[RFC PATCH 1/5] OMAP3:I2C: Add device tree nodes for beagle board

Shawn Guo shawn.guo at freescale.com
Thu Jul 21 08:33:49 EST 2011


On Wed, Jul 20, 2011 at 12:55:13PM -0600, Grant Likely wrote:
> On Wed, Jul 20, 2011 at 07:04:20PM +0800, Shawn Guo wrote:
> > > Mostly consistency.  Most of the experience we have with the flattened
> > > device tree up to this point hasn't bothered with the 'status'
> > > property.  It is only when AMP and hypervisors cam online that it
> > > became important to use a status property, and that only when the
> > > kernel needs to be told that the device does indeed exist, but it must
> > > not be touched.  I'd like to continue that pattern for new DT users
> > > with the default assumption that a device is enabled unless the board
> > > .dts explicitly disables it.
> [...]
> > Besides the bothering that we have to list so many unused controllers
> > in individual board dts file, it's also hard to tell which controllers
> > are actually available on the board.  People have to look at imx53.dts
> > to get a full list and then exclude the ones in imx53-<board>.dts as
> > "disabled".
> > 
> > And if we go the way opposite, adding "disabled" status for everyone
> > in imx53.dts, we will only need to specify the peripherals that are
> > actually available on board with "okay" status in imx53-<board>.dts.
> > And it's much more clear for people to see what peripherals are
> > available on individual board.
> > 
> > So I'm going the way than you suggested.  Please let me know if you
> > strongly dislikes it.
> 
> Yes, I strongly dislike it.  I understand the concern, but at this
> early stage with converting to device tree I think consistency between
> platforms is more important.  We can talk about the issue at Linaro
> Connect in 2 weeks, but in the mean time please use the
> enabled-by-default/explicitly-disabled pattern.
> 
Okay, hope you will not ask me to use the opposite pattern when you
actually see the patch :)

-- 
Regards,
Shawn



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