Re: Status variable

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On Friday 29 January 2016 14:13:20 Ryan wrote:
> Hello,
> 
> I am confused about the "status" variables on a device tree. What is
> the meaning of
> status="okay", status="enabled", status="disabled".
> 
> the function: __of_device_is_available returns 1 if the entry itself
> is not there.
> 
> Why is this?
> 
> Thanks for your time.

On status="disabled" is defined to have an effect and will prevent
the device from being used. Any other value or an absent status
property is interpreted as a working device.

The common way this is used is that a soc-specific .dtsi file lists
all devices that are present within the soc, but marks the ones as
disabled that are not always usable because they depend on a external
connection (e.g. a uart only makes sense if it talks to something,
while a timer device is always usable). A board specific file then
does not need to define the entire device but just override the
status as "okay".

	Arnd
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