Merge tag 'docs-for-linus' of git://git.lwn.net/linux-2.6

Pull documentation updates from Jonathan Corbet:
 "Numerous fixes, the overdue removal of the i2o docs, some new Chinese
  translations, and, hopefully, the README fix that will end the flow of
  identical patches to that file"

* tag 'docs-for-linus' of git://git.lwn.net/linux-2.6: (34 commits)
  Documentation/memcg: update memcg/kmem status
  Documentation: blackfin: Makefile: Typo building issue
  Documentation/vm/pagemap.txt: correct location of page-types tool
  Documentation/memory-barriers.txt: typo fix
  doc: Add guest_nice column to example output of `cat /proc/stat'
  Documentation/kernel-parameters: Move "eagerfpu" to its right place
  Documentation: gpio: Update ACPI part of the document to mention _DSD
  docs/completion.txt: Various tweaks and corrections
  doc: completion: context, scope and language fixes
  Documentation:Update Documentation/zh_CN/arm64/memory.txt
  Documentation:Update Documentation/zh_CN/arm64/booting.txt
  Documentation: Chinese translation of arm64/legacy_instructions.txt
  DocBook media: fix broken EIA hyperlink
  Documentation: tweak the maintainers entry
  README: Change gzip/bzip2 to xz compression format
  README: Update version number reference
  doc:pci: Fix typo in Documentation/PCI
  Documentation: drm: Use '->' when describing access through pointers.
  Documentation: Remove mentioning of block barriers
  Documentation/email-clients.txt: Fix one grammar mistake, add extra info about TB
  ...

1 files changed, 37 insertions, 4 deletions

diff --git a/Documentation/gpio/board.txt b/Documentation/gpio/board.txt
index 8b35f51fe7b6..b80606de545a 100644
--- a/Documentation/gpio/board.txt
+++ b/Documentation/gpio/board.txt
@@ -50,10 +50,43 @@ gpiod_is_active_low(power) will be true).
 
 ACPI
 ----
-ACPI does not support function names for GPIOs. Therefore, only the "idx"
-argument of gpiod_get_index() is useful to discriminate between GPIOs assigned
-to a device. The "con_id" argument can still be set for debugging purposes (it
-will appear under error messages as well as debug and sysfs nodes).
+ACPI also supports function names for GPIOs in a similar fashion to DT.
+The above DT example can be converted to an equivalent ACPI description
+with the help of _DSD (Device Specific Data), introduced in ACPI 5.1:
+
+        Device (FOO) {
+                Name (_CRS, ResourceTemplate () {
+                        GpioIo (Exclusive, ..., IoRestrictionOutputOnly,
+                                "\\_SB.GPI0") {15} // red
+                        GpioIo (Exclusive, ..., IoRestrictionOutputOnly,
+                                "\\_SB.GPI0") {16} // green
+                        GpioIo (Exclusive, ..., IoRestrictionOutputOnly,
+                                "\\_SB.GPI0") {17} // blue
+                        GpioIo (Exclusive, ..., IoRestrictionOutputOnly,
+                                "\\_SB.GPI0") {1} // power
+                })
+
+                Name (_DSD, Package () {
+                        ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+                        Package () {
+                                Package () {
+                                        "led-gpios",
+                                        Package () {
+                                                ^FOO, 0, 0, 1,
+                                                ^FOO, 1, 0, 1,
+                                                ^FOO, 2, 0, 1,
+                                        }
+                                },
+                                Package () {
+                                        "power-gpios",
+                                        Package () {^FOO, 3, 0, 0},
+                                },
+                        }
+                })
+        }
+
+For more information about the ACPI GPIO bindings see
+Documentation/acpi/gpio-properties.txt.
 
 Platform Data
 -------------