[PATCH 1/2] ARM i.MX51: setup mipi

Sascha Hauer s.hauer at pengutronix.de
Sat Jun 9 07:32:20 EDT 2012

On Thu, Jun 07, 2012 at 09:37:35PM +0800, Shawn Guo wrote:
> On Thu, Jun 07, 2012 at 10:43:36AM +0200, Sascha Hauer wrote:
> > On Thu, Jun 07, 2012 at 03:10:05PM +0800, Shawn Guo wrote:
> > > But why can't we do ipu reset (the second patch) in ipu driver then?
> > 
> > Ok, we might have to come up with something better. I originally had the
> > IPU reset in the IPU driver (copied from the FSL BSP). There are two
> > problems with this:
> > 
> > - The IPU reset is external to the IPU which means that we have to
> >   distinguish between SoCs.
> > - The IPU reset takes quite a long time (about 300ms). Doing this in
> >   the IPU driver means that the kernel boot delays for this time. Doing
> >   this in early init means that the 300ms can be spent bringing the rest
> >   of the system up.
> > 
> > As said, there are more clean ways to do this without having the two
> > mentioned problems, I'm just not sure whether it's worth it to put
> > significant amount of work into this.
> > 
> IMO, it's worth the effort.  Otherwise, we will end up with having
> such reset functions for IPU, VPU and GPU (maybe more on later SoC)
> over individual SoC initialization functions.  Well, VPU and GPU may
> be less concerned by the mainline tree, but from FSL perspective, we
> have to care about them.
> Also, how will you support that for imx6q, considering we already have
> src.c created as a little "driver" for imx6q System Reset Controller
> (SRC)?  I feel like that we should extend this little "driver" to
> support what you need for IPU reset here.

Do you have an idea what kind of API such a reset unit should export?
Are you thinking about some kind of reset_me(struct device *dev) or
what else?


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