xref: /linux/Documentation/devicetree/bindings/watchdog/aspeed,ast2400-wdt.yaml (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0) 
1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/watchdog/aspeed,ast2400-wdt.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: Aspeed watchdog timer controllers
8
9maintainers:
10  - Andrew Jeffery <andrew@codeconstruct.com.au>
11
12properties:
13  compatible:
14    enum:
15      - aspeed,ast2400-wdt
16      - aspeed,ast2500-wdt
17      - aspeed,ast2600-wdt
18
19  reg:
20    maxItems: 1
21
22  clocks:
23    maxItems: 1
24    description: >
25      The clock used to drive the watchdog counter. From the AST2500 no source
26      other than the 1MHz clock can be selected, so the clocks property is
27      optional.
28
29  aspeed,reset-type:
30    $ref: /schemas/types.yaml#/definitions/string
31    enum:
32      - cpu
33      - soc
34      - system
35      - none
36    default: system
37    description: >
38      The watchdog can be programmed to generate one of three different types of
39      reset when a timeout occcurs.
40
41      Specifying 'cpu' will only reset the processor on a timeout event.
42
43      Specifying 'soc' will reset a configurable subset of the SoC's controllers
44      on a timeout event. Controllers critical to the SoC's operation may remain
45      untouched. The set of SoC controllers to reset may be specified via the
46      aspeed,reset-mask property if the node has the aspeed,ast2500-wdt or
47      aspeed,ast2600-wdt compatible.
48
49      Specifying 'system' will reset all controllers on a timeout event, as if
50      EXTRST had been asserted.
51
52      Specifying 'none' will cause the timeout event to have no reset effect.
53      Another watchdog engine on the chip must be used for chip reset operations.
54
55  aspeed,alt-boot:
56    $ref: /schemas/types.yaml#/definitions/flag
57    description: >
58      Direct the watchdog to configure the SoC to boot from the alternative boot
59      region if a timeout occurs.
60
61  aspeed,external-signal:
62    $ref: /schemas/types.yaml#/definitions/flag
63    description: >
64      Assert the timeout event on an external signal pin associated with the
65      watchdog controller instance. The pin must be muxed appropriately.
66
67  aspeed,ext-pulse-duration:
68    $ref: /schemas/types.yaml#/definitions/uint32
69    description: >
70      The duration, in microseconds, of the pulse emitted on the external signal
71      pin.
72
73  aspeed,ext-push-pull:
74    $ref: /schemas/types.yaml#/definitions/flag
75    description: >
76      If aspeed,external-signal is specified in the node, set the external
77      signal pin's drive type to push-pull. If aspeed,ext-push-pull is not
78      specified then the pin is configured as open-drain.
79
80  aspeed,ext-active-high:
81    $ref: /schemas/types.yaml#/definitions/flag
82    description: >
83      If both aspeed,external-signal and aspeed,ext-push-pull are specified in
84      the node, set the pulse polarity to active-high. If aspeed,ext-active-high
85      is not specified then the pin is configured as active-low.
86
87  aspeed,reset-mask:
88    $ref: /schemas/types.yaml#/definitions/uint32-array
89    minItems: 1
90    maxItems: 2
91    description: >
92      A bitmask indicating which peripherals will be reset if the watchdog
93      timer expires. On AST2500 SoCs this should be a single word defined using
94      the AST2500_WDT_RESET_* macros; on AST2600 SoCs this should be a two-word
95      array with the first word defined using the AST2600_WDT_RESET1_* macros,
96      and the second word defined using the AST2600_WDT_RESET2_* macros.
97
98required:
99  - compatible
100  - reg
101
102allOf:
103  - if:
104      anyOf:
105        - required:
106            - aspeed,ext-push-pull
107        - required:
108            - aspeed,ext-active-high
109        - required:
110            - aspeed,reset-mask
111    then:
112      properties:
113        compatible:
114          enum:
115            - aspeed,ast2500-wdt
116            - aspeed,ast2600-wdt
117  - if:
118      required:
119        - aspeed,ext-active-high
120    then:
121      required:
122        - aspeed,ext-push-pull
123
124additionalProperties: false
125
126examples:
127  - |
128    watchdog@1e785000 {
129        compatible = "aspeed,ast2400-wdt";
130        reg = <0x1e785000 0x1c>;
131        aspeed,reset-type = "system";
132        aspeed,external-signal;
133    };
134  - |
135    #include <dt-bindings/watchdog/aspeed-wdt.h>
136    watchdog@1e785040 {
137        compatible = "aspeed,ast2600-wdt";
138        reg = <0x1e785040 0x40>;
139        aspeed,reset-type = "soc";
140        aspeed,reset-mask = <AST2600_WDT_RESET1_DEFAULT
141                            (AST2600_WDT_RESET2_DEFAULT & ~AST2600_WDT_RESET2_LPC)>;
142    };
143