Merge branches 'acpi-misc', 'acpi-tools' and 'acpi-docs'

.. SPDX-License-Identifier: GPL-2.0

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

Overriding DSDT

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

Linux supports a method of overriding the BIOS DSDT:

CONFIG_ACPI_CUSTOM_DSDT - builds the image into the kernel.

When to use this method is described in detail on the

Linux/ACPI home page:

https://01.org/linux-acpi/documentation/overriding-dsdt

  - Devices behind real busses where there is a connector resource

    are represented as struct spi_device or struct i2c_device. Note

    that standard UARTs are not busses so there is no struct uart_device,

    although some of them may be represented by sturct serdev_device.

    although some of them may be represented by struct serdev_device.

As both ACPI and Device Tree represent a tree of devices (and their

resources) this implementation follows the Device Tree way as much as

		}

		...

The SPI device drivers only need to add ACPI IDs in a similar way than with

The SPI device drivers only need to add ACPI IDs in a similar way to

the platform device drivers. Below is an example where we add ACPI support

to at25 SPI eeprom driver (this is meant for the above ACPI snippet)::

specifies the path to the controller. In order to use these GPIOs in Linux

we need to translate them to the corresponding Linux GPIO descriptors.

There is a standard GPIO API for that and is documented in

There is a standard GPIO API for that and it is documented in

Documentation/admin-guide/gpio/.

In the above example we can get the corresponding two GPIO descriptors with

PCI hierarchy representation

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

Sometimes could be useful to enumerate a PCI device, knowing its position on the

PCI bus.

Sometimes it could be useful to enumerate a PCI device, knowing its position on

the PCI bus.

For example, some systems use PCI devices soldered directly on the mother board,

in a fixed position (ethernet, Wi-Fi, serial ports, etc.). In this conditions it

the chipset root port to the final device, through all the intermediate

bridges/switches of the board.

For example, let us assume to have a system with a PCIe serial port, an

For example, let's assume we have a system with a PCIe serial port, an

Exar XR17V3521, soldered on the main board. This UART chip also includes

16 GPIOs and we want to add the property ``gpio-line-names`` [1] to these pins.

In this case, the ``lspci`` output for this component is::

	Bus: 0 - Device: 14 - Function: 1

To find this information is necessary disassemble the BIOS ACPI tables, in

particular the DSDT (see also [2])::

To find this information, it is necessary to disassemble the BIOS ACPI tables,

in particular the DSDT (see also [2])::

	mkdir ~/tables/

	cd ~/tables/

R:	Len Brown <lenb@kernel.org>

L:	linux-acpi@vger.kernel.org

S:	Supported

W:	https://01.org/linux-acpi

Q:	https://patchwork.kernel.org/project/linux-acpi/list/

B:	https://bugzilla.kernel.org

T:	git git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

R:	Zhang Rui <rui.zhang@intel.com>

L:	linux-acpi@vger.kernel.org

S:	Supported

W:	https://01.org/linux-acpi

B:	https://bugzilla.kernel.org

F:	drivers/acpi/*thermal*

M:	Sujith Thomas <sujith.thomas@intel.com>

L:	linux-pm@vger.kernel.org

S:	Supported

W:	https://01.org/linux-acpi

F:	drivers/thermal/intel/intel_menlow.c

INTEL P-Unit IPC DRIVER

	  Management (APM) specification.  If both ACPI and APM support 

	  are configured, ACPI is used.

	  The project home page for the Linux ACPI subsystem is here:

	  <https://01.org/linux-acpi>

	  Linux support for ACPI is based on Intel Corporation's ACPI

	  Component Architecture (ACPI CA).  For more information on the

	  ACPI CA, see:

	depends on !STANDALONE

	help

	  This option supports a custom DSDT by linking it into the kernel.

	  See Documentation/admin-guide/acpi/dsdt-override.rst

	  Enter the full path name to the file which includes the AmlCode

	  or dsdt_aml_code declaration.

	str = obj->string.pointer;

	chr = strchr(str, ',');

	strlcpy(modalias, chr ? chr + 1 : str, len);

	strscpy(modalias, chr ? chr + 1 : str, len);

	return true;

}

		       char *modalias, size_t len)

{

	if (!acpi_of_modalias(adev, modalias, len))

		strlcpy(modalias, default_id, len);

		strscpy(modalias, default_id, len);

}

EXPORT_SYMBOL_GPL(acpi_set_modalias);