In platforms/devices which have CONFIG_OF turned on but don't have a
populated DT, the calls to device_links_supplier_sync_state_pause() and
device_links_supplier_sync_state_resume() can get mismatched. This will
cause a warning during boot. Fix the warning by making sure the calls are
matched even in that case.
Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190807020559.74458-1-saravanak@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

of_link_is_valid() can be static since it's not used anywhere else.

of_link_property() return type should have been int instead of bool.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20190806192654.138605-1-saravanak@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Platform drivers now have the option to have the platform core create
and remove any needed sysfs attribute files.  So take advantage of that
and do not register "by hand" a lid sysfs file.

Cc: Darren Hart <dvhart@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: platform-driver-x86@vger.kernel.org
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20190731124349.4474-7-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Platform drivers now have the option to have the platform core create
and remove any needed sysfs attribute files.  So take advantage of that
and do not register "by hand" a bunch of sysfs files.

Cc: Darren Hart <dvhart@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: platform-driver-x86@vger.kernel.org
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20190731124349.4474-8-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Platform drivers now have the option to have the platform core create
and remove any needed sysfs attribute files.  So take advantage of that
and do not register "by hand" a bunch of sysfs files.

Cc: dri-devel@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20190731124349.4474-11-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Platform drivers now have the option to have the platform core create
and remove any needed sysfs attribute files.  So take advantage of that
and do not register "by hand" a bunch of sysfs files.

Cc: Tony Prisk <linux@prisktech.co.nz>
Cc: linux-arm-kernel@lists.infradead.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20190731124349.4474-10-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Platform drivers now have the option to have the platform core create
and remove any needed sysfs attribute files.  So take advantage of that
and do not register "by hand" a sysfs file.

Cc: Tony Prisk <linux@prisktech.co.nz>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20190731124349.4474-9-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Platform drivers now have the option to have the platform core create
and remove any needed sysfs attribute files.  So take advantage of that
and do not register "by hand" a sysfs group of attributes.
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20190731124349.4474-6-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Platform drivers now have the option to have the platform core create
and remove any needed sysfs attribute files.  So take advantage of that
and do not register "by hand" a sysfs group of attributes.

Link: https://lore.kernel.org/r/20190731124349.4474-3-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

dev_groups added to struct driver

Persistent tag for others to pull this branch from

This is the first patch in a longer series that adds the ability for the
driver core to create and remove a list of attribute groups
automatically when the device is bound/unbound from a specific driver.

See:
	https://lore.kernel.org/r/20190731124349.4474-2-gregkh@linuxfoundation.org
for details on this patch, and examples of how to use it in other
drivers.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add the ability for the driver core to create and remove a list of
attribute groups automatically when the device is bound/unbound from a
specific driver.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Tested-by: Richard Gong <richard.gong@linux.intel.com>
Link: https://lore.kernel.org/r/20190731124349.4474-2-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Default busses also have devices created for them. But there's no point
in creating device links for them. It's especially wasteful as it'll
cause the traversal of the entire device tree and also spend a lot of
time checking and figuring out that creating those links isn't allowed.
So check for default busses and skip trying to create device links for
them.
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190731221721.187713-8-saravanak@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

A parent device can have child devices that it adds when it probes. But
this probing of the parent device can happen way after kernel init is done
-- for example, when the parent device's driver is loaded as a module.

In such cases, if the child devices depend on a supplier in the system, we
need to make sure the supplier gets the sync_state() callback only after
these child devices are added and probed.

To achieve this, when creating device links for a device by looking at its
DT node, don't just look at DT references at the top node level. Look at DT
references in all the descendant nodes too and create device links from the
ancestor device to all these supplier devices.

This way, when the parent device probes and adds child devices, the child
devices can then create their own device links to the suppliers and further
delay the supplier's sync_state() callback to after the child devices are
probed.

Example:
In this illustration, -> denotes DT references and indentation
represents child status.

Device node A
	Device node B -> D
	Device node C -> B, D

Device node D

Assume all these devices have their drivers loaded as modules.

Without this patch, this is the sequence of events:
1. D is added.
2. A is added.
3. Device D probes.
4. Device D gets its sync_state() callback.
5. Device B and C might malfunction because their resources got
   altered/turned off before they can make active requests for them.

With this patch, this is the sequence of events:
1. D is added.
2. A is added and creates device links to D.
3. Device link from A to B is not added because A is a parent of B.
4. Device D probes.
5. Device D does not get it's sync_state() callback because consumer A
   hasn't probed yet.
5. Device A probes.
5. a. Devices B and C are added.
5. b. Device links from B and C to D are added.
5. c. Device A's probe completes.
6. Device D does not get it's sync_state() callback because consumer A
   has probed but consumers B and C haven't probed yet.
7. Device B and C probe.
8. Device D gets it's sync_state() callback because all its consumers
   have probed.
9. None of the devices malfunction.
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190731221721.187713-7-saravanak@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When all the top level devices are populated from DT during kernel
init, the supplier devices could be added and probed before the
consumer devices are added and linked to the suppliers. To avoid the
sync_state() callback from being called prematurely, pause the
sync_state() callbacks before populating the devices and resume them
at late_initcall_sync().

