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Add documentation to describe the "Other Logic Block" system-controller.
It deals with three platforms: EyeQ5, EyeQ6L and EyeQ6H. First two have
a single instance, whereas EyeQ6H has seven named instances.
Features provided are:
- Clocks, children to main crystal. Some PLLs and divider clocks.
- Resets. Some instances DO NOT have reset.
- Pinctrl. Only EyeQ5 has such feature.
Those are NOT the only features exposed in OLB system-controllers! Many
individual registers, related to IP block integration, can be found.
Additional features will be exposed over time.
We simplify devicetree phandles to OLB in two ways:
- Compatibles exposing a single clock do not ask for a index argument.
This means we use EyeQ6H OLB south (it has four clocks):
clocks = <&olb_south EQ6HC_SOUTH_PLL_PER>;
But use EyeQ6H OLB east (it has one clock):
clocks = <&olb_east>;
- Compatibles exposing a single reset domain do not ask for a domain
index, only a reset index.
This means we use EyeQ5 OLB (it has three domains):
resets = <&olb 0 10>;
But use EyeQ6H west reset (it has one domain):
resets = <&olb_west 3>;
About pinctrl subnodes: all pins have two functionality, either GPIO or
something-else. The latter is pin dependent, we express constraints
using many if-then.
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.