1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) 2020 Western Digital Corporation or its affiliates.
4 */
5#include <linux/of.h>
6#include <linux/platform_device.h>
7#include <linux/reset-controller.h>
8#include <linux/delay.h>
9#include <linux/mfd/syscon.h>
10#include <linux/regmap.h>
11#include <soc/canaan/k210-sysctl.h>
12
13#include <dt-bindings/reset/k210-rst.h>
14
15#define K210_RST_MASK	0x27FFFFFF
16
17struct k210_rst {
18	struct regmap *map;
19	struct reset_controller_dev rcdev;
20};
21
22static inline struct k210_rst *
23to_k210_rst(struct reset_controller_dev *rcdev)
24{
25	return container_of(rcdev, struct k210_rst, rcdev);
26}
27
28static inline int k210_rst_assert(struct reset_controller_dev *rcdev,
29				  unsigned long id)
30{
31	struct k210_rst *ksr = to_k210_rst(rcdev);
32
33	return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 1);
34}
35
36static inline int k210_rst_deassert(struct reset_controller_dev *rcdev,
37				    unsigned long id)
38{
39	struct k210_rst *ksr = to_k210_rst(rcdev);
40
41	return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 0);
42}
43
44static int k210_rst_reset(struct reset_controller_dev *rcdev,
45			  unsigned long id)
46{
47	int ret;
48
49	ret = k210_rst_assert(rcdev, id);
50	if (ret == 0) {
51		udelay(10);
52		ret = k210_rst_deassert(rcdev, id);
53	}
54
55	return ret;
56}
57
58static int k210_rst_status(struct reset_controller_dev *rcdev,
59			   unsigned long id)
60{
61	struct k210_rst *ksr = to_k210_rst(rcdev);
62	u32 reg, bit = BIT(id);
63	int ret;
64
65	ret = regmap_read(ksr->map, K210_SYSCTL_PERI_RESET, &reg);
66	if (ret)
67		return ret;
68
69	return reg & bit;
70}
71
72static int k210_rst_xlate(struct reset_controller_dev *rcdev,
73			  const struct of_phandle_args *reset_spec)
74{
75	unsigned long id = reset_spec->args[0];
76
77	if (!(BIT(id) & K210_RST_MASK))
78		return -EINVAL;
79
80	return id;
81}
82
83static const struct reset_control_ops k210_rst_ops = {
84	.assert		= k210_rst_assert,
85	.deassert	= k210_rst_deassert,
86	.reset		= k210_rst_reset,
87	.status		= k210_rst_status,
88};
89
90static int k210_rst_probe(struct platform_device *pdev)
91{
92	struct device *dev = &pdev->dev;
93	struct device_node *parent_np = of_get_parent(dev->of_node);
94	struct k210_rst *ksr;
95
96	dev_info(dev, "K210 reset controller\n");
97
98	ksr = devm_kzalloc(dev, sizeof(*ksr), GFP_KERNEL);
99	if (!ksr)
100		return -ENOMEM;
101
102	ksr->map = syscon_node_to_regmap(parent_np);
103	of_node_put(parent_np);
104	if (IS_ERR(ksr->map))
105		return PTR_ERR(ksr->map);
106
107	ksr->rcdev.owner = THIS_MODULE;
108	ksr->rcdev.dev = dev;
109	ksr->rcdev.of_node = dev->of_node;
110	ksr->rcdev.ops = &k210_rst_ops;
111	ksr->rcdev.nr_resets = fls(K210_RST_MASK);
112	ksr->rcdev.of_reset_n_cells = 1;
113	ksr->rcdev.of_xlate = k210_rst_xlate;
114
115	return devm_reset_controller_register(dev, &ksr->rcdev);
116}
117
118static const struct of_device_id k210_rst_dt_ids[] = {
119	{ .compatible = "canaan,k210-rst" },
120	{ /* sentinel */ },
121};
122
123static struct platform_driver k210_rst_driver = {
124	.probe	= k210_rst_probe,
125	.driver = {
126		.name		= "k210-rst",
127		.of_match_table	= k210_rst_dt_ids,
128	},
129};
130builtin_platform_driver(k210_rst_driver);
131