GPIO LEDS

2012-12-11T10:13:50Z

Jean-jacquesC: /* Configuration */

How to use leds-gpio driver to manage states of connected leds of your Armadeus board.

==Introduction==

You can manage a led connected to a GPIO pin. The LED management is similar with the standard GPIO sysfs driver, but you have some new features like triggers (e.g. "heartbeat" LED blinks like a heart at the rate oh the CPU load) . Here are the GPIO used for the user LED for each APF board:
* APF9328: PORT A / bit 2
* APF27: GPIO_PORTF | 14
* APF28: PINID_GPMI_RDY1 (Bank 0 - pin 21)
* APF51: GPIO_PORTA | 2

==Configuration==

First, you need to enable the leds-gpio driver in your kernel and some triggers like the "heartbeat" trigger to make the LED flash like a heartbeat.

* Configure Linux kernel:
<pre class="host">
$ make linux-menuconfig
</pre>
<pre class="config">
Device Drivers --->
--- LED support
[*] LED Class Support
*** LED drivers ***
<*> LED Support for GPIO connected LEDs
[*] Platform device bindings for GPIO LEDs
*** LED Triggers ***
[*] LED Trigger support
<*> LED Timer Trigger
<*> LED Heartbeat Trigger
<*> LED backlight Trigger
<*> LED Default ON Trigger
</pre>

Then, in your ''apfXX-dev.c'', you would need to define your LED <b>before</b> the variable ''platform_devices[]''. This code is already implemented for the APF27, APF28 and APF51 so the source code hereafter (for the APF27) is only present as a reference sample to understand how to activate a GPIO LED driver.

<source lang="c">

#include <linux/leds.h>

/* GPIO LED */
#if defined(CONFIG_LEDS_GPIO) || defined(CONFIG_LEDS_GPIO_MODULE)
static struct gpio_led apf27dev_led[] = {
{
.name = "apfdev:green:user",
.default_trigger = "heartbeat",
.gpio = (GPIO_PORTF | 14),
.active_low = 1,
},
};

static struct gpio_led_platform_data apf27dev_led_data = {
.num_leds = ARRAY_SIZE(apf27dev_led),
.leds = apf27dev_led
};

static struct platform_device apf27dev_led_dev = {
.name = "leds-gpio",
.id = -1,
.dev = {
.platform_data = &apf27dev_led_data,
},
};
#endif /* CONFIG_LEDS_GPIO */
</source>

Add the LED to get it managed by the kernel.

<source lang="c">
static struct platform_device *platform_devices[] __initdata = {
#if defined(CONFIG_LEDS_GPIO) || defined(CONFIG_LEDS_GPIO_MODULE)
&apf27dev_led_dev,
#endif
ALSA_SOUND

};
</source>

Then rebuild and update your bard with the new kernel.
Upon the next kernel boot you should see the LED flash like a heartbeat (if you have activated the "heartbeat" trigger)

==Usage==
<pre class="apf">
# ls /sys/class/leds/apfdev\:green\:user/
brightness max_brightness subsystem uevent
device power trigger
</pre>

You can change the trigger behaviors. By default, Heartbeat is selected:
* "heatbeat": led blinks like a heart and blink frequency will change according o the CPU activity.
* "nand-disk": the led will blink each time nand access occur (try with ''sync'' command to see it blinking).
<pre class="apf">
# cat /sys/class/leds/apfdev\:green\:user/trigger
none nand-disk mmc0 timer [heartbeat] backlight gpio default-on

# echo none > /sys/class/leds/apfdev\:green\:user/trigger
</pre>

Switch on and off the LED

<pre class="apf">
# cat /sys/class/leds/apfdev\:green\:user/max_brightness > /sys/class/leds/apfde
v\:green\:user/brightness

# echo 0 > /sys/class/leds/apfdev\:green\:user/brightness
</pre>

It is possible to switch led state using the APF28Dev user button. This button is seen as gpio17 (as seen under APF28Dev [[datasheet]]) under Linux, then configure the led trigger as gpio :

<pre class="apf">
# echo "gpio" > /sys/class/leds/apfdev:green:user/trigger
</pre>

New config files are available :
<pre class="apf">
# ls /sys/class/leds/apfdev:green:user/
brightness gpio power uevent
desired_brightness inverted subsystem
device max_brightness trigger
</pre>

Then the trigger gpio can be configured with ''gpio'' file :

<pre class="apf">
# echo 17 > /sys/class/leds/apfdev:green:user/gpio
</pre>

Then pushing the user switch will now commute the LED state.

