Re: [PATCH] sysfs, device-tree: aid for debugging device tree boot problems
On Wed, Apr 23, 2014 at 11:48 PM, Frank Rowand wrote: > On 4/23/2014 4:54 AM, Grant Likely wrote: >> On Tue, 22 Apr 2014 20:20:44 -0700, Greg Kroah-Hartman >> wrote: >>> On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote: Create some infrastructure to aid trouble shooting device tree related boot issues. Add a %driver_name file to each device tree node sysfs directory which has had a driver bound to it. This allows detecting device tree nodes which failed to be bound to any driver. >>> >>> Why is this needed, shouldn't there already be a "driver" symlink in >>> sysfs for these devices when a driver binds to them? The rest of the >>> driver model works that way, why is of devices any different? >>> >> >> Because it hasn't been added yet! I only just committed the change to >> convert device_nodes into kobjects in v3.14. The next step is to add >> driver symlinks. > > No need to add a "driver" symlink. The device directories in sysfs already > have a driver symlink. Sorry, I meant of_node symlink. That is the bit I've been planning to add. g. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] sysfs, device-tree: aid for debugging device tree boot problems
On Wed, Apr 23, 2014 at 11:48 PM, Frank Rowand frowand.l...@gmail.com wrote: On 4/23/2014 4:54 AM, Grant Likely wrote: On Tue, 22 Apr 2014 20:20:44 -0700, Greg Kroah-Hartman gre...@linuxfoundation.org wrote: On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote: Create some infrastructure to aid trouble shooting device tree related boot issues. Add a %driver_name file to each device tree node sysfs directory which has had a driver bound to it. This allows detecting device tree nodes which failed to be bound to any driver. Why is this needed, shouldn't there already be a driver symlink in sysfs for these devices when a driver binds to them? The rest of the driver model works that way, why is of devices any different? Because it hasn't been added yet! I only just committed the change to convert device_nodes into kobjects in v3.14. The next step is to add driver symlinks. No need to add a driver symlink. The device directories in sysfs already have a driver symlink. Sorry, I meant of_node symlink. That is the bit I've been planning to add. g. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] sysfs, device-tree: aid for debugging device tree boot problems
On Wed, Apr 23, 2014 at 03:45:11PM -0700, Frank Rowand wrote:
> >> 3) To find list of device tree nodes with a bound driver:
> >>
> >> # output is: driver_name node_full_path
> >> #
> >> cd /proc/device-tree
> >> for k in `find . -name %driver_name` ; do
> >> echo `cat ${k}` `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'`
> >> done | sort
> >
> > If we take this patch, these examples should be somewhere in the
> > documentation to make it easy for others.
>
> That is a good idea. I'll package up the equivalent shell code from
> Grant's email. Any suggestions on location?
>
> scripts/debug/devicetree/
> scripts/devicetree/debug/
> Documentation/devicetree/scripts/
tools/ is probably the best place for them, or in Documentation/, either
would work.
thanks,
greg k-h
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Re: [PATCH] sysfs, device-tree: aid for debugging device tree boot problems
On 4/23/2014 4:54 AM, Grant Likely wrote: > On Tue, 22 Apr 2014 20:20:44 -0700, Greg Kroah-Hartman > wrote: >> On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote: >>> Create some infrastructure to aid trouble shooting device tree related >>> boot issues. >>> >>> Add a %driver_name file to each device tree node sysfs directory which has >>> had >>> a driver bound to it. This allows detecting device tree nodes which failed >>> to be bound to any driver. >> >> Why is this needed, shouldn't there already be a "driver" symlink in >> sysfs for these devices when a driver binds to them? The rest of the >> driver model works that way, why is of devices any different? >> > > Because it hasn't been added yet! I only just committed the change to > convert device_nodes into kobjects in v3.14. The next step is to add > driver symlinks. No need to add a "driver" symlink. The device directories in sysfs already have a driver symlink. > > That said, the devicetree node is already exposed in the uevent for a > device. It should already be possible to find all device tree nodes that > don't have a device, or devices without a driver: > > To get a list of all nodes: > > find /proc/device-tree/ -type d | sed -e 's/\/proc\/device-tree//' > > or a little more nuanced, only choosing nodes with a compatible property: > > for k in `find /proc/device-tree/ -name compatible`; do > echo $(dirname $k) | sed -e 's/\/proc\/device-tree//' > done | sort > > It can get even more refined than that if need be. > > To get a list of all nodes with a device that has been created: > > for k in `find devices -name uevent`; do > grep '^OF_FULLNAME' $k | sed -e 's/OF_FULLNAME=//' > done | sort < snip > Thanks Grant! I did not realize that uevent contained that information. -Frank -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] sysfs, device-tree: aid for debugging device tree boot problems
On 4/22/2014 8:20 PM, Greg Kroah-Hartman wrote:
> On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote:
>> Create some infrastructure to aid trouble shooting device tree related
>> boot issues.
