On 09/08/2016 08:38 AM, Rob Herring wrote:
On Wed, Aug 31, 2016 at 4:41 PM, Tony Lindgren <tony@xxxxxxxxxxx> wrote:
[...]
It is unfortunate that Linux has adopted the practice of overloading status
to determine whether a piece of hardware exists or does not exist. This
is extremely useful for the way we structure the .dts and .dtsi files but
should have used a new property name. We are stuck with that choice of
using the status property for two purposes, first the state of a device,
and secondly the hardware description of existing or not existing.
I don't agree. Generally, disabled means the h/w is there, but don't
use it. There may be some cases where the hardware doesn't exist for
the convenience of having a single dts, but that's the exception.
Minor point here: when SoCs are manufactured, even though the silicon
die may have a hardware block, it is completely efused out based on
paper spin. in effect such a hardware block "does not exist". The
number of such paper spins are not exception cases, but rather
standard for SoC vendors - maintaining dts per paper spin is just too
impossible to maintain (DRA7 as an example maintains a single
dra7.dtsi as the root for all paper spins.. the variations if
maintained as seperate dts might infact end up being larger in number
than all the dts we have in arch/arm/boot/dts) - typically as an soc
vendor pushes a specific SoC to multiple markets, this tends to be a norm.
--
Regards,
Nishanth Menon
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
