On 10/1/2014 9:25 AM, Nic Cyn wrote: > Hi All > > I am seeking some clarification and/or insights into the current state and > future of BBB GPIO and device support. > > It is my understanding that the Cape Manager will not be ported to kernels > greater than 3.8. This, as far as I can tell, does not seem to be an > official position rather it seems there is no momentum behind the Cape > Manager in its current form and nobody who has the skills to do so is very > keen on working on a port to future kernels. Is that a fair assessment?
"Cape Manager" functionality has been added to newer mainline kernels in the form of device tree change sets. It is expected this functionality will be back-ported to the 3.14 kernel likely to become the next 'standard' BeagleBone kernel after 3.8. > I have seen references to a sort of Generic Device Driver which will make > it possible to configure the GPIO and muxed devices from user space kind of > like a super sysfs. However, I can no longer find the name or the link. > Does such a thing exist and if so, is it the likely way forward? You're probably thinking of my universal cape: https://github.com/cdsteinkuehler/beaglebone-universal-io ...which can be controlled with the config-pin utility (or manually via sysfs). This allows user-mode run-time configuration of pin multiplexing and GPIO state, with most "useful" hardware (UARTs, PWMs, etc) enabled. > I also have also seen references to a sort of generic .dbs file which > contains a number of #includes people can comment and uncomment in order to > enable specific cape functionality. Is this anything other than an idea at > present and is this likely to be the way device tree support for capes is > implemented going forward? This sounds like the current state of the 3.14 device tree for the 'Bone. This will likely remain in place (to allow easy user-mode setup of most common I/O needs), but will be enhanced by the ability to use device tree changesets once this feature gets back-ported. > What is currently thought to be the best practice to configure GPIO's and > muxed devices for kernels with no cape manager? I am currently editing the > Device Tree .dbs file manually. However, since the .dbs file is complicated > and usually requires edits in multiple locations, this is not the easiest > of configuration steps to communicate to users. I would appreciate any > advice. I would recommend using the cape-universal features RCN has merged into the 3.14 'Bone kernels and the config-pin utility for everything you can. Some things, however, will still require manually editing the device tree source and installing a new *.dtb file. -- Charles Steinkuehler [email protected]
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