1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) 2016-2017 Linaro Ltd.
4 * Copyright (c) 2016-2017 HiSilicon Technologies Co., Ltd.
5 */
6#include <linux/kernel.h>
7#include <linux/mfd/syscon.h>
8#include <linux/module.h>
9#include <linux/of.h>
10#include <linux/platform_device.h>
11#include <linux/regmap.h>
12#include <linux/reset-controller.h>
13
14struct hi3660_reset_controller {
15	struct reset_controller_dev rst;
16	struct regmap *map;
17};
18
19#define to_hi3660_reset_controller(_rst) \
20	container_of(_rst, struct hi3660_reset_controller, rst)
21
22static int hi3660_reset_program_hw(struct reset_controller_dev *rcdev,
23				   unsigned long idx, bool assert)
24{
25	struct hi3660_reset_controller *rc = to_hi3660_reset_controller(rcdev);
26	unsigned int offset = idx >> 8;
27	unsigned int mask = BIT(idx & 0x1f);
28
29	if (assert)
30		return regmap_write(rc->map, offset, mask);
31	else
32		return regmap_write(rc->map, offset + 4, mask);
33}
34
35static int hi3660_reset_assert(struct reset_controller_dev *rcdev,
36			       unsigned long idx)
37{
38	return hi3660_reset_program_hw(rcdev, idx, true);
39}
40
41static int hi3660_reset_deassert(struct reset_controller_dev *rcdev,
42				 unsigned long idx)
43{
44	return hi3660_reset_program_hw(rcdev, idx, false);
45}
46
47static int hi3660_reset_dev(struct reset_controller_dev *rcdev,
48			    unsigned long idx)
49{
50	int err;
51
52	err = hi3660_reset_assert(rcdev, idx);
53	if (err)
54		return err;
55
56	return hi3660_reset_deassert(rcdev, idx);
57}
58
59static const struct reset_control_ops hi3660_reset_ops = {
60	.reset    = hi3660_reset_dev,
61	.assert   = hi3660_reset_assert,
62	.deassert = hi3660_reset_deassert,
63};
64
65static int hi3660_reset_xlate(struct reset_controller_dev *rcdev,
66			      const struct of_phandle_args *reset_spec)
67{
68	unsigned int offset, bit;
69
70	offset = reset_spec->args[0];
71	bit = reset_spec->args[1];
72
73	return (offset << 8) | bit;
74}
75
76static int hi3660_reset_probe(struct platform_device *pdev)
77{
78	struct hi3660_reset_controller *rc;
79	struct device_node *np = pdev->dev.of_node;
80	struct device *dev = &pdev->dev;
81
82	rc = devm_kzalloc(dev, sizeof(*rc), GFP_KERNEL);
83	if (!rc)
84		return -ENOMEM;
85
86	rc->map = syscon_regmap_lookup_by_phandle(np, "hisilicon,rst-syscon");
87	if (rc->map == ERR_PTR(-ENODEV)) {
88		/* fall back to the deprecated compatible */
89		rc->map = syscon_regmap_lookup_by_phandle(np,
90							  "hisi,rst-syscon");
91	}
92	if (IS_ERR(rc->map)) {
93		return dev_err_probe(dev, PTR_ERR(rc->map),
94			"failed to get hisilicon,rst-syscon\n");
95	}
96
97	rc->rst.ops = &hi3660_reset_ops,
98	rc->rst.of_node = np;
99	rc->rst.of_reset_n_cells = 2;
100	rc->rst.of_xlate = hi3660_reset_xlate;
101
102	return reset_controller_register(&rc->rst);
103}
104
105static const struct of_device_id hi3660_reset_match[] = {
106	{ .compatible = "hisilicon,hi3660-reset", },
107	{},
108};
109MODULE_DEVICE_TABLE(of, hi3660_reset_match);
110
111static struct platform_driver hi3660_reset_driver = {
112	.probe = hi3660_reset_probe,
113	.driver = {
114		.name = "hi3660-reset",
115		.of_match_table = hi3660_reset_match,
116	},
117};
118
119static int __init hi3660_reset_init(void)
120{
121	return platform_driver_register(&hi3660_reset_driver);
122}
123arch_initcall(hi3660_reset_init);
124
125MODULE_LICENSE("GPL");
126MODULE_ALIAS("platform:hi3660-reset");
127MODULE_DESCRIPTION("HiSilicon Hi3660 Reset Driver");
128