Re: [PATCH v4 08/63] Documentation: ACPI: move gpio-properties.txt to firmware-guide/acpi and convert to reST

[Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>]

Em Wed, 24 Apr 2019 00:28:37 +0800
Changbin Du <changbin.du@xxxxxxxxx> escreveu:

> This converts the plain text documentation to reStructuredText format and
> add it to Sphinx TOC tree. No essential content change.
> 
> Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx>
> ---
>  .../acpi/gpio-properties.rst}                 | 78 +++++++++++--------
>  Documentation/firmware-guide/acpi/index.rst   |  1 +
>  MAINTAINERS                                   |  2 +-
>  3 files changed, 46 insertions(+), 35 deletions(-)
>  rename Documentation/{acpi/gpio-properties.txt => firmware-guide/acpi/gpio-properties.rst} (81%)
> 
> diff --git a/Documentation/acpi/gpio-properties.txt b/Documentation/firmware-guide/acpi/gpio-properties.rst
> similarity index 81%
> rename from Documentation/acpi/gpio-properties.txt
> rename to Documentation/firmware-guide/acpi/gpio-properties.rst
> index 88c65cb5bf0a..89c636963544 100644
> --- a/Documentation/acpi/gpio-properties.txt
> +++ b/Documentation/firmware-guide/acpi/gpio-properties.rst
> @@ -1,5 +1,8 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +======================================
>  _DSD Device Properties Related to GPIO
> ---------------------------------------
> +======================================
>  
>  With the release of ACPI 5.1, the _DSD configuration object finally
>  allows names to be given to GPIOs (and other things as well) returned
> @@ -8,7 +11,7 @@ the corresponding GPIO, which is pretty error prone (it depends on
>  the _CRS output ordering, for example).
>  
>  With _DSD we can now query GPIOs using a name instead of an integer
> -index, like the ASL example below shows:
> +index, like the ASL example below shows::
>  
>    // Bluetooth device with reset and shutdown GPIOs
>    Device (BTH)
> @@ -34,15 +37,19 @@ index, like the ASL example below shows:
>        })
>    }
>  
> -The format of the supported GPIO property is:
> +The format of the supported GPIO property is::
>  
>    Package () { "name", Package () { ref, index, pin, active_low }}
>  
> -  ref - The device that has _CRS containing GpioIo()/GpioInt() resources,
> -        typically this is the device itself (BTH in our case).
> -  index - Index of the GpioIo()/GpioInt() resource in _CRS starting from zero.
> -  pin - Pin in the GpioIo()/GpioInt() resource. Typically this is zero.
> -  active_low - If 1 the GPIO is marked as active_low.
> +ref
> +  The device that has _CRS containing GpioIo()/GpioInt() resources,
> +  typically this is the device itself (BTH in our case).
> +index
> +  Index of the GpioIo()/GpioInt() resource in _CRS starting from zero.
> +pin
> +  Pin in the GpioIo()/GpioInt() resource. Typically this is zero.
> +active_low
> +  If 1 the GPIO is marked as active_low.
>  
>  Since ACPI GpioIo() resource does not have a field saying whether it is
>  active low or high, the "active_low" argument can be used here.  Setting
> @@ -55,7 +62,7 @@ It is possible to leave holes in the array of GPIOs. This is useful in
>  cases like with SPI host controllers where some chip selects may be
>  implemented as GPIOs and some as native signals. For example a SPI host
>  controller can have chip selects 0 and 2 implemented as GPIOs and 1 as
> -native:
> +native::
>  
>    Package () {
>        "cs-gpios",
> @@ -67,7 +74,7 @@ native:
>    }
>  
>  Other supported properties
> ---------------------------
> +==========================
>  
>  Following Device Tree compatible device properties are also supported by
>  _DSD device properties for GPIO controllers:
> @@ -78,7 +85,7 @@ _DSD device properties for GPIO controllers:
>  - input
>  - line-name
>  
> -Example:
> +Example::
>  
>    Name (_DSD, Package () {
>        // _DSD Hierarchical Properties Extension UUID
> @@ -100,7 +107,7 @@ Example:
>  
>  - gpio-line-names
>  
> -Example:
> +Example::
>  
>    Package () {
>        "gpio-line-names",
> @@ -114,7 +121,7 @@ See Documentation/devicetree/bindings/gpio/gpio.txt for more information
>  about these properties.
>  
>  ACPI GPIO Mappings Provided by Drivers
> ---------------------------------------
> +======================================
>  
>  There are systems in which the ACPI tables do not contain _DSD but provide _CRS
>  with GpioIo()/GpioInt() resources and device drivers still need to work with
> @@ -139,16 +146,16 @@ line in that resource starting from zero, and the active-low flag for that line,
>  respectively, in analogy with the _DSD GPIO property format specified above.
>  
>  For the example Bluetooth device discussed previously the data structures in
> -question would look like this:
> +question would look like this::
>  
> -static const struct acpi_gpio_params reset_gpio = { 1, 1, false };
> -static const struct acpi_gpio_params shutdown_gpio = { 0, 0, false };
> +  static const struct acpi_gpio_params reset_gpio = { 1, 1, false };
> +  static const struct acpi_gpio_params shutdown_gpio = { 0, 0, false };
>  
> -static const struct acpi_gpio_mapping bluetooth_acpi_gpios[] = {
> -  { "reset-gpios", &reset_gpio, 1 },
> -  { "shutdown-gpios", &shutdown_gpio, 1 },
> -  { },
> -};
> +  static const struct acpi_gpio_mapping bluetooth_acpi_gpios[] = {
> +    { "reset-gpios", &reset_gpio, 1 },
> +    { "shutdown-gpios", &shutdown_gpio, 1 },
> +    { },
> +  };
>  
>  Next, the mapping table needs to be passed as the second argument to
>  acpi_dev_add_driver_gpios() that will register it with the ACPI device object
> @@ -158,12 +165,12 @@ calling acpi_dev_remove_driver_gpios() on the ACPI device object where that
>  table was previously registered.
>  
>  Using the _CRS fallback
> ------------------------
> +=======================
>  
>  If a device does not have _DSD or the driver does not create ACPI GPIO
>  mapping, the Linux GPIO framework refuses to return any GPIOs. This is
>  because the driver does not know what it actually gets. For example if we
> -have a device like below:
> +have a device like below::
>  
>    Device (BTH)
>    {
> @@ -177,7 +184,7 @@ have a device like below:
>        })
>    }
>  
> -The driver might expect to get the right GPIO when it does:
> +The driver might expect to get the right GPIO when it does:：

