BeagleBoard.org-GSoC

BeagleBoard.org-GSoC
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"gsoc" via jkridner in Google Reader

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Week 3 report

Posted: 13 Jun 2010 12:37 PM PDT
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Report for the week 7-6-10 to 14-6-10
This week was a bit slow due to some college project presentations, vivas,
etc.

Status
*Got the OE as well as the Code Sourcery toolchain setup.
*Got to test existing existing code . Instructions from the README for
patching the defconfig did not work out for me so instead just manually
edited the defconfig and all went fine. Two things have to be changed to
make the existing code work out for a Beagleboard.
-Enable clock reset (CONFIG_OMAP_RESET_CLOCKS=y)
-Set the CONFIG_OMAP_MBOX_FWK=m
*My fork of the above repo can be found here.

Plans
*Currently the module has to be reloaded to change the frequency of
PWM.This is because it is being passed as a kernel parameter at load time.
Will try and fix this.

I don't have time at the moment to look at the code but have you checked to
see if it can be modified through sysfs? IIRC, sysfs can let you modify a
module parameter as long as you are using the variable attached to it and not
a copy.

*Only one PWM pin can be activated currently (PWM on pin 10). This will be
fixed by making the PWM pin as a load time parameter.
*Make final tasks list for mid term evaluation and get working on it.

Risks
*Still very new to kernel programming, so will take longer for simple
tasks.

Along the lines of what Koen said in another mail, please ask if something is
taking a long time. Doesn't have to be a blocker.

> Plans
> *Currently the module has to be reloaded to change the frequency of
> PWM.This is because it is being passed as a kernel parameter at load time.
> Will try and fix this.

I don't have time at the moment to look at the code but have you checked to
see if it can be modified through sysfs? IIRC, sysfs can let you modify a
module parameter as long as you are using the variable attached to it and not
a copy.

That worked out well, just required me to change permission for
frequency parameter from S_IRUGO to S_IWUSR. Frequency can now be
changed with
echo <new frequency> > /sys/module/pwm/parameters/
frequency .

Varun
http://github.com/neo01124/omap3-pwm