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doc: move kconfig docs into one document

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New functions section belongs in the overall Kconfig document.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
This commit is contained in:
Anas Nashif 2019-02-01 11:40:33 -05:00
commit f9cc8f081c
3 changed files with 67 additions and 70 deletions
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9
doc/tools/index.rst
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@ -1,9 +0,0 @@
.. _developer_guides:
Tools
######
.. toctree::
:maxdepth: 1
kconfig/functions.rst

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doc/tools/kconfig/functions.rst
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.. _kconfig-functions:
Kconfig Functions
#################
Kconfiglib provides user-defined preprocessor functions that
we use in Zephyr to expose Device Tree information to Kconfig.
For example, we can get the default value for a Kconfig symbol
from the device tree.
Device Tree Related Functions
*****************************
.. code-block:: none
dt_int_val(kconf, _, name, unit):
This function looks up 'name' in the DTS generated "conf" style database
and if its found it will return the value as an decimal integer. The
function will divide the value based on 'unit':
None No division
'k' or 'K' divide by 1024 (1 << 10)
'm' or 'M' divide by 1,048,576 (1 << 20)
'g' or 'G' divide by 1,073,741,824 (1 << 30)
dt_hex_val(kconf, _, name, unit):
This function looks up 'name' in the DTS generated "conf" style database
and if its found it will return the value as an hex integer. The
function will divide the value based on 'unit':
None No division
'k' or 'K' divide by 1024 (1 << 10)
'm' or 'M' divide by 1,048,576 (1 << 20)
'g' or 'G' divide by 1,073,741,824 (1 << 30)
Example Usage
*************
The following example shows the usage of the ``dt_int_val`` function:
.. code-block:: none
boards/arm/mimxrt1020_evk/Kconfig.defconfig
config FLASH_SIZE
default $(dt_int_val,DT_NXP_IMX_FLEXSPI_402A8000_SIZE_1,K)
In this example if we examine the generated generated_dts_board.conf file
as part of the Zephyr build we'd find the following entry:
.. code-block:: none
DT_NXP_IMX_FLEXSPI_402A8000_SIZE_1=8388608
The ``dt_int_val`` will search the generated_dts_board.conf that is derived from
the dts for the board and match the ``DT_NXP_IMX_FLEXSPI_402A8000_SIZE_1`` entry.
The function than will than scale the value by ``1024``. This effective causes
the above to look like:
.. code-block:: none
config FLASH_SIZE
default 8192

67
doc/tools/kconfig/index.rst
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@ -3,6 +3,10 @@
Kconfig - Tips and Best Practices
#################################
.. contents::
:local:
:depth: 2
This page covers some Kconfig best practices and explains some Kconfig
behaviors and features that might be cryptic or that are easily overlooked.
@ -600,6 +604,69 @@ output for the symbols, instead of no output:
...
.. _kconfig-functions:
Kconfig Functions
*****************
Kconfiglib provides user-defined preprocessor functions that
we use in Zephyr to expose Device Tree information to Kconfig.
For example, we can get the default value for a Kconfig symbol
from the device tree.
Device Tree Related Functions
=============================
.. code-block:: none
dt_int_val(kconf, _, name, unit):
This function looks up 'name' in the DTS generated "conf" style database
and if its found it will return the value as an decimal integer. The
function will divide the value based on 'unit':
None No division
'k' or 'K' divide by 1024 (1 << 10)
'm' or 'M' divide by 1,048,576 (1 << 20)
'g' or 'G' divide by 1,073,741,824 (1 << 30)
dt_hex_val(kconf, _, name, unit):
This function looks up 'name' in the DTS generated "conf" style database
and if its found it will return the value as an hex integer. The
function will divide the value based on 'unit':
None No division
'k' or 'K' divide by 1024 (1 << 10)
'm' or 'M' divide by 1,048,576 (1 << 20)
'g' or 'G' divide by 1,073,741,824 (1 << 30)
Example Usage
=============
The following example shows the usage of the ``dt_int_val`` function:
.. code-block:: none
boards/arm/mimxrt1020_evk/Kconfig.defconfig
config FLASH_SIZE
default $(dt_int_val,DT_NXP_IMX_FLEXSPI_402A8000_SIZE_1,K)
In this example if we examine the generated generated_dts_board.conf file
as part of the Zephyr build we'd find the following entry:
.. code-block:: none
DT_NXP_IMX_FLEXSPI_402A8000_SIZE_1=8388608
The ``dt_int_val`` will search the generated_dts_board.conf that is derived from
the dts for the board and match the ``DT_NXP_IMX_FLEXSPI_402A8000_SIZE_1`` entry.
The function than will than scale the value by ``1024``. This effective causes
the above to look like:
.. code-block:: none
config FLASH_SIZE
default 8192
Other resources
***************