Hmm... there is a small typo here:

	": :" -> "::"

For the conversion itself, after correcting the above typo:

Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>



>  
>    desc = gpiod_get(dev, "reset", GPIOD_OUT_LOW);
>  
> @@ -193,22 +200,25 @@ the ACPI GPIO mapping tables are hardly linked to ACPI ID and certain
>  objects, as listed in the above chapter, of the device in question.
>  
>  Getting GPIO descriptor
> ------------------------
> +=======================
> +
> +There are two main approaches to get GPIO resource from ACPI::
>  
> -There are two main approaches to get GPIO resource from ACPI:
> -	desc = gpiod_get(dev, connection_id, flags);
> -	desc = gpiod_get_index(dev, connection_id, index, flags);
> +  desc = gpiod_get(dev, connection_id, flags);
> +  desc = gpiod_get_index(dev, connection_id, index, flags);
>  
>  We may consider two different cases here, i.e. when connection ID is
>  provided and otherwise.
>  
> -Case 1:
> -	desc = gpiod_get(dev, "non-null-connection-id", flags);
> -	desc = gpiod_get_index(dev, "non-null-connection-id", index, flags);
> +Case 1::
> +
> +  desc = gpiod_get(dev, "non-null-connection-id", flags);
> +  desc = gpiod_get_index(dev, "non-null-connection-id", index, flags);
> +
> +Case 2::
>  
> -Case 2:
> -	desc = gpiod_get(dev, NULL, flags);
> -	desc = gpiod_get_index(dev, NULL, index, flags);
> +  desc = gpiod_get(dev, NULL, flags);
> +  desc = gpiod_get_index(dev, NULL, index, flags);
>  
>  Case 1 assumes that corresponding ACPI device description must have
>  defined device properties and will prevent to getting any GPIO resources
> diff --git a/Documentation/firmware-guide/acpi/index.rst b/Documentation/firmware-guide/acpi/index.rst
> index 0e05b843521c..61d67763851b 100644
> --- a/Documentation/firmware-guide/acpi/index.rst
> +++ b/Documentation/firmware-guide/acpi/index.rst
> @@ -11,3 +11,4 @@ ACPI Support
>     enumeration
>     osi
>     DSD-properties-rules
> +   gpio-properties
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 09f43f1bdd15..87f930bf32ad 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6593,7 +6593,7 @@ M:	Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
>  L:	linux-gpio@xxxxxxxxxxxxxxx
>  L:	linux-acpi@xxxxxxxxxxxxxxx
>  S:	Maintained
> -F:	Documentation/acpi/gpio-properties.txt
> +F:	Documentation/firmware-guide/acpi/gpio-properties.rst
>  F:	drivers/gpio/gpiolib-acpi.c
>  
>  GPIO IR Transmitter



Thanks,
Mauro