>>
>> Add a %driver_name file to each device tree node sysfs directory which has
>> had
>> a driver bound to it. This allows detecting device tree nodes which failed
>> to be bound to any driver.
>
> Why is this needed, shouldn't there already be a "driver" symlink in
> sysfs for these devices when a driver binds to them? The rest of the
> driver model works that way, why is of devices any different?
Yes, the devices do have a "driver" symlink in sysfs.
The problem I had was that I could not deterministically determine the
device name in /sysfs that was associated with a device tree node that
the device was created for. And I couldn't find a link from the device
tree entries to the device tree node.
Grant's reply to your email provided the solution to my problem; the
device uevents file contains the full device tree path of the associated
device tree node.
Grant's reply removes the need for my patch.
>
>> Examples of using the %driver_name file (note that /proc/device-tree is a
>> link to the base of the device tree sysfs tree):
>>
>>
>> 1) To find list of device tree nodes with no driver:
>>
>> # A few false positives may be reported. For example,
>> # node_full_path of "." is the board.
>> #
>> # output is: node_full_path compatible_string
>> #
>> cd /proc/device-tree
>> for k in `find . -type d`; do
>> if [[ -f ${k}/compatible && ! -f ${k}/%driver_name ]] ; then
>> if [[ "`cat ${k}/compatible`" != "simple-bus" ]] ; then
>>echo `echo ${k} | sed -e 's|./||'` `cat ${k}/compatible`
>> fi
>> fi
>> done | sort
>>
>>
>> 2) To find list of device tree nodes with a bound driver:
>>
>> # output is: node_full_path driver_name
>> #
>> cd /proc/device-tree
>> for k in `find . -name %driver_name` ; do
>> echo `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'` `cat ${k}`
>> done | sort
>>
>>
>> 3) To find list of device tree nodes with a bound driver:
>>
>> # output is: driver_name node_full_path
>> #
>> cd /proc/device-tree
>> for k in `find . -name %driver_name` ; do
>> echo `cat ${k}` `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'`
>> done | sort
>
> If we take this patch, these examples should be somewhere in the
> documentation to make it easy for others.
That is a good idea. I'll package up the equivalent shell code from
Grant's email. Any suggestions on location?
scripts/debug/devicetree/
scripts/devicetree/debug/
Documentation/devicetree/scripts/
If there is no good location in the kernel tree, then I will put them
either on the devicetree wiki, or the devicetree section of the
elinux wiki.
>
>> Signed-off-by: Frank Rowand
>
> Minor nit, your From: line doesn't match this signed-off-by: so
> something has to change (or add a new From: line, like SubmittingPatches
> decribes how to do.)
Oops, thanks for pointing that out.
>
> thanks,
>
> greg k-h
-Frank
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Re: [PATCH] sysfs, device-tree: aid for debugging device tree boot problems
On Tue, 22 Apr 2014 20:20:44 -0700, Greg Kroah-Hartman
wrote:
> On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote:
> > Create some infrastructure to aid trouble shooting device tree related
> > boot issues.
> >
> > Add a %driver_name file to each device tree node sysfs directory which has
> > had
> > a driver bound to it. This allows detecting device tree nodes which failed
> > to be bound to any driver.
