From: Mans Rullgard <mans@mansr.com>
To: Rob Herring <robh+dt@kernel.org>, Mark Rutland <mark.rutland@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-usb@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [RFC][PATCH] dt-bindings: usb: add non-removable device property
Date: Thu, 28 Feb 2019 14:33:44 +0000 [thread overview]
Message-ID: <20190228143344.16312-1-mans@mansr.com> (raw)
Add a boolean property indicating that a device is hardwired to the
upstream port. Although hubs can provide this information, they are not
always configured correctly. An alternate means of indicating this for
built-in USB devices is thus useful.
Signed-off-by: Mans Rullgard <mans@mansr.com>
---
I have a situation where userspace would like to know which USB devices
are built-in, but the on-board hub doesn't have the right setting.
Also, the hub itself can't be indicated as fixed in any other way that
I'm aware of.
In a way, adding this property seems a bit silly since dt can only
sensibly be used for hardwired devices in the first place. Thus the
mere presence of a dt node could be taken to indicate the same thing.
On the other hand, it's conceivable that someone might dynamically
generate a devicetree based on what happens to be connected on boot or
something. For that reason, and explicit property seems safer.
---
Documentation/devicetree/bindings/usb/usb-device.txt | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/Documentation/devicetree/bindings/usb/usb-device.txt b/Documentation/devicetree/bindings/usb/usb-device.txt
index 036be172b1ae..903d39b7e415 100644
--- a/Documentation/devicetree/bindings/usb/usb-device.txt
+++ b/Documentation/devicetree/bindings/usb/usb-device.txt
@@ -26,6 +26,10 @@ Required properties for device nodes:
- reg: the number of the USB hub port or the USB host-controller port to which
this device is attached. The range is 1-255.
+Optional properties for device nodes:
+- non-removable: boolean, if present the device is hardwired to the
+ upstream port.
+
Required properties for device nodes with interface nodes:
- #address-cells: shall be 2
@@ -55,6 +59,10 @@ Required properties for combined nodes:
- reg: the number of the USB hub port or the USB host-controller port to which
this device is attached. The range is 1-255.
+Optional properties for combined nodes:
+- non-removable: boolean, if present the device is hardwired to the
+ upstream port.
+
Required properties for hub nodes with device nodes:
- #address-cells: shall be 1
--
2.20.1
next reply other threads:[~2019-02-28 14:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-28 14:33 Mans Rullgard [this message]
2019-02-28 15:13 ` [RFC][PATCH] dt-bindings: usb: add non-removable device property Greg Kroah-Hartman
2019-02-28 15:22 ` Måns Rullgård
2019-02-28 15:52 ` Greg Kroah-Hartman
2019-02-28 17:34 ` Måns Rullgård
2019-02-28 18:06 ` Greg Kroah-Hartman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190228143344.16312-1-mans@mansr.com \
--to=mans@mansr.com \
--cc=devicetree@vger.kernel.org \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=robh+dt@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox