Merging OLPC XO-1 DCON driver to mainstream kernel tree?

Andres Salomon dilinger at
Wed Feb 24 17:43:43 UTC 2010

On Wed, 24 Feb 2010 05:44:35 -0800
Greg KH <gregkh at> wrote:

> On Wed, Feb 24, 2010 at 12:26:55PM +0800, Raymond Lai wrote:
> > >
> > > Usually we just want a "clean" driver in one patch, but if you
> > > have the full history, in the proper place, I would consider it.
> > > Have a pointer to it somewhere?
> > >
> > 
> > Definitely.
> > 
> > It's in a full kernel tree, at
> > Driver itself is
> > integrated under drivers/video/geode
> > 
> > However, I also looked at the kernel tree on OLPC's own git too
> > 
> >
> > 
> > The DCON driver is moved out of drivers/video/geode and renamed as
> > olpc_dcon.* (previously gxfb_dcon.*) and had refactoring for
> > supporting XO-1 and XO-1.5. Seems the integration effort is not
> > small to me...
> Ok, then a "clean" patch would probably be the best thing to do.
> But first, why do you want this in drivers/staging/ ?  Why can't it be
> merged to the "proper" place in the kernel tree?  What is wrong with
> the code?

Multiple reasons; code like this:

                /* And turn off the DCON */
                outl(1<<11, gpio_base + GPIOx_OUT_VAL);

...which completely bypasses the cs5535-gpio driver.

and this:


geode_gpio_set became cs5535_gpio_set; not to mention that someone
needs to go through and look at which of these gpio calls need the
cs5535-specific gpio functions, and which can use the generic gpio

That's from the xo-1.5 branch, which doesn't contain the Via 1.5 work.
The olpc-2.6.31-updates contains more recent code, with
separate olpc_dcon.c, olpc_dcon_xo_1.c, and olpc_dcon_xo_1_5.c.
By putting the dcon into staging, I'm hoping not to conflict w/ their
work while cleaning up the driver.

Fwiw, I consider the dcon to only need a few hours of cleanup before
it's ready for drivers/video.  However, I consider the OFW driver work
that I'm currently in the midst of to be higher priority.  I'd planned
to clean up the dcon driver afterwards.

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