Similarly, when children devices are populated after kernel init using
of_platform_populate(), there could be supplier-consumer dependencies
between the children devices that are populated. To avoid the same
problem with sync_state() being called prematurely, pause and resume
sync_state() callbacks across of_platform_populate().
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190731221721.187713-6-saravanak@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This sync_state driver/bus callback is called once all the consumers
of a supplier have probed successfully.

This allows the supplier device's driver/bus to sync the supplier
device's state to the software state with the guarantee that all the
consumers are actively managing the resources provided by the supplier
device.

To maintain backwards compatibility and ease transition from existing
frameworks and resource cleanup schemes, late_initcall_sync is the
earliest when the sync_state callback might be called.

There is no upper bound on the time by which the sync_state callback
has to be called. This is because if a consumer device never probes,
the supplier has to maintain its resources in the state left by the
bootloader. For example, if the bootloader leaves the display
backlight at a fixed voltage and the backlight driver is never probed,
you don't want the backlight to ever be turned off after boot up.

Also, when multiple devices are added after kernel init, some
suppliers could be added before their consumer devices get added. In
these instances, the supplier devices could get their sync_state
callback called right after they probe because the consumers devices
haven't had a chance to create device links to the suppliers.

To handle this correctly, this change also provides APIs to
pause/resume sync state callbacks so that when multiple devices are
added, their sync_state callback evaluation can be postponed to happen
after all of them are added.

kbuild test robot reported missing documentation for device.state_synced
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190731221721.187713-5-saravanak@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add device-links after the devices are created (but before they are
probed) by looking at common DT bindings like clocks and
interconnects.

Automatically adding device-links for functional dependencies at the
framework level provides the following benefits:

- Optimizes device probe order and avoids the useless work of
  attempting probes of devices that will not probe successfully
  (because their suppliers aren't present or haven't probed yet).

  For example, in a commonly available mobile SoC, registering just
  one consumer device's driver at an initcall level earlier than the
  supplier device's driver causes 11 failed probe attempts before the
  consumer device probes successfully. This was with a kernel with all
  the drivers statically compiled in. This problem gets a lot worse if
  all the drivers are loaded as modules without direct symbol
  dependencies.

- Supplier devices like clock providers, interconnect providers, etc
  need to keep the resources they provide active and at a particular
  state(s) during boot up even if their current set of consumers don't
  request the resource to be active. This is because the rest of the
  consumers might not have probed yet and turning off the resource
  before all the consumers have probed could lead to a hang or
  undesired user experience.

  Some frameworks (Eg: regulator) handle this today by turning off
  "unused" resources at late_initcall_sync and hoping all the devices
  have probed by then. This is not a valid assumption for systems with
  loadable modules. Other frameworks (Eg: clock) just don't handle
  this due to the lack of a clear signal for when they can turn off
  resources. This leads to downstream hacks to handle cases like this
  that can easily be solved in the upstream kernel.

  By linking devices before they are probed, we give suppliers a clear
  count of the number of dependent consumers. Once all of the
  consumers are active, the suppliers can turn off the unused
  resources without making assumptions about the number of consumers.

By default we just add device-links to track "driver presence" (probe
succeeded) of the supplier device. If any other functionality provided
by device-links are needed, it is left to the consumer/supplier
devices to change the link when they probe.

kbuild test robot reported clang error about missing const
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190731221721.187713-4-saravanak@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The driver core/bus adding supplier-consumer dependencies by default
enables functional dependencies to be tracked correctly even when the
consumer devices haven't had their drivers registered or loaded (if they
are modules).

However, when the bus incorrectly adds dependencies that it shouldn't
have added, the devices might never probe.

For example, if device-C is a consumer of device-S and they have
phandles to each other in DT, the following could happen:

1.  Device-S get added first.
2.  The bus add_links() callback will (incorrectly) try to link it as
    a consumer of device-C.
3.  Since device-C isn't present, device-S will be put in
    "waiting-for-supplier" list.
4.  Device-C gets added next.
5.  All devices in "waiting-for-supplier" list are retried for linking.
6.  Device-S gets linked as consumer to Device-C.
7.  The bus add_links() callback will (correctly) try to link it as
    a consumer of device-S.
8.  This isn't allowed because it would create a cyclic device links.

Neither devices will get probed since the supplier is marked as
dependent on the consumer. And the consumer will never probe because the
consumer can't get resources from the supplier.

