From: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
To: Ryan <ryanphilips19-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: Status variable
Date: Fri, 29 Jan 2016 09:49:37 +0100 [thread overview]
Message-ID: <3706345.JqhHqFGYfF@wuerfel> (raw)
In-Reply-To: <CANMsd02jhaouPBuySWXQ2edE+gyMZ3dncobipKa-dg1vLJCE2Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
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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next prev parent reply other threads:[~2016-01-29 8:49 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-29 8:43 Status variable Ryan
[not found] ` <CANMsd02jhaouPBuySWXQ2edE+gyMZ3dncobipKa-dg1vLJCE2Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-01-29 8:49 ` Arnd Bergmann [this message]
2016-01-29 9:10 ` Ryan
[not found] ` <CANMsd01PnqUe+NVp-OGE3aMN=k1b4KX_D5YBnQAbPuHcT1+SWQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-01-29 9:18 ` Arnd Bergmann
2016-01-29 9:23 ` Ryan
[not found] ` <CANMsd01ty4H3mP0-6kyc0ZxMBAd7p2Y6o7dHy4sFSGhog22R2w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-01-29 9:30 ` Arnd Bergmann
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