>
> Why is this needed, shouldn't there already be a "driver" symlink in
> sysfs for these devices when a driver binds to them? The rest of the
> driver model works that way, why is of devices any different?
>
Because it hasn't been added yet! I only just committed the change to
convert device_nodes into kobjects in v3.14. The next step is to add
driver symlinks.
That said, the devicetree node is already exposed in the uevent for a
device. It should already be possible to find all device tree nodes that
don't have a device, or devices without a driver:
To get a list of all nodes:
find /proc/device-tree/ -type d | sed -e 's/\/proc\/device-tree//'
or a little more nuanced, only choosing nodes with a compatible property:
for k in `find /proc/device-tree/ -name compatible`; do
echo $(dirname $k) | sed -e 's/\/proc\/device-tree//'
done | sort
It can get even more refined than that if need be.
To get a list of all nodes with a device that has been created:
for k in `find devices -name uevent`; do
grep '^OF_FULLNAME' $k | sed -e 's/OF_FULLNAME=//'
done | sort
To get a list of all nodes with a device that has been bound to a driver:
for k in `find devices -name uevent`; do
if [[ -d $(dirname $k)/driver ]]; then
grep '^OF_FULLNAME' $k | sed -e 's/OF_FULLNAME=//'
fi
done | sort
The suggestions you have below would be the anything in the first list
that isn't in the second or third:
bound=$(for k in `find /sys/devices -name uevent`; do
if [[ -d $(dirname $k)/driver ]]; then
grep '^OF_FULLNAME' $k | sed -e 's/OF_FULLNAME=//'
fi
done)
nodes=$(for k in `find /proc/device-tree/ -name compatible`; do
echo $(dirname $k) | sed -e 's/\/proc\/device-tree//'
done | sort)
for n in $nodes; do
if ! echo $bound | grep -q "$n"; then
echo $n $(cat /proc/device-tree/$n/compatible)
fi
done
> > Examples of using the %driver_name file (note that /proc/device-tree is a
> > link to the base of the device tree sysfs tree):
> >
> >
> > 1) To find list of device tree nodes with no driver:
> >
> > # A few false positives may be reported. For example,
> > # node_full_path of "." is the board.
> > #
> > # output is: node_full_path compatible_string
> > #
> > cd /proc/device-tree
> > for k in `find . -type d`; do
> > if [[ -f ${k}/compatible && ! -f ${k}/%driver_name ]] ; then
> > if [[ "`cat ${k}/compatible`" != "simple-bus" ]] ; then
> >echo `echo ${k} | sed -e 's|./||'` `cat ${k}/compatible`
> > fi
> > fi
> > done | sort
> >
> >
> > 2) To find list of device tree nodes with a bound driver:
> >
> > # output is: node_full_path driver_name
> > #
> > cd /proc/device-tree
> > for k in `find . -name %driver_name` ; do
> > echo `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'` `cat ${k}`
> > done | sort
> >
> >
> > 3) To find list of device tree nodes with a bound driver:
> >
> > # output is: driver_name node_full_path
> > #
> > cd /proc/device-tree
> > for k in `find . -name %driver_name` ; do
> > echo `cat ${k}` `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'`
> > done | sort
>
> If we take this patch, these examples should be somewhere in the
> documentation to make it easy for others.
>
> > Signed-off-by: Frank Rowand
>
> Minor nit, your From: line doesn't match this signed-off-by: so
> something has to change (or add a new From: line, like SubmittingPatches
> decribes how to do.)
>
> thanks,
>
> greg k-h
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Re: [PATCH] sysfs, device-tree: aid for debugging device tree boot problems
On 4/22/2014 8:20 PM, Greg Kroah-Hartman wrote:
On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote:
Create some infrastructure to aid trouble shooting device tree related
boot issues.
Add a %driver_name file to each device tree node sysfs directory which has
had
a driver bound to it. This allows detecting device tree nodes which failed
to be bound to any driver.
