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| author |   Linus Torvalds <torvalds@linux-foundation.org> | 2021-05-06 09:56:26 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-05-06 09:56:26 -0700 |
| commit | 164e64adc246dd4239ab644dff86241d17cef218 (patch) | |
| tree | 9f5c402a7f2b36f9e012d3c79cb993422a099494 /Documentation | |
| parent | Merge tag 'devicetree-fixes-for-5.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux (diff) | |
| parent | Merge branches 'acpi-pm' and 'acpi-docs' (diff) | |
| download | linux-dev-164e64adc246dd4239ab644dff86241d17cef218.tar.xz linux-dev-164e64adc246dd4239ab644dff86241d17cef218.zip | |
Merge tag 'acpi-5.13-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI fixes from Rafael Wysocki:
"These revert one recent commit that turned out to be problematic,
address two issues in the ACPI "custom method" interface and update
GPIO properties documentation.
Specifics:
- Revent recent commit related to the handling of ACPI power
resources during initialization, because it turned out to cause
problems to occur on some systems (Rafael Wysocki).
- Fix potential use-after-free and potential memory leak in the ACPI
"custom method" debugfs interface (Mark Langsdorf).
- Update ACPI GPIO properties documentation to cover assumptions
regarding GPIO polarity (Andy Shevchenko)"
* tag 'acpi-5.13-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
Revert "ACPI: scan: Turn off unused power resources during initialization"
ACPI: custom_method: fix a possible memory leak
ACPI: custom_method: fix potential use-after-free issue
Documentation: firmware-guide: gpio-properties: Add note to SPI CS case
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/firmware-guide/acpi/gpio-properties.rst | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/firmware-guide/acpi/gpio-properties.rst b/Documentation/firmware-guide/acpi/gpio-properties.rst index 4e264c16ddff..df4b711053ee 100644 --- a/Documentation/firmware-guide/acpi/gpio-properties.rst +++ b/Documentation/firmware-guide/acpi/gpio-properties.rst @@ -99,6 +99,12 @@ native:: } } +Note, that historically ACPI has no means of the GPIO polarity and thus +the SPISerialBus() resource defines it on the per-chip basis. In order +to avoid a chain of negations, the GPIO polarity is considered being +Active High. Even for the cases when _DSD() is involved (see the example +above) the GPIO CS polarity must be defined Active High to avoid ambiguity. + Other supported properties ========================== |