Without this patch, things stay in this broken state. However, with this
patch, the execution will continue like this:

9.  Device-C's driver is loaded.
10. Device-C's driver removes Device-S as a consumer of Device-C.
11. Device-C's driver adds Device-C as a consumer of Device-S.
12. Device-S probes.
14. Device-C probes.

kbuild test robot reported missing documentation for device.has_edit_links
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190731221721.187713-3-saravanak@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When devices are added, the bus might want to create device links to track
functional dependencies between supplier and consumer devices. This
tracking of supplier-consumer relationship allows optimizing device probe
order and tracking whether all consumers of a supplier are active. The
add_links bus callback is added to support this.

However, when consumer devices are added, they might not have a supplier
device to link to despite needing mandatory resources/functionality from
one or more suppliers. A waiting_for_suppliers list is created to track
such consumers and retry linking them when new devices get added.
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190731221721.187713-2-saravanak@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Document the parameters for bus_find_next_device() to avoid
htmldocs build warnings as reported below :

include/linux/device.h:236: warning: Function parameter or member 'bus' not described in 'bus_find_next_device'
include/linux/device.h:236: warning: Function parameter or member 'cur' not described in 'bus_find_next_device'
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20190801102026.27312-3-suzuki.poulose@arm.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix a typo in the comment describing the parameters for the new API, which
triggers the following warning for htmldocs:

include/linux/device.h:479: warning: Function parameter or member 'drv' not described in 'driver_find_device_by_acpi_dev'
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20190801102026.27312-2-suzuki.poulose@arm.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The patch "drivers: Introduce device lookup variants by ACPI_COMPANION device"
converted an incorrect instance in i2c driver to a new helper. Revert this
change.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Fixes: 00500147 ("drivers: Introduce device lookup variants by ACPI_COMPANION device")
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20190801102026.27312-1-suzuki.poulose@arm.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20190706164722.18766-3-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20190706164722.18766-2-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20190706164722.18766-1-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add a coccinelle script to check for the usage of dev_err() after a call
to platform_get_irq{,_byname}() as it's redundant now that the function
already prints an error when it fails.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Russell King - ARM Linux <linux@armlinux.org.uk>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Markus Elfring <Markus.Elfring@web.de>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730053845.126834-4-swboyd@chromium.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

A grep of the kernel shows that many drivers print an error message if
they fail to get the irq they're looking for. Furthermore, those drivers
all decide to print the device name, or not, and the irq they were
requesting, or not, etc. Let's consolidate all these error messages into
the API itself, allowing us to get rid of the error messages in each
driver.

Cc: Rob Herring <robh@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Russell King - ARM Linux <linux@armlinux.org.uk>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Markus Elfring <Markus.Elfring@web.de>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730053845.126834-2-swboyd@chromium.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This was on a separate branch so that others can pull it in.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Provide a helper to lookup platform devices by matching device
driver in order to avoid drivers trying to use platform bus
internals.

Cc: Eric Anholt <eric@anholt.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Heiko Stübner" <heiko@sntech.de>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Sandy Huang <hjc@rock-chips.com>
Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20190723221838.12024-8-suzuki.poulose@arm.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add a generic helper to match any/all devices. Using this
introduce new wrappers {bus/driver/class}_find_next_device().

Cc: Elie Morisse <syniurge@gmail.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Nehal Shah <nehal-bakulchandra.shah@amd.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Shyam Sundar S K <shyam-sundar.s-k@amd.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> # PCI
Link: https://lore.kernel.org/r/20190723221838.12024-7-suzuki.poulose@arm.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add a generic helper to match a device by the ACPI_COMPANION device
and provide wrappers for the device lookup APIs.

Cc: Len Brown <lenb@kernel.org>
Cc: linux-acpi@vger.kernel.org
Cc: linux-spi@vger.kernel.org
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: linux-i2c@vger.kernel.org
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de> # I2C parts
Link: https://lore.kernel.org/r/20190723221838.12024-6-suzuki.poulose@arm.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add a helper to match a device by its type and provide wrappers
for {bus/class/driver}_find_device() APIs.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-usb@vger.kernel.org
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20190723221838.12024-5-suzuki.poulose@arm.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add a helper to match the firmware node handle of a device and provide
wrappers for {bus/class/driver}_find_device() APIs to avoid proliferation
of duplicate custom match functions.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-usb@vger.kernel.org
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Joe Perches <joe@perches.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20190723221838.12024-4-suzuki.poulose@arm.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Introduce wrappers for {bus/driver/class}_find_device() to
locate devices by its of_node.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: dri-devel@lists.freedesktop.org
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: devicetree@vger.kernel.org
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: linux-i2c@vger.kernel.org
Cc: linux-rockchip@lists.infradead.org
Cc: linux-spi@vger.kernel.org
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Alan Tull <atull@kernel.org>
Cc: linux-fpga@vger.kernel.org
Cc: Peter Rosin <peda@axentia.se>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Thor Thayer <thor.thayer@linux.intel.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Peter Rosin <peda@axentia.se>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de> # I2C part
Acked-by: Moritz Fischer <mdf@kernel.org> # For FPGA part
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20190723221838.12024-3-suzuki.poulose@arm.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add a helper to match the device name for device lookup. Also
reuse this generic exported helper for the existing bus_find_device_by_name().
and add similar variants for driver/class.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: linux-leds@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Cc: linux-wpan@vger.kernel.org
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Stefan Schmidt <stefan@datenfreihafen.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20190723221838.12024-2-suzuki.poulose@arm.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