Why is this needed, shouldn't there already be a driver symlink in
sysfs for these devices when a driver binds to them? The rest of the
driver model works that way, why is of devices any different?
Yes, the devices do have a driver symlink in sysfs.
The problem I had was that I could not deterministically determine the
device name in /sysfs that was associated with a device tree node that
the device was created for. And I couldn't find a link from the device
tree entries to the device tree node.
Grant's reply to your email provided the solution to my problem; the
device uevents file contains the full device tree path of the associated
device tree node.
Grant's reply removes the need for my patch.
Examples of using the %driver_name file (note that /proc/device-tree is a
link to the base of the device tree sysfs tree):
1) To find list of device tree nodes with no driver:
# A few false positives may be reported. For example,
# node_full_path of . is the board.
#
# output is: node_full_path compatible_string
#
cd /proc/device-tree
for k in `find . -type d`; do
if [[ -f ${k}/compatible ! -f ${k}/%driver_name ]] ; then
if [[ `cat ${k}/compatible` != simple-bus ]] ; then
echo `echo ${k} | sed -e 's|./||'` `cat ${k}/compatible`
fi
fi
done | sort
2) To find list of device tree nodes with a bound driver:
# output is: node_full_path driver_name
#
cd /proc/device-tree
for k in `find . -name %driver_name` ; do
echo `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'` `cat ${k}`
done | sort
3) To find list of device tree nodes with a bound driver:
# output is: driver_name node_full_path
#
cd /proc/device-tree
for k in `find . -name %driver_name` ; do
echo `cat ${k}` `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'`
done | sort
If we take this patch, these examples should be somewhere in the
documentation to make it easy for others.
That is a good idea. I'll package up the equivalent shell code from
Grant's email. Any suggestions on location?
scripts/debug/devicetree/
scripts/devicetree/debug/
Documentation/devicetree/scripts/
If there is no good location in the kernel tree, then I will put them
either on the devicetree wiki, or the devicetree section of the
elinux wiki.
Signed-off-by: Frank Rowand frank.row...@sonymobile.com
Minor nit, your From: line doesn't match this signed-off-by: so
something has to change (or add a new From: line, like SubmittingPatches
decribes how to do.)
Oops, thanks for pointing that out.
thanks,
greg k-h
-Frank
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Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] sysfs, device-tree: aid for debugging device tree boot problems
On 4/23/2014 4:54 AM, Grant Likely wrote: On Tue, 22 Apr 2014 20:20:44 -0700, Greg Kroah-Hartman gre...@linuxfoundation.org wrote: On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote: Create some infrastructure to aid trouble shooting device tree related boot issues. Add a %driver_name file to each device tree node sysfs directory which has had a driver bound to it. This allows detecting device tree nodes which failed to be bound to any driver. Why is this needed, shouldn't there already be a driver symlink in sysfs for these devices when a driver binds to them? The rest of the driver model works that way, why is of devices any different? Because it hasn't been added yet! I only just committed the change to convert device_nodes into kobjects in v3.14. The next step is to add driver symlinks. No need to add a driver symlink. The device directories in sysfs already have a driver symlink. That said, the devicetree node is already exposed in the uevent for a device. It should already be possible to find all device tree nodes that don't have a device, or devices without a driver: To get a list of all nodes: find /proc/device-tree/ -type d | sed -e 's/\/proc\/device-tree//' or a little more nuanced, only choosing nodes with a compatible property: for k in `find /proc/device-tree/ -name compatible`; do echo $(dirname $k) | sed -e 's/\/proc\/device-tree//' done | sort It can get even more refined than that if need be. To get a list of all nodes with a device that has been created: for k in `find devices -name uevent`; do grep '^OF_FULLNAME' $k | sed -e 's/OF_FULLNAME=//' done | sort snip Thanks Grant! I did not realize that uevent contained that information. -Frank -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] sysfs, device-tree: aid for debugging device tree boot problems
On Wed, Apr 23, 2014 at 03:45:11PM -0700, Frank Rowand wrote:
3) To find list of device tree nodes with a bound driver:
# output is: driver_name node_full_path
#
cd /proc/device-tree
for k in `find . -name %driver_name` ; do
echo `cat ${k}` `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'`
done | sort
If we take this patch, these examples should be somewhere in the
documentation to make it easy for others.
