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1 | // SPDX-License-Identifier: GPL-2.0 | |
2 | /* | |
3 | * ARM System Control and Management Interface (ARM SCMI) reset driver | |
4 | * | |
5 | * Copyright (C) 2019-2021 ARM Ltd. | |
6 | */ | |
7 | ||
8 | #include <linux/module.h> | |
9 | #include <linux/of.h> | |
10 | #include <linux/device.h> | |
11 | #include <linux/reset-controller.h> | |
12 | #include <linux/scmi_protocol.h> | |
13 | ||
14 | static const struct scmi_reset_proto_ops *reset_ops; | |
15 | ||
16 | /** | |
17 | * struct scmi_reset_data - reset controller information structure | |
18 | * @rcdev: reset controller entity | |
19 | * @ph: ARM SCMI protocol handle used for communication with system controller | |
20 | */ | |
21 | struct scmi_reset_data { | |
22 | struct reset_controller_dev rcdev; | |
23 | const struct scmi_protocol_handle *ph; | |
24 | }; | |
25 | ||
26 | #define to_scmi_reset_data(p) container_of((p), struct scmi_reset_data, rcdev) | |
27 | #define to_scmi_handle(p) (to_scmi_reset_data(p)->ph) | |
28 | ||
29 | /** | |
30 | * scmi_reset_assert() - assert device reset | |
31 | * @rcdev: reset controller entity | |
32 | * @id: ID of the reset to be asserted | |
33 | * | |
34 | * This function implements the reset driver op to assert a device's reset | |
35 | * using the ARM SCMI protocol. | |
36 | * | |
37 | * Return: 0 for successful request, else a corresponding error value | |
38 | */ | |
39 | static int | |
40 | scmi_reset_assert(struct reset_controller_dev *rcdev, unsigned long id) | |
41 | { | |
42 | const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev); | |
43 | ||
44 | return reset_ops->assert(ph, id); | |
45 | } | |
46 | ||
47 | /** | |
48 | * scmi_reset_deassert() - deassert device reset | |
49 | * @rcdev: reset controller entity | |
50 | * @id: ID of the reset to be deasserted | |
51 | * | |
52 | * This function implements the reset driver op to deassert a device's reset | |
53 | * using the ARM SCMI protocol. | |
54 | * | |
55 | * Return: 0 for successful request, else a corresponding error value | |
56 | */ | |
57 | static int | |
58 | scmi_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id) | |
59 | { | |
60 | const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev); | |
61 | ||
62 | return reset_ops->deassert(ph, id); | |
63 | } | |
64 | ||
65 | /** | |
66 | * scmi_reset_reset() - reset the device | |
67 | * @rcdev: reset controller entity | |
68 | * @id: ID of the reset signal to be reset(assert + deassert) | |
69 | * | |
70 | * This function implements the reset driver op to trigger a device's | |
71 | * reset signal using the ARM SCMI protocol. | |
72 | * | |
73 | * Return: 0 for successful request, else a corresponding error value | |
74 | */ | |
75 | static int | |
76 | scmi_reset_reset(struct reset_controller_dev *rcdev, unsigned long id) | |
77 | { | |
78 | const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev); | |
79 | ||
80 | return reset_ops->reset(ph, id); | |
81 | } | |
82 | ||
83 | static const struct reset_control_ops scmi_reset_ops = { | |
84 | .assert = scmi_reset_assert, | |
85 | .deassert = scmi_reset_deassert, | |
86 | .reset = scmi_reset_reset, | |
87 | }; | |
88 | ||
89 | static int scmi_reset_probe(struct scmi_device *sdev) | |
90 | { | |
91 | struct scmi_reset_data *data; | |
92 | struct device *dev = &sdev->dev; | |
93 | struct device_node *np = dev->of_node; | |
94 | const struct scmi_handle *handle = sdev->handle; | |
95 | struct scmi_protocol_handle *ph; | |
96 | ||
97 | if (!handle) | |
98 | return -ENODEV; | |
99 | ||
100 | reset_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_RESET, &ph); | |
101 | if (IS_ERR(reset_ops)) | |
102 | return PTR_ERR(reset_ops); | |
103 | ||
104 | data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); | |
105 | if (!data) | |
106 | return -ENOMEM; | |
107 | ||
108 | data->rcdev.ops = &scmi_reset_ops; | |
109 | data->rcdev.owner = THIS_MODULE; | |
110 | data->rcdev.of_node = np; | |
111 | data->rcdev.nr_resets = reset_ops->num_domains_get(ph); | |
112 | data->ph = ph; | |
113 | ||
114 | return devm_reset_controller_register(dev, &data->rcdev); | |
115 | } | |
116 | ||
117 | static const struct scmi_device_id scmi_id_table[] = { | |
118 | { SCMI_PROTOCOL_RESET, "reset" }, | |
119 | { }, | |
120 | }; | |
121 | MODULE_DEVICE_TABLE(scmi, scmi_id_table); | |
122 | ||
123 | static struct scmi_driver scmi_reset_driver = { | |
124 | .name = "scmi-reset", | |
125 | .probe = scmi_reset_probe, | |
126 | .id_table = scmi_id_table, | |
127 | }; | |
128 | module_scmi_driver(scmi_reset_driver); | |
129 | ||
130 | MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>"); | |
131 | MODULE_DESCRIPTION("ARM SCMI reset controller driver"); | |
132 | MODULE_LICENSE("GPL v2"); |