Difference between revisions of "IMX LED Driver TP"

Revision as of 18:43, 17 March 2009

Page under construction... Informations on this page are not guaranteed !!

Proposal

The goal of this tutorial is to build from scratch a simple led driver wire on GPIO of the iMX. This document will describes step by step how to implement a such driver

Howto Load/unload modules : "hwmon" module

Load module is quite simple once it is compile an in the rootfs of the apf board. All the compiled driver modules are in the "/lib/modules/<kernel version>/kernel". To find all the loadable modules by the kernel in the board type :

 # find /lib/modules/`uname -r`/kernel -name "*.ko"
/lib/modules/2.6.27.13/kernel/sound/arm/snd-imx-alsa-tsc2102.ko
/lib/modules/2.6.27.13/kernel/sound/arm/snd-mx2.ko
/lib/modules/2.6.27.13/kernel/sound/core/snd-page-alloc.ko
/lib/modules/2.6.27.13/kernel/sound/core/snd-timer.ko
/lib/modules/2.6.27.13/kernel/sound/core/snd.ko
/lib/modules/2.6.27.13/kernel/sound/core/snd-pcm.ko
/lib/modules/2.6.27.13/kernel/sound/soundcore.ko
/lib/modules/2.6.27.13/kernel/drivers/spi/tsc2102.ko
/lib/modules/2.6.27.13/kernel/drivers/scsi/scsi_wait_scan.ko
/lib/modules/2.6.27.13/kernel/drivers/hwmon/hwmon.ko
/lib/modules/2.6.27.13/kernel/drivers/input/touchscreen/tsc2102_ts.ko
/lib/modules/2.6.27.13/kernel/drivers/video/backlight/lcd.ko
/lib/modules/2.6.27.13/kernel/drivers/video/backlight/backlight.ko
/lib/modules/2.6.27.13/kernel/drivers/armadeus/max1027/max1027.ko
/lib/modules/2.6.27.13/kernel/drivers/armadeus/backlight/imx_bl.ko

For example, I will load "/lib/modules/2.6.27.13/kernel/drivers/hwmon/hwmon.ko" module :

 # modprobe hwmon
 #

To list all mod loaded :

 # lsmod
Module                  Size  Used by    Not tainted
hwmon                   2356  0 

To unload it just type :

 # rmmod hwmon
 #

TBC

Howto Build a simple module and load/unload it : the "Hello World" module

Howto Provide read/write commands to the user though /dev/hello : "Hello World Read Write" module

Howto Build a register use module : "iMX LED" module