulting LED brightness is undefined. Reading the pattern +back returns an empty string. + +Patterns with less than two values, no value with time length > 50 +milliseconds, or no two values with differing brightnesses +result in the LED being set at the brightness of the first value, +or zero if the pattern contains no value. EINVAL is returned, +and reading the pattern back returns an empty string. + +Because sysfs is used to define the pattern, patterns that need more than +PAGE_SIZE characters to describe aren't supported. PAGE_SIZE is system +dependent. diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig index 49794b4..ce27bdb 100644 --- a/drivers/leds/trigger/Kconfig +++ b/drivers/leds/trigger/Kconfig @@ -108,4 +108,14 @@ config LEDS_TRIGGER_CAMERA This enables direct flash/torch on/off by the driver, kernel space. If unsure, say Y. +config LEDS_TRIGGER_PATTERN + tristate "LED Pattern Trigger" + depends on LEDS_TRIGGERS + help + This allows LEDs blinking with an arbitrary pattern. Can be useful + on embedded systems with no screen to give out a status code to + a human. + + If unsure, say N + endif # LEDS_TRIGGERS diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile index 1abf48d..a739429 100644 --- a/drivers/leds/trigger/Makefile +++ b/drivers/leds/trigger/Makefile @@ -8,3 +8,4 @@ obj-$(CONFIG_LEDS_TRIGGER_CPU) += ledtrig-cpu.o obj-$(CONFIG_LEDS_TRIGGER_DEFAULT_ON) += ledtrig-default-on.o obj-$(CONFIG_LEDS_TRIGGER_TRANSIENT) += ledtrig-transient.o obj-$(CONFIG_LEDS_TRIGGER_CAMERA) += ledtrig-camera.o +obj-$(CONFIG_LEDS_TRIGGER_PATTERN) += ledtrig-pattern.o diff --git a/drivers/leds/trigger/ledtrig-pattern.c b/drivers/leds/trigger/ledtrig-pattern.c new file mode 100644 index 0000000..fdf231d --- /dev/null +++ b/drivers/leds/trigger/ledtrig-pattern.c @@ -0,0 +1,432 @@ +/* + * Arbitrary pattern trigger + * + * Copyright 2015, Epsiline + * + * Author : Raphaël Teysseyre <rteysseyre@xxxxxxxxx> + * + * Idea discussed with Pavel Machek <pavel@xxxxxx> on + * <linux-leds@xxxxxxxxxxxxxxx> (march 2015, thread title + * [PATCH RFC] leds: Add status code trigger) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/leds.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include "../leds.h" + +struct pattern_step { + int brightness; + int time_ms; +}; + +struct pattern_trig_data { + struct pattern_step *steps; /* Array describing the pattern */ + struct mutex lock; + char is_sane; + struct pattern_step *curr; + struct pattern_step *next; + int time_ms; /* Time in current step */ + int nsteps; /* Number of steps */ + int repeat; /* < 0 means repeat indefinitely */ + struct workqueue_struct *queue; + struct delayed_work dwork; + struct led_classdev *led_cdev; /* Needed by pattern_trig_update() */ +}; + +#define UPDATE_INTERVAL 50 +/* When doing gradual dimming, the led brightness + will be updated every UPDATE_INTERVAL milliseconds */ + +#define PATTERN_SEPARATOR "," + +#define MAX_NSTEPS (PAGE_SIZE/4) +/* The "pattern" attribute contains at most PAGE_SIZE characters. + Each pattern step in this attribute needs at least 4 characters + (a 1-digit number for the led brighntess, a space, + a 1-digit number for the time, a PATTERN_SEPARATOR). + Therefore, there is at most PAGE_SIZE/4 steps. */ + +static int pattern_trig_initialize_data(struct pattern_trig_data *data) +{ + mutex_init(&data->lock); + mutex_lock(&data->lock); + + data->is_sane = 0; + data->steps = kzalloc(MAX_NSTEPS*sizeof(struct pattern_step), + GFP_KERNEL); + if (!data->steps) + return -ENOMEM; + + data->curr = NULL; + data->next = NULL; + data->time_ms = 0; + data->nsteps = 0; + data->repeat = -1; + mutex_unlock(&data->lock); + return 0; +} + +static void pattern_trig_clear_data(struct pattern_trig_data *data) +{ + data->is_sane = 0; + kfree(data->steps); +} + +/* + * is_sane : pattern checking. + * A pattern satisfying these three conditions is reported as sane : + * - At least two steps + * - At least one step with time >= UPDATE_INTERVAL + * - At least two steps with differing brightnesses + * When @data->pattern isn't sane, a sensible brightness + * default is