That is a good idea. I'll package up the equivalent shell code from
Grant's email. Any suggestions on location?
scripts/debug/devicetree/
scripts/devicetree/debug/
Documentation/devicetree/scripts/
tools/ is probably the best place for them, or in Documentation/, either
would work.
thanks,
greg k-h
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] sysfs, device-tree: aid for debugging device tree boot problems
On Tue, 22 Apr 2014 20:20:44 -0700, Greg Kroah-Hartman
gre...@linuxfoundation.org wrote:
On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote:
Create some infrastructure to aid trouble shooting device tree related
boot issues.
Add a %driver_name file to each device tree node sysfs directory which has
had
a driver bound to it. This allows detecting device tree nodes which failed
to be bound to any driver.
Why is this needed, shouldn't there already be a driver symlink in
sysfs for these devices when a driver binds to them? The rest of the
driver model works that way, why is of devices any different?
Because it hasn't been added yet! I only just committed the change to
convert device_nodes into kobjects in v3.14. The next step is to add
driver symlinks.
That said, the devicetree node is already exposed in the uevent for a
device. It should already be possible to find all device tree nodes that
don't have a device, or devices without a driver:
To get a list of all nodes:
find /proc/device-tree/ -type d | sed -e 's/\/proc\/device-tree//'
or a little more nuanced, only choosing nodes with a compatible property:
for k in `find /proc/device-tree/ -name compatible`; do
echo $(dirname $k) | sed -e 's/\/proc\/device-tree//'
done | sort
It can get even more refined than that if need be.
To get a list of all nodes with a device that has been created:
for k in `find devices -name uevent`; do
grep '^OF_FULLNAME' $k | sed -e 's/OF_FULLNAME=//'
done | sort
To get a list of all nodes with a device that has been bound to a driver:
for k in `find devices -name uevent`; do
if [[ -d $(dirname $k)/driver ]]; then
grep '^OF_FULLNAME' $k | sed -e 's/OF_FULLNAME=//'
fi
done | sort
The suggestions you have below would be the anything in the first list
that isn't in the second or third:
bound=$(for k in `find /sys/devices -name uevent`; do
if [[ -d $(dirname $k)/driver ]]; then
grep '^OF_FULLNAME' $k | sed -e 's/OF_FULLNAME=//'
fi
done)
nodes=$(for k in `find /proc/device-tree/ -name compatible`; do
echo $(dirname $k) | sed -e 's/\/proc\/device-tree//'
done | sort)
for n in $nodes; do
if ! echo $bound | grep -q $n; then
echo $n $(cat /proc/device-tree/$n/compatible)
fi
done
Examples of using the %driver_name file (note that /proc/device-tree is a
link to the base of the device tree sysfs tree):
1) To find list of device tree nodes with no driver:
# A few false positives may be reported. For example,
# node_full_path of . is the board.
#
# output is: node_full_path compatible_string
#
cd /proc/device-tree
for k in `find . -type d`; do
if [[ -f ${k}/compatible ! -f ${k}/%driver_name ]] ; then
if [[ `cat ${k}/compatible` != simple-bus ]] ; then
echo `echo ${k} | sed -e 's|./||'` `cat ${k}/compatible`
fi
fi
done | sort
2) To find list of device tree nodes with a bound driver:
# output is: node_full_path driver_name
#
cd /proc/device-tree
for k in `find . -name %driver_name` ; do
echo `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'` `cat ${k}`
done | sort
3) To find list of device tree nodes with a bound driver:
# output is: driver_name node_full_path
#
cd /proc/device-tree
for k in `find . -name %driver_name` ; do
echo `cat ${k}` `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'`
done | sort
If we take this patch, these examples should be somewhere in the
documentation to make it easy for others.
