1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 %YAML 1.2
3 ---
4 $id: http://devicetree.org/schemas/soc/ti/wkup-m3-ipc.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
6
7 title: Wakeup M3 IPC device
8
9 maintainers:
10 - Dave Gerlach <d-gerlach@ti.com>
11 - Drew Fustini <dfustini@baylibre.com>
12
13 description: |+
14 The TI AM33xx and AM43xx family of devices use a small Cortex M3 co-processor
15 (commonly referred to as Wakeup M3 or CM3) to help with various low power tasks
16 that cannot be controlled from the MPU, like suspend/resume and certain deep
17 C-states for CPU Idle. Once the wkup_m3_ipc driver uses the wkup_m3_rproc driver
18 to boot the wkup_m3, it handles communication with the CM3 using IPC registers
19 present in the SoC's control module and a mailbox. The wkup_m3_ipc exposes an
20 API to allow the SoC PM code to execute specific PM tasks.
21
22 Wkup M3 Device Node
23 ====================
24 A wkup_m3_ipc device node is used to represent the IPC registers within an
25 SoC.
26
27 Support for VTT Toggle with GPIO pin
28 ====================================
29 On some boards like the AM335x EVM-SK and the AM437x GP EVM, a GPIO pin is
30 connected to the enable pin on the DDR VTT regulator. This allows the
31 regulator to be disabled upon suspend and enabled upon resume. Please note
32 that the GPIO pin must be part of the GPIO0 module as only this GPIO module
33 is in the wakeup power domain.
34
35 Support for IO Isolation
36 ========================
37 On AM437x SoCs, certain pins can be forced into an alternate state when IO
38 isolation is activated. Those pins have pad control registers prefixed by
39 'CTRL_CONF_' that contain DS0 (e.g. deep sleep) configuration bits that can
40 override the pin's existing bias (pull-up/pull-down) and value (high/low) when
41 IO isolation is active.
42
43 Support for I2C PMIC Voltage Scaling
44 ====================================
45 It is possible to pass the name of a binary file to load into the CM3 memory.
46 The binary data is the I2C sequences for the CM3 to send out to the PMIC
47 during low power mode entry.
48
49 properties:
50 compatible:
51 enum:
52 - ti,am3352-wkup-m3-ipc # for AM33xx SoCs
53 - ti,am4372-wkup-m3-ipc # for AM43xx SoCs
54
55 reg:
56 description:
57 The IPC register address space to communicate with the Wakeup M3 processor
58 maxItems: 1
59
60 interrupts:
61 description: wkup_m3 interrupt that signals the MPU
62 maxItems: 1
63
64 ti,rproc:
65 $ref: /schemas/types.yaml#/definitions/phandle
66 description:
67 phandle to the wkup_m3 rproc node so the IPC driver can boot it
68
69 mboxes:
70 description:
71 phandles used by IPC framework to get correct mbox
72 channel for communication. Must point to appropriate
73 mbox_wkupm3 child node.
74 maxItems: 1
75
76 firmware-name:
77 description:
78 Name of binary file with I2C sequences for PMIC voltage scaling
79
80 ti,vtt-gpio-pin:
81 $ref: /schemas/types.yaml#/definitions/uint32
82 description: GPIO pin connected to enable pin on VTT regulator
83
84 ti,set-io-isolation:
85 type: boolean
86 description:
87 If this property is present, then the wkup_m3_ipc driver will instruct
88 the CM3 firmware to activate IO isolation when suspending to deep sleep.
89 This can be leveraged by a board design to put other devices on the board
90 into a low power state.
91
92 allOf:
93 - if:
94 properties:
95 compatible:
96 not:
97 contains:
98 const: ti,am4372-wkup-m3-ipc
99 then:
100 properties:
101 ti,set-io-isolation: false
102
103 required:
104 - compatible
105 - reg
106 - interrupts
107 - ti,rproc
108 - mboxes
109
110 additionalProperties: false
111
112 examples:
113 - |
114 /* Example for AM335x SoC */
115 soc {
116 #address-cells = <1>;
117 #size-cells = <1>;
118
119 am335x_mailbox: mailbox {
120 #mbox-cells = <1>;
121 };
122
123 wkup_m3_ipc@1324 {
124 compatible = "ti,am3352-wkup-m3-ipc";
125 reg = <0x1324 0x24>;
126 interrupts = <78>;
127 ti,rproc = <&wkup_m3>;
128 mboxes = <&am335x_mailbox &mbox_wkupm3>;
129 ti,vtt-gpio-pin = <7>;
130 firmware-name = "am335x-evm-scale-data.bin";
131 };
132 };
133
134 - |
135 /*
136 * Example for AM473x SoC:
137 * On the AM437x-GP-EVM board, gpio5_7 is wired to enable pin of the DDR VTT
138 * regulator. The 'ddr_vtt_toggle_default' pinmux node configures gpio5_7
139 * for pull-up during normal system operation. However, the DS0 (deep sleep)
140 * state of the pin is configured for pull-down and thus the VTT regulator
141 * will be disabled to save power when IO isolation is active. Note that
142 * this method is an alternative to using the 'ti,vtt-gpio-pin' property.
143 */
144 #include <dt-bindings/pinctrl/am43xx.h>
145 soc {
146 #address-cells = <1>;
147 #size-cells = <1>;
148
149 am437x_mailbox: mailbox {
150 #mbox-cells = <1>;
151 };
152
153 am43xx_pinmux {
154 pinctrl-names = "default";
155 pinctrl-0 = <&ddr3_vtt_toggle_default>;
156
157 ddr3_vtt_toggle_default: ddr_vtt_toggle_default {
158 pinctrl-single,pins = <
159 0x25C (DS0_PULL_UP_DOWN_EN | PIN_OUTPUT_PULLUP | DS0_FORCE_OFF_MODE | MUX_MODE7)
160 >;
161 };
162 };
163
164 wkup_m3_ipc@1324 {
165 compatible = "ti,am4372-wkup-m3-ipc";
166 reg = <0x1324 0x24>;
167 interrupts = <78>;
168 ti,rproc = <&wkup_m3>;
169 mboxes = <&am437x_mailbox &mbox_wkupm3>;
170 ti,set-io-isolation;
171 firmware-name = "am43x-evm-scale-data.bin";
172 };
173 };
174
175 ...
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.