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TI SysCon Reset Controller
=======================
Almost all SoCs have hardware modules that require reset control in addition
to clock and power control for their functionality. The reset control is
typically provided by means of memory-mapped I/O registers. These registers are
sometimes a part of a larger register space region implementing various
functionalities. This register range is best represented as a syscon node to
allow multiple entities to access their relevant registers in the common
register space.
A SysCon Reset Controller node defines a device that uses a syscon node
and provides reset management functionality for various hardware modules
present on the SoC.
SysCon Reset Controller Node
============================
Each of the reset provider/controller nodes should be a child of a syscon
node and have the following properties.
Required properties:
--------------------
- compatible : Should be,
"ti,k2e-pscrst"
"ti,k2l-pscrst"
"ti,k2hk-pscrst"
"ti,syscon-reset"
- #reset-cells : Should be 1. Please see the reset consumer node below
for usage details
- ti,reset-bits : Contains the reset control register information
Should contain 7 cells for each reset exposed to
consumers, defined as:
Cell #1 : offset of the reset assert control
register from the syscon register base
Cell #2 : bit position of the reset in the reset
assert control register
Cell #3 : offset of the reset deassert control
register from the syscon register base
Cell #4 : bit position of the reset in the reset
deassert control register
Cell #5 : offset of the reset status register
from the syscon register base
Cell #6 : bit position of the reset in the
reset status register
Cell #7 : Flags used to control reset behavior,
availible flags defined in the DT include
file <dt-bindings/reset/ti-syscon.h>
SysCon Reset Consumer Nodes
===========================
Each of the reset consumer nodes should have the following properties,
in addition to their own properties.
Required properties:
--------------------
- resets : A phandle to the reset controller node and an index number
to a reset specifier as defined above.
Please also refer to Documentation/devicetree/bindings/reset/reset.txt for
common reset controller usage by consumers.
Example:
--------
The following example demonstrates a syscon node, the reset controller node
using the syscon node, and a consumer (a DSP device) on the TI Keystone 2
66AK2E SoC.
/ {
soc {
psc: power-sleep-controller@2350000 {
compatible = "syscon", "simple-mfd";
reg = <0x02350000 0x1000>;
pscrst: reset-controller {
compatible = "ti,k2e-pscrst", "ti,syscon-reset";
#reset-cells = <1>;
ti,reset-bits = <
0xa3c 8 0xa3c 8 0x83c 8 (ASSERT_CLEAR | DEASSERT_SET | STATUS_CLEAR) /* 0: dsp0 */
0xa40 5 0xa44 3 0 0 (ASSERT_SET | DEASSERT_CLEAR | STATUS_NONE) /* 1: example */
>;
};
};
dsp0: dsp0 {
...
resets = <&pscrst 0>;
...
};
};
};
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