Signed-off-by: Frank Rowand frank.row...@sonymobile.com
Minor nit, your From: line doesn't match this signed-off-by: so
something has to change (or add a new From: line, like SubmittingPatches
decribes how to do.)
thanks,
greg k-h
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] sysfs, device-tree: aid for debugging device tree boot problems
On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote:
> Create some infrastructure to aid trouble shooting device tree related
> boot issues.
>
> Add a %driver_name file to each device tree node sysfs directory which has had
> a driver bound to it. This allows detecting device tree nodes which failed
> to be bound to any driver.
Why is this needed, shouldn't there already be a "driver" symlink in
sysfs for these devices when a driver binds to them? The rest of the
driver model works that way, why is of devices any different?
> Examples of using the %driver_name file (note that /proc/device-tree is a
> link to the base of the device tree sysfs tree):
>
>
> 1) To find list of device tree nodes with no driver:
>
> # A few false positives may be reported. For example,
> # node_full_path of "." is the board.
> #
> # output is: node_full_path compatible_string
> #
> cd /proc/device-tree
> for k in `find . -type d`; do
> if [[ -f ${k}/compatible && ! -f ${k}/%driver_name ]] ; then
> if [[ "`cat ${k}/compatible`" != "simple-bus" ]] ; then
>echo `echo ${k} | sed -e 's|./||'` `cat ${k}/compatible`
> fi
> fi
> done | sort
>
>
> 2) To find list of device tree nodes with a bound driver:
>
> # output is: node_full_path driver_name
> #
> cd /proc/device-tree
> for k in `find . -name %driver_name` ; do
> echo `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'` `cat ${k}`
> done | sort
>
>
> 3) To find list of device tree nodes with a bound driver:
>
> # output is: driver_name node_full_path
> #
> cd /proc/device-tree
> for k in `find . -name %driver_name` ; do
> echo `cat ${k}` `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'`
> done | sort
If we take this patch, these examples should be somewhere in the
documentation to make it easy for others.
> Signed-off-by: Frank Rowand
Minor nit, your From: line doesn't match this signed-off-by: so
something has to change (or add a new From: line, like SubmittingPatches
decribes how to do.)
thanks,
greg k-h
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Re: [PATCH] sysfs, device-tree: aid for debugging device tree boot problems
On Tue, Apr 22, 2014 at 06:25:25PM -0700, Frank Rowand wrote:
Create some infrastructure to aid trouble shooting device tree related
boot issues.
Add a %driver_name file to each device tree node sysfs directory which has had
a driver bound to it. This allows detecting device tree nodes which failed
to be bound to any driver.
Why is this needed, shouldn't there already be a driver symlink in
sysfs for these devices when a driver binds to them? The rest of the
driver model works that way, why is of devices any different?
Examples of using the %driver_name file (note that /proc/device-tree is a
link to the base of the device tree sysfs tree):
1) To find list of device tree nodes with no driver:
# A few false positives may be reported. For example,
# node_full_path of . is the board.
#
# output is: node_full_path compatible_string
#
cd /proc/device-tree
for k in `find . -type d`; do
if [[ -f ${k}/compatible ! -f ${k}/%driver_name ]] ; then
if [[ `cat ${k}/compatible` != simple-bus ]] ; then
echo `echo ${k} | sed -e 's|./||'` `cat ${k}/compatible`
fi
fi
done | sort
2) To find list of device tree nodes with a bound driver:
# output is: node_full_path driver_name
#
cd /proc/device-tree
for k in `find . -name %driver_name` ; do
echo `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'` `cat ${k}`
done | sort
3) To find list of device tree nodes with a bound driver:
# output is: driver_name node_full_path
#
cd /proc/device-tree
for k in `find . -name %driver_name` ; do
echo `cat ${k}` `echo ${k} | sed -e 's|./||' -e 's|/%driver_name$||'`
done | sort
If we take this patch, these examples should be somewhere in the
documentation to make it easy for others.
Signed-off-by: Frank Rowand frank.row...@sonymobile.com
Minor nit, your From: line doesn't match this signed-off-by: so
something has to change (or add a new From: line, like SubmittingPatches
decribes how to do.)
thanks,
greg k-h
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