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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-07 10:53:36 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-07 10:53:36 -0700 |
commit | f558b8364e19f9222e7976c64e9367f66bab02cc (patch) | |
tree | c50c0fc9a3ab8430c4aaa1170d1cc1e08448bd7b /Documentation/driver-api | |
parent | 80ef846e9909f22ccdc2a4a6d931266cecce8b2c (diff) | |
parent | 8c3e315d4296421cd26b3300ee0ac117f0877f20 (diff) |
Merge tag 'driver-core-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here is the set of driver core patches for 5.8-rc1.
Not all that huge this release, just a number of small fixes and
updates:
- software node fixes
- kobject now sends KOBJ_REMOVE when it is removed from sysfs, not
when it is removed from memory (which could come much later)
- device link additions and fixes based on testing on more devices
- firmware core cleanups
- other minor changes, full details in the shortlog
All have been in linux-next for a while with no reported issues"
* tag 'driver-core-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (23 commits)
driver core: Update device link status correctly for SYNC_STATE_ONLY links
firmware_loader: change enum fw_opt to u32
software node: implement software_node_unregister()
kobject: send KOBJ_REMOVE uevent when the object is removed from sysfs
driver core: Remove unnecessary is_fwnode_dev variable in device_add()
drivers property: When no children in primary, try secondary
driver core: platform: Fix spelling errors in platform.c
driver core: Remove check in driver_deferred_probe_force_trigger()
of: platform: Batch fwnode parsing when adding all top level devices
driver core: fw_devlink: Add support for batching fwnode parsing
driver core: Look for waiting consumers only for a fwnode's primary device
driver core: Move code to the right part of the file
Revert "Revert "driver core: Set fw_devlink to "permissive" behavior by default""
drivers: base: Fix NULL pointer exception in __platform_driver_probe() if a driver developer is foolish
firmware_loader: move fw_fallback_config to a private kernel symbol namespace
driver core: Add missing '\n' in log messages
driver/base/soc: Use kobj_to_dev() API
Add documentation on meaning of -EPROBE_DEFER
driver core: platform: remove redundant assignment to variable ret
debugfs: Use the correct style for SPDX License Identifier
...
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r-- | Documentation/driver-api/driver-model/driver.rst | 32 |
1 files changed, 27 insertions, 5 deletions
diff --git a/Documentation/driver-api/driver-model/driver.rst b/Documentation/driver-api/driver-model/driver.rst index 63887b813005..7d5040f6a3d8 100644 --- a/Documentation/driver-api/driver-model/driver.rst +++ b/Documentation/driver-api/driver-model/driver.rst @@ -4,7 +4,6 @@ Device Drivers See the kerneldoc for the struct device_driver. - Allocation ~~~~~~~~~~ @@ -167,9 +166,26 @@ the driver to that device. 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:: +released all resources it allocated. + +Optionally, probe() may return -EPROBE_DEFER if the driver depends on +resources that are not yet available (e.g., supplied by a driver that +hasn't initialized yet). The driver core will put the device onto the +deferred probe list and will try to call it again later. If a driver +must defer, it should return -EPROBE_DEFER as early as possible to +reduce the amount of time spent on setup work that will need to be +unwound and reexecuted at a later time. + +.. warning:: + -EPROBE_DEFER must not be returned if probe() has already created + child devices, even if those child devices are removed again + in a cleanup path. If -EPROBE_DEFER is returned after a child + device has been registered, it may result in an infinite loop of + .probe() calls to the same driver. + +:: - void (*sync_state)(struct device *dev); + 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 @@ -212,6 +228,8 @@ 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 @@ -224,11 +242,15 @@ not. It should free any resources allocated specifically for the device; i.e. anything in the device's driver_data field. If the device is still present, it should quiesce the device and place -it into a supported low-power state:: +it into a supported low-power state. + +:: int (*suspend) (struct device *dev, pm_message_t state); -suspend is called to put the device in a low power state:: +suspend is called to put the device in a low power state. + +:: int (*resume) (struct device *dev); |