After commit 515db266 ("driver core: Remove device link creation
limitation"), if PM-runtime flags are passed to device_link_add(), it
will fail (returning NULL) due to an overly restrictive flags check
introduced by that commit.

Fix this issue by extending the check in question to cover the
PM-runtime flags too.

Fixes: 515db266 ("driver core: Remove device link creation limitation")
Reported-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/7674989.cD04D8YV3U@kreacherSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In kernfs_path_from_node_locked(), there is an if statement on line 147
to check whether buf is NULL:
    if (buf)

When buf is NULL, it is used on line 151:
    len += strlcpy(buf + len, parent_str, ...)
and line 158:
    len += strlcpy(buf + len, "/", ...)
and line 160:
    len += strlcpy(buf + len, kn->name, ...)

Thus, possible null-pointer dereferences may occur.

To fix these possible bugs, buf is checked before being used.
If it is NULL, -EINVAL is returned.

These bugs are found by a static analysis tool STCheck written by us.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Link: https://lore.kernel.org/r/20190724022242.27505-1-baijiaju1990@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Get root safely after kn is ensureed to be not null.
Signed-off-by: Peng Wang <rocking@whu.edu.cn>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20190708151611.13242-1-rocking@whu.edu.cnSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

If device_link_add() is called for a consumer/supplier pair with an
existing device link between them and the existing link's type is
not in agreement with the flags passed to that function by its
caller, NULL will be returned.  That is seriously inconvenient,
because it forces the callers of device_link_add() to worry about
what others may or may not do even if that is not relevant to them
for any other reasons.

It turns out, however, that this limitation can be made go away
relatively easily.

The underlying observation is that if DL_FLAG_STATELESS has been
passed to device_link_add() in flags for the given consumer/supplier
pair at least once, calling either device_link_del() or
device_link_remove() to release the link returned by it should work,
but there are no other requirements associated with that flag.  In
turn, if at least one of the callers of device_link_add() for the
given consumer/supplier pair has not passed DL_FLAG_STATELESS to it
in flags, the driver core should track the status of the link and act
on it as appropriate (ie. the link should be treated as "managed").
This means that DL_FLAG_STATELESS needs to be set for managed device
links and it should be valid to call device_link_del() or
device_link_remove() to drop references to them in certain
sutiations.

To allow that to happen, introduce a new (internal) device link flag
called DL_FLAG_MANAGED and make device_link_add() set it automatically
whenever DL_FLAG_STATELESS is not passed to it.  Also make it take
additional references to existing device links that were previously
stateless (that is, with DL_FLAG_STATELESS set and DL_FLAG_MANAGED
unset) and will need to be managed going forward and initialize
their status (which has been DL_STATE_NONE so far).

Accordingly, when a managed device link is dropped automatically
by the driver core, make it clear DL_FLAG_MANAGED, reset the link's
status back to DL_STATE_NONE and drop the reference to it associated
with DL_FLAG_MANAGED instead of just deleting it right away (to
allow it to stay around in case it still needs to be released
explicitly by someone).

With that, since setting DL_FLAG_STATELESS doesn't mean that the
device link in question is not managed any more, replace all of the
status-tracking checks against DL_FLAG_STATELESS with analogous
checks against DL_FLAG_MANAGED and update the documentation to
reflect these changes.

While at it, make device_link_add() reject flags that it does not
recognize, including DL_FLAG_MANAGED.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Saravana Kannan <saravanak@google.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Review-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/2305283.AStDPdUUnE@kreacherSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull Devicetree fixes from Rob Herring:
 "Fix several warnings/errors in validation of binding schemas"

* tag 'devicetree-fixes-for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
  dt-bindings: pinctrl: stm32: Fix missing 'clocks' property in examples
  dt-bindings: iio: ad7124: Fix dtc warnings in example
  dt-bindings: iio: avia-hx711: Fix avdd-supply typo in example
  dt-bindings: pinctrl: aspeed: Fix AST2500 example errors
  dt-bindings: pinctrl: aspeed: Fix 'compatible' schema errors
  dt-bindings: riscv: Limit cpus schema to only check RiscV 'cpu' nodes
  dt-bindings: Ensure child nodes are of type 'object'