Merge remote-tracking branch 'driver-core/driver-core-next' into gpio/for-next

Documentation/driver-api/device_link.rst

@@ -281,7 +281,8 @@ State machine
   :c:func:`driver_bound()`.)
 
 * Before a consumer device is probed, presence of supplier drivers is
-  verified by checking that links to suppliers are in ``DL_STATE_AVAILABLE``
+  verified by checking the consumer device is not in the wait_for_suppliers
+  list and by checking that links to suppliers are in ``DL_STATE_AVAILABLE``
   state.  The state of the links is updated to ``DL_STATE_CONSUMER_PROBE``.
   (Call to :c:func:`device_links_check_suppliers()` from
   :c:func:`really_probe()`.)

Documentation/driver-api/driver-model/devres.rst

@@ -316,6 +316,10 @@ IOMAP
   devm_ioremap_nocache()
   devm_ioremap_wc()
   devm_ioremap_resource() : checks resource, requests memory region, ioremaps
+  devm_ioremap_resource_wc()
+  devm_platform_ioremap_resource() : calls devm_ioremap_resource() for platform device
+  devm_platform_ioremap_resource_wc()
+  devm_platform_ioremap_resource_byname()
   devm_iounmap()
   pcim_iomap()
   pcim_iomap_regions()	: do request_region() and iomap() on multiple BARs

Documentation/driver-api/driver-model/driver.rst

@@ -169,6 +169,49 @@ A driver's probe() may return a negative errno value to indicate that
 the driver did not bind to this device, in which case it should have
 released all resources it allocated::
 
+	void (*sync_state)(struct device *dev);
+
+sync_state is called only once for a device. It's called when all the consumer
+devices of the device have successfully probed. The list of consumers of the
+device is obtained by looking at the device links connecting that device to its
+consumer devices.
+
+The first attempt to call sync_state() is made during late_initcall_sync() to
+give firmware and drivers time to link devices to each other. During the first
+attempt at calling sync_state(), if all the consumers of the device at that
+point in time have already probed successfully, sync_state() is called right
+away. If there are no consumers of the device during the first attempt, that
+too is considered as "all consumers of the device have probed" and sync_state()
+is called right away.
+
+If during the first attempt at calling sync_state() for a device, there are
+still consumers that haven't probed successfully, the sync_state() call is
+postponed and reattempted in the future only when one or more consumers of the
+device probe successfully. If during the reattempt, the driver core finds that
+there are one or more consumers of the device that haven't probed yet, then
+sync_state() call is postponed again.
+
+A typical use case for sync_state() is to have the kernel cleanly take over
+management of devices from the bootloader. For example, if a device is left on
+and at a particular hardware configuration by the bootloader, the device's
+driver might need to keep the device in the boot configuration until all the
+consumers of the device have probed. Once all the consumers of the device have
+probed, the device's driver can synchronize the hardware state of the device to
+match the aggregated software state requested by all the consumers. Hence the
+name sync_state().
+
+While obvious examples of resources that can benefit from sync_state() include
+resources such as regulator, sync_state() can also be useful for complex
+resources like IOMMUs. For example, IOMMUs with multiple consumers (devices
+whose addresses are remapped by the IOMMU) might need to keep their mappings
+fixed at (or additive to) the boot configuration until all its consumers have
+probed.
+
+While the typical use case for sync_state() is to have the kernel cleanly take
+over management of devices from the bootloader, the usage of sync_state() is
+not restricted to that. Use it whenever it makes sense to take an action after
+all the consumers of a device have probed.
+
 	int 	(*remove)	(struct device *dev);
 
 remove is called to unbind a driver from a device. This may be