Difference between revisions of "How to use GPIOs"

From IGEP - ISEE Wiki

Jump to: navigation, search
Line 12: Line 12:
 
<pre>wget -r -np  http://svn.hylands.org/linux/gpio/
 
<pre>wget -r -np  http://svn.hylands.org/linux/gpio/
 
</pre>  
 
</pre>  
−
Due the Makefiles are wrote for Gumstix SDK, it is necessary change some constants to our Host. There are:  
+
Due the source Makefiles are implemented for Gumstix SDK, it is necessary change some constants for compile with our Host. These constants are:
 +
 
 +
In files:  
  
 
$/svn.hylands.org/linux/gpio/app/Makefile  
 
$/svn.hylands.org/linux/gpio/app/Makefile  
Line 22: Line 24:
 
CROSS_COMPILE ?= $(OVEROTOP)/tmp/sysroots/x86_64-linux/usr/armv7a/bin/arm-angstrom-linux-gnueabi-
 
CROSS_COMPILE ?= $(OVEROTOP)/tmp/sysroots/x86_64-linux/usr/armv7a/bin/arm-angstrom-linux-gnueabi-
 
</pre>  
 
</pre>  
−
Replace by, your cross compiler path, for example:  
+
Replaced by your cross compiler path, for example:  
 
<pre>OVEROTOP ?= /
 
<pre>OVEROTOP ?= /
 
CROSS_COMPILE ?= $(OVEROTOP)/usr/bin/arm-linux-gnueabi-
 
CROSS_COMPILE ?= $(OVEROTOP)/usr/bin/arm-linux-gnueabi-
 
</pre>  
 
</pre>  
 +
In file:<br>
 +
 
$/svn.hylands.org/linux/gpio/modules/Makefile<br>  
 
$/svn.hylands.org/linux/gpio/modules/Makefile<br>  
  
Line 34: Line 38:
 
KERNEL_PATH    &nbsp;?= ../../../../../gumstix/overo-oe/tmp/sysroots/overo-angstrom-linux-gnueabi/kernel
 
KERNEL_PATH    &nbsp;?= ../../../../../gumstix/overo-oe/tmp/sysroots/overo-angstrom-linux-gnueabi/kernel
 
ARCH ?= arm</pre>  
 
ARCH ?= arm</pre>  
−
Replace by, your cross compiler path and your kernel source path used, for example:  
+
Replaced by your cross compiler path and your kernel source used path, for example:  
 
<pre>OVEROTOP ?= /
 
<pre>OVEROTOP ?= /
 
#CROSS_COMPILE ?= $(OVEROTOP)/tmp/cross/armv7a/bin/arm-angstrom-linux-gnueabi-
 
#CROSS_COMPILE ?= $(OVEROTOP)/tmp/cross/armv7a/bin/arm-angstrom-linux-gnueabi-
Line 40: Line 44:
 
KERNEL_PATH    &nbsp;?= ../../../../../&lt;your kernel source path used&gt;
 
KERNEL_PATH    &nbsp;?= ../../../../../&lt;your kernel source path used&gt;
 
ARCH ?= arm</pre>  
 
ARCH ?= arm</pre>  
−
Go to: $/svn.hylands.org/linux/gpio/Makefile and compile app, lib and module using make command.  
+
Go to: $/svn.hylands.org/linux/gpio/Makefile and compile all source code downloaded using make command. <br>
  
−
Transfer binaries created to IGEP v2
+
Send binaries created from Host to Igep v2. <br>
  
 
= Install binaries  =
 
= Install binaries  =
 +
 +
Install binaries via root user.
  
 
=== Install module  ===
 
=== Install module  ===
Line 51: Line 57:
 
<pre>insmod user-gpio-drv.ko
 
<pre>insmod user-gpio-drv.ko
 
</pre>  
 
</pre>  
−
Check that user-gpio-drv.ko is currently loaded with the following command:
+
Check that user-gpio-drv.ko is currently loaded with the following command:  
−
<pre>lsmod</pre>
+
<pre>lsmod</pre>  
−
 
+
The module is loaded until system halt.  
−
The module is loaded until system halt.
 
  
 
=== Install dynamic library  ===
 
=== Install dynamic library  ===
  
−
Go to:$/svn.hylands.org/linux/gpio/lib/. libgpio.so will be found here.
+
Go to:$/svn.hylands.org/linux/gpio/lib/. libgpio.so will be found here.  
−
 
 
−
You must tell to SO where the dynamic libraries are. Now we define the environment variable LD_LIBRARY_PATH for SO can link a library with a program when a program make a call. Type the follow commnad:
 
−
<pre>
 
−
export LD_LIBRARY_PATH=/root/svn.hylands.org/linux/gpio/lib/
 
−
</pre>
 
  
 +
You must tell to SO where the dynamic libraries are. Now we define the environment variable LD_LIBRARY_PATH for SO can link a library with a program when a program make a call. Type the follow commnad:
 +
<pre>export LD_LIBRARY_PATH=/root/svn.hylands.org/linux/gpio/lib/
 +
</pre>
 
=== Execute app<br>  ===
 
=== Execute app<br>  ===
  
Line 72: Line 75:
 
<pre> ldd gpio  
 
<pre> ldd gpio  
 
</pre>  
 
</pre>  
−
See if libgpio.so is found it. If you execute program in bash without linking library dependencies, bash give you a error message.
+
See if libgpio.so is found it. If you execute program in bash without linking library dependencies, bash give you a error message.  
  
 
= Testing driver  =
 
= Testing driver  =
  
−
<br>
+
<br>  
−
 
 
−
<br>
 
  
−
'''Under construction'''<br>
+
<br>  
  
 +
'''Under construction'''<br>
  
 +
<br>
  
 
<br> Example:[[What can I do with IGEP0020#How_to_handle_the_gpio-LED.27s]]  
 
<br> Example:[[What can I do with IGEP0020#How_to_handle_the_gpio-LED.27s]]  
  
 
[[Category:Work_in_progress]] [[Category:Communications]]
 
[[Category:Work_in_progress]] [[Category:Communications]]

Revision as of 14:00, 9 January 2012

Overview

This How-To is meant to be a starting point for people to learn use GPIOs for IGEP v2 devices as quickly and easily as possible. For this how-to i used Linaro Headless, Ubuntu 10.04 with Linaro Toolchain, IGEP v2 RC5 and GPIO driver wrote by Dave Hylands. There are more ways to use GPIOs in IGEP v2, but this one is simple and reliable.

Feedback and Contributing

At any point, if you see a mistake you can contribute to this How-To.

Compile GPIO driver source code

Download source code from author website using the next command:

wget -r -np  http://svn.hylands.org/linux/gpio/

Due the source Makefiles are implemented for Gumstix SDK, it is necessary change some constants for compile with our Host. These constants are:

In files:

$/svn.hylands.org/linux/gpio/app/Makefile

$/svn.hylands.org/linux/gpio/lib/Makefile

Search lines: 

OVEROTOP	?= /home/gumstix/overo-oe
CROSS_COMPILE	?= $(OVEROTOP)/tmp/sysroots/x86_64-linux/usr/armv7a/bin/arm-angstrom-linux-gnueabi-

Replaced by your cross compiler path, for example: 

OVEROTOP	?= /
CROSS_COMPILE	?= $(OVEROTOP)/usr/bin/arm-linux-gnueabi-

In file:

$/svn.hylands.org/linux/gpio/modules/Makefile

Search lines: 

OVEROTOP	?= /home/gumstix/overo-oe
#CROSS_COMPILE	?= $(OVEROTOP)/tmp/cross/armv7a/bin/arm-angstrom-linux-gnueabi-
CROSS_COMPILE	?= $(OVEROTOP)/tmp/sysroots/x86_64-linux/usr/armv7a/bin/arm-angstrom-linux-gnueabi-
KERNEL_PATH     ?= ../../../../../gumstix/overo-oe/tmp/sysroots/overo-angstrom-linux-gnueabi/kernel
ARCH		?= arm

Replaced by your cross compiler path and your kernel source used path, for example: 

OVEROTOP	?= /
#CROSS_COMPILE	?= $(OVEROTOP)/tmp/cross/armv7a/bin/arm-angstrom-linux-gnueabi-
CROSS_COMPILE	?= $(OVEROTOP)//usr/bin/arm-linux-gnueabi-
KERNEL_PATH     ?= ../../../../../<your kernel source path used>
ARCH		?= arm

Go to: $/svn.hylands.org/linux/gpio/Makefile and compile all source code downloaded using make command.

Send binaries created from Host to Igep v2.

Install binaries

Install binaries via root user.

Install module

Go to:$/svn.hylands.org/linux/gpio/modules/ and insert user-gpio-drv.ko into linux kernel with the following command: 

insmod user-gpio-drv.ko

Check that user-gpio-drv.ko is currently loaded with the following command: 

lsmod

The module is loaded until system halt.

Install dynamic library

Go to:$/svn.hylands.org/linux/gpio/lib/. libgpio.so will be found here.

You must tell to SO where the dynamic libraries are. Now we define the environment variable LD_LIBRARY_PATH for SO can link a library with a program when a program make a call. Type the follow commnad: 

export LD_LIBRARY_PATH=/root/svn.hylands.org/linux/gpio/lib/

Execute app

Go to:$/svn.hylands.org/linux/gpio/app, gpio will be found here.

To make sure that libgpio.so can be founded as a dependency of gpio program use the following command: 

 ldd gpio

See if libgpio.so is found it. If you execute program in bash without linking library dependencies, bash give you a error message.

Testing driver



Under construction



Example:What can I do with IGEP0020#How_to_handle_the_gpio-LED.27s

Retrieved from "http://labs.isee.biz/index.php?title=How_to_use_GPIOs&oldid=3118"