==Links==
* http://www.kernel.org/doc/Documentation/leds/leds-class.txt

Boa

2012-12-11T09:03:40Z

Jean-jacquesC: /* Create the access log directory */

<span style="font-size: 2em; font-weight:bold;"> How-to install and configure the Boa Web server on your Armadeus board </span>

[[Image:boa.png|right]]
<br />
==Installation==
* Launch Buildroot's configuration:
<pre class="host">
$ make menuconfig
</pre>
* Select:
<pre class="config">
...
Package Selection for the target --->
[*] Show packages that are also provided by busybox
...
[*] Networking --->
...
[*] boa
</pre>
* Save the configuration
* Then build the binaries and the default filesystem. This will be useful later to perform the configuration:
<pre class="host">
$ make
</pre>

==Configuration==

=== Generalities ===

To apply a permanent configuration, be sure not to change anything on the board filesystem: that would be erased the next time you reflash the rootfs. <br>
Instead, do all changes on the filesystem located on the Host, i.e. on ''buildroot/project_build_armv4t/apf9328/root/'' for the APF9328 or ''buildroot/project_build_armv5te/apf27/root/'' for the [[APF27]].

The Boa configuration file is located in ''/etc/boa/boa.conf'' on the board; this means that to permanently change the configuration, you need to edit the file ''buildroot/project_build_armvXX/apfXX/root/etc/boa/boa.conf'' '''on the Host'''.<br>

As the root directory name is dependent of the target, there is a way to find it automatically:
$ make shell_env && source armadeus_env.sh
Then the directory can be accessed with ''$ARMADEUS_ROOTFS_DIR''.

=== Create a Dummy page ===

*By default, DocumentRoot is set to /var/www, so let's add a dummy file here to test our configuration:

$ mkdir $ARMADEUS_ROOTFS_DIR/var/www
$ vim $ARMADEUS_ROOTFS_DIR/var/www/index.html

*And fill the file with:
<source lang="html4strict">
<html>
<head>
<title> Welcome on the Armadeus Board </title>
</head>
<body>
<nowiki><h1> Welcome on the Armadeus Board </h1></nowiki>
</body>
</html>
</source>

=== Enable hostname resolution ===

*Boa has to be able to resolve the hostname to work, so let's do:

$ echo "127.0.0.1 `cat $ARMADEUS_ROOTFS_DIR/etc/hostname`" >> $ARMADEUS_ROOTFS_DIR/etc/hosts

=== Create the access log directory ===

*By default, Boa logs will be stored in ''/var/log/boa/''. If you didn't not change this setting, you will need to perform the following :
$ ls -l $ARMADEUS_ROOTFS_DIR/var/log

*If it's a link to ''/tmp'', then
$ rm -f $ARMADEUS_ROOTFS_DIR/var/log && mkdir $ARMADEUS_ROOTFS_DIR/var/log/

*Then, create the boa directory :
$ mkdir $ARMADEUS_ROOTFS_DIR/var/log/boa

-----
Why shoud I delete the symbolink link? <br>
This is because during the filesystem creation, mkfs.jffs2 will keep the link from ''/var/log'' to ''/tmp'' on the board.
Thus, once on the board, you will have:
<pre class=apf>
# ls -l /var/log
lrwxrwxrwx 1 root root 4 Apr 15 2007 /var/log -> /tmp
</pre>

With such a behavior, even if you fill the directory ''$ARMADEUS_ROOTFS_DIR/var/log/'' on your host
(which actually fill ''/tmp'' on your host), nothing will be saved once the filesystem will be flashed on your board.

== Test the result ==

*Create the final rootfs:
$ make

*Then [[Target_Software_Installation | update the rootfs]] on your board. Reboot it, and start Boa:
<pre class=apf>
# boa
</pre>

*To access your web page, use a browser:
http://''<your board's IP Address>''/

You should see the page ! <br />
If not, check the file ''/var/log/boa/error_log'' on your board

[[Image:Boa_welcome.png]]

== Working with cgi ==

*First, check the ''boa.conf'' file. Once more, you should use the one located on your host before changing anything.
$ vi $ARMADEUS_ROOTFS_DIR/etc/boa/boa.conf

*Be sure to have an uncommented line like this:
ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/

*Now, let's write a dummy cgi:

$ mkdir $ARMADEUS_ROOTFS_DIR/usr/lib/cgi-bin
$ vim $ARMADEUS_ROOTFS_DIR/usr/lib/cgi-bin/get_ipconfig.sh

*And add the following :
<source lang="bash">
#!/bin/sh
echo -e "Content-type: text/html\r\n\r\n";
echo -e `/sbin/ifconfig eth0 | grep 'inet addr'`;
</source>
The script have to be executable:
$ chmod a+x $ARMADEUS_ROOTFS_DIR/usr/lib/cgi-bin/get_ipconfig.sh

*Then change your index.html page to add a link to the cgi:

$ vi $ARMADEUS_ROOTFS_DIR/var/www/index.html
<source lang="html4strict">
<html>
<head>
<title> Welcome on the Armadeus Board </title>
</head>
<body>
<h1> Welcome on the Armadeus Board </h1>
<br> <br>
<a href=http://<Your board IP Address>/cgi-bin/get_ipconfig.sh> Get the board ip config </a>
<br>
</body>
</html>
</source>

*Create the new rootfs:
$ make

*Finally, [[Target_Software_Installation | transfer the rootfs]] to the board & flash it.

You can now access to the new web page and click on the cgi link !

==Links==
* [http://www.boa.org The Boa Web page]

[[Category:Network]]
[[Category:Web]]

ArmadeusWiki - User contributions [en]

GPIO LEDS

Boa