[PATCH] Add GPIO, I2C and SPI support for the RPi BSP

[Sebastian Huber]

On 12/23/2014 09:52 PM, Alan Cudmore wrote:
> Sebastian,
> Makes sense. I think I understand the idea a little better now, we are
> using the linux uapi i2c API, but not the actual i2c bus and device driver
> implementations from linux, right?

Yes, it is only the user space API.

>
> For the Pi ( and others like the Beagleboard ) we need to come up with an
> i2c BSP bus driver ( similar to cadence-i2c.c/h ) then a set of i2c device
> drivers to go in cpukit/dev/i2c.

Yes.

>
> Do the individual device drivers, such as cpukit/dev/i2c/gpi-nxp-pca9535.c,
> resemble the equivalent linux driver?

No, they don't run on Linux.  The I2C device drivers use some custom 
stuff in RTEMS like the registration as a file system node.  It is 
possible to write a device driver that runs on RTEMS and Linux, but in 
this case its not possible to provide a file system node which can be 
used by others.  Since we use IMFS generic nodes, this automatically 
provides safe destruction and reference counting.

>
> Thanks,
> Alan
>
>
> On Tue, Dec 23, 2014 at 1:01 AM, Sebastian Huber <
> sebastian.huber at embedded-brains.de> wrote:
>
>> On 22/12/14 22:17, Alan Cudmore wrote:
>>
>>> Why was the Linux API chosen over FreeBSD? Wouldn't we want to keep going
>>> down the *BSD path to provide drivers and libraries?
>>>
>> We also looked at the FreeBSD, OpenBSD and NetBSD I2C stuff, but the Linux
>> I2C API appeared to be the best and most widely used.
>>
>>
>> --
>> Sebastian Huber, embedded brains GmbH
>>
>> Address : Dornierstr. 4, D-82178 Puchheim, Germany
>> Phone   : +49 89 189 47 41-16
>> Fax     : +49 89 189 47 41-09
>> E-Mail  : sebastian.huber at embedded-brains.de
>> PGP     : Public key available on request.
>>
>> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
>>
>>


-- 
Sebastian Huber, embedded brains GmbH

Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone   : +49 89 189 47 41-16
Fax     : +49 89 189 47 41-09
E-Mail  : sebastian.huber at embedded-brains.de
PGP     : Public key available on request.

Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.