1 TI SysCon Reset Controller
2 =======================
3
4 Almost all SoCs have hardware modules that require reset control in addition
5 to clock and power control for their functionality. The reset control is
6 typically provided by means of memory-mapped I/O registers. These registers are
7 sometimes a part of a larger register space region implementing various
8 functionalities. This register range is best represented as a syscon node to
9 allow multiple entities to access their relevant registers in the common
10 register space.
11
12 A SysCon Reset Controller node defines a device that uses a syscon node
13 and provides reset management functionality for various hardware modules
14 present on the SoC.
15
16 SysCon Reset Controller Node
17 ============================
18 Each of the reset provider/controller nodes should be a child of a syscon
19 node and have the following properties.
20
21 Required properties:
22 --------------------
23 - compatible : Should be,
24 "ti,k2e-pscrst"
25 "ti,k2l-pscrst"
26 "ti,k2hk-pscrst"
27 "ti,syscon-reset"
28 - #reset-cells : Should be 1. Please see the reset consumer node below
29 for usage details
30 - ti,reset-bits : Contains the reset control register information
31 Should contain 7 cells for each reset exposed to
32 consumers, defined as:
33 Cell #1 : offset of the reset assert control
34 register from the syscon register base
35 Cell #2 : bit position of the reset in the reset
36 assert control register
37 Cell #3 : offset of the reset deassert control
38 register from the syscon register base
39 Cell #4 : bit position of the reset in the reset
40 deassert control register
41 Cell #5 : offset of the reset status register
42 from the syscon register base
43 Cell #6 : bit position of the reset in the
44 reset status register
45 Cell #7 : Flags used to control reset behavior,
46 available flags defined in the DT include
47 file <dt-bindings/reset/ti-syscon.h>
48
49 SysCon Reset Consumer Nodes
50 ===========================
51 Each of the reset consumer nodes should have the following properties,
52 in addition to their own properties.
53
54 Required properties:
55 --------------------
56 - resets : A phandle to the reset controller node and an index number
57 to a reset specifier as defined above.
58
59 Please also refer to Documentation/devicetree/bindings/reset/reset.txt for
60 common reset controller usage by consumers.
61
62 Example:
63 --------
64 The following example demonstrates a syscon node, the reset controller node
65 using the syscon node, and a consumer (a DSP device) on the TI Keystone 2
66 66AK2E SoC.
67
68 / {
69 soc {
70 psc: power-sleep-controller@2350000 {
71 compatible = "syscon", "simple-mfd";
72 reg = <0x02350000 0x1000>;
73
74 pscrst: reset-controller {
75 compatible = "ti,k2e-pscrst", "ti,syscon-reset";
76 #reset-cells = <1>;
77
78 ti,reset-bits = <
79 0xa3c 8 0xa3c 8 0x83c 8 (ASSERT_CLEAR | DEASSERT_SET | STATUS_CLEAR) /* 0: dsp0 */
80 0xa40 5 0xa44 3 0 0 (ASSERT_SET | DEASSERT_CLEAR | STATUS_NONE) /* 1: example */
81 >;
82 };
83 };
84
85 dsp0: dsp0 {
86 ...
87 resets = <&pscrst 0>;
88 ...
89 };
90 };
91 };
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