Commit fe151462 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'driver-core-5.10-rc1' of... 

Merge tag 'driver-core-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the "big" set of driver core patches for 5.10-rc1

  They include a lot of different things, all related to the driver core
  and/or some driver logic:

   - sysfs common write functions to make it easier to audit sysfs
     attributes

   - device connection cleanups and fixes

   - devm helpers for a few functions

   - NOIO allocations for when devices are being removed

   - minor cleanups and fixes

  All have been in linux-next for a while with no reported issues"

* tag 'driver-core-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (31 commits)
  regmap: debugfs: use semicolons rather than commas to separate statements
  platform/x86: intel_pmc_core: do not create a static struct device
  drivers core: node: Use a more typical macro definition style for ACCESS_ATTR
  drivers core: Use sysfs_emit for shared_cpu_map_show and shared_cpu_list_show
  mm: and drivers core: Convert hugetlb_report_node_meminfo to sysfs_emit
  drivers core: Miscellaneous changes for sysfs_emit
  drivers core: Reindent a couple uses around sysfs_emit
  drivers core: Remove strcat uses around sysfs_emit and neaten
  drivers core: Use sysfs_emit and sysfs_emit_at for show(device *...) functions
  sysfs: Add sysfs_emit and sysfs_emit_at to format sysfs output
  dyndbg: use keyword, arg varnames for query term pairs
  driver core: force NOIO allocations during unplug
  platform_device: switch to simpler IDA interface
  driver core: platform: Document return type of more functions
  Revert "driver core: Annotate dev_err_probe() with __must_check"
  Revert "test_firmware: Test platform fw loading on non-EFI systems"
  iio: adc: xilinx-xadc: use devm_krealloc()
  hwmon: pmbus: use more devres helpers
  devres: provide devm_krealloc()
  syscore: Use pm_pr_dbg() for syscore_{suspend,resume}()
  ...
parents 5d6c413c ee490677

Documentation/driver-api/device_connection.rst

deleted100644 → 0
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==================

Device connections

==================



Introduction

------------



Devices often have connections to other devices that are outside of the direct

child/parent relationship. A serial or network communication controller, which

could be a PCI device, may need to be able to get a reference to its PHY

component, which could be attached for example to the I2C bus. Some device

drivers need to be able to control the clocks or the GPIOs for their devices,

and so on.



Device connections are generic descriptions of any type of connection between

two separate devices.



Device connections alone do not create a dependency between the two devices.

They are only descriptions which are not tied to either of the devices directly.

A dependency between the two devices exists only if one of the two endpoint

devices requests a reference to the other. The descriptions themselves can be

defined in firmware (not yet supported) or they can be built-in.



Usage

-----



Device connections should exist before device ``->probe`` callback is called for

either endpoint device in the description. If the connections are defined in

firmware, this is not a problem. It should be considered if the connection

descriptions are "built-in", and need to be added separately.



The connection description consists of the names of the two devices with the

connection, i.e. the endpoints, and unique identifier for the connection which

is needed if there are multiple connections between the two devices.



After a description exists, the devices in it can request reference to the other

endpoint device, or they can request the description itself.



API

---



.. kernel-doc:: drivers/base/devcon.c

   :functions: device_connection_find_match device_connection_find device_connection_add device_connection_remove

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

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@@ -354,6 +354,7 @@ MEM 
  devm_kmalloc()

  devm_kmalloc_array()

  devm_kmemdup()

  devm_krealloc()

  devm_kstrdup()

  devm_kvasprintf()

  devm_kzalloc()

Documentation/driver-api/firmware/fallback-mechanisms.rst

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@@ -42,6 +42,7 @@ fallback mechanism: 
  supported for request_firmware_into_buf().



* Firmware is not accessible through typical means:



        * It cannot be installed into the root filesystem

        * The firmware provides very unique device specific data tailored for

          the unit gathered with local information. An example is calibration

Documentation/driver-api/index.rst

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@@ -22,7 +22,6 @@ available subsections can be seen below. 
   pm/index

   clk

   device-io

   device_connection

   dma-buf

   device_link

   component

Documentation/filesystems/sysfs.rst

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@@ -241,12 +241,10 @@ Other notes: 
  is 4096.



- show() methods should return the number of bytes printed into the

  buffer. This is the return value of scnprintf().

  buffer.



- show() must not use snprintf() when formatting the value to be

  returned to user space. If you can guarantee that an overflow

  will never happen you can use sprintf() otherwise you must use

  scnprintf().

- show() should only use sysfs_emit() or sysfs_emit_at() when formatting

  the value to be returned to user space.



- store() should return the number of bytes used from the buffer. If the

  entire buffer has been used, just return the count argument.

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