2020-10-30 15:40:38 +08:00
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Note:
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This documents additional properties of any device beyond what
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is documented in Documentation/admin-guide/sysfs-rules.rst
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drivers/core/of: Add symlink to device-tree from devices with an OF node
So I've been annoyed lately with having a bunch of devices such as i2c
eeproms (for use by VPDs, server world !) and other bits and pieces that
I want to be able to identify from userspace, and possibly provide
additional data about from FW.
Basically, it boils down to correlating the sysfs device with the OF
tree device node, so that user space can use device-tree info such as
additional "location" or "label" (or whatever else we can come up with)
propreties to identify a given device, or get some attributes of use
about it, etc...
Now, so far, we've done that in some subsystem in a fairly ad-hoc basis
using "devspec" properties. For example, PCI creates them if it can
correlate the probed device with a DT node. Some powerpc specific busses
do that too.
However, i2c doesn't and it would be nice to have something more generic
since technically any device can have a corresponding device tree node.
This patch adds an "of_node" symlink to devices that have a non-NULL
dev->of_node pointer, the patch is pretty trivial and seems to work just
fine for me.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-02-18 08:25:18 +08:00
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2016-05-20 20:23:38 +08:00
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What: /sys/devices/*/of_node
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drivers/core/of: Add symlink to device-tree from devices with an OF node
So I've been annoyed lately with having a bunch of devices such as i2c
eeproms (for use by VPDs, server world !) and other bits and pieces that
I want to be able to identify from userspace, and possibly provide
additional data about from FW.
Basically, it boils down to correlating the sysfs device with the OF
tree device node, so that user space can use device-tree info such as
additional "location" or "label" (or whatever else we can come up with)
propreties to identify a given device, or get some attributes of use
about it, etc...
Now, so far, we've done that in some subsystem in a fairly ad-hoc basis
using "devspec" properties. For example, PCI creates them if it can
correlate the probed device with a DT node. Some powerpc specific busses
do that too.
However, i2c doesn't and it would be nice to have something more generic
since technically any device can have a corresponding device tree node.
This patch adds an "of_node" symlink to devices that have a non-NULL
dev->of_node pointer, the patch is pretty trivial and seems to work just
fine for me.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-02-18 08:25:18 +08:00
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Date: February 2015
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Contact: Device Tree mailing list <devicetree@vger.kernel.org>
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Description:
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Any device associated with a device-tree node will have
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an of_path symlink pointing to the corresponding device
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node in /sys/firmware/devicetree/
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2016-10-07 03:06:12 +08:00
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What: /sys/devices/*/devspec
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Date: October 2016
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Contact: Device Tree mailing list <devicetree@vger.kernel.org>
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Description:
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If CONFIG_OF is enabled, then this file is present. When
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read, it returns full name of the device node.
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What: /sys/devices/*/obppath
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Date: October 2016
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Contact: Device Tree mailing list <devicetree@vger.kernel.org>
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Description:
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If CONFIG_OF is enabled, then this file is present. When
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read, it returns full name of the device node.
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2021-09-27 21:59:38 +08:00
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What: /sys/devices/*/dev
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Date: Jun 2006
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Contact: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Description:
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Major and minor numbers of the character device corresponding
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to the device (in <major>:<minor> format).
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