Topic: Buildroot + chumby kernel + mpd + gpio

Hi everybody! I repurposed my insignia infocast 3.5" as a mpd server that can play all the music in my network. I've replaced the chumby bootloader with barebox and create the rootfs with buildroot and compile a new little kernel. I created an interface with some buttons and one led managed through gpio pins.

If somebody wants to set up a chumby as an mpd server please let me know it!

Cheers!

2 (edited by infocastme 2013-08-16 14:38:10)

Re: Buildroot + chumby kernel + mpd + gpio

pazos wrote:

If somebody wants to set up a chumby as an mpd server please let me know it!

Pazos,

Would love to try it out. Please let us know where to find the info.

Is it related to this program? ChuMPD http://www.danielcasner.org/chumpd/

Re: Buildroot + chumby kernel + mpd + gpio

I too am interested in this.  I'm mostly curious about the bootloader change, buildroot build, and kernel.

Why the bootloader change?  I'm not familiar with barebox, do you think uBoot would work?  Can you provide more information on using barebox?
With buildroot, did you use uclibc, or glibc?  Do you have a config file you can share?  What version of buildroot?
What kernel version?

Linux Guy - Occasional Chumby Hacker

Re: Buildroot + chumby kernel + mpd + gpio

buildroot uses uclibc as default c library. I'm using buildroot 2013.05, kernel 2.6.28-chumby and barebox 2013.05. I'll try to document here how to create a new sd with barebox + buildroot filesystem. I think u-boot may work but I don't test it. barebox works ok and boots linux in less than 2 seconds ( chumby bootloader : +4 seconds)

Please give me a few days wink

pd: i use my infocast in headless mode (ie without any screen), instead of use the ts as input device I rely on some buttons attached to gpios to control mpd locally (with mpc). The ChuMPD seems a good piece of software, but runs in the chumby ecosystem (needs flash to work) and seems to be a client itself, not a server

Re: Buildroot + chumby kernel + mpd + gpio

Thanks pazos for the reply and info. Will wait patiently for further instructions! big_smile

Re: Buildroot + chumby kernel + mpd + gpio

Also, can you post a diagram of the GPIO wiring?

Re: Buildroot + chumby kernel + mpd + gpio

pazos wrote:

buildroot uses uclibc as default c library. I'm using buildroot 2013.05

Yes, but glicb can be used in buildroot as of a few years ago.  I wasn't sure if you went that route depending on what all you have compiled for the system.

Linux Guy - Occasional Chumby Hacker

Re: Buildroot + chumby kernel + mpd + gpio

Hello:

@Doktor Jones: GPIO diagram is really simple. Look it -> https://www.dropbox.com/sh/94p4xrv6zmhs … iagram.png

I use D0-D3 for input buttons and D4 for a single led. When linux is loaded all gpio pins go high (3.3V) which is ok for the buttons. I use regutil to toggle the led high or low and to read the state of the buttons, the script I use only cares about one hexadecimal number, cause it represents the 4 bits used for the buttons... I'm going to share all my scripts here but my dev machine went down last week and I had no time to look at it

@Matterdaddy: i think uclibc fits better in embedded systems like the chumby. the gnu libc is ok is those cases you have a binary compiled with it and can't access to the source code.

sorry about my english tongue
see you soon

Re: Buildroot + chumby kernel + mpd + gpio

pazos wrote:

@Matterdaddy: i think uclibc fits better in embedded systems like the chumby. the gnu libc is ok is those cases you have a binary compiled with it and can't access to the source code.

I agree, but wondered how hard it was getting things up and running with uclibc.  I never spent too much time getting something up and running on the chumby using buildroot and was curious.

pazos wrote:

sorry about my english tongue

Your English is fine! No apologies are necessary.  Thanks for sharing your project.

Linux Guy - Occasional Chumby Hacker

Re: Buildroot + chumby kernel + mpd + gpio

I too would be interested in this image and any related documentation. What I want most of all is a workable Linux distro for my Infocast 3.5s (3 of them) and Chumby One. It's fantastic that Chumby didn't cripple them out of the box, but they'd be infinitely more useful to me if they were running archlinuxarm or something. I attempted to build an Angstrom image based on

Chumby-OE but that failed mid-boot on my Infocast. I assume because of some subtle difference between the hackerboard and the Infocast hardware, but haven't had the time/tuits to figure that out.

So tl;dr; version: image file and any notes please?

Re: Buildroot + chumby kernel + mpd + gpio

Let me add my voice here. I would love to get some alternate form of Linux on my Infocast 8. Where is a set of sources which *should* actually build without errors?

Haven't done anything recently, but I've always had errors when building from these instructions.:

http://wiki.chumby.com/index.php?title= … for_chumby
http://wiki.chumby.com/index.php?title= … %28Beta%29
http://www.kosagi.com/blog/category/doc … on/page/2/

Anyway, I might be doing something dopey. If anyone has a checklist of actions that have worked for them on an Infocast 8, I'd appreciate knowing about them.

Brian, #1 Joan Jett Fan

Re: Buildroot + chumby kernel + mpd + gpio

Hi Joan Jett, AFAIK silvermoon platform uses uboot as default bootloader and the processor is mainlined, you only need the chumby sources if you want to access some drivers like the top button.

My dev machine died and I need to do some work to make the sources & patches avaliable here, but I think its posible to build some kind of buildroot distro that boots in both silvermoon & falconwing platforms ( the same target in buildroot )

Most of linux distributions out there rely on udev to handle hotplug events, and udev needs a newer kernel = NOT WORKING FOR FALCONWING, I don't know if silvermoon kernel has devtmpfs implemented but it is necessary to boot the kernel with udev. Some clever people >> https://github.com/WarheadsSE/OX820-2.6-linux  backported devtmpfs to an oxnas kernel in order to boot archlinuxarm with newer udev versions, I think it can be done for chumby kernels too, but for me buildroot + mdev mechanism works like a charm!

I'll post a video of my chumby mpd server here in a couple of days and expect to finish the sd card guide (barebox & kernel)  in a few days too.

Lets hack our chumbies!

13 (edited by Joan Jett 2013-09-12 03:53:41)

Re: Buildroot + chumby kernel + mpd + gpio

pazos wrote:

Hi Joan Jett, AFAIK silvermoon platform uses uboot  [snip]

Well thanks for the reply pazos. I have an infocast 8 (silvermoon) so if I can be of any help testing I'd be happy to. First job is to get a serial port cobbled up!

Brian

Brian, #1 Joan Jett Fan