suggested in @brightness + * + * DO NOT call pattern_trig_update() on a not-sane pattern + * with is_sane = 1, you'll be punished with an infinite + * loop in the kernel. + */ +static int is_sane(struct pattern_trig_data *data, int *brightness) +{ + int i; + char stept_ok = 0; + char stepb_ok = 0; + + *brightness = 0; + if (data->nsteps < 1) + return 0; + + *brightness = data->steps[0].brightness; + if (data->nsteps < 2) + return 0; + + for (i = 0; i < data->nsteps; i++) { + if (data->steps[i].time_ms >= UPDATE_INTERVAL) { + if (stepb_ok) + return 1; + stept_ok = 1; + } + if (data->steps[i].brightness != data->steps[0].brightness) { + if (stept_ok) + return 1; + stepb_ok = 1; + } + } + + return 0; +} + +static int reset_pattern(struct pattern_trig_data *data, + struct led_classdev *led_cdev) +{ + int brightness; + + mutex_lock(&data->lock); + data->is_sane = 0; /* Prevent pattern_trig_update() + from scheduling new work */ + mutex_unlock(&data->lock); + + flush_workqueue(data->queue); + + mutex_lock(&data->lock); + if (is_sane(data, &brightness)) { + data->curr = data->steps; + data->next = data->steps + 1; + data->time_ms = 0; + data->is_sane = 1; + queue_delayed_work(data->queue, &data->dwork, 0); + mutex_unlock(&data->lock); + return 0; + } + + mutex_unlock(&data->lock); + led_set_brightness(led_cdev, brightness); + return -EINVAL; +} + +/* --- Sysfs handling --- */ + +static ssize_t pattern_trig_show_repeat( + struct device *dev, struct device_attribute *attr, char *buf) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct pattern_trig_data *data = led_cdev->trigger_data; + + return scnprintf(buf, PAGE_SIZE, "%d\n", data->repeat); +} + +static ssize_t pattern_trig_store_repeat( + struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct pattern_trig_data *data = led_cdev->trigger_data; + long res; + int err; + + err = kstrtol(buf, 10, &res); + if (err) + return err; + + mutex_lock(&data->lock); + data->repeat = res < 0 ? -1 : res; + mutex_unlock(&data->lock); + + reset_pattern(data, led_cdev); + + return count; +} + +DEVICE_ATTR(repeat, S_IRUGO | S_IWUSR, + pattern_trig_show_repeat, pattern_trig_store_repeat); + +static ssize_t pattern_trig_show_pattern( + struct device *dev, struct device_attribute *attr, char *buf) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct pattern_trig_data *data = led_cdev->trigger_data; + ssize_t count = 0; + int i; + + if (!data->steps || !data->nsteps) + return 0; + + for (i = 0; i < data->nsteps; i++) + count += scnprintf(buf + count, PAGE_SIZE - count, + "%d %d" PATTERN_SEPARATOR, + data->steps[i].brightness, + data->steps[i].time_ms); + buf[count - 1] = '\n'; + buf[count] = '\0'; + + return count + 1; +} + +static ssize_t pattern_trig_store_pattern( + struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct pattern_trig_data *data = led_cdev->trigger_data; + int cr = 0; /* Characters read after a successful sscanf call */ + int ccr = 0; /* Characters read before looking for PATTERN_SEPARATOR */ + int tcr = 0; /* Total characters read in buf */ + int ccount; /* Number of successful conversions in a sscanf call */ + + mutex_lock(&data->lock); + data->is_sane = 0; + + for (data->nsteps = 0; data->nsteps < MAX_NSTEPS; data->nsteps++) { + cr = 0; + ccount = sscanf(buf + tcr, " %d %d %n" PATTERN_SEPARATOR " %n", + &data->steps[data->nsteps].brightness, + &data->steps[data->nsteps].time_ms, &ccr, &cr); + + if (!cr) { /* PATTERN_SEPARATOR not reached */ + if (ccount == 2) { + /* Successful conversion before + looking for PATTERN_SEPARATOR. */ + data->nsteps++; + tcr += ccr; + } + + if (tcr != count) { + /* Invalid syntax */ + data->nsteps = 0; + mutex_unlock(&data->lock); + return -EINVAL; + } + + mutex_unlock(&data->lock); + + if (reset_pattern(data, led_cdev)) { + /* Invalid pattern */ + data->nsteps = 0; + return -EINVAL; + } + + return count; + } + + tcr += cr; + } + + /* Shouldn't reach that */ + WARN(1, "MAX_NSTEP too small. Please report\n"); + data->nsteps = 0; + mutex_unlock(&data->lock); + return -EINVAL; +} + +DEVICE_ATTR(pattern, S_IRUGO | S_IWUSR, + pattern_trig_show_pattern, pattern_trig_store_pattern); + +static int pattern_trig_create_sysfs_files(struct device *dev) +{ + int err; + + err = device_create_file(dev, &dev_attr_repeat); + if (err) + return err; + + err = device_create_file(dev, &dev_attr_pattern); + if (err) + device_remove_file(dev, &dev_attr_repeat); + + return err; +} + +static void pattern_trig_remove_sysfs_files(struct device *dev) +{ + device_remove_file(dev, &dev_attr_pattern); + device_remove_file(dev, &dev_attr_repeat); +} + +/* --- Led intensity updating --- */ + +static int compute_brightness(struct pattern_trig_data *data) +{ + if (data->time_ms == 0) + return data->curr->brightness; + + if (data->curr->time_ms == 0) /* Don't divide by zero */ + return data->next->brightness; + + return data->curr->brightness + data->time_ms + * (data->next->brightness - data->curr->brightness) + / data->curr->time_ms; +} + +static void update_to_next_step(struct pattern_trig_data *data) +{ + data->curr = data->next; + if (data->curr == data->steps) + data->repeat--; + + if (data->next == data->steps + data->nsteps - 1) + data->next = data->steps; + else + data->next++; + + data->time_ms = 0; +} + +static void pattern_trig_update(struct work_struct *work) +{ + struct delayed_work *dwork = to_delayed_work(work); + struct pattern_trig_data *data = + container_of(dwork, struct pattern_trig_data, dwork); + + mutex_lock(&data->lock); + + if (!data->is_sane || !data->repeat) { + mutex_unlock(&data->lock); + return; + } + + if (data->time_ms > data->curr->time_ms) + update_to_next_step(data); + + /* is_sane() checked that there is at least + one step with time_ms >= UPDATE_INTERVAL + so we won't go in an infinite loop */ + while (data->curr->time_ms < UPDATE_INTERVAL) + update_to_next_step(data); + + if (data->next->brightness == data->curr->brightness) { + /* Constant brightness for this step */ + led_set_brightness(data->led_cdev, data->curr->brightness); + queue_delayed_work(data->queue, &data->dwork, + msecs_to_jiffies(data->curr->time_ms)); + update_to_next_step(data); + } else { + /* Gradual dimming */ + led_set_brightness(data->led_cdev, compute_brightness(data)); + data->time_ms += UPDATE_INTERVAL; + queue_delayed_work(data->queue, &data->dwork, + msecs_to_jiffies(UPDATE_INTERVAL)); + } + + mutex_unlock(&data->lock); +} + +/* --- Trigger activation --- */ + +static void pattern_trig_activate(struct led_classdev *led_cdev) +{ + struct pattern_trig_data *data = NULL; + int err; + + data = kzalloc(sizeof(*data), GFP_KERNEL); + if (!data) + return; + + err = pattern_trig_initialize_data(data); + if (err) { + kfree(data); + return; + } + + led_cdev->trigger_data = data; + data->led_cdev = led_cdev; + data->queue = alloc_ordered_workqueue("pattern trigger on %s", 0, + led_cdev->name ? led_cdev->name : "?"); + INIT_DELAYED_WORK(&data->dwork, pattern_trig_update); + pattern_trig_create_sysfs_files(led_cdev->dev); +} + +static void pattern_trig_deactivate(struct led_classdev *led_cdev) +{ + struct pattern_trig_data *data = led_cdev->trigger_data; + + if (data) { + pattern_trig_remove_sysfs_files(led_cdev->dev); + + mutex_lock(&data->lock); + data->is_sane = 0; /* Prevent pattern_trig_update() + from scheduling new work */ + mutex_unlock(&data->lock); + + flush_workqueue(data->queue); + destroy_workqueue(data->queue); + + led_set_brightness(led_cdev, LED_OFF); + pattern_trig_clear_data(data); + kfree(data); + + led_cdev->trigger_data = NULL; + } +} + +static struct led_trigger pattern_led_trigger = { + .name = "pattern", + .activate = pattern_trig_activate, + .deactivate = pattern_trig_deactivate, +}; + +/* --- Module loading/unloading --- */ + +static int __init pattern_trig_init(void) +{ + return led_trigger_register(&pattern_led_trigger); +} + +static void __exit pattern_trig_exit(void) +{ + led_trigger_unregister(&pattern_led_trigger); +} + +module_init(pattern_trig_init); +module_exit(pattern_trig_exit); + +MODULE_AUTHOR("Raphael Teysseyre <rteysseyre@xxxxxxxxx"); +MODULE_DESCRIPTION("Statuscode LED trigger"); +MODULE_LICENSE("GPL v2"); -- 1.7.1
Attachment:
signature.asc
Description: Digital signature