Difference between revisions of "How to use GPIOs"
From IGEP - ISEE Wiki
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At any point, if you see a mistake you can contribute to this How-To.<br> | At any point, if you see a mistake you can contribute to this How-To.<br> | ||
− | = Compile GPIO driver source code | + | = Compile GPIO driver source code in SDK<br> = |
Download source code from author website using the next command:<br> | Download source code from author website using the next command:<br> | ||
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Go to: $/svn.hylands.org/linux/gpio/Makefile and compile all source code downloaded using make command. <br> | Go to: $/svn.hylands.org/linux/gpio/Makefile and compile all source code downloaded using make command. <br> | ||
− | Send binaries created from Host to Igep v2. <br> | + | Send binaries created from Host to Igep v2. <br> |
= Install binaries = | = Install binaries = |
Revision as of 14:02, 9 January 2012
Contents
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 in SDK
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