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path: root/Documentation/firmware-guide/acpi/gpio-properties.rst
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2023-02-14Documentation: firmware-guide: gpio-properties: Clarify Explicit and ImplicitAndy Shevchenko1-11/+24
Clarify the Explicit and Implicit meanings in the table of Pull Bias. While at it, distinguish pull bias keywords used in ACPI by using bold font in the table of the respective terms. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-03-08ACPI: docs: gpio-properties: Unify ASL style for GPIO examplesAndy Shevchenko1-12/+14
GPIO examples of ASL in the board.rst, enumeration.rst and gpio-properties.rst are not unified. Unify them for better reader experience. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2021-04-28Documentation: firmware-guide: gpio-properties: Add note to SPI CS caseAndy Shevchenko1-0/+6
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 an ambiguity, the GPIO polarity is considered being always Active High. Add note about this to the respective documentation file. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2021-01-22Documentation: ACPI: add new rule for gpio-line-namesFlavio Suligoi1-0/+1
The gpio-line-names lists must respect some rules. This patch adds a new rule in documentation, to avoid the use of duplicate names in the same gpiochip. Signed-off-by: Flavio Suligoi <f.suligoi@asem.it> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-11-16Documentation: ACPI: explain how to use gpio-line-namesFlavio Suligoi1-1/+55
The "gpio-line-names" declaration is not fully documented, so can be useful to add some important information and one more example. Signed-off-by: Flavio Suligoi <f.suligoi@asem.it> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-11-09Documentation: firmware-guide: gpio-properties: Clarify initial output stateAndy Shevchenko1-0/+23
GpioIo() doesn't provide an explicit state for an output pin. Linux tries to be smart and uses a common sense based on other parameters. Document how it looks like in the code. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-11-09Documentation: firmware-guide: gpio-properties: active_low only for GpioIo()Andy Shevchenko1-0/+3
It appears that people may misinterpret active_low field in _DSD for GpioInt() resource. Add a paragraph to clarify this. Reported-by: Ricardo Ribalda <ribalda@chromium.org> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Ricardo Ribalda <ribalda@chromium.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-11-09Documentation: firmware-guide: gpio-properties: Fix factual mistakesAndy Shevchenko1-14/+15
Fix factual mistakes and style issues in GPIO properties document. This converts IoRestriction from InputOnly to OutputOnly as pins in the example are used as outputs. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-04-26Documentation: ACPI: move gpio-properties.txt to firmware-guide/acpi and ↵Changbin Du1-0/+233
convert to reST This converts the plain text documentation to reStructuredText format and adds it to Sphinx TOC tree. No essential content change. Signed-off-by: Changbin Du <changbin.du